Note: Descriptions are shown in the official language in which they were submitted.
CA 02566416 2006-11-01
WO 2005/120069 PCT/US2005/018557
IN-FLIGHT ENTERTAINMENT SYSTEM WITH
WIRELESS COMMUNICATION AMONG COMPONENTS
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS
[0001] This patent application is a continuation-in-part of U.S. Patent
Application
No. 10/145,464, pending, and further claims the benefit of U.S. Provisional
Patent
Application No. 60/574,873 filed May 27, 2004.
BACKGROUND
[0002] The present invention is generally directed toward wireless
communication
over a network, and, more particularly, to a reduced-architecture in-flight
entertainment
(IFE) system providing wireless comiectivity.
[0003] Many commercial aircraft today are equipped with an IFE system. In-
flight
entertainment systems are known for providing audio and/or video presentations
and other
services to passengers on board an aircraft.
[0004] A known type of IFE system generally comprises a reduced-architecture
network of computer components, including one or more server units, processor
units,
input devices, and display devices installed throughout the aircraft. Such an
IFE systein
can be configured to utilize network commands to perform traditional passenger
functions,
such actuation of audio volume control, reading lights, and flight attendant
call indicator.
Some IFE systems offer additional functionality such as individual passenger
video
displays and a variety of entertainment offerings.
[0005] Conventional IFE systems include a plurality of display units mounted
for
passenger viewing. Display units are commonly mounted in seat backs, facing
the
passengers in the row behind. Display units may also be mounted overhead or on
seat
arms. A cable to carry a video signal extends to the display unit from a port
on the IFE,
and wiring is also provided to deliver power to the display unit.
[0006] Weight minimization is a priority for aircraft components. Known
reduced-
architecture IFE systems have allowed a weight savings over earlier systems by
providing
an onboard network backbone to carry signals previously communicated over a
plurality
of cables to respective individual components. Further weight reduction
remains desirable
in view of the constant effort to improve aircraft performance and efficiency.
A need
exists for an IFE system that can provide improved performance and lower the
cost of use,
manufacture, and/or installation.
CA 02566416 2006-11-01
WO 2005/120069 PCT/US2005/018557
SUMMARY
[0007] The present invention provides an IFE system that includes display
devices
equipped to receive a signal via a wireless data transmission. The display
devices are
mounted for viewing by passengers, such as to seat backs or arm rests. The
wireless
configuration eliminates a need for a cable to deliver the signal to the
display from the
network backbone, advantageously providing a weight savings. Moreover, the
eliminated
wiring results in easier installation.
[0008] The signal transmitted wirelessly to the IFE display contains at least
video
data. In an embodiment, the IFE display is further equipped with an audio
player, in
which case the signal contains audio or coinbined audio/video data. In an
embodiinent,
the IFE systein is provided with a server that stores and dispenses files of
audio and/or
video entertainment offerings.
[0009] According to an aspect of the invention, in order to prevent
unauthorized use
of the wireless IFE signal, the IFE system utilizes an encryption system. The
transmitted
signal is in a securely encoded, non-standard format. Authorized playback
devices are
provided with a decryption means, thereby facilitating proper playing of the
wireless
signal at the device. Without the decryption means, unauthorized devices would
not be
able to play the signal. In an embodiment, the decryption means may be a
corresponding
decryption key that can be transmitted to authorized devices.
[0010] Additional features and advantages of the present invention are
described in,
and will be apparent from, the description, figures, and claims herein.
2
CA 02566416 2006-11-01
WO 2005/120069 PCT/US2005/018557
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Certain embodiments of the present invention will be described with
reference to the following drawings, wherein:
[0012] FIG. 1 is a schematic architecture diagrani illustrating an embodinlent
of a
wirelessly networked IFE system;
[0013] FIG. 2 is a control flow diagram illustrating an embodiment of a
process for
establishing a communication link between a client device and a content server
in the
architecture illustrated in FIG. 1, wherein the client device is authenticated
by a server;
[0014] FIG. 3 is a message flow diagrain illustrating an embodiment of a
message
flow between processes for authentication and content streaming based on
challenge and
authentication;
[0015] FIG. 4 is a control flow diagram for a process for user selection of
content in
a client agent, wherein authentication is based upon a client device address
value;
[0016] FIG. 5 is a control flow diagram for an embodiment of a process in a
server
for authorizing a client's content request, wherein authentication is based
upon the client
device address value;
[0017] FIG. 6 is a message flow diagram illustrating an example of the message
flow
between the processes of FIGS. 4 and 5;
[0018] FIG. 7 is a schematic architecture diagram illustrating an embodiment
of a
wireless IFE system wherein wireless client devices in communication with a
server may
include user supplied devices;
[0019] FIG. 8 is a message flow diagram illustrating an embodiment of a
process
wherein multiple content streams are broadcast via the wireless network of a
wireless IFE
and a user selects which stream to decode and display;
[0020] FIG. 9 is a protocol stack diagram illustrating a protocol stack for an
embodiment of wireless connection between a content server and a client agent
wherein a
modified transport protocol layer is utilized to receive multiple broadcast
streams; and
3
CA 02566416 2006-11-01
WO 2005/120069 PCT/US2005/018557
[0021] FIG. 10 is a protocol stack diagram illustrating a protocol staclc for
an
einbodiment of wireless connection between a content server and a client agent
wherein a
content stream is encrypted using a private/public key encryption scheme.
DETAILED DESCRIPTION
[0022] IFE systems are generally described in commonly owned and assigned U.S.
Patent Application No. 10/136,237, filed May 1, 2002, entitled Method and
System for
Configuration and Download in a Restricted Architecture Network, published as
U.S.
Publication No. 2003 0208579 Al, and U.S. Patent Application No. 10/145,464,
filed May
14, 2002, entitled Method For Controlling An In-Flight Entertainment System,
published
as U.S. Publication No. 2003 0217363 Al, each of which is incorporated herein
by
reference in its entirety for purposes of disclosure.
[0023] FIG. 1 is a diagram illustrating an embodiment of a reduced
architecture IFE
system 100. IFE system 100 includes a backbone network 110, such as a high
speed local
area network (LAN), to which are connected, in this example, a satellite
interface 112 for
transfer of content to and from a satellite, a management terminal 114 for
control and
administration of the IFE system 100, and a cockpit interface 116 for
conlmunications
with the cockpit crew.
[0024] The IFE system further includes a digital server unit (DSU) 130 for
distributing a variety of streaming audio/video offerings. Preferably, the
server can
support multiple clients and can broadcast inultiple independent programs.
Video content
is typically stored on a storage unit (132), such as a disk drive of the DSU,
in a
compressed format, such as the Motion Picture Expert Group (MPEG) formats MPEG-
1
and MPEG-2. Similarly, the audio content is typically stored in a compressed
format,
such as MPEG-3 (MP3). The storage unit is typically accessed using a high
speed
interface, such as a SCSI interface, which may be accessed by a technician in
order to load
content onto the storage unit. Multiple DSUs may be utilized in order to
provide content
to ADBs, tapping units, or other client devices.
[0025] According to an aspect of the invention, the IFE system 100 is
wirelessly
networked. For example, IFE system 100 also includes a wireless router 120 for
wirelessly communicating with wireless client devices in the system, which
include, in
this example, seat back video display units (VDUs) 140A-D, and an overhead
display unit
144. Preferably, a common wireless standard is used, such as IEEE 802.11 a or
IEEE
802.11g. In an embodiment, each of the VDU's 140 A-D is mounted in the
aircraft cabin
4
CA 02566416 2006-11-01
WO 2005/120069 PCT/US2005/018557
for viewing by a passenger. For example, the VDU may be mounted in a seat
back, facing
rearwardly. Those skilled in the art will appreciate that the VDU can be
mounted to any
appropriate structure, such as atm rest, an overhead console or ceiling, or a
bulkhead.
[0026] In an embodiment wherein a passenger can select from a variety of
entertainment offerings to be displayed at the VDU, the VDU includes a
passenger input
device. The device may include, for example, a touch screen display or buttons
located in
a housing of the VDU, in an arm of the passenger seat, or some other
convenient position.
[0027] In a preferred embodiment, IFE system distributes content in an on-
demand
manner as selected from a particular VDU. However, it will be understood that
some or
all of the content may be distributed in a broadcast manner, as will be
described in further
detail below. So that the operator of the IFE system can control services
provided by the
IFE system 100 of FIG. 1, it rriay be desirable to encrypt the content streams
to the client
devices. For example, encryption may be desirable in order to prevent
reception and use
of the content by unauthorized devices. This may be particularly important for
providing
copyright-protected content, such as movies. Also, in an embodiment,
encryption may be
desirable to implement a pay-per-view process that distributes content only to
paying
passengers.
[0028] FIG. 2 is a control flow diagram illustrating an embodiment of a
process 150
for establishing a communication link between a client device and a content
server in the
architecture illustrated in FIG. 1, wherein the client device is authenticated
by a server.
Each client device, such as VDUs 140A-D, establishes a media access control
(MAC)
connection to the wireless network provided by wireless router 120. In one
example, a
wireless card in each VDU communicates with the router. Following an
established
protocol, such as IEEE 802.11 a or g, a communication link is established
between the
client device and a server, such as content server 130 in FIG. 1, at step 154.
At step 156,
the client device is authenticated by the server as a device authorized to
receive content
through IFE system 100. Several example of methods for authentication are
discussed
below.
[0029] If the client device is authenticated, then control branches at step
160 to step
162, where an encrypted link is established between the server and the client
device. For
example, content may be encrypted using a private key that can be decrypted
using a
public key provided to the client devices. This public key value may be
purchased or
authorized via the authentication process. Alternatively, an encrypted tunnel
connection
may be established between the client and server. Or content may only be
provided to
CA 02566416 2006-11-01
WO 2005/120069 PCT/US2005/018557
certain pre-authorized client address values. Examples are discussed further
below. Once
a link is established, service is provided to the client device and content is
streamed from
the content server 130, through wireless router 120 over the wireless IFE
network to the
client device.
[0030] Iii one approach, a client agent process 200 (FIG. 3) in a client
device, e.g.
VDU 140A, is provided with a universal resource locator (URL) for an HTML page
that is
served to a user so that the user can provide information for a challenged
handshake
authentication protocol (CHAP). For example, the user may purchase services or
provide
authentication data indicating that user is authorized to receive services.
Such
authentication may be particularly useful in an embodiment wherein the client
device is a
portable device supplied by the user, rather than a dedicated device built
into the aircraft.
The HTML page alternatively may be used as a convenient interface for a
maintenance
technician to configure client devices for operation as part of the wireless
IFE system 100,
e.g. when the systein is initialized or additional units are introduced.
[0031] FIG. 3 is a message flow diagram illustrating an embodiment of a
message
flow between processes for authentication and content streaming based on
challenge and
authentication using an HTML page. Client agent 200 transmits a request to the
IFE
system 100 with a URL value for the HTML page. The request is picked up by a
domain
name server (DNS) process 210, which, in this example, maps the URL value to
the
HTML page and serves the HTML page to client agent process 200 along with the
CHAP
server address value for CHAP server process 220. The HTML page, which is
rendered
and displayed to the user by the client agent, prompts the user for
authentication
information, such as an account and password, which results in a CGI request
being sent to
CHAP server process 220 along with the network address for the client device.
[0032] CHAP server process 220 checks the authentication information provided
by
the user to a database, for example, to authenticate the user and the client
device. Note
that some or all of the server processes discussed here may reside in the same
machine or
may be spread out over multiple machines, depending upon the demands on the
IFE
system 100. If the user provides valid authentication information, then CHAP
server
process 220 sends a message to content server process 230, which, in this
example, resides
in content server 130 of FIG. 1, indicating that a client device has been
authenticated and
providing the address of the client device on the network. CHAP server process
220 also
provides the address of the content server process 230 to client agent process
200. Client
agent 200 then sends a user's request for content to content server process
230 with the
client device address. Content server process 230 checks the client device
address against
6
CA 02566416 2006-11-01
WO 2005/120069 PCT/US2005/018557
its list of authenticated client address values as provided by CHAP server
process 220 and,
since the client address value has been validated, streams the requested
content to client
agent process 200 at the client device address.
[0033] Turning to FIG. 4, a control flow diagram is illustrated for a process
for user
selection of content in a client agent where authentication is based upon a
client device
address value. At step 202, the client agent receives a user selection. Note
that, at various
points in the authentication process discussed above, the client agent may be
supplied with
an HTML page that provides the user with a selection of options for content to
choose
from or a separate step may be provided for obtaining data for the user's
available choices.
At step 204, the user's selection causes a request to be sent for the selected
content to the
content server process address provided above, where the request message
includes the
client device address. The agent process then waits at step 206 to receive the
requested
content, which is rendered and displayed to the user at step 208 when it is
received. For
example, audio or video content may be served to the user in this manner.
[0034] The request sent by the client agent in FIG. 4 is processed by a
content server
process. FIG. 5 is a control flow diagram for an embodiment of content server
process
230 in a server where authentication is based upon the client device address
value. At step
232, the server process receives the request for selected content from the
client agent. At
step 234, the server process conlpares the client address value from the
request for content
with the list of valid client address values compiled on the basis of messages
from CHAP
server process 220. If the address value is valid, then control flow branches
at step 240 to
step 242 where the content requested by the user is streamed to the client
address via the
wireless connection to the client device. If the address value is not one of
the validated
addresses provided to the content server process 230, then, in this example, a
rejection
message is sent to the client address. The rejection message may include the
CHAP
HTML page in order to reinitiate the authentication process.
[0035] FIG. 6 is a message flow diagram illustrating an example of the message
flow
between the processes of FIGS. 4 and 5. The client agent 200 sends requests
for content to
the content server process 230. Content server process 230 validates the
address from
information in storage 132, e.g. a hard drive, retrieves the requested client
from storage
132, and streams the content to client agent 200 through wireless router 120
over a
wireless connection to the address of the client device, e.g. VDUs 140A-D, to
the client
agent.
7
CA 02566416 2006-11-01
WO 2005/120069 PCT/US2005/018557
[0036] As noted above, the client devices may be VDUs or other devices that
are
provided with the IFE system 100. In this case, the CHAP process may take the
form of a
maintenance routine whereby an IFE system technician enters and validates each
of the
client devices that are part of the IFE system and the system is tliereby
configured for
operation. Alternatively, the client device may be provided by the user. FIG.
7 is an
architecture diagram illustrating an embodiment of a wireless IFE system 300
wherein
wireless client devices in communication with a server may include user
supplied devices.
For example, the user may have a wireless enabled device capable of receiving
content for
the user, such as a portable personal computer 302, a personal data appliance
(PDA) 304,
or a mobile telephone 308. In this case, wireless router 130 of FIG. 1 is
configured to
establish a communication link with these user provided client devices. As
noted above,
the CHAP process may involve authorizing the client device on the basis of
payment made
by the user, in which case the CHAP process includes an interface for
collecting the
necessary billing information. Alternatively, the authentication information
(e.g. an
account and password or a public key for use in decrypting data streams) may
be
purchased from a flight attendant or other secure means.
[0037] Broadcast message streams may be preferred in certain applications for
providing content. For example, streaming broadcast content may be preferred
for IFE
systems that do not have sufficient capacity to provide a custom data stream
for each user.
In this approach, each data stream may be simultaneously broadcast. For
example,
packets are transmitted in the systein using a broadcast address provided by
an appropriate
protocol, such as transport control protocol (TCP), with the different
streanls being
differentiated from one another by unique socket values. Alternatively,
multiple broadcast
addresses may be provided by a transport layer protocol with each stream
corresponding to
one broadcast address.
[0038] It should be noted that for transmitting data that is not specific to
an
individual seat connection (e.g., PA, Overhead video audio) or in an area of
the aircraft
where VDU's are mounted for shared viewing among multiple passengers, it is
preferable
to distribute the data using a streaming network protocol that does not
perform error
checking, such as Real-Time Protocol (RTP), rather than a guaranteed delivery
protocol
such as TCP/IP. Streaming protocols that support broadcast services (like RTP)
do not
detect errors and do not perform retransmissions. Decoding such a signal,
therefore,
allows for more synchronous transmission. Erroneous portions are merely
dropped.
[0039] FIG. 8 is a message flow diagram illustrating an embodiment of a scheme
wherein multiple content streams are broadcast via the wireless network of a
wireless IFE
8
CA 02566416 2006-11-01
WO 2005/120069 PCT/US2005/018557
and a user selects which stream to decode and display. A client agent process
400 is
configured to receive multiple broadcast content streams transmitted by a
content server
process 430 that is configured to transinit packets for each content stream.
For example,
three different video programs may be transmitted as a stream of broadcast
packets with
different socket or broadcast address values, incidated in FIG. 8 as broadcast
addresses 1,
2 and 3.
[0040] A user selection received by the client agent 400 determines which of
the
broadcast content data streams is to be buffered and displayed to the user.
For example, if
the user selects video program 1, client agent 400 buffers the broadcast
packets it receives
for broadcast address 1, or socket 1 depending upon the implementation, and
renders those
packets for display. The packets for all other broadcast streams are
discarded.
[00411 FIG. 9 is a protocol stack diagram illustrating a protocol stack for an
embodiment of wireless connection between a content server and a client agent
wherein a
modified transport protocol layer, e.g. a modified TCP scheme, is utilized to
receive
multiple broadcast streains. In this scheine, a content server containing the
content server
process 430 is in wireless communication with a client device, e.g. a user
supplied device
or a device that is a dedicated part of the IFE system, that contains client
agent process
400. In this exainple, the protocol stack illustrates a network interface, MAC
or link level
control (LLC), and internet protocol (IP) relation at the physical, link and
network levels,
respectively, between content server 130 and wireless router 120. Wireless
router 120 also
has a wireless interface, MAC/LLC, IP relation at the physical, link and
network levels,
respectively, with the client device. In this example, the content server
process 430 uses a
modified TCP layer 432 to transmit each content data stream as packets having
either a
different broadcast address or using the standard broadcast address in
combination with
different socket values. A modified TCP layer 402 in the client device
monitors the
broadcast packets transmitted by content server process 430 and buffers and
passes up to
the client agent 400 only those broadcast packets corresponding to the stream
selected by
the user. The broadcast packets for the selected stream are then rendered and
displayed
for the user.
[0042] Encryption of content data streams, such as individualized content
streams
unique to each user or broadcast streams, to prevent unauthorized access was
noted above.
FIG. 10 is a protocol stack diagram illustrating a protocol stack for an
embodiment of
wireless connection between a content server and a client agent wherein a
content stream
is encrypted using a private/public key encryption scheme. Other encryption
schemes may
also be applied, such as dedicated keys preconfigured in the content server
and client
9
CA 02566416 2006-11-01
WO 2005/120069 PCT/US2005/018557
devices by maintenance or installation personnel. Two variations are shown in
FIG. 10
where a public/private key encryption scheme is utilized, which, in this
example, is pretty
good protection (PGP). In one approach, PGP runs at the session layer 532
above the
transport layer 534 on the server side and at session layer 502 above
transport layer 504 on
the client side. In another approach, PGP is a service of the transport layer.
In both cases,
content data at the content server is encrypted using a private key and
transmitted to the
client device where it is decrypted using a public key provided to the user by
a flight
attendant, for example. As a further alternative, an encryption/decryption
process can be
implemented in data communicated between the router and client device running
in a layer
below the IP layer at the client device and router, as illustrated in FIG. 10.
Such
encryption/decryption can be in accordance with IEEE 802.11i. Other encryption
schemes
may be utilized.
[0043] Aircraft passengers commonly travel with individual personal computers
that
are equipped with wireless networking interfaces. These wireless interfaces
are typically
used in land-based environments to communicate with a server over high-
frequency RF
signals. The presence of these laptops or other portable wireless
communication devices
within the environment of the present IFE system presents potential for the
IFE wireless
signal to be received by devices other than the IFE displays. On the one hand,
an operator
of the IFE system may want to prevent the content of the wireless IFE signal
to be
playable by portable wireless communication devices, permitting the signal to
be properly
played only by the IFE displays. On the other hand, an operator of the IFE
system may
want to facilitate the reception and playing of the IFE content on the
portable wireless
devices, but in a controlled manner whereby a pay-per-view fee can be charged
and/or
unauthorized copying of the signal content can be prevented. Control over
playability of
the signal is important, for example, when the video offering is a copyright
protected
work; such as most movies.
[0044] In addition to entertainment, the IFE system is useful for other
critical cabin
functions such as for public address (PA) announcements. The PA function
enables crew
members to broadcast audio announcements to all passengers in the aircraft.
The IFE
permits such announcements to be heard without interference. Preferably, the
IFE ceases
transmission of audio relating to entertainment presentations and instead
transmits the PA
announcement instead to the headsets. Alternatively, the IFE could cease the
transmission
of audio relating to entertainment presentations, resulting in no headphone
output so that
the passengers can hear the PA announcement over the ambient speakers. This
means that
silence at the headset is certifiable but customer expectations are that the
PA audio will be
CA 02566416 2006-11-01
WO 2005/120069 PCT/US2005/018557
presented to the passenger headset as well. All other entertainment
transmissions cease
upon transmission of the selected entertainment presentation.
[0045] Area passenger announcements are PA announcements that are restricted
to a
specific area of the aircraft (like first class, economy, crew rest, etc.).
Seats in the
corresponding area should meet the requirements for PA (silence or
presentation of the PA
speaker audio). During an area PA, entertainment signals must continue
delivery to seats
that are not in the designated area in order to operate unaffected. The area
passenger
announcements preferably have are delivered to the headset with a delay of no
more than
about 35 ms delay from input into system. The PA area may cover multiple
wireless
areas. A wireless area may be able to cover multiple PA areas. Entertainment
should
continue during announcement.
[0046] In an IFE system having at least some overhead video displays (displays
arranged to be viewed by multiple passengers), the same image is presented to
each of the
overhead displays in a specified area. The presentation is preferably
synchronized to
within about 60 ms across all displays. The audio associated with an overhead
video
program is presented to each passenger wanting to watch the overhead video
program. The
audio associated with the overhead video program must also be presented to the
passenger's ear within about the same 60 ms. In an embodiment, uncompressed
digital
audio is delivered to the seat for the one overhead video program in the area.
Overhead
may be provided with analog/ARINC722 standard interface to avoid overhead
display
synchronization issues.
[0047] The IFE system may be configured to present a video announcement (VA)
as
an overhead video program having associated audio that is played over the PA
system as
an area PA. In an embodiment, the IFE system operates with a video override
feature that,
when activated, forces all in-seat video displays in the designated Overhead
Video area to
ON and presents a single specific video program in each of these displays.
[0048] In an embodiment, the wireless activity is ceased during critical
flight phases
if deemed necessary to avoid interference with aircraft communication
equipment or
navigation instruments. In an embodiment where the display units wirelessly
communicate passenger service system (PSS) selections, the PSS functions would
be
unavailable during such critical flight phases.
[0049] In an embodiment, a database is provided to establish parameters for
the
features of area PA, video announcements, class oriented features, and PSS on
a seat-by-
11
CA 02566416 2006-11-01
WO 2005/120069 PCT/US2005/018557
seat basis. The database may be distributed to the seats (e.g. as part of
maintenance
activity) to ensure that time critical responses (like PSS and area PA) can be
met.
[0050] It can thus be seen that a new and useful wirelessly networked IFE
system
has been described. Note that there are many possible variations of the
embodiments
described herein that fall within the scope of the following claims.
Additionally, every
implementation and configuration described herein is meant to be an example
only and
should not be taken as limiting the scope of the claims. Also, note that the
use of the terms
"a" and "an" and "the" and similar referents in the context of describing the
invention
(especially in the context of the following claims) are to be construed to
cover both the
singular and the plural. Furthermore, recitation of ranges of values herein
are merely
intended to serve as a shorthand method of referring individually to each
separate value
falling within the range, unless otherwise indicated herein, and each separate
value is
incorporated into the specification as if it were individually recited herein.
Finally, the
steps of all methods described herein can be performed in any suitable order
unless
otherwise indicated herein or otherwise clearly contradicted by context.
12
