Note: Descriptions are shown in the official language in which they were submitted.
1440a
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AN INTERACTIVE MULTIMEDIA PRESENTATION AND COMMUNICATIONS SYSTEM
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FIELD OF THE INVENTION
The present invention relates to an interactive
multimedia presentation and communications system which can
deliver to a subscriber's television set particular video images
depicting information about items of interest which the
subscriber has requested, along with accompanying audio
commentary or music. In broad terms, a subscriber who uses the
system (generally transmitted on cable TV) tunes his TV set to a
predetermined channel, telephones a local number, follows log-on
instructions given over the telephone, and then uses the
Touch-Tone keypad of his telephone to navigate through an
electronic information system which displays multimedia
presentations in the form of video images and accompanying audio
on various items selected by the subscriber. The invention
relates to the apparatus and means by which these presentations
are selectively transmitted to particular subscribers, and not
with the specific subject matter described in the presentations.
In particular, this type of interactive multimedia
presentation and communications system is well suited, though
not at all limited, to providing the functions and capabilities
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of an electronic shopping mall. In this context, a subscriber
generally sees video images and hears an audio commentary about
shopping products he has chosen to look at and possibly
purchase. In addition to audio commentary, background music and
other general information may be available. Limited forms of
motion video which may include short sequences of panning,
zooming, and live motion are also provided. Thus, the system
permits a shopper, in the comfort of his home, to browse through
an "electronic mall" of different shops, obtain detailed
information on particular items, and make purchases. More
particularly, this invention relates to and describes an
interactive multimedia presentation and communications system
("IMPACS"), in which all the video and audio information is
stored, processed and transmitted to the locality of the
subscriber in digital form.
BACKGROUND OF THE INVENTION
Home shopping by use of the television has been
growing in popularity in recent years. Generally, home shopping
channels are transmitted on a community antenna television
(CATV) facility. The CATV facility, which has the capacity for
transmitting a large number of commercial and public television
signals, is usually connected to homes via a network of coaxial
cables. In most of the home shopping systems being offered to
date, subscribers passively view the home shopping channel,
watch items and pricing being presented by television sales
people, and if interested in a particular item, place an order
over the telephone or by mail. Similarly, televised real
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estate offerings which present still-video pictures and
information about homes for sale in a particular area are also
becoming a popular method of communicating such information to a
mass audience. These systems are non-interactive, in the sense
that a viewer may passively watch items as they are presented on
the television screen, but cannot control the course of the
presentation.
More advanced interactive systems have been designed
and implemented, wherein viewers are able to request a display
of particular items in which they have an interest, and can
control their information retrieval or perform individualized
shopping as they proceed. A system of this sort is described in
U.S. Patent No. 4,734,764, entitled "Cable Television System
Selectively Distributing Pre-Recorded Video and Audio
Messages". This prior art invention describes a system which
conveys still-frame television-quality video with overlaid
graphics information and an audio message (when appropriate), to
a multiplicity of CATV subscribers who tune to a specific cable
channel. The subscriber, by use of a Touch-Tone telephone,
transmits particular codes in response to message prompts which
are displayed in menu form on the TV screen, and is able to
request video displays and information on specific products as
well as make purchases. The user of this system requires no
additional equipment at his location other than a Touch-Tone
telephone and a television set.
In order to interactively operate this type of prior
art system, a subscriber tunes to the CATV channel which is
being used for transmission, and dials a telephone number to
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gain access to the system. Each subscriber is given a
particular identification number upon subscribing to the
service. When this identifying number is entered via the
Touch-Tone telephone keypad, the system recognizes the
subscriber and his location. Graphic overlays which depict
menus and directories of "electronic stores" that are on the
system are then displayed, and by responding to these menus with
a sequence of keystrokes on the Touch-Tone telephone keypad, the
subscriber may, by means of selected video images, enter and
browse through a particular store of his choice (or follow other
shopping paradigms such as going down a particular aisle in a
supermarket), select a particular product of interest, make
purchases or request additional information or help. By
selecting from a list of menu prompts which are displayed on the
television screen, and which the subscriber enters on the
Touch-Tone keypad, his television screen displays still-frame
video, having overlaid graphics where appropriate, and possibly
accompanied by a sound track that presents information about the
reguested item.
This prior art system uses a CATV cable network to
transmit the requested video presentations and accompanying
audio messages to its subscribers. In conventional television
transmission, video images are transmitted at the rate of 30
frames per second (the North American or Japanese standard), or
25 frames per second (the European standard). A video frame is
an interleaved composition of two video fields, with each video
field being further composed of a plurality of scan lines which
contain the video image information and a smaller plurality of
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scan lines referred to as the "vertical blanking interval". The
interactive system described in U.S. Patent No. 4,734,764 makes
use of the vertical blanking interval (which consists of the
first 21 lines of the video field) to store information which
identifies the particular subscriber's reception device to which
the requested video images and audio commentary are addressed.
The control center of the CATV system (the CATV headend)
transmits the frames of video and audio data, with this
addressing information encoded in the vertical blanking
interval, along the main "trunk" coaxial cables of the system in
analog form. In order to compensate for signal losses which
naturally occur as a result of transmission, CATV cable systems
utilize amplifiers positioned at various locations downstream
from the control center. At each of these locations, the
signals from the control center are amplified and further
transmitted down a plurality of secondary distribution cables.
At points along the secondary distribution cables are "taps", at
which the signals are split into a plurality of "drop" cables
which terminate at subscribers' television sets.
To accommodate a large number of concurrent
subscribers, the interactive system described in U.S. Patent No.
4,734,764 utilizes a reception device known as a frame store
unit, or "frame grabber", typically located near each amplifier
of the distribution system. Each frame store unit services a
small number of cable drops, and functions to capture the
information that is destined for a subscriber whose particular
identification code, encoded in the vertical blanking interval,
matches an identification code associated with the frame store
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unit. The video and audio information is transmitted to the
frame store unit on two separate channels, The frame store unit
captures the analog video and audio information which has the
appropriate address encoded in the vertical blanking interval of
the frames and stores the information into its memory. The
frame store unit then replays the stored video information 30
times per second (according to the U.S. National Television
Standards Committee (NTSC) requirement), and transmits the video
along with any accompanying audio message to the particular
subscriber that it is servicing.
In the prior art system of U.S. Patent No. 4,734,764,
which has been briefly described above, the video and audio
presentation which comprises a particular merchandise offering
by a commercial client, must first be prepared and encoded onto
conventional laser video discs. A plurality of conventional
video disc players at the central system site comprise the data
storage and playback portion of a subsystem which transmits the
appropriate video and audio information in analog form, under ~:
control of a central processing unit. The video information is
time-multiplexed in the proper sequence, and the audio is
appropriately modulated and frequency-division multiplexed for
transmission down the CATV cable network.
Numerous problems and limitations are associated with
this type of "analog" interactive system, even though the small
amaunt of data that is generated may be transmitted with a link
having much less bandwidth. First, a large number of video disc
players are required, making the cost and physical size of the
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electronics for this prior art system exorbitant. Adding to
this cost is the utilization of a full bandwidth telephone link
for each connection between a subscriber and the host computer
of the system,- even though the small amount of data that is
generated may be transmitted with a link having much less
bandwidth. Second, the response time between a subscriber
entering a particular code on the telephone keypad and the
appearance of a display in response to that code is too slow to
establish a comfortable interactive session. The response time
in the analog system is limited primarily by the time it takes
the video disc player to access a particular location on the
disc and can be on the order of three to ten seconds. The slow
response time is exacerbated by the graphics overlay process, in
which a graphics decoder receives graphics information that is
associated with a particular video frame from the central
processing unit, generates the appropriate graphics display data
and routes this data to a video combiner. The video combiner
must first receive the video frame from the video player and
then overlay the graphics information onto the frame.
Further, in the prior art analog system, the audio
information is stored on the video disc in the electronic format
of a video frame. This imposes a maximum limit of ten seconds
for the duration of the audio portion associated with a
particular frame. In many cases, this time limitation is too
restrictive for practical use. In other cases it is wasteful of
space.
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An additional limitation arises from the choice of a
laser disc as the storage medium for the video and audio data.
A commercial client who desires to market his merchandise or
services on the interactive system of the prior art must
undertake a lengthy premastering procedure, required to convert
his advertising material (possibly in the format of catalog
photographs, video tape information, etc.) into a format which
can be encoded onto a video disc master. Multiple copies of the
master disc must then be made so that each video disc player in
the system can have a copy of the information when it is called
upon to deliver a particular presentation to a subscriber. This
premastering and duplication process is a time-consuming, linear
and batch-oriented procedure, generally taking up to 10 weeks
from initial setup to final product. The process provides no
mechanism for making minor modifications to audio or video
images at a later date. If changes are required, a new video
disc must be mastered and reproduced. Thus, no reusable
archiving is possible.
The prior art analog system is structured with an
overly complicated pathway between the subscriber and host
computer system which does not generate adequate feedback to
either the subscriber or the system. For example, when a
subscriber enters a particular sequence of keystrokes, he has no
acknowledgment that the sequence has been properly received by
the system. Similarly, the system has no feedback that a
subscriber has received whatever was transmitted to him.
Further, when help from a consumer service representative is
requested by a subscriber, the consumer service representative
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can hear what the subscriber is saying over the telephone, but
cannot see what is being displayed on the subscriber's TV screen.
Another important drawback of the prior art system is
the manner in which the analog data is distributed from the
system to the CATV center and the subscribers. The cost of
transmitting data from the host computer to the CATV is
expensive and the prior art system makes sub-optimal use of the
distribution channel capacity. In the prior art system, the
video information is time-multiplexed onto one distribution
channel while the audio is frequency-division multiplexed onto
another distribution channel. Thus, the CATV headend must
allocate two distribution channels to the system. Not only are
these channels costly to acquire, but many CATV companies may
not have enough channel capacity for all their users, and from a
business perspective, may be hesitant to sell more than one
channel to a single user.
Finally, the prior art system has problems which are
fundamentally related to the storing, copying and transmission
of data in analog form. Analog signals are more prone to
degradation by noise sources that generally arise in any
electronic system. Degradation of analog signals as they are
transmitted down the long lengths of coaxial line which comprise
the transmission network of the CATV system is inevitable.
Additionally, the maximum signal-to-noise of the video signals
which are attainable at the output of a video disc player is
much lower than the noise figure for studio quality video
broadcast. This adds to the degradation in quality of the final
video images seen by the subscriber.
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SUMMARY OF THE INVENTION
It is an object of the present invention to provide a
new and improved digital interactive multimedia presentation and
communications system for interactively distributing information
to subscribers via television.
It is a further object of the present invention to
overcome the deficiencies of the prior art analog system
described above, by providing a digital interactive multimedia
presentation and communications system in which all relevant
data, from inception to final presentation, is processed,
stored, and distributed in digital form, thereby permitting
accurate reproduction of the original signals.
It is another object of this invention to provide for
a digital interactive multimedia presentation and communications
system which is considerably more cost effective and physically
smaller in size than the prior art analog system described above.
It is yet another object of this invention to provide
for a digital interactive multimedia presentation and
communications system which responds rapidly to a subscriber's
input, and which does not impose severe constraints on the
length of audio information which can be transmitted.
It is still another object of the invention to provide
for a digital interactive system in which commercial clients
have a facility whereby their presentations may be rapidly
produced and stored in digital form, thereby obviating the
cumbersome premastering and duplication procedure necessary in
the prior art analog system.
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Another object of this invention is to provide a
digital interactive presentation and communications system in
which digital mass storage is used for storing and retrieving
all relevant da'a, thereby obviating the need to prepare masters
and multiple copies of video discs, as required in the prior art.
It is an additional object of this invention to
provide a digital interactive system which more efficiently
utilizes the full bandwidth of the telephone connections, so
that an inexpensive telephone link can be maintained between
subscribers and the system.
A further object of this invention is to provide a
digital interactive system wherein appropriate feedback
indications are rapidly transmitted between the system and the
subscriber, to confirm the integrity of the data transmissions
on both ends.
Yet another object of this invention is to provide a
digital interactive system which has the capability of
displaying parts of a presentation using motion video.
A still further object of this invention is to provide
a digital interactive system wherein the communications
connections between all the computer processors which comprise
the system are designed to permit rapid data transfer between
any two processors within the system.
An additional object of the invention is to provide a
data transmission means which more efficiently utilizes the
available distribution channel capacity to permit many active
subscribers to be concurrently supported by the system, and
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which only requires one distribution channel for transmission of
all data to the subscribers.
It is still another object of the invention to provide
a digital interactive system which can be readily expanded to
encompass multiple operating centers. Now data can be acquired
by an operating center by importing and storing data on demand
from other operating c~nters of the system, thus maintaining a
simple and inexpensive systems architecture.
It is yet another object of this invention to provide
a digital interactive system wherein presentations may be
tailored to particular markets, based upon demographic
information about the subscribers which is stored on the system.
In general terms, the present invention is directed to
an interactive multimedia presentation and communications system
which is accessible to a plurality of subscribers, wherein each
subscriber may select a particular multimedia presentation for
viewing on his television set that is chosen from a plurality of
such presentations available on the system. Each of these
presentations generally includes a sequence of video images,
accompanying audio, and a menu of choices related to the
presentation which appears as a graphics overlay. In response
to viewing the presentation, the subscriber may make a selection
of one of the choices offered in the menu to either perform
transactions related to the presentation, or to select yet
another particular presentation for viewing on his television
set.
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The interactive multimedia presentation and
communications system of the present invention comprises a
computing means for preparing, storing and processing digital
data that is related to and representative of the plurality of
multimedia presentations and which can perform various
transactions. In response to the subscriber's selections, the
computing means can either perform chosen transactions, or can
retrieve and process digital data related to a particular
multimedia presentation that has been chosen. Input means are
available to each of the subscribers for communicating their
selections to the computing means. Signal transmission means
are provided for transmitting digital data between the computing
means and a signal processing means. The signal processing
means receives, stores and further processes the digital data
that is related to a particular multimedia presentation that has
been selected by a subscriber, converts the digital data into
analog TV signals and then transmits the analog TV signals to
the television set of the subscriber who has selected that
particular multimedia presentation.
A preferred embodiment of the present invention is
directed to a digital interactive multimedia presentation and
communications system in which a subscriber enters codes via a
standard Touch-Tone telephone keypad in response to menus,
graphics, and audio which are presented on a television screen,
and by so doing selects a presentation which comprises video
images and audio commentary about particular items that are
displayed on the TV screen.
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The present invention manipulates, processes and
transmits all data destined for a particular subscriber in
digital format. In order to reach a subscriber's TV set, the
digital data i~ transmitted from a particular local operating
center to the CATV company's headend on a high speed digital
link comprising a single distribution channel. Transmission of
all the digital audio, video, graphic overlay and control
information on a single distribution channel results in
efficient use of the channel's capacity. At the CATV headend,
the data is block converted onto a CATV distribution frequency,
and transmitted to a plurality of field devices which are
locally distributed throughout the area serviced by the system.
These field devices, known as "presentation players", each have
their own identification ("ID") number, and can identify and
intercept the digital data addressed to them. When a subscriber
requests a particular presentation, the interactive system
ensures that the particular digital data required to construct
that presentation is transmitted to the subscriber's local
presentation player. At this local presentation player, the
digital data is transformed into an analog format which is
compatible with television transmission and playback. The
presentation player then transmits the analog information along
a short section of cable between the presentation player and the
subscriber's television set. Thus, the data, from the time it
is produced by the commercial client until it is received at a
presentation player is maintained in digital form, thereby
ensuring that the integrity and visual quality of the
presentations is far superior to that available in the prior art
analog system.
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BRIEF DESCRIPTIONS OF THE DRAWINGS
For a fuller understanding of the nature and objects
of the invention, reference should be made to the following
detailed description, as illustrated in the accompanying
drawings wherein:
FI~. 1 represents an overview, in schematic form, of
the various elements which form the digital interactive
multimedia presentation and communications system, and their
relationship to each other.
FIG. 2 illustrate a local operating center (LOC) of
the digital interactive system, and illustrates the signal
pathways between a subscriber, the local operating center, the
CATV distribution network, and the presentation player.
FIG. 3 shows, in block diagram form, a 20-slot chassis
which holds the single board computers that comprise the local
operating center. The different types of peripherals which
connect to some of these single board computers are specifically
illustrated.
FIG. 4 illustrates the message flow which occurs
during the log-on process, and the relationship between the
log-on server and other servers which provide the software
functions that establish the environment of an electronic
shopping mall.
FIG. 5 illustrates the message flow which occurs
between the session server and other servers of the system,
during a typical shopping session.
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FIGS. 6(A), (B) and (C) illustrate the physical layout
of the chassis and peripheral equipment within a small local
operating center of the system.
FIG. 7 schematically illustrates an intra-LOC
communications scheme, wherein chassis are redundantly
interconnected by SCSI buses.
FIG. 8 shows an intra-LOC communications scheme which
supports a large number of chassis, without redundancy.
FIG. 9 illustrates an intra-LOC communications scheme
designed for a local operating center which can service up to
three thousand concurrent subscribers.
FIG. 10 illustrates, in block format, the typical data
flow from the channel server to the presentation player. More
particularly, FIG. 10 schematically illustrates how stream data
sources and block data sources are multiplexed prior to
transmission to the CATV headend, and how these sources are
demultiplexed at the presentation player.
FIG. 11 schematically illustrates the manner in which
stream data sources are sequentially passed through the
multiplexers, each of which services a plurality of channel
servers within the local operating center.
FIG. 12 shows the block data channels and the stream
data channels as a function of time, and indicates the framing
and multiplexing technique in which stream data channels are
interspersed with the block data for transmission along with
error correction code to the CATV headend.
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FIG. 13 shows the main functional components of the
channel multiplexer in block form.
FIG. 14 shows the main functional components of the
presentation player.
FIG. 15 illustrates, in block form, the components
which comprise the converter of the presentation player.
FIG. 16 illustrates, in block form, the main
components of the converter controller subsection of the
presentation player.
FIG. 17 shows the format of the channel status message
that is transmitted, at regular intervals, by a channel server
on its distribution channel.
FIG. 18 illustrates, in block form, the main
components which are included in each of the subscriber servers
that comprise the presentation player.
FIG. 19 illustrates, in block diagram form, the
various types of subscriber servers that can be incorporated in
the digital interactive multimedia presentation and
communications system.
FIG. 20 illustrates, in block diagram form, the
various types of client services servers that can be
incorporated in the digital interactive multimedia presentation
and communications system.
FIG. 21 illustrates, in block diagram form, the
various types of network servers that can be incorporated in the
digital interactive multimedia presentation and communications
system.
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FIG. 22 illustrates, in block d.i~gv~m f_.rm, the
various types of systems management and app]~c:~ions servers
that can be incorporated in the digital int~r..-~iv~. muitimedia
presentation and communications system.
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DESCRIPTION OF A PREFERRED EMBODIMENT
It is helpful at this point to define some particular
terms used in this disclosure which relate to the presently
preferred embodiment of the interactive multimedia presentation
and communications system.
1. Data Object: A data object represents the essential unit
of information used by the system, and is a generic term
for any string of data. The data object string generally
includes structural information about itself (e.g. its
length and what type of object it is). The largest data
objects stored by the system are compressed video images,
which may be 20,000-80,000 bytes in length. Keystroke echo
characters, sent to the subscriber's TV screen to provide
visual feedback of the subscriber's keystroke entries are
examples of small data objects, typically only several
bytes in length. Other data objects may contain audio
data, processing information, e.g. instructions for
generating graphics overlays, etc.
2. Script: A script is a data object, generally of several
hundred to several thousand bytes in length, which contains
information that defines the time sequence for the display
of particular video images and audio accompaniment which
constitute a presentation. The script is used to not only
determine when and for how long video images and audio will
be displayed, but also what graphics or text will be
overlaid onto the video images. The information in the
scripts is utilized to structure a presentation.
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The digital interactive system of the present invention,
when configured and operated as an electronic shopping system,
electronically simulates many aspects of "live" shopping in a
mall. Moreover, a number of interesting features not possible
in "live" shopping excursions are also provided. For example,
the digital interactive system of the present invention permits
a commercial client who displays his goods or services in the
"electronic" mall to select his viewing audience based upon
demographic data which is stored in the system. The demographic
data may consist of information which is readily available, e.g.
the postal zip code of a subscriber, or may consist of
information which the subscriber has volunteered during his
initial log-on to the system. Such information may include data
of a more personal nature such as ethnic background, earnings
capacity, particular interests and hobb~es, etc.
This customized "market segment" approach to shopping
is useful both to the commercial clients who display their
products on the system, and to the subscribers who utilize the
system for their shopping. From the perspective of the
commercial clients, the market segment capability permits them
to tailor and transmit presentations to only that market segment
which is believed to be most likely to purchase their products.
From the perspective of the subscribers, providing the system
with personal data as to hobbies and interests, allows them to
view customized presentations which relate to those interests.
The digital interactive system of the present
invention is designed to service many subscribers who reside in
different geographical locations, and may be incrementally
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expanded into a nationwide network. A plurality of local
operating centers service various geographical localities within
a region. These local operatin~ centers are linked to each
other, and to a regional operating center, via high speed data
communications pathways.
A novel design philosophy incorporated into the
digital interactive system of the present invention involves the
notion of "storage on demand". This capability is important in
establishing a system which can easily expand in size and adapt
to changing requirements without burdensome external
supervision. When a subscriber requests data from his local
operating center, the local operating center checks to see
whether the requested data are present in local storage, and if i
not, requests that the data be imported from other local
operating centers to which it is connected. If none of the
local operating centers which form the regional network have the
data, it is imported from the regional operating center, one of
whose functions is to store a full set of data for the entire
region.
By storing data upon demand from subscribers, the
local operating center is assured of always having the most
frequently requested data ready for rapid and inexpensive
retrieval. When necessary to free up storage capacity, the
least frequently used data is deleted from the local operating
center. Thus, the notion of "storage on demand" ensures that
data in the local operating centers is dynamically optimized
over time to be the most often requested data. This is done
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with minimal human supervision over the data flow. Moreover, as
the system expands geographically, and new local operating
centers are established, these new centers can automatically
acquire the data to service the local subscribers, as needed.
Easy maintenance and expandibility of the system is
further assured by a system architecture which embodies the main
functionality of the system in a plurality of identical computer
processors which operate on an equally ranked basis to provide a
powerful and efficient distributed processing capability at each
of the operating centers. These processors are loosely coupled
to each other in the sense that they communicate with each other
to avoid conflicts and share data from a common database, but
nevertheless have independently executing processes which
establish the environment and provide the different functions
required by the system.
The digital interactive multimedia presentation and
communications system ("IMPACS") of the present invention is
composed of a number of interrelated functional elements
depicted in FIG. 1. With reference to that figure, a subscriber
to the system, denoted by reference numeral 20, uses a
Touch-Tone telephone to commuAicate with one of a plurality of
local access points ("LAP's") 22, which are geographically
distributed throughout the region served by the digital
interactive system, and are designed to minimize telephone
connection charges. The local access points have facilities
which decode the standard Dual-Tone Multi-Frequency ("DTMF")
signals generated by Touch-Tone keypads and convert these
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signals into standard ASCII-formatted data packets which can be
more readily interpreted by digital systems. In order to reduce
telephone costs, many of these small data packets from different
active subscribers 20 are combined for transmission via a modem
along a single telephone line to a local operating center
("LOC") 24 of the digital interactive multimedia presentation
and communications system. Consequently, the number of long
distance telephone lines required, and their attendant costs,
are kept to a minimum.
The LAP 22 may also be connected to a consumer service
center 26, so that when the occasion arises, subscribers 20 who
require help with their shopping may talk over the telephone to
a consumer service representative. For example, consider the
case where a subscriber 20 is shopping for tickets to a
particular concert. The system has displayed a seating chart
for the auditorium where the concert will be held, and the
subscriber 20 has selected a particular seating section. When
the subscriber 20 wishes to purchase a ticket, a telephone
bridge may be made automatically between the subscriber 20 and a
ticket agent, who will receive the call and provide up-to-date
ticket availability information to the would-be ticket
purchaser. In a preferred embodiment of this invention, the
consumer service representative situated at the consumer service
center 26 also has a TV set connected to the system, and sees
exactly what the subscriber 20 sees on the TV screen.
Another example illustrating the usefulness of the
consumer service center 26 occurs when a new subscriber 20 to
the home shopping service dials in and begins using the system.
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If a formal enrollment procedure has not yet been executed by
the subscriber 20, the consumer service center 26 will be
automatically bridged to the subscriber 20 via LAP 22 so that a
formal sign-up can be made wherein certain demographic and
credit card information will be solicited from the subscriber 20.
In addition to providing standard shopping
presentations consisting of still-video displays and
accompanying audio, the digital interactive multimedia
presentation and communications system of the present invention
provides for a motion video capability. For example, when
assistance from the consumer service center 26 is requested by a
subscriber, this capability can be used to provide a more
"user-friendly" human interface by showing a "live" video image
of the consumer service representative in a corner of the
television screen.
The local operating center ("LOC") 24 contains the
centralized part of the hardware and software elements which are
required to service a local community having from several
hundred to several thousand concurrent subscribers actively
engaged in individual shopping sessions on the system.
Information keyed in by a particular subscriber 20 via a
Touch-Tone phone is transmitted by the local access point 22 to
the LOC 24. LOC 24 searches its local data base for the
appropriate video and audio information that is being requested,
and transmits this digital data in modulated analog format and
in the appropriate sequence along a distribution channel 23 to
one of the cable television companies 25 which services
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subscriber 20. LOC 24 may be connected to a number of different
cable television companies 25 which service different
geographical regions. These companies remodulate the
distribution channel onto transmission frequencies which they
have assigned to the digital interactive multimedia presentation
and communications system and thus transmit the data to
appropriate presentation players 54 which are distributed in the
field to service subscribers 20. As will be more fully
described herein, each presentation player 54 accepts the
digital data which is addressed to it, and processes the data to
produce the final presentation. The presentation player 54
further converts the data into a standard television signal
format, and transmits the presentation to the TV set of the
particular subscriber who has requested the information.
The local operating center 24 typically has a data
storage capacity of up to 0.4 terabytes, depending on what is
required to contain the data objects necessary to accommodate
subscribers who are serviced by that center. The mix of product
presentations stored at a given LOC 24 depends upon what
subscribers have requested to see and upon what commercial
clients wish to have shown to subscribers based upon the
subscribers' demographics. The product presentations as well as
product data, customer data and software to operate the LOC 24
are generally stored locally within the LOC 24, but if not
available, can be obtained from other interconnected LOC's in
the system on demand.
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Depending upon the size of the subscriber population
being served, the digital interactive multimedia presentati.on
and communications system of the present invention may be
configured to have multiple LOC's 24, each LOC 24 serving a
particular geographical area, and connected to other LOC's 24 in
a hierarchical manner so that shopping presentations which are
not available at one particular LOC can be acquired upon demand
from other LOC's in the system. The digital interactive
multimedia presentation and communications system of the present
invention is generally further configured to have a regional
operating center ("ROC") 28 to which a multiplicity of local
operating centers are connected. Typically, one ROC 28 will
service approximately 12 LOC's. ROC 28 is operationally similar
to LOC's 24, but has additional data storage to store all the
possible presentations that are available within the region.
The data storage at such a regional operating center will vary
up to approximately one terabyte of storage capacity.
A nationwide system in the United States of
approximately 60 LOC's and ROC's would be needed to service
approximately 20 million subscribers. This integrated system
would be able to service 40,000 subscribers concurrently. It
wculd allow any subscriber to have access within less than one
second to any one of approximately 800,000 product presentations
locally stored at various LOC's, which would typically consist
of ten seconds of audio commentary, three video images, and
appropriate background music.
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The local operating centers 24 and regional operating
centers 28 are interconnected by high speed data transmission
gateways so that presentations not available within a particular
LOC 24 can be imported from another LOC 24 or ROC 28 and stored
in the local operating system without significant transmission
delay. A response time of 1.5 seconds is provided for non-local
presentations which have to be imported from other LOC's 24 or
ROC's 28. As storage capacity at a LOC 24 approaches its limit,
the least frequently requested presentations are deleted from
the LOC 24. By incorporating this kind of "storage on demand"
protocol into the system environment, the system automatically
ensures that LOC 24 will contain those presentations which have
been requested most recently by subscribers 20 within the local
geographical area serviced by the LOC 24. Re-allocation of data
is performed dynamically as new presentations are added to the
system, so that the optimum mix of presentations is always
stored within each LOC 24, with minimal human intervention.
Commercial clients who wish to display their goods and
services on the digital interactive multimedia presentation and
communications system use the store manager facility ("SM") 30,
to prepare pictures, text and audio accompaniment for viewing by
subscribers 20. In effect, the store manager facility 30 is a
production tool with which commercial clients can construct and
maintain the presentations depicting their electronic stores.
To meet this need, the store manager facility 30 incorporates
computer systems which can capture and manipulate video images
and audio segments from materials which may originate in any
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number of different formats ~e.g. photographs, drawings, textual
material, compact discs, video tape etc.), add information about
the products by appropriate graphics overlays, and tailor an
appropriate audio accompaniment. Store manager facility 30
provides the commercial client 34 with a flexible way of
combining this information, so that a complete presentation may
be easily produced, modified, verified for accuracy, and stored
in the LOC 2~ for viewing by subscriber 20 without undue delay.
In the preferred embodiment, the store manager
facility 30 includes a production facility for preparing
presentations which can capture and store images in digital form
and perform common manipulations on these images, such as
shrinking, stretching, rotating, coloring, etc. The digital
image can then be compressed in the store manager facility 30
from 500K bytes to about 40K bytes. In addition, the store
manager facility 30 has the capability of adding, deleting and
concatenating audio segments. The store manager facility 30 is
also used to construct appropriate initial scripts and menus.
These initial scripts are finalized during the shopping session
by utilizing the subscriber's demographic information which is
stored within the LOC 24. When the final presentation is
composed, it may be previewed by the commercial client 34 in the
same manner as it will appear to the subscribers 20. After
verification and approval by the commercial client 34, the
script, video images, and audio information representing the
complete presentation is transmitted in digital form to the mass
storage system of the LOC 24, where it is stored for
distribution upon request to subscribers 20.
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A client network services facility 32 is provided by
the digital interactive multimedia presentation and
communications system of the present invention to permit
information exchange between the system and the commercial
clients 34 who have presentations on the system. The
information exchange may include lists of product orders which
are delivered from the system to the commercial clients for
fulfillment, and associated order acknowledgments transmitted
back to LOC 24 from the commercial clients 34. The client
network services facility 32 provides a way in which order
status information used by the system for servicing customer
inquiries may be updated. The information exchange also
supplies product availability data requested by subscribers 20,
and product information which may be used by the LOC 24 to
maintain up-to-date product information such as in stock or
out-of-stock conditions. Credit authorization and settlement
information for credit card purchasers may also be transmitted
via this facility.
The digital interactive multimedia presentation and
communications system of the present invention fulfills a number
of design philosophies and criteria, aimed at successfully
serving all the constituencies which transact business on the
system. These business constituents include consumers, who are
represented by the cable TV subscribers that use the digital
interactive multimedia presentation and communications system;
commercial clients, whose goods and services are sold through
the system; and the CATV companies who provide access to their
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cable network, and who permit the presentation players to be
installed in the field at various locations on the cable network.
From the consumer's perspective, the system provides a
number of distinct advantages over prior art systems which are
presently available. The present system provides the consumer
with fast response time and positive feedback. The response
time in most situations is designed to be less than 0.8 seconds
for local transactions. Local transactions are those which
require no access to data other than what is stored at the local
LOC 24 serving the subscriber 20. Transactions requiring access
to a remote center, such as another LOC 24 or ROC 28, may take
up to one second longer. This time includes approximately 500
milliseconds of propagation delay for satellite transmission.
In addition, the subscriber 20 is provided a means for sensing
that each of his commands has been received. Input characters
corresponding to Touch-Tone input signals may be displayed on
the TV screen in a designated location in approximately 100
milliseconds from the time the Touch-Tone key is released. The
intent is to provide immediate feedback to the consumer.
Erroneous entries can be echoed as a beep, message or other
indicator. Further, the architecture of the digital interactive
system of the present invention permits a wide breadth of
products to be displayed through a friendly and feature-rich
user interface, and permits enhanced features to be developed
quickly and inexpensively.
The present invention gives commercial clients the
ability to design and maintain their "electronic stores" from
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their own premises. The store manager facility 30 permits the
commercial clients to construct, augment, or modify a
presentation in such a manner that results can be readily viewed
as changes are entered. Further, the present invention has
storage means for saving presentation materials in a way which
permits these materials to be retrieved, modified, and
reactivated at a later date.
From the perspective of the CATV companies, the
digital interactive system as a whole, and in particular the
presentation players which are installed in field locations near
the homes of the subscribers they service, are designed to be
installed and maintained in a non-intrusive manner so that
normal cable company service is not affected should they fail.
As a further aid in servicing, the presentation players
incorporate self testing procedures, which they use to diagnose
and report their own failures via built-in transponders.
HARDWARE IMPLEMENTATION OF THE MULTIMEDIA PRESENTATION
AND COMMUN_ ATIONS SYSTEM
The innovative architecture of the preferred
embodiment of the LOC 24 fulfills the design criteria outlined
above. Additionally, the architecture as a whole is capable of
being scaled in small increments, i.e. it is possible to add or
remove performance capability in an operating LOC 24 a small
piece at a time. By adopting the architecture described herein,
the LOC 24 is rendered highly fault tolerant, and remains
functional after any single point failure and many multi-point
failures. The loss of functional capability caused by failures
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incrementally degrades the overall system performance, and can
usually be compensated for by idle equipment resident in LOC 24.
The overall architecture of a typical local operating
center 24 is schematically depicted in FIG. 2. With reference
to that figure, a subscriber 20 uses a Touch-Tone telephone 42
to communicate with the local operating center (LOC) 24. As
already described, the signals transmitted from Touch-Tone
telephone 42 are carried over conventional telephone lines to a
local access point 22, and from there over other telephone lines
to the local operating center 24. LOC 24 may be part of a
network consisting of a plurality of such LOC's, interconnected
so that information may be shared. The LAP 22 transforms
Touch-Tone signals into packets of ASCII characters, and then
combines the packets from a plurality of other subscribers for
transmission via a modem to the voice network interface ("VNI")
46 of the LOC 24. The packets are received by VNI 46,
interpreted, and then sent to a high speed data bus 44 which
connects all the functional elements of the LOC 24.
LOC 24 is comprised of a plurality of single-board
computers ("SBC's") or processors, which are interconnected by
the high speed data bus 44, and which support approximately
thirty or more different processes that provide the software
functions which define the environment of the system. Each
single-board computer is a fully configured processor having a
central processing unit ("CPU"), random access memory ("RAM"), a
clock and input/output facilities, and is loaded with
specialized software by the system.
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The single-board computers comprising the LOC 24 are
housed in a plurality of industry standard 20-slot chassis. A11
of the single-board computers on a chassis communicate with each
other through an industry standard Multibus II system bus, which
is provided on ~he chassis backplane. An industry standard
Small Computer System Interface ("SCSI"~ link, whose specific
chassis interconnect architecture will be described more fully
below, provides the communications link between different
chassis of the system. In a preferred embodiment of the
invention, the single-hoard computers communicate via the
combination of SCSI and Multibus II links to each other at
transmission speeds of at least four million bytes per second.
The smallest practical local operating center 24 generally
accommodates about 40 concurrent subscribers who require about
100 processes. A more typical LOC 24 comprises approximately
100 20-slot chassis, and supports up to 3000 concurrent
subscribers requiring about 4000 processes.
Although all the SBC's comprising the LOC 24 are
physically identical processors, some of the SBC's have
different peripherals connected to them via industry standard
interfaces. FIG. 3 shows a representative layout of a single
chassis, and more clearly illustrates the different peripherals
that may be connected to some of the SBC's. As indicated in
FIG. 3, the Multibus II backplane of the chassis can accommodate
twenty individual slots. Nineteen of these slots may be filled
with single-board computers. The twentieth slot contains a
central services module ("SCM") which performs housekeeping
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functions for the chassis, and which is a required component in
the Multibus II system. In particular, some single board
computers, such as SBC 12 in slot #2 (in the example illustrated
by FIG. 3), are connected via the SCSI interface module 14 to a
disk drive controller 16, which is in turn connected to a high
capacity disk drive 18 via an industry standard Enhanced Small
Disk Interface ("ESDI") connection. A plurality of disk drives
such as disk drive 18, connected as in the foregoing sentence,
comprise the local data base of the LOC 24. The SBC's which
have these peripherals act as "volume managers" to control the
reading and writing of data to and from the data base. Other
SBC's which may be allocated the role of communications devices
(or communications servers), as exemplified in FIG. 3 by SBC 11
in slot #n, generally have a high speed SCSI interface link as
shown, which connects to other communications servers on other
chassis of the system. Likewise, SBC's which act as gateways to
provide communications with other LOC's or ROC's will generally
be connected as shown in slot #19 of FIG. 3, wherein SBC 13 is
provided with a serial interface module 15 for communication
with a gateway device 17 to a satellite transponder or other
communications pathway. In order to transfer data ~rom the LOC
to the distribution channel of the CATV headend, certain SBC's,
such as SBC 19 in slot #3 of FIG. 3, are provided with
additional hardware that perform the multiplexing of ~arious
typés of data prior to transmission onto a distribution
channel. In particular, SBC 19 is provided with a serial
interface module 10, which transfers data to a multiplexer 9,
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and from there to a modulator 8, and a transmitter 7, from which
the data is distributed to the CATV headend 38. The particular
reasons and method for performing the multiplexing will be more
fully described below. Finally, SBC's which may be called upon
to provide the functionality of a voice network interface, are
provided with an appropriate modem connection through an
industry standard RS232 interface, so that data may be
transmitted along telephone lines. This particular peripheral
connection is illustrated for SBC 6 of slot #18 in FIG. 3. Slot
#1 of FIG. 3 illustrates an SBC 5 which has no peripherals
connected to it. This SBC would be chosen to run processes
which do not require external peripherals.
Apart from the different peripherals which may be
attached to some SBC's, all the SBC's in the system are
identical units. Depending upon the p~rticular demands of the
system at any point in time, they may be allocated any software
task, provided that they have appropriate peripherals to satisfy
that task. This architecture permits the system to dynamically
reconfigure the mix of processes which are distributed among the
S3C's so that system performance is always optimized in response
to the varying demands placed on the system as a function of
time.
If enough memory or other computing resources are
available, any single-board computer may be called upon to
perform more than one concurrent process. The existence of more
than one process on an SBC is transparent to most other
processes in the system. A loose coupling exists in the sense
~07ZS
that any process sending a message to another does so in a
uniform manner, but without knowledge of whether the receiving
process is on the same processor, or on another processor
located elsewhere in the system. An example of a single-board
computer which meets the operating requirements of LOC 24 is
Model Number ISBC 386/100 computer manufactured by Intel
Corporation of Santa Clara, California.
In the present context, a process is a continuously
executing program which has sufficient resources allocated to it
to accomplish its task, and is generally referred to as a
"server". Some of the various categories of servers typically
implemented in the LOC 24 to establish the environment of an
electronic shopping mall are denoted in FIG. 2 as subscriber
services 45, client services 47, network services 49, and
systems management and applications 51. The specific servers
which comprise these categories are more fully described below.
Two servers in particular are explicitly depicted in
FIG. 2. The channel servers 36 are part of the group of network
services 49, and provide an interface between LOC 24 and the
CATV headends 38 of the cable television companies that are
connected to the LOC 24. Each channel server 36 receives
digital video, audio and control information which is destined
to particular subscribers served by the channel server's 36
distribution channel 41. Each channel server 36 supports a
single distribution channel 41 which comprises a high speed
digital pathway for transmitting this information on a baseband
frequency to the CATV headend 38 to which the channel server is
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connected. An LOC 24 may typically support between 1 and 16
CATV distribution channels 41, with each distribution channel
being served by one channel server process. The process itself,
as described above, may be physically distributed over more than
one SBC.
Each CATV headend 38 modulates the data onto a
particular distribution frequency for transmission through the
cable television network. Trunk lines 40 emanate from each CATV
headend 38 and constitute the primary distribution paths. At
prescribed positions along each trunk line, generally
corresponding to distances which result in a signal attenuation
of 22 db, are bridge amplifiers 48 which boost the signals to
compensate for this attenuation. Secondary distribution feeder
cables 50 emanate from the bridge amplifiers 48. Along these
secondary distribution feeder cables are taps where the signals
are split off to supply approximately 40 homes via drop cables
52, each of which terminates at a particular home. Presentation
players 54 are generally located in the field adjacent to bridge
amplifiers 48, and are positioned in parallel with the secondary
feeder cables 50.
The digital data containing the video and audio
presentations is addressed to a specific presentation player 54
which is connected via drop cable 52 to the television set of
the subscriber who has requested the information. Each
presentation player 54 receives the modulated digital data from
the CATV headend 38, converts the data into video and audio
presentations having the appropriate television signal format
Z3~07ZS~
and transmits the particular presentations that have been
requested by a subscrlber on a predetermined display channel
frequency to which the subscriber's television is tuned. Up to
500 presentaticn players 54 may have active sessions at any one
time on a given CATV distribution channel 41 served by LOC 24.
The distribution of presentation data to all these presentation
players 54 is handled by one channel server pro~ess 36.
The second server explicitly shown in FIG. 2 is the
disk volume manager server 35. SBC's which are attached to disk
drive peripherals may function as volume managers 35. The
plurality of disk drives serves as the storage means for storing
all the digital data in the LOC 24, and as such constitute a
repository for all the presentations and other data objects
stored in the LOC 24. The plurality of disk drives thus
establishes the data base 33 for the LOC 24. The basic building
block of the data base 33 is a disk storage volume, which
comprises a disk drive unit such as the Maxtor 760 megabyte
device, a controller for the disk drive unit, and a single board
computer which acts as the disk volume manager 35. As will be
more fully described below, the disk volume managers 35 have the
function of storing, retrieving and deleting data objects.
Further, each disk volume manager 35 also stores a record of the
object name index of its associated disk storage volume for
retrieval and recovery purposes.
SOFTWARE IMPLEMENTATION OF THE INTERACTIVE MULTIMEDIA
PRESENTATION AND COMMUNICATIONS SYSTEM
As referred to above, the software functions which
provide the environment for the digital interactive multimedia
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presentation and communications system are continually executing
processes or "servers" which are dynamically distributed as
needed among the single board computers which comprise the local
operating center. The functions provided by these servers
define the system and provide appropriate interfaces both for
subscribers and commercial clients. In addition, the servers
provide the capabilities required for systems management and
applications, consumer services, and overall network
supervision. An overview of some of the various servers and the
different functions which they provide is now presented to
illustrate one way in which the system may operate. The servers
are broadly characterized into categories of subscriber
services, client services, and network services. The context of
an electronic mall is again chosen as a specific embodiment of
the system, although it will be clear to a person skilled in the
art that other applications having different contexts are
possible.
Within the context of an electronic mall, it is useful
to view each position within the mall to which a subscriber may
possibly navigate, as consituting a "node" of the system. Each
node has a unique appearance and structure. The appearance of
the node constitutes what the subscriber is being shown and told
at that point of his shopping excursion. The underlying
structure of the node is represented by data which enable a
particular subscriber to make particular choices. For example,
the node may contain structural data which denote the particular
markets that are available to the subscriber, based on his
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demographic information, and the choices available to the
subscriber may be accordingly limited to only those markets.
As the subscriber navigates to different nodes of the
system, an automatic look-ahead is performed, and the next set
of possible nodes to which the subscriber may navigate is
obtained. The data objects necessary to rapidly implement this
next set of nodes are pre-fetched, in order to reduce overall
system response time.
Operation of the system may be more fully understood
and appreciated, upon consideration of the detailed functions
suppiied by various servers which would be used to establish the
environment of an electronic mall, as presented herein.
SUBSCRIBER SERVICES (FIG. 1~)
LO&ON
After the subscriber dials a telephone number
displayed on the television screen, a logon server 76
within LOC 24 gives the subscriber access to the digital
interactive multimedia presentation and communications
system of the present invention. If the digital
interactive system is broadcasting on two or more display
channels, each channel displays a different telephone
number for system access. Generally, the local access
point will have the ability to automatically deliver the
calling telephone number to the LOC. However, should this
ability not be implemented, the subscriber can be prompted
by the logon server 76 to manually enter his telephone
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number on the Touch-Tone keypad. Once initial communica-
tion is complete, the system checks its available resources
to see if it has the resources necessary to support the
subscriber and then proceeds to allocate these resources. ;~
If any necessary resource is currently in use, the
subscriber is prompted via telephone to enter the latest
time he would like to be called back. -
The logon server 76 uses a market segmenter
function to determine which markets are available to a
subscriber to allow the system to configure different
stores and malls for different subscribers based on their
demographics and shopping history, and according to the
commercial clients' specifications.
Once the logon server 76 has determined that
sufficient resources exist to support the subscriber, it
proceeds to send data to a session server 74 which is
allocated to the subscriber for the duration of the
shopping session. This data includes information
identifying the subscriber, a market segment table defining
the markets which this particular subscriber may view, and
the identity of the channel server which will provide the
distribution path to the subscriber.
If proper resources are not presently available
on the system, the subscriber's identifying information is
transmitted to a call-back manager server 71 and a voice
network server 70 so that the subscriber may be contacted
when resources become available.
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CALL-BACK MANAGER
When insufficient system resources exist to
support a subscriber at logon time, the call-back manager
server 71 allows the system to call the subscriber back
when resources are available. The call-back manager 71 has
two main functions. First, it obtains times, suitable to
the subscriber, to perform the actual call-back, and
second, it periodically checks to see whether the necessary
system resources are now available, and if so, it initiates
a call-back procedure through voice networ~ server 70
(FIG. 21~.
CHANNEL CALCULATOR
When a subscriber has a choice of at least two
display channels which broadcast the digital interactive
multimedia presentation and communications system on his
television, each channel specifies a different dial-up
telephone number to be used when gaining access to the
system. The channel calculator server 78 determines which
display channel the subscriber is tuned to so that this
information can be Sent to the presentation player which
services the subscriber to ensure that it will broadcast on
the correct display channel frequency. Additionally, the
channel calculator 78 determines which channel server 36
(FIG. 2 and FIG. 21) to use.
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MARKET SEGMENTER AND MARKET CHECKER
The market segmenter server 75 and market checker
server 85 work together to provide a market-specific mall
to the subscriber. To do so, the market segmenter compares
demographic information which the consumer has previously
entered with the demographic requirements specified by
commercial clients to determine which markets the consumer
may access. The market segmenter server 75 then builds a
table of market entries with an indication as to whether or
not the subscriber is eligible for a particular market
entry. This table is used by the market checker server 85
as the subscriber navigates the mall. The market checker
server 85 and market segmenter server 75 work in
conjunction with each other to provide a specific mall
environment for a subscriber based on his particular
demographic information. The market checker server as
compares the market segment table entry with information in
the navigation nodes to determine what should be displayed
to the particular subscriber, and where within the mall he
may navigate. Markets in ~his sense also determine which
of several prices are displayed for a given product.
SUBSCRIBER ENROLLMENT
New subscribers are permitted to browse the mall
but cannot purchase items until they have been properly
enrolled in the system. When a new subscriber attempts to
purchase an item, he is automatically bridged to the
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consumer services center by the subscriber enrollment
server 87. Consumer service creates identifying
information for the subscriber and provides him with a
personal identification number ("PIN"). The subscriber is
prompted to enter the PIN number before utilizing any
shopping functions. Thus, in addition to demographic
information, credit card numbers and personal directories
can be maintained for individual household members.
SESSION SERVER
The session server 74 accommodates navigation
through the electronic mall, updates the subscriber's
records, and controls what the subscriber is shown. It
also arranges for support services from other processes
such as cashiering, stock availaDility checking and the
consumer service center.
As such, the session server 74 maintains the
complete context of the subscriber's shopping session and
provides the means for the subscriber to navigate through
the mall. When a subscriber logs on to the system, he is
allocated a session server 74 for his exclusive use for the
duration of the shopping session. The session server 74
provides the software capability necessary to retrieve all
re~uired data objects, including consumer and client
information. The session server 74 maintains this data in
the local data base of the LOC. To increase its
efficiency, during idle processing, e.g. while waiting for
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the subscriber to respond, the session server 74 initiates
pre-fetches of objects it is most likely to require to
respond to the subscriber's next action.
The session server 74 not only receives the
subscriber's keystrokes, but also sends appropriate scripts
and keystrokes to the relevant channel server 36 for
immediate echo-back to the subscriber, thereby providing an
important feedback function. Additionally, it maintains
the history of the subscriber's naviga~ion through the
mall, as a means for easily reversing direction to previous
nodes of the system.
The session servers 74 maintain those portions of
the subscriber's records which deal with demonstrated
shopping preferences. This information is used to
personalize the shopping navigation for subsequent shopping
sessions.
Purchases may be made by adding items to a
"shopping cart". Servers are provided which allow a
subscriber during a shopping session to add items to the
shopping cart, and review or modify the contents of the
shopping cart.
CASHIER
Subscribers may split items in the shopping cart
into groups which utilize different payment methods and
shipping instructions. Further, subscribers who have
purchased items from grocery store clients may specify
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their desired delivery date, time, and address. Once all
the op~ions have been determined, the cashier server 84
sends a summary screen of the entire order to the
subscrib2r, which includes information on total cost,
estimated taxes, delivery and shipping charges.
ORDER POSTING
The order posting server 98 performs the saving
of consumer orders to disk, so that in the event of network
failures, the orders can be recovered and delivered at some
later time.
Customized servers which add more functions to the
basic subscriber services may be easily added to the digital
interactive multimedia presentation and communications system.
Such services may include a personal directory for keeping
customized list of items which cross store boundaries. For
example, a subscriber may keep lists of groceries he regularly
buys so that he can add the entire list to his shopping cart.
Other customized shopping services which may be easily
implemented by appropriate servers include a bridal registry
server, maintained on a mall~wide basis, a product search server
to provide subscribers with the ability to easily find products
in a store based upon various input information, e.g. price,
sex, age, etc., and a size reminder server, which allows
subscribers to keep information on clothing sizes for various
individuals. Other specialized subscriber servers may be easily
added as the system grows to provide additional individualized
software functions.
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CLIENT SERVICES (FIG. 20)
The digital interactive multimedia presentation and
communications system supplies a number of servers which provide
useful software functions to the commercial clients who are on
the system. Several illustrative examples of such client
servers 47 in a preferred embodiment of the invention are:
CLIENT DATA BASE
The client database server 99 maintains a data
base of client information. It provides the ability to
add, change, and delete clients, maintain client billing
rates, client history and provide data base reports. This
server also supplies the capability to initiate a
transmission of new or changed client information to a
particular LOC of the system.
STATISTICS REPORTING
The statistical reporting server 107 provides
information required for marketing analysis. Data is
captured during each subscriber's shopping session, and is
used to generate logs of demographic information as to
purchasing activity in different markets. Additional
information on how subscribers navigate through the mall is
also available. Reports providing statistical information
generated from these logs are produced and provided to
commercial clients.
~2007259
Other client services servers 47 on the system provide
for the production of billing reports to the clients, settlement
functions for all credit card purchases, and various end of day
reconciliation functions.
NETWORK SERVICES (FI~. 21)
In a preferred embodiment of the invention, a number
of specialized network servers 49 (FIG. 2) provide software
functions which define and support the overall multimedia
presentation and communications system and are exemplified below:
VOICE NETWORK SERVER
The voice network server 70 ("VNS") is the
interface between the subscriber's response and the
software necessary to service his session. For fault
tolerance, each LOC may be configured to have at least two
telephone data lines, connected via modem interfaces from
the local access point ("LAP") to at least two voice
network servers 70 on separate chassis. The voice network
server 70 controls the modems, retrieves the subscriber's
key presses and sends the key presses to the subscriber's
session server 74. If a bridge to the consumer services
center is required, the voice network server 70, upon
instruction from the session server 74, initiates the
bridge through the local access point.
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CHANNEL SERVER
The channel server 36 has the important role of
fetching data objects require by the scripts representing
presentations chosen by subscribers to view. The channel
server 36 then meters these data objects out to the
distribution channel modulator at a rate which will not
overrun the storage capacity of the presentation players.
The modulator and transmitter then send the data from the
LOC to the CATV headend 38. By using the channel
information obtained during consumer logon, the channel
server 36 associates a shopping session with a particular
presentation player 54. The channel server is supplied
with a presentation script object which it uses to request
the objects it requires to make up the presentation, and
transmits them as they are -receiyed directly from other
applications to the presentation player 54 along with a
copy of the script object. The channel server 36 obtains
large objects, such as video images, directly from a volume
manager 35. Other objects, such as variable text may be
received from other applications servers. The channel
server 36 is designed to recognize high priority objects,
such as echo-back key presses, pause/resume navigation
commands and any presentation player commands, and
expedites their delivery. Since the distribution channel
associated with a particular channel server 36 services
multiple presentation players 54, the channel server 36
generally processes requests for multiple concurrent
sessions.
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IMPORT/EXPORT GATEWAY
The import/export gateway server 77 permits
transfer of data between local operating centers (LOC's)
and regional operating centers (ROC's). Since an entire
collection of data objects for the system is maintained
only at the ROC, an LOC must import objects not currently
resident. If an LOC receives a request for an object it
does not have, the import/export gateway server 77 tries to
obtain the object from the next LOC in the network
hierarchy. Further, when data updates occur at an LOC,
theimport/export gateway server 77 is used to ensure that
other LOC's receive the same update. In the event that
insufficient resources are available at an LOC to
accommodate an object, the least-recently used object will
be purged from the LOC to provide space for the new
object. In this manner, the system provides for dynamic
reallocation of stored objects. In a preferred embodiment,
the LOC is configured with sufficient resources to
accommodate the anticipated volume of data, so that such
- reallocation does not have to be performed during a
shopping session.
Additional network servers 49 are provided to handle
order delivery, report on inventory availability, verify credit
authorization, and provide automatic bridging and linked-
shopping to consumer services, so that consumer services
personnel may view the context of the shopping presentation.
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.
SYSTEM MANAGEMENT (FIG, 22)
A number of systems management and applications
servers 51 provide system management functions for the digital
interactive multimedia presentation and communications system.
For example, an operations interface server provides a human
interface with ~he system. It permits the system to accept data
from operators via terminals, and to return both solicited and
unsolicited information to the terminals. The operations
interface server allows operators to kill processes, install a
new mall, store, or presentation, and initiate file uploads or
downloads. Other examples of system management servers, in a
preferred embodiment of the invention, are: .
COMMISSIONER
The main purpose of the commissioner server 140
is to configure an LOC. During start-up, an empty LOC is
recognized and a single board computer ~SBC) is randomly
allocated by a countdown process to serve as a commissioner
server 140. The commissioner server 140 then broadcasts
its presence and identity, and uses a configuration table -~
to assign other single-board computers to provide the
capabilities of the various servers, with the allocation
mix being dependent upon the historical use of servers at
other LOC's. In addition to setting the initial system
configuration, the commissioner server 140 also can
dynamically recommission single board computers during
system operation using the operational configuration data
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2007259
objects supplied by a configuration manager in response to
the activity of the system.
ACTIVITY RECORDER
All processes "report in to" the activity
recorder server 73, either to record a specific event, or
at specified times. The activity recorder server 73
maintains a table of the status of all single board
computers in the system. As they report in, processes
include activity and status data. The activity recorder
server 73 buffers, and during idle processing stores this
data for use by the activity monitor server 142 and
configuration manager 143. Typical of reported data are
systems statistics maintained by such servers as the object
locator and volume manager. The activity recorder server
73 further receives information from the subscriber
services applications that reflect subscriber activity.
ACTIVITY MONITOR
The activity monitor server 142 provides activity
reports on the LOC either at set periods or on an
as-requested basis. Some of this information is used to
redistribute objects across volume managers and thereby
provide for better load leveling. The activity monitor
server 142 has sufficient information to calculate
subscriber response times. An analysis of this information
can indicate when performance at the LOC is degrading to
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unacceptable levels. When this occurs, an alert is sent to
the operations interface.
CONFIGURATION MANAGER
The function of the configuration manager server
143 is to update a configuration table to be used by the
commissioner server 140 to determine which processes are
needed to serve the LOC. The configuration manager server
143 periodically accesses the activity table produced by
the activity recorder. The activity table is then compared
with the current operations configuration table. A new
configuration table is then generated based on usage
profiles by day-of-week and time-of-day contained in the
configuration table and based on conclusions drawn when the
configuration manager analyzes the activity table to
predict future requirements. The configuration manager
server 143 adjusts the configuration data object
accordingly to obtain a more efficient distribution of
applications. As part of this analysis, a specified
percentage of idle applications, as the norm, is compared
with a permitted normal variance.
PRE-LOAD
Certain objects, such as main indices, screen
objects used in the buying process, and system parameters
are always required to be resident at the local operating
center (LOC). The pre-load server 144 is a process which
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obtains these objects when the LOC is configured, thereby
reducing the overhead and degradation of response times
that would occur i all objects were imported on a demand
basis. mhe pre-load server 144 accesses an object which is
itself a list of all objects to be pre-loaded to the LOC.
Using statistics reported by the object locator server 148
and volume manager server 149 to the ac~ivity recorder
server 73, this pre-load object is dynamically maintained
so that the pre-load server 144 runs at a low priority and
does not preclude subscribers from using the system.
JOB SCHEDULER
The job scheduler server 145 is used to control
batch-type applications such as end-of-day processing. It
can schedule applications by month, by week, by day-of-week
and by time of day.
HIT MAN
The hit man server 146 is used to specify the
deletion of outdated objects from an LOC. Periodically,
the hit man server 146 accesses a list of objects to be
deleted from an LOC. The list is imported via the
import/export gateway server 77. The hit man server 146
interfaces with the obj~ct locators and volume managers to
ensure that the objects are deleted.
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PLACEMENT AGENT
The placement agent server 72 is the coordinator
of applications which require the assistance of other
applications. Applications that are not being utilized
volunteer to one of several placement agent servers 72
strategically commissioned by the system. These
applications are maintained as a table of single-board
computers known to that particular placement agent server
72. When an application requires the services of another
application, it sends a request for assistance to a
placement agent server 72. If that placement agent has a
volunteer of the application type requested in its table,
it provides communication between the two applications. If
a placement agent server 72 cannot satisfy the request, it
sends the request to other placement agents on the system.
OBJECT LOCATOR
The object locator server 148 allows the system
to access a data object. The object locator server 148
determines the volume on which a data object is expected to
reside, based on an algorithm using the object's name. The
object locator server 148 maintains a table which maps
particular data object groups to particular volume manager
servers 149. The object locator server 148 first applies a
formula to the requested object's name in order to
determine to which of about 10,000 groups the data object
belongs. Each volume manager server 149 maintains a list
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of each of the data objects it contains together with the
disk storage location and other maintenance statistics.
This information is then sufficient to locate any specific
objects within the LOC storage facility.
VOLUME MANAGER
The volume manager server 149 is an application
managing all the data objects on a single disk drive. It
provides both read and write access of data objects for use
by other applications as well as data use statistics. If
an object is not found, a request to import the object is
generated. Some requests, such as from the cache requester
server 150 may not be to return an object, but only to
cache it in controller main memory in preparation for a
future request. These requests` are performed during the
volume manager server's idle processing. During idle
processing, or when disk utilization has reached a
specified limit, the volume manager server 149 may delete
infrequently used objects. Data services 79 (FIG. 5)
comprises the object locator servers 148, the volume
manager servers 149 and the cache requester servers lS0.
CACHE REQUESTER
The cache requester server 150 initiates
pre-fetches of objects likely to be required in the
future. This is done to assure quick access to the data
objects thus cached when an actual request to retrieve such
an object is made.
2~n 7xss
All the server processes execute within an application
programming environment ("APE"). In this environment, processes
generally have no knowledge of the context of any other process,
nor do the processes have access to global data areas. Although
processes may reside on the same SBC, the same chassis, or
possibly in different cabinets within an LOC, the location of
any process is transparent to the other processes.
Whereas session servers 74 must be specifically
allocated to a subscriber during a session, other servers are
available directly through the application programming
environment. Examples of servers which may be obtained directly
through a request to the application programming environment are
the placement agent servers 72, and the hitman servers 146.
Further, requests which require the reading and writing of data
from the data base, and therefore require use of the object
locator server 148 and volume manager servers 149, may also be
directly requested through the APE, by placing a request for
"data services". Message passing from one application to
another, and memory allocation and deallocation may also be
requested directly through the APE.
In order to provide a better understanding of the
interplay between the different servers described above during
operation of the digital interactive system, it is useful to
specifically describe the chain of events which might occur
during the system's operation by giving some specific examples.
The first example illustrates the events which occur during the
logon process, in which initial communications between the
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subscriber and the system are established, and whereby specific
servers, such as a session server, are assigned to handle the
subscriber's requests. The second illustrative example
describes the sequence of events which occurs during a simple
series of shopping transactions made by the subscriber.
The message flow during the logon procedure is
outlined in block diagram form in FIG. 4. With reference to
that figure, the logon procedure is initiated when LAP 22
connects a subscriber's phone line to the voice network
interface, which is controlled by a voice network server ("VNS")
70. The voice network server 70 in turn sends a message to the
placement agent server 72, requesting an available logon server
76. The placement agent server 72 responds to the voice network
server 70 with the address of the available logon server 76.
The voice network server 70 also requests the placement agent
server 72 to find an available session server 74. Again, the
placement agent server 72 acts to return the address of an
available session server 74 to the voice network server 70. The
voice network server 70 then performs an initializing handshake
communication with the logon server 76, in which the address of
the session server 74 is passed to the logon server 76.
The logon server 76 next initiates a request to the
voice network server 70 that the voice network interface produce
a voice message asking the subscriber to enter his phone number
on his Touch-Tone telephone keypad. LAP 22 receives the key
presses and passes them to the voice network server 70, which in
turn transmits this data to the logon server 76. The logon ~-
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server 76 next sends a message to data services 79 requesting
the subscriber's household data object (which contains specific
information on the subscriber, e.g. his personal identification
number, etc.). If data services 79 is unable to locate this
object, the logon server 76 is informed and then sends a message
to the import~export server 77 requesting that the subscriber's
household object be imported from other LOC's. If this ob~ect
is not found at the other LOC's, the logon server 76 then
initiates a request to the voice network server 70 which asks
the subscriber to enter a sequence of digits displayed on his
television as part of the "attractor" screen. These digits
represent routing information to the system which identifies the
particular presentation player that is servicing the
subscriber. LAP 22 accepts the subscriber's keypress responses
and passes them to the voice network server 70, which transmits
the information (the presentation player ID) to the logon server
76.
The logon server 76 next requests the placement agent
server 72 to give it the address of an available channel
calculator server 78. Logon server 76 then sends a message to
the selected channel calculator 78, providing it with the
presentation player ID and the subscriber's display channel and
obtains from the channel calculator 78 the ID of the
distribution channel required to service the subscriber's
presentation player. The distribution channel ID also defines a
particular channel server 36 that will be allocated to the
subscriber. Through communication with placement agent server
2007~S9
72, the logon server 76 is given the address of the appropriate
channel server 36. The channel server 36 determines if the
appropriate presentation player is available and returns this
information to the logon server 76.
At this point, if resources are not available, the
logon server 76 places the subscriber into call-back status by
communication with callback manager 71. Assuming that all
resources are available, the logon server 76 then requests the
placement agent 72 to find an available market segmenter 75 and
communicates with the market segmenter 75 to obtain the market
segmentation table for that subscriber. Logon server 76 then
initiates a handshake communications with the session server 74,
and passes the subscriber's household data object, the market
segment table, channel server data and all addresses of
associated servers to the session server 74. The logon server
76 then sends a message to data services 79 to obtain a script
designed to display a "welcome" presentation to the subscriber.
The script is returned to the logon server 76, which in turn
sends the script, the distribution channel ID and the
presentation player ID to the channel server 36. The channel
server 36 then obtains from data services 79 the particular
welcome presentation objects, which it assembles and sends to
the subscriber's presentation player.
When this is done, the channel server 36 responds to
thie logon server 76 that the welcome presentation has been
presented to the subscriber. The logon server 76 responds with
an appropriate message to the activity recorder 73. Finally,
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the logon server 76 sends a message to voice network server 70
informing it that the subscriber is now logged onto the system
and that a specified session server 74 is in use. At this
stage, the logon server 76 is free, and volunteers its services
to the placement agent 72. Future key presses from the
subscriber will he forwarded in regular fashion by the LAP 22 to
the voice network server 76, which will in turn forward the key
presses directly to the appropriate session server 74 that has
been allocated to the subscriber.
Once logon has been established, and the subscriber
has gained access to the system, navigation to different nodes
of the system where shopping transactions are performed is
supervised by the session server 74. What follows is an example
illustrating the sequence of events which occurs when a simple
series of transactions is made by a subscriber. In a real
shopping session, many more transactions would occur, and many
more servers would be involved. However, the following example
serves to further demonstrate the nature of the interactions
between the session server and other servers within the digital
interactive multimedia presentation and communication system of
the present invention.
In this example, the logon procedure, as described
above, has resulted in a particular session server 74 being
assigned to the subscriber. The identification of the session
server is known to the voice network server 70. The voice
network server 70 also knows the identification of the physical
port on the telephone interface equipment which the subscriber
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is using. With this information, the voice network server 70
can route digits entered by the subscriber via the Touch-Tone
keypad on his telephone ~o the correct session server 74.
The illustrative example of a simple series of
transactions begins with the voice network server 70 passing on
the digital characters which result when the subscriber 20 makes
a choice from a menu displayed on the television screen. The
interaction between the session server 74 and other servers of
the system during the shopping session is illustrated in block
form in FIG. 5. The sequence of events which typically occurs
is now described, and may be best understood with reference to
that figure.
The digital characters corresponding to the key
presses are transmitted to a local access point 22 and via modem
27 to a voice network server 70. These signals are then sent by
voice network server 70 to the particular session server 74 that
has been allocated to the subscriber 20. In order to provide
rapid feedback of the key presses to the subscriber 20, the
session server 74 constructs a script to display the digits that
have been entered by the subscriber, and sends the script to the
channel server 36 which services that particular subscriber.
The channel server 36 in turn sends the script to the
multiplexer/modulator 81 and transmitter 83 for transmission to
the CATV headend 38, and from there to the particular
presentation player 54 which is connected to the television set
being used by subscriber 20.
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Meanwhile, the session server 74 fetches a script
shell, which comprises a partially formed script, from data
services 79, and which relates to the selection made by the
subscriber 20. The session server 74 updates the script shell
with the subscriber current market data, perhaps excluding some
products not offered to the subscriber because of demographic
considerations, or perhaps changing the price of some display
product to correspond to the subscriber's situation. The
completed script is then sent on to the channel server 36. Upon
receipt of the script, channel server 36 requests the necessary
audio and video image objects from data services 79, and
proceeds to send a copy of the script to the subscriber's
presentation player 54.
Data services 79 delivers the requested objects to the
channel server 36, which then sends` the objects through the
multiplexer/modulator 81 and transmitter 83, and on to the
subscriber's presentation player 54. At this point, we assume
that the subscriber again sees a menu, and makes his choice by
entering Touch-Tone signals on his telephone. These Touch-Tone
signals are converted to digital characters at the local access
point 22, and are delivered through the voice network server the
subscriber's session server 74. In this particular example, we
assume that the subscriber 20 has chosen to purchase an item.
To complete the purchase request, session server 74
interacts with the client's network server 82 to access the
client's inventory system and verify that the particular
selected item is available. For purposes of this example, we
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assume that the merchandise item is available. The session
server 74 then requests a cashier server 84 from the placement
agent 72. The placement agent 72 returns the name of an
available cashier server 84 to the session server 74. The
session server 74 then interacts with the cashier server 84 and
with a credit authorization server (not show) which would
normally be provided via the client network server 82 and the
gateway 86, to authorize the sale if payment is to be made by
credit card. The session server 74 proceeds to interact with
the cashier server 84 to "ring up" the sale. This would
normally include certain calculations such as sales tax and
would include certain subscriber interactions, such as delivery
information specification, which are not shown here. When the
cashier server 84 is finished with the sale, it volunteers
itself back to the placement agent 72. A sale confirmation
script is constructed by the session server 74 and sent to the
channel server 36 for transmission to the subscriber 20.
The order for the merchandise is sent to the client
network server 82, and then on to the particular client through
gateway 86. The channel server 36 proceeds to send the sale
confirmation script, and accompanying audio or video images to
the subscriber presentation player 54 via the multiplexer/
modulator 81 and transmitter 83. Meanwhile, the session server
74 has pre-fetched the script shell from data services 79 for
each possible choice that the subscriber is offered in the sale
confirmation presentation. The subscriber 20 makes a choice
from the menu presented (such as suggestions for synergistic
2~07;;~S9
sales). His choice reaches the session server 74 via the voice
network server 70. Session server 74 proceeds to update the
script shell which has been pre-fetched, with the information
representing the subscriber's choice, and sends it to the
channel server 36.
As before, channel server 36 sends a copy o the
script to the subscriber's presentation player 54. Channel
server 36 also requests the audio and video objects called for
by the script from the data services 79. For illustrative
purposes, WQ assume here that one of the image objects is not
present in the local operating center 24. To obtain the
required data object, data services 79 sends an import request
to the import/export server 77 to obtain the image data from
another local operating center or possibly a regional operating
center. Gateway 86 acts to fetch the`image data from the other
operating center and delivers it to the import/export server 77,
which delivers it to data services 79. Data services 79 stores
the image data on one of its local disk volumes, reclaiming
space if necessary on a least recen~ly used basis, and then
sends the image data to channel server 36. As before, channel
server 36 sends the image data to the subscriber's presentation
player 54.
We now assume for purposes of this illustrative
example, that the subscriber choses to terminate the shopping
session by hanging up the phone. The "hang up" signal comes to
session server 74 via the voice network server 70. The session
server fetches a termination script shell from data services 79,
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Z007259
updates it, and sends it to the subscriber 20 through channel
server 36. In this manner, the subscriber 20 sees a "Thank You
For Shopping~ presentation and then a "Welcome" screen inviting
a new shoppin~ session. The subscriber's personal data records
are sent by the session server 74 to data services 79, where
they are stored for rou~ine processing and later used by the
subscriber 20 when he logs on in the future. Since the shopping
session is now ended, the session server 74 volunteers itself to
the placement agent server 72 for assignment to a subsequent
shopper.
The above overview of the different kinds of servers,
their functions, and specific examples of how they interact with
each other serves to illustrate how the environment of an
"electronic mall" may be established on the digital interactive
system of this invention. Since the environment is established
within a distributed processing architecture, as embodied in the
use of a plurality of identical single-board computers, the
digital interactive system of the present invention may easily
adapt to changing demands by dynamically reallocating its
resources. Further, the system may easily grow in
functionality, and may be expanded to service new geographical
areas, by the simple incremental addition of new single board
computers and the formation of new LOC's, as required.
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INTRA-LOC COMMUNICATIONS ARCHITECTURE
As described above, the basic hardware structure of a local
operating center 24 (LOC), is comprised of a plurality of single
board computers (SBC's) which are installed in standard 20 slot
chassis. These SBC's run various processes or servers, which
comprise the software functionalities of the system.
FIGS. 6(A), (B) and (C) illustrate a typical arrangement of
equipment cabinets containing chassis and other peripheral
equipment for a "small" local operating center which can serve
upwards of 500 concurrent subscribers~
As shown in FIGS. 6(A), (B) and (C) the chassis of
single-board computers which make up the session servers, volume
managers, voice network servers (VNS), channel servers, and all
other function servers, along with sufficient spares, are
mounted into six standard equipment cabinets 60-65. These
cabinets generally provide appropriate power supplies and
cooling equipment for the chassis. Disk drives are distributed,
as shown, among the equipment cabinets which house the volume
managers. The local operating center shown in FIG. 6(A) contain
two gateways (the equivalent to gateway 86 in FIG. 5). Gateway
66 on equipment cabinet 60 provides a link to the client site
operations of the commercial clients who have presentations on
the system, whereas gateway 67 on equipment cabinet 63 is the
communications link to other local operating centers and
regional operating centers of the digital interactive system.
Equipment cabinets 64 and 65, which house the channel
servers 68 and 69 and the VNS servers 58 and 59, also house
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peripheral equipment consisting of modems, multiplexers and
modulators. The output of the modulators goes to a transmitter
56 for transmission to the headend facilities of the CATV
companies to which the local operating center is connected.
Multiplexer-Modulator 57 obtains stream data from external
audio/video sources, and multiplexes this stream data, for
reasons which will be explained with more particularity below,
with the data which is internally present within the database of
the local operatin~ center. Communications between single board
computers on the same chassis is performed via an industry
standard Multibus II protocol, as provided on the common
backplane of each chassis into which the SBC's are connected.
Communications servers are allocated to SBC's marked "COM" in
FIGS. 6(A), (B) and (C), and are connected to each other via a
plurality of SCSI buses. The particular scheme by which the
individual chassis are interconnected to each other by these
buses to establish a communications network within the LOC is
described more fully in this section.
Communications within the local operating center must
satisfy performance criteria which relate to the functional
scope and size of the LOC. For example, a typical LOC of the
digital interactive system of this invention must be able to
support approximately 100 chassis, with sixteen channel servers,
in order to sustain as many as three thousand concurrently
active subscribers. It is desirable that the communications
architecture be implemented in such a way that only a small
number of SBC's need to function as communications servers.
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Further, in order to provide high data throughput while
maintaining low latency, particularly along the high volume
pathways between the volume managers and the channel servers, it
is important that the architecture provide communications
between any SBC on any chassis, in a manner which requires a
minimum number of intermediate hops to move data to any point
within the system. In this context, a hop designates a transfer
of data between two chassis (along a SCSI bus). The intra-LOC
communications architecture must also satisfy a number of
practical requirements related to system cost and effectiveness,
which translate into an implementation having a low number of
cables and connectors, good reliability and resulting in
efficient utilization of all data pathways.
An intra-LOC communications architecture which
satisfies the above requirements is shown in FIGS. 7-9. The
connection scheme utilizes the industry standard Small Computer
Systems Interface (SCSI). Since this is an industry standard
interface, several inexpensive integrated circuits are
commercially available to perform the required interface
functions. A SCSI data bus can support a maximum of eight SCSI
interfaces, and can transmit data at a maximum rate of four
megabits per second. FIG. 7 shows a typical scheme for
redundantly interconnecting 232 chassis, such that the transfer
of data between any single board computer on any chassis
requires no more than three intermediate hops. More
particularly, and with reference to FIG. 7, the 232 chassis are
shown arranged in four main stacks, denoted by reference
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numerals Sl-S4. Each of these stacks contains eight columns of
chassis, denoted by reference numerals Cl-C8. Each column of
chassis comprises seven individual chassis denoted by row
designations Rl-R7. Eight individual chassis comprise row O
(RO). Thus, FIG. 7 schematically represents 8x7x4~8 = 232
chassis.
As shown in FIG. 7, two SCSI buses 88 and 89 connect
the chassis in the column Cl of stack Sl, to chassis 90 and 91
in row 0. Although not explicitly shown in FIG. 7, each of the
other columns (C2-C8) within stack Sl also have two SCSI buses
which connect to chassis 90 and 91 of row 0. The eight
terminals on each of the SCSI buses terminate on single board
computers which act as communication servers. The parallel
communication pathways provided by the two SCSI buses on each
column of chassis increases the ove~all transmission speed of
the system, and provides for redundancy in the event that one of
these buses should fail. Moreover, even if one communication
server on a chassis is out of order, a data pathway is still
available through the second communications server which
communicates with the other SCSI bus. The columns Cl-C8 of
stacks S2, S3 and S4 are similarly connected, via two redundant
SCSI buses, to corresponding chassis within row O; For example,
each of the columns within stack S2 connect via two SCSI buses
to chassis 92 and 93 of row 0, each of the columns within stack
S3 connect via two SCSI buses to chassis 94 and 95 of row 0, and
each of the columns within stack S4 connect, as shown, via two
SCSI buses to chassis 96 and 97 of row 0. To complete the
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intra-LOC communications sys~em, a preferred embodiment of the
present invention provides that each chassis in row 0 is
connected by a separate point-to-point, two terminal SCSI bus to
each of the other chassis in row 0. As before the SCSI bus
terminations connect to SBC's which function as communications
servers. For purposes of clarity, the complete connection
scheme is only partially shown in FIG. 7 with respect to the
leftmost chassis 90 in row 0.
A study of FIG. 7 indicates that communications to
channel servers may be optimized, if the channel servers reside
in row 0. This is because data from any single-board computer
on any chassis in the system requires at most two hops to be
routed to any single board computer in row 0. One hop is
required to move down to a particular chassis in row 0 from
anywhere in the system, and a second hop is required, as a
result of the point-to-point connections between each chassis in
row 0, to move from one particular chassis of row 0 to any other
within row 0. Thus, since latency of data transmissions is
reduced by minimizing the number of hops, and because latency is
a particular problem during transmission of large data objects,
it is desirable to have the channel servers located within the
chassis of row 0. Further inspection of FIG. 7 also illustrates
that, at worst, three hops are required to move data from any
single board computer within the LOC to any other, i.e. two hops
to move to any chassis within row 0, and a third hop to move up
to a particular column within a stack.
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All the SCSI buses connect to single-board computers
which function as communications servers. These servers perform
the routing of data between chassis. As part of the operating
system which implements the application program environment
(APE), every process contains information identifying the
particular chassis number where it resides. This chassis number
identification is transmitted via the Multibus II backplane to
communication servers resident on the chassis. Each communica~
tion server knows the number of the chassis in which it resides,
and to which chassis numbers it can deliver data. This
information is stored within a routing table at each communica-
tion server. When a data message is to be transmitted, the
operating system first tries to deliver the message via the
Multibus II backplane to other single-board computers on the
chassis. If these single-board computers are not the designated
recipients of the message, the communication server that is
resident within the chassis checks its routing table, and sees
what other chassis it can deliver to. The data message is then
placed on the SCSI bus attached to the communication server, and
is transmitted to another chassis. Upon arrival of the data at
the next chassis, the operating system again tries to deliver
the message to single board computers within that chassis, and
if it fails, a communication server places the message once more
onto a SCSI bus for delivery to another chassis. This procedure
is repeated until the message arrives at a particular chassis
number which contains the .single board computer that is the
designated recipient of the message. As shown above, the
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interconnect architecture disclosed herein requires no more thanthree hops (excursions along a SCSI bus pathway), before a
recipient anywhere within the system acquires the message.
FIG. 8 illustrates how this particular interconnect
scheme can be expanded to provide intra-LOC co~munications
capability between as many as 456 chassis, with no more than
three hops between any two particular chassis. In FIG. 8, there
are eight stacks Sl-S8, each of which comprises eight columns
Cl-C8 of chassis. Each column contains seven chassis. as
denoted by rows Rl-R7. Row 0 contains eight individual
chassis. In FIG. 8, the redundant connections present in FIG. 7
have been removed, and replaced with a single SCSI bus which
connects each of the eight columns Cl-C8 in each of the eight
stacks Sl-S8, to each of eight chassis in row 0 which perform
the exchange of information between different stacks. As in
FIG. 7, each chassis in row 0 is further connected to every
other chassis in row 0 by a point-to-point, two-terminal SCSI
bus.
Accordingly, and as described above, no more than two
hops are required to move data from any other function server
which resides anywhere in the system, to a designated chassis in
row 0. To reduce latency, it is therefore desirable that the
channel servers or any other very active functions be placed
within row 0. This is important because transmission of data
from the volume managers to the channel servers represents the
major transmission path and load on the system. Further, and as
illustrated with respect to FIG. 7, FTG. 8 similarly ensures
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that no more than three hops occur in communicating data from
any single-board computer within the 456 chassis, to any other.
As illustrated in FIG. 8, the particular intra-LOC
communication architecture scheme of the present invention may
be applied to a large number of chassis. A typical local
operating center for the digital interactive multimedia
presentation and communication system is generally required to
service up to three thousand concurrent subscribers. FIG. 9
shows the chassis requirement for an LOC of this size. With
reference to FIG. 9, the functionality required by the volume
managers is distributed among 14 chassis which are schematically
depicted as being placed within two columns 104 and 106. Other
function servers are distributed among 84 chassis which are
schematically depicted as positioned within the other 12 columns
shown in FIG. 9. Each column in FIG. 9 contains seven chassis.
Two interchange chassis 100 and 102, are also shown which
preferably house the single board computers that provide channel
server functions. For an LOC of this size, which generally
comprises 16 channel servers, each of the interchange chassis
100 and 102 may be configured to house eight channel servers.
In order to provide the LOC with the high throughput
necessary for transmission of data between the volume managers
and channel servers, the two columns which represent the volume
manager locations are each provided with four SCSI buses. To
provide redundancy for purposes of fault tolerance, the SCSI
buses from each of the two columns 104 and 106 of volume
managers are split and connected to each of the two interchange
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chassis 100 and 1~2 which contain the channel servers. Further,
each of the 12 columns which house various function servers have
a single SCSI bus which connects to one of the interchange
chassis 100 and 102. Six of the function server chassis columns
connect to interchange chassis 100, and the other six to
interchange chassis 102. To complete the intra-LOC communica-
tions architecture, the two interchange chassis are connected to
each other with a single point-to-point SCSI bus. Thus, each
interchange chassis 100, 102 has six SCSI buses connected to six
columns of function servers, four SCSI buses which connect the
two columns of volume managers, and a single SCSI bus which
provides communications between the two interconnect chassis
100, 102. The total of eleven SCSI buses entering each of the
interconnect chassis 100, 102 are connected to the same number
of communications servers resident on each of the interchange
chassis 100, 102. In the preferred embodiment of this intra-LOC
communications architecture, the remaining space on each
interchange chassis is allocated to 8 channel servers.
As described with respect to the general interconnect
architecture schematically illustrated in FIGS. 7 and 8, the
more specific architecture of a typical LOC illustrated in FIG.
9 also ensures that there are at most two hops required to move
data from any particular single-board computer which serves as
volume manager to a channel server resident on one of the two
interconnect chassis. Further, any single-board computer
located on any chassis in the system can communicate with any
other single-board computer within the system by utilizing at
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most three hops for data transmission. In addition to
satisfying system requirements related to latency and data
throughput, the particular interconnect schemes illustrated in
FIG. 7-9, wherein the SCSI interface provides buses which employ
eight terminal connections in combination with buses which
provide specific point-to-point two terminal connections, result
in a communications architecture which is easily expanded, which
can be implemented with a low number of cables, connectors, and
communication seryers, and which results in good utilization of
all the data pathways.
THE DISTRIBUTION CHANNEL FRAMING TEC~NIQUE
The distribution channels on which data are
transmitted to the presentation players are standard 6 megahertz
wide CATV channels whose base frequencies are often outside the
normal subscriber tuning range and which conform to appropriate
NTSC and FCC requirements. In the prior art technology
described in U.S. Patent No. 4,734,764, for each display channel
allocated by the CATV company for viewing presentations, two
distribution channels must be allocated to carry the signals
from the prior art system to the frame store units distributed
in the field. One channel is dedicated to the transmission of
analog audio signals, and the second to the transmission of
analog video signals. In the digital interactive multimedia
presentation and communications system of the present invention,
all information necessary to serve a subscriber is carried on a
single distribution channel in digital form. Peripherals
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associated with the channel servers that are resident in the LOC
modulate the digital data onto the distribution channel at a
rate of up to 24 megabits per second (including forward error
correction ~FEC) code).
FIG. 10 illustrates the typical data flow sequence
along a distribution channel which connects a channel server to
a presentation player. The channel server acquires variable
length blocks of data which may comprise digital representations
of video images, audio accompaniment, graphics overlays, various
scripts necessary to construct presentations, small packets of
echo characters, software updates sent to particular
presentation players, etc. As such, the channel server
constitutes a source of block data 160.
Other sources of data which the local operating system
supplies, and which of necessity ~ust be distributed in a
continuous fashion, are denoted in FIG. 10 by the stream data
sources 164. These stream data sources may provide a number of
different types of background music which the commercial client
can select when he prepares the scripts for his presentations,
or may include ticker tape information to display stock market
reports, provide sports scores, weather announcements, etc.
This type of information would be displayed in continuous
fashion across a small portion of the television screen during
the shopping presentations. Thus, the stream sources 164, by
their continuous nature, are distinct from the block data
sources 160, which are generally stored on the disk drives of
the LO~. Moreover, by providing the ability to transmit stream
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data sources 164, the digital interactive multimedia presenta-
tion and communications system of the present invention can
provide real-time motion video to a subscriber.
The digital interactive system disclosed herein can
support two different kinds of motion video. The first kind of
motion may be termed "fixed motion sequences". For example, a
commercial client may wish to provide several views when
displaying a particular shopping item. In some cases, the
commercial client may find it desirable to display a shopping
item which rotates so that the viewer may see all sides. These
kinds of predetermined "fixed motion sequences" do not have to
be transmitted in real-time, and are treated in a manner similar
to that of still-video presentations. During initial production
of the presentation by the store manager, a script is prepared
which specifies the appropriate timing for the sequence of
still-video images to impart the illusion of motion to the
desired "fixed-motion sequence" upon playback. The appropriate
sequence of frames is stored and recalled in the same manner as
still-video images, and is presented as a block of data to the
channel server.
The second kind of motion which can be displayed by
the digital interactive multimedia presentation and
communications system of the present invention is a limited form
of real-time motion which necessitates that it be delivered as a
stream data source 164. This kind of motion may be used when a
bridge is made between the subscriber and a consumer service
representative. When this occurs, an inset in the corner of the
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subscriber's television screen may display the head of the
consumer service representative, so that the subscriber has a
direct visual link with consumer service. Real-time motion
cannot be handled as block data because the buffering
reguirements that would be necessary would produce unacceptable
delays. The consumer service representative would be responding
in normal time over the telephone, but the appearance on the
screen would be delayed by several hundred milliseconds if
buffering were necessary. This type of data must be handled by
the system as "stream" data which is brought into the system on
separate stream channels and distributed in the manner described
herein.
~ s shown in FIG. 10, the channel server acquires the
block data source 160 from the database of the LOC 24 and
transmits the same to a channel multiplexer 162. Stream data
sources 164, which may comprise the above-mentioned real-time
motion, background music, etc., are also input to the channel
multiplexer 162, where they are appropriately combined with the
block sources and passed to a forward error correction (FEC)
encoder 166, which adds the appropriate FEC code. The
multiplexed and FEC-coded data is passed to a modulator 168 and
transmitted via a data link to the CATV headend 169. After
reception by the appropriate presentation player 54, the
sequence of events is reversed. At the presentation player 54,
a demodulator 170 acts to remove the distribution frequency
carrier from the data, forward error correction on the data is
performed by decoder 172 and the block data are separated by a
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channel demultiplexer 174 to produce distinct block data 176 and
stream data 177 which are processed separately by the
presentation player 54.
As shown with more particularity in FIG. 11, each of
the plurality of channel servers 36 resident in an LOC 24
acquires particular block data 160 for distribution. The stream
data, which generally comes from independent sources denoted in
FIG. 11 by A, B, C, are multiplexed onto a single data channel
by source multiplexer 180 and pass sequentially through each of
the individual channel multiplexers 182 which are associated
with each of the channel servers 36. In this way, the
appropriate block data 160 is interspersed with particular
source data for each channel server 36. The combined data is
then passed to the FEC encoders and modulators associated with
each distribution channel.
The particular method used for multiplexing the block
data and stream data to support "real-time" motion displays and
other stream channel usages is schematically illustrated in
FIG. 12. FIG. 12 (a) illustrates the block data channel 192 and
the stream data channel 194, as a function of time. As seen,
the block data channel 192 comprises adjacent blocks of data
having different lengths. Typically the transmission rate of
the block data channel is 18 megabits/sec. Long blocks are
generally data objects which contain compressed video images and
which may range in size from 20 to 80 kilobytes. As nsted
above, these video bloc~s may consist of either individual
still-video frames, or a sequence of still-video frames which,
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when shown with appropriate timing instructions encoded in a
script, will display fixed-motion sequences. Audio data and
graphics overlay information comprise shorter blocks of data.
The shortest blocks of data will generally be script data
objects and data objects representing key press echo characters.
In a preferred embodiment of the present invention,
the stream data channel 194, generally consists of up to 96
independent and physically distinct stream channels which have
been multiplexed onto a single transmission channel. Each of
the 96 stream channels may have real-time motion data,
background audio data, etc. Further, depending upon the video
and audio fidelity required, a particular data source may be
transmitted over more than one physical stream channel
simultaneously. For example, if stream data consists of only
spoken words then one channel may provide a high enough data
rate to ensure appropriate fidelity. On the other hand, FM
quality broadcast may have to be encoded into 4-8 physical
stream channels to provide the appropriate bandwidth.
In a preferred embodiment of the present invention,
the block data channel and 96 possible stream data channels are
time-multiplexed onto a single 24 megabit/sec distribution
channel as shown in FIG. 12(b) and (c). In particular, a 4 KHz
clock provides the timing for producing frame synchronization
(synch) characters at 250 microsecond intervals along the
distribution channel. The position of sequential synch
characters is schematically represented in FIG. 12 by reference
numeral 196. Since the maximum data capacity of the
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distribution channel is 24 megabits/sec, the 4KHz clock permits
6,000 bits to be interspersed in the time interval between two
frame synch characters including all housekeeping data such as
forward error detection and correction. This time-slice of data
is called a "frame". Framing of data in this manner is
typically performed by forward error correction encoders,
because the standard FEC algorithms are generally unable to
efficiently process blocks of data which have varying lengths.
In this invention, the framing technique is also utilized to
multiplex block and stream data channels together in an
appropriately encoded manner.
The particular manner of multiplexing employed by the
digital interactive system of the present invention is further
depicted in FIG. 12(b). Following each frame synch character
(which may occupy 16 bits), is an 8-bit stream control character
denoted by reference numeral 198. The number of stream channels
being transmitted, and the assignment of channels to particular
stream sources is specified by a control channel derived from
the concatenation of these stream control characters 198. Each
of the stream data channels is divided into one-byte increments,
and a single byte of each stream data channel is consecutively
interspersed along each subsequent frame in the space following
the stream control character. For example, after the control
character, frame 1 will contain the first byte 200 of stream
data channel 1, followed by the first byte 202 of stream data
channel 2, etc., until as many as 96 stream data channels are
distributed along the frame. The next byte of data correspond-
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ing to each of the 96 stream data channels is correspondingly
positioned in frame 2 and so on. For example, byte 204
represents the second byte of stream data channel 1, byte 206
represents the second byte of stream data channel 2, etc. After
positioning all the stream data channels in this manner the
remaining space in each frame is sequentially filled with the
block data. If a block is too large to fit within the space of
a single frame, it continues to fill the available space in
succeeding frames, as shown in FIG. 12(b). To complete the
multiplexing scheme, bits required by the forward error
correction (FEC) algorithms are added and dispersed along each
frame as shown in FIG. 12(c).
Since each of the stream data channels has a single
8-bit byte of information interspersed at a 4 KHz frame rate,
this encoding method permits the s.ream data sources to be
distributed at a rate of 32 Kbits/sec per stream channel. A 32
Kbit/sec data rate, although not adequate to support real-time
motion video over a full television screen, is sufficient to
provide a real-time display in a small corner of the screen,
particularly when use is made of available interframe and
intraframe compression techniques.
FIG. 13 shows the components comprising the
distribution channel multiplexer 162, which act to combine the
block data and stream data in the manner illustrated above. As
described, each of the 96 channels of stream data 194 pass
through the mu].tiplexer at a rate of 32 Kbits/sec. Block data
192 is supplied from channel server 36.
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With particular reference to FI~. 13, clock controller
118 receives a 20 megabit/sec clock from FEC encoder 166 and
genera~es a 4 KHz frame clock. A bit clock of approximately
17-18 megabit~/sec is output from the clock controller 118 to
channel server 36 on line 99. This clock controls the clocking
of block data bits into a data buffer 110 which is one frame
(6,000 bits). Stream control information is transmitted to the
multiplexer controller 112 from the channel server 36 along line
1~4. The stream control information defines how many stream
channels are presently active on the system, and identifies the
type of stream source which is available on each of the active
stream channels ~e.g. country-western music, motion-video for a
particular subscriber, etc.). In addition, the control channel
information on line 114 also defines which particular stream
data channels are to be selected for combining with the block
data. This information is transmitted to the time slot selector
98 which comprises a data buffer.
As the stream data moves through the channel
multiplexer, it i5 loaded into an input buffer 116. When the
time slot selector 98 in response to information supplied by the
stream control channel, recognizes that the data in the input
buffer 116 is stream data which is to be distributed along the
distribution channel supported by channel server 36, it acquires
the data from the input buffer 116. The time slot selector 98
is a data buffer which, based upon information received from the
multiplexer controller 112 holds the data until the particular
time slot allocated to this particular stream channel is ready
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to be filled in data buffer 110. Under control of multiplexer
controller 112, and the timing information obtained from clock
controller 118, the time slot selector 98 inserts the stream
data 177 into the appropriate time slot of data buffer 110 which
corresponds to a particular stream channel. After all the
stream data has been properly positioned within the single frame
data buffer 110, the channel server 36, under control of the bit
clock transmitted along line 99, fills the remaining space of
data buffer 110 with block data 176. When data buffer 110 is
full, the data which it contains, i.e. the block data 176 and
stream data 177, and which is appropriately multiplexed
according to the format shown in FIG. 12~b), is output to the
forward error correction encoder 166, where error correction
bits are added to the data. Forward error correction encoder
166 transmits the fully formatted and multiplexed data to
modulator 168, where it is modulated at the rate of 24
megabits/sec onto a base frequency for transmission to the CATV
headend.
By virtue of this particular multiplexing scheme, in
which block data 176 and stream data 177 are combined, the
interactive digital system of the present invention makes it
possible to transmit block data 176, comprising video images,
audio, control data in the form of scripts, etc., in combination
with stream data 177 which provides for real time motion video,
background music, etc., to the CATV headend on a single
distribution channel.
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THE PRESENTATION PLAYER
Referring to FIG. 2, upon receipt of the multiplexed
and baseband modulated data from a particular channel server 36
of the local operating center 24, the CATV headend 38 upconverts
the data and places it onto one of the distribution frequencies
which have been allocated to the digital interactive system.
The CATV headend 38 transmits this data throughout its cable
network on that distribution frequency. Generally, the
distribution frequency is outside of the normal tuning band
which is accessible to subscribers of the cable service. In
order to convert the digital data into a presentation which is
compatible with the standard television signal format, and
perform the routing of the presentation to the subscriber who
has requested it, a plurality of field devices known as
presentation players 54 are distributed throughout the
geographical area ser~iced by the cable company.
As outlined above, the presentation player 54 is a
device that captures, stores and expands digital data which is
transmitted to it in order to produce a final product
presentation which it then transmits to the particular
subscriber who has requested the information via his Touch-Tone
telephone 42. As shown in FIG. 2, the presentation player is
mounted parallel to a secondary distribution feeder line 50, so
that in the event of failure, other signals on the feeder line
will not be affected. As further shown in FIG. 2,
presentation player 54 is typically positioned adjacent to a
bridge amplifier 48 of the cable distribution system, and is
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connected via the secondary distribution feeder line 50 to
approximately forty drop lines 52 which qo to individual
subscribers. A presentation player may also be connected across
more than one feeder line.
The presentation players 54 monitor all the CATV
distribution frequencies that are being transmitted and lock in
on the particular distribution frequency which is transmitting
data for the digital interactive multimedia presentation and
communications system. Each presentation player has a unique
identification code in the form of a digital address. The
presentation players 54 select for further processing only that
data which is addressed to them. Each presentation player 54
then converts the data that is destined to a particular
subscriber along its line, produces a finished presentation, and
transmits the finished presentation on the correct display
channel frequency which the subscriber is viewing.
Referring to FIG. 14, in a preferred embodiment, the
presentation player 54 incorporates at least one and as many as
eight subscriber servers 120. Each subscriber server 120 is
shared amongst a small group of subscribers serviced by the
feeder line 50 to which it is connected. Once the shopping
session is in progress, the subscriber server 120 is devoted to
a single subscriber on that particular secondary distribution
feeder line 50, who has captured it on a contention basis. If
the subscriber server 120 is busy with a shopper, the second and
subsequent would-be shoppers on that distribution feeder line 50
who view the first shopper's display channel will see the
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presentations that are transmitted to the active shopper, but
will not be able to participate. If more than one display
frequency is available to the system, then several subscriber
servers 120 may be simultaneously transmitting along the same
feeder line, with each one broadcasting on a different display
channel frequency to service different active subscribers. A
presentation player s4 may also be connected to as many as four
separate feeder lines 50 which emanate from a bridge amplifier
48. Each feeder line may have several subscriber servers 120
connected to it which broadcast on different display
frequencies. Subscriber servers 120 which are connected to
separate feeder lines may broadcast on the same display
frequency to different active subscribers, since this
arrangement does not result in any interference. However, when
a subscriber has captured the use of a particular subscriber
server 120, no other subscriber may use it.
As shown in FIG. 14, in addition to the plurality of
subscriber servers 120, each presentation player 54 includes a
presentation player converter 122 and a transponder 124. The
function of presentation player converter 122 is to locate, tune
to, and demodulate the distribution channel frequency provided
by the CATV headend 3~, The demodulated, but still multiplexed
data is transferred along the subscriber server bus 125 to the
subscriber servers for further processing. In broad terms, the
presentation player converter 122 selects the correct
distribution channel frequency, demodulates the signal received
on that channel to form a digital stream appropriate for local
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processing by the subscriber servers 120, and performs forward
error correction.
The transponder 124 obtains and stores diagnostic
information relating to the status and activity of all the
components within the presentation player 54, and transmits this
information upon command to field service vehicles which travel
through the ~ervice area.
FIG. 15 illustrates with more particularity, the basic
components which comprise the presentation player converter
122. Referring to FIG. 15, one of the elemen~s of the
presentation player converter 122 is a broadband frequency agile
receiver 130. It is capable of being cycled through the CATV
frequency spectrum by the converter controller 132 so that it
sequentially receives all of the distribution channel
frequencies which are being transmitted by the CATV headend 38
down the secondary distribution feeder line 50. The digital
interactive multimedia presentation and communications system
will be allocated at least one but possibly several distribution
frequencies. The frequency agile receiver 130 receives the
incoming RF signal which is modulated with digital data. In
conventional fashion, the frequency agile receiver 130 outputs
an intermediate frequency (IF) to demodulator 134. The
demodulated data is passed on in serial fashion to the forward
error correction processor 136. The demodulated and error
corrected data is then placed onto the subscriber server bus 125
which connects to the converter controller 132, and to the
plurality of subscriber servers 120 in the presentation player
54.
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The converter controller 132 controls the overall
functions within the converter 122. As shown in more detail in
FIG. 16, the converter controller 132 has a central processing
unit (CPU) 200 which communicates with read-only memory (ROM)
200, random access memory (RAM) 201, and electri~ally-erasable
programmable read only memory (EEPROM) 204. The ROM 201
generally contains the start-up program routines, whereas the
R~M stores the operating and diagnostic programs as well as
diagnostic- data collected about the components of the
presentation player 54 for transmission upon command via the
transponder 124 to personnel in field service vehicles. The CPU
200 responds to incoming data on the bus 125, and through
peripheral interface adapters 206 and 208 sends output signals
which control the frequency agile receiver 130 and the
transponder 124.
The converter controller 132 is able to cycle the
frequency agile receiver 130 through the appropriate CATV
frequency spectrum until it finds distribution frequency which
is transmitting digital data in the format established by the
digital interactive system of the present invention. A
distribution channel with corresponding frequency is selected
according to a procedure described below. The distribution
frequency is stored in the EEPROM memory 204 so that this
information can survive power failures and be used in a power
resumption sequence to re-lock the frequency agile receiver 130
onto the proper distribution frequency, without the necessity of
once again cycling through all possible distribution
frequencies. The converter controller 132 also stores within
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its EEPROM memory 204 information which designates the
distribution channel that has been assigned to that particular
presentation player 5~. This information uniquely identifies
the channel s~rver 36 (FIG. 2) within the digital interactive
system which services that particular presentation player 54.
It further stores within the address switches 210 the
identifying number of the presentation player 54. The
identifying slot number for the subscriber servers is included
as part of the presentation player identification.
The converter controller 132 can perform extensive
diagnostics on itself and the devices that it controls, and
report fault conditions and other traffic and status information
to the transponder 124. New program logic which is occasionally
distributed from the local operating center for the purpose of
reprogramming the presentation players, is also received, stored
in RAM 201, and acted upon by the converter controller 132.
As each distribution channel is transmitted from a
channel server 36 to the CATV headend 38, certain information
comprising a channel status message is periodically inserted
into the stream of digital data. Typically this channel status
message is transmitted every ten seconds as block data. The
format of the channel status message is illustrated in FIG. 17.
With reference to FIG. 17, the first data blo~k 310 in the
channel status message after a message identifier 300 represents
data which identifies the particular channel server 36 that is
transmitting the status message, and the number associated with
its distribution channel. The next data block 320 is a channel
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availability message, which indicates whether the distribution
channel has sufficient capacity to service additional
presentation players 54. The identification of the particular
CATV company (or companies) serving that particular feeder cable
is given in the next data block 330. This is followed by a list
of display channel numbers that are allocated to the digital
interactive system. As shown in the exploded portion of
FIG. 17, the list of display channels for each CATV company
provides a display channel number, and a corresponding telephone
number to call when logging onto the digital interactive system
from that display channel. The identification numbers of those
subscriber servers 120 which can service a particular display
channel are also supplied in the channel status message. In the
exzmple shown in FIG. 17, the odd numbered subscriber servers
are allocated one display channel, `while the even numbered
subscriber servers transmit on a second display channel. Other
arrangements may also be envisioned for allocating subscriber
servers 120 to particular display channels.
A new presentation player 54, when first installed in
the field, has a table stored in the ROM of its converter
controller 132, which lists all standard CATV distribution
frequencies. When a presentation player is powered up for the
first time, the converter controller 132 begins to cycle the
frequency agile receiver 130 through all of the possible
distribution CATV frequencies. The corresponding signals are
sent to the demodulator 134, which in turn transmits the
demodulated signals to the FEC processor 136 and along bus 125
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to the converter controller 132. As the broadband receiver 130
is automatically stepped through each of the possible
distribution frequencies, the demodulator 134 attempts to
demodulate the data. If unsuccessful, the receiver 130 is
stepped to the next possible CATV frequency, and so on, until
the receiver 130 finds a frequency which can be properly
demodulated and which therefore corresponds to a distribution
channel for the digital interactive system.
When a distribution channel is found, the channel
status message that is transmitted along that channel at regular
intervals is examined to see whether additional presentation
players are being accepted. If the channel availability message
indicates the additional traffic is being accepted, that
distribution channel's ID number and the frequency at which it
is transmitting are stored in the converter controller's
electrically erasable programmable read only memory (EEPROM)
204. Until otherwise instructed, the presentation player
automatically adopts this distribution channel and frequency for
all subsequent communications. Since the distribution channel's
ID number and distribution frequency are stored in the EEPROM
204, this information is preserved in the event of a power
failure, and upon resumption of operation, the presentation
player will immediately tune itself to that particular frequency
and wait to see if this frequency still contains the correct
distribution channel identifier 310 value as stored in EEPROM
204. If not, a new distribution channel will be found as
described above. In this manner, converter controller 132
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,
ensures that the presentation player 54 finds a distribution
frequency which corresponds to a distribution channel having
excess capacity, and adopts that frequency and channel for all
future transmissions.
When a subscriber logs onto the system for the first
time, the "attractor" screen he sees on his television set
contains information which identifies the subscriber's
presentation player 54, the distribution channel serving the
subscriber's presentation player, and the subscriber's CATV
cable company. Before the subscriber can use the system's
services, he is requested to key in this information via his
Touch-Tone telephone. In this manner, the system learns the
identity of the distribution channel (i.e. channel server), the
presentation player 54 and the subscriber server(s) 120 which
can communicate with that particular s~bscriber.
The present invention further anticipates that the
digital interactive multimedia presentation and communications
system will adopt a policy that if, after a fixed period of
time, a presentation player 54 is not receiving information over
its s01ected distribution channel frequency, the presentation
player 54 will select a new distribution channel frequency in
the ma~ner described above. Further, the digital interactive
system has the capability of transmitting new software through
the distribution channel to converter con~roller 132, thereby
reprogramming the converter controller 132 in the field. In
this fashion, the procedure for selecting a distribution channel
frequency may be changed by the LOC 24. For example, if a
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decision by a CATV cable company results in the distribution
channel frequencies being changed, a message may be transmitted
advising presentation players using "channel 2", for example, to
tune to "channcl 4" for all future communications with the LOC.
Still other means of distribution channel frequency selection
could be provided by the LOC individually advising each
presentation player 54 as to which distribution channel it is to
use.
Each of the plurality of subscriber servers 120 in the
presentation player 54 monitor the digital information which is
being transmitted down the subscriber server bus 125, and
receives and stores data which is addressed to its particular
identification number or address. As described previously, the
data that is being transmitted to the subscriber server 120
generally includes digital representations of audio, video
images, and scripts which define the makeup and timing of
presentations. In particular, these scripts determine when and
for what period of time the subscriber server 120 will transmit
the particular audio and video images which comprise a
presentation to the subscriber and also which graphics
information (such as characters in a given font, color or size)
will be overlaid upon the video images.
FIG. 18 shows the major components which comprise a
subscriber server 120. In accordance with a preferred
embodiment of the present invention, the subscriber server 120,
upon receipt of data which is addressed to its particular
identification number, utilizes its central processor unit (CPU)
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400 to demultiplex the incoming data into separate block data
and stream channel data. Accordingly, the CPU 400 acts as the
channel demultiplexer 174 (FIG. 10~ All of the demultiplexed
data is appropriately labeled and stored within the RAM 410 of
the subscriber server 120. ROM 430 provides permanent storage
for initialization programs. In order to perform the
demultiplexing function, the CPU 400 looks at each frame of
incoming multiplexed data, and reads the first byte, which
represents the stream control channel. In combination with
information which it acquires from the script, the CPU 400 has
sufficient information to perform the demultiplexing function.
More specifically, stream data which is always
available on a general basis within the system, such as various
kinds of background music, may be requested through a script.
For example, the script may call for country and western music
to be played as background during a particular presentation.
The stream control channel will tell the subscriber server 120
that country and western music is being broadcast, for example,
on stream channels 1, 2 and 3. Stream data channels which are
designated to go to a specific subscriber, such as real time
motion or stock market quotes, will also be designated and
allocated to a particular subscriber by information in a
script. Thus, by combining information from the script, with
that broadcast on the stream control channel, the CPU 400 knows
which physical stream channels are particularly destined to the
subscriber it is currently serving.
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By properly clocking each frame, the CPU 400 selects
those particular stream channels and stores them in RAM 410. By
reading the stream control channel, the CPU 400 further
identifies how many stream data channels are being distributed
at any time, and can therefore calculate where the block data
begins. The CPU 400 proceeds to read the appropriate block data
into other locations within the RAM 410. At the beginning of
each block of data is a descriptor which designate the length of
the particular block. This information allows the CPU 400 to
properly concatenate and reconstruct the individual block data
objects which were parsed during the multiplexing process into
different frames. In this manner, the CPU 400 acts to
demultiplex the incoming data from the subscriber server bus
125, and causes the separated block and stream data to be stored
in properly identified locations within RAM 410.
In broad terms, the further processing of the
demultiplexed data by the subscriber server 120 includes the
expansion and conversion of the compressed digital audio and
video image data into a standard television signal format, and
the transmission of this information according to the script
along a display channel to which the subscriber is tuned.
Referring to FIG. 18, the CPU 400 determines which of
the information it has received is a script, and then uses the
script to control audio processor 412 and image processor 414
which expand the audio and video data respectively. The digital
audio processor 412 decompresses the audio data. After passing
through a data buffer 416, the expanded audio data is passed to
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digital to analog converter 418 and then to a video modulator
420 where the audio data is placed into an NTSC or other
standard television signal format. The digital image processor
414, in addition to being able to expand a previously compressed
video image, includes a graphics overlay capability. The
expanded video image is then passed to a frame buffer 422, from
which it is input to a digital to analog converter 424. The
analog video output of the digital to analog converter 424 is
combined with the audio signals in video modulator 420, to
produce the NTSC or other standard baseband TV signal. The CPU
400 within the subscriber server 120 noiifies a frequency agile
transmitter 426 of the appropriate display frequency, and the
baseband signal is upconverted by the frequency agile
transmitter 426 to that display frequency. The presentation is
then transmitted along the feeder line 50 to the particular
subscriber who has requested the information and to all other
cable subscribers served by that feeder. Accordingly it is
through presentation player 54 that the requested presentations
are transmitted on pre-assigned display frequencies to
particular subscribers.
Devices to perform the expansion and digital to analog
conversion are commercially available from companies such as
Texas Instruments (Model No. TMS320C25) or from RCA Laboratories
Digital Video Interactive (DVI~, VDPl and VDP2. Transmitting
devices are readily available and are common parts in commercial
VCR's.
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Attached externally to each subscriber server 120 is a
standard four-bit manually setable switch (not shown). When
presentation player 54 is installed within a CATV cable system,
this four-bit switch is set to a predetermined number which
designates the particular CATV cable system in which it is to be
installed. The designation of the CATV cable system is
transmitted from subscriber server 120 and appears on the first
screen viewed by the subscriber when he tunes to the digital
interactive multimedia presentation and communications system.
As previously discussed, other relevant information about the
subscriber and the presentation player servicing the subscriber
is also present on this first screen. Upon request from the
system during the initial logon procedure, the number
designating the subscriber's CATV cable system is entered via
the Touch-Tone keypad, and transmitted to the LOC of the system
along with this other relevant information.
In an alternative embodiment of this invention, a
television set-top presentation player which services a single
subscriber may be implemented. The set-top player may be
integrated with the converter appliance generally supplied by
the CATV company when the initial cable connection is made.
Whereas presentation players which are field resident serve many
subscribers who contend for their use in party line fashion, the
set-top player is designed to serve only one subscriber and
therefore requires only one subscriber server. Since the
set-top player is designed for indoor use, the environmental and
power consumption requirements are different from those for the
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field resident presentation players. However, in all other
respects the set-top presentation player functions in the same
way as the presentation players which are resident in the field.
A fault reporter is prsvided within the presentation
player, and comprises a subsystem which receives and stores
status information from various parts of the presentation
player, and then transmits these messages upon command. The
communications medium for the fault reporter is a transponder,
which is designed to transmit its diagnostic information to a
service vehicle that requests and receives these transmissions.
The diagnostic data would be interpreted by equipment within the
service vehicle. Alternatively, the fault reporter may be a
software device distributed between the converter controller and
the subscriber servers whose function is to report some faults
immediately to the subscriber, and to store other fault
indicators for transmission to the field service vehicle upon
demand.
Although illustrative embodiments of the present
invention have been described in detail with reference to the
accompanying drawings, it is to be understood ~hat the invention
is not limited to these precise embodiments. The presently
preferred embodiments are to be considered as merely
illustrative and not restrictive and a latitude of
modifications, changes and substitutions is intended to be
encompassed by the foregoing disclosure. The scope and spirit
of this invention, as recited in the following claims, embraces
all such modifications, changes, and substitutions which come
within the meaning and range of equivalence of the claims.
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