Note: Descriptions are shown in the official language in which they were submitted.
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METHOD FOR PERFORMING WIRELESS MOBILE INSTANT
MESSAGING
Technical Field
This invention relates in general to wireless mobile communication systems,
and more particularly to methods of sending messages between mobile
communication devices and between mobile communication devices and clients
using data networlc equipment.
Background of the Invention
Wireless mobile communications has had a profound impact on the way
many people conduct business, and it has provided a great convenience to the
general public. In some situations, however, it may be inappropriate or
otherwise
undesirable to use a mobile communication device, such as during an important
business meeting, or any other time when it would be considered disruptive.
Yet it
may be desirable to transmit or receive a short non verbal message that does
not
necessarily require a real-time response, or any response at all. This type of
messaging is done regularly between fixed computing stations, such as by
electronic mail, or to a mobile device such as a pager. Some methods even
provide
for pseudo real-time response, such as the so called online chat where
multiple
users can simultaneously engage in a discussion with low apparent latency.
Instant
messaging, as it has come to be known, is a variety of the online chat where
discussion is between two people located at remote stations.
Instant messaging and online chat in general involve activating a software
program at a computer that is connected to a network. The software program is
an
instant messaging "client" which runs on a general purpose computer connected
to
a networlc. Upon activation, the instant messaging client requests the users
account
information, and connects to a messaging server. The messaging client relays
the
account information to the messaging server, along with the present network
address of the machine currently being used for the present instant messaging
session. This allows the user to use different machines at different times
with the
same instant messaging account, provided that the machine has a copy of the
instant
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messaging client program and is connected to the network. An instant message
is
an alpha-numeric text string composed by a first user, typically in a text
entry
window in the program's user interface, that is sent to a second user or a
group of
users over the instant messaging server. The server forwards this message to
the
final recipient's client and the client displays the message as soon as it is
received.
The fact that conventional instant messaging services rely on servers that
queue messages indicates that there is always the server processing delay,
which,
during peak times of messaging traffic can be noticeable. Other types of
messaging, such a paging and electronic mail (email) also suffer from inherent
delivery latency during periods of peals network activity. Wireless messaging
such
as paging and email offer the benefit mobility and can present a minimal
disturbance, unlike receiving a mobile phone call where the user engages in a
conversation with the calling party upon receiving a call. Therefore there is
a need
for a wireless instant messaging system for mobile clients that does not delay
messages, even during times of peak traffic.
Brief Description of The Drawings
FIG. 1 shows a communication system for performing wireless instant
messaging, in accordance with the invention;
FIG 2 shows a flow chart diagram of a method of performing wireless
instant messaging between mobile communication devices, in accordance with the
invention; and
FIG. 3 shows a diagram of a typical data packet including a header and a
payload;
FIG. 4 show a flow chart diagram of a method of determining if a mobile
station is presently online, in accordance with the invention;
FIG. 5 shows a flow chart diagram of a method of performing wireless
instant messaging between a mobile station and a network chat client, in
accordance with invention; and
FIG. 6 shows a flow chart diagram of a method of performing wireless
instant messaging between a mobile station and a network chat client, in
accordance with invention.
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Detailed Description of a Preferred Embodiment
While the specification concludes with claims defining the features of the
invention that are regarded as novel, it is believed that the invention will
be better
understood from a consideration of the following description in conjunction
with
the drawing figures, in which like reference numerals are carried forward. A
brief
description of the prior art is also thought to be useful.
As mentioned above, prior art messaging for wireless systems, and for many
wired networks systems, is server queued. By server queued it is meant that
the
message sent from the sender's equipment is temporarily stored on a server
before
it is delivered. Examples of such systems include email, paging, and Internet
chat
messaging. A chat server may also duplicate messages so that they may be
routed
to multiple users involved in the same discussion. Being server based, the
messaging network delay is determined by the amount of dedicated resources and
the volume of messaging traffic. Obviously as the traffic volume increases,
the
more demand there is on system resources, and at some point delays begin to be
experienced in message delivery. Furthermore, many messaging systems are
blind,
such as paging systems, meaning that the sender has no way of knowing if the
intended receiver actually received the message.
The present invention mitigates these problems by avoiding the use of a
server, and providing feedback as to whether or not the intended receiver
actually
received the sent message. This is accomplished by use of a direct client to
client
communication over the network. In the preferred embodiment the message is
transmitted through the system without being queued at any server. One benefit
of
using a dispatch channel instead of a more conventional duplex channel is that
roughly half the system resources used for a duplex connection are utilized
since
only a half duplex connection is needed at any one instant.
Referring now to FIG. 1, there is shown a communication system 100 fox
performing wireless instant messaging, in accordance with the invention. A
mobile
communication device or mobile station 102 is shown, connected over an air
interface 103 to a fixed equipment network including an enhanced base
transceiver
(EBTS) 104. The mobile station comprises a display means for displaying
information such as text and various icons, and an input means such as an
alpha-
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numeric lceypad. It is a mobile wireless communication device, meaning that
mobile station may move from location to location within a serving area and
maintain contact with the fixed equipment network by handing over to different
base sites, as is well known in the art. Furthermore, the mobile station is
capable of
making both dispatch and telephone calls, such as any of the communication
devices sold under the trade name iDEN, manufactured by Motorola, Inc. These
devices have a push-to-talk feature that allows the mobile station to engage
in
dispatch calls with one or more other stations. The EBTS is operably connected
to
a base site controller (BSC) 106, which controls one or more EBTS units on a
given
l0 site to establish a serving cell. The BSC in turn is operably connected to,
among
other network devices, a mobile data gateway (MDG) 108. The BSC may also be
operably connected to, for a example, a mobile switching center (not shown),
as is
well known in the art, for establishing duplex telephone calls over a public
switched telephone network. By dispatch call it is meant any half duplex type
of
communication where the parties alternatively speak and listen. This can occur
between two mobile operators, or from one to many mobile operators in a so
called
fleet mode, as is known in the art. As used here, the term should not be
confused
with the more common, and more narrow meaning as used in, for example, public
safety radio systems.
The MDG 108 is operably connected to a dispatch application processor
(DAP) 110, which is a communication agent processor for facilitating dispatch
calls. These calls are half duplex, where only one station talks at a time,
and the
receiving stations can only listen. A dispatch call may be between two or more
stations. When a mobile station user wishes to initiate a dispatch call, the
system
identifier of the station the user wishes to call, or the talk group
identifier the user
wishes to speak in is selected at the user's station. Upon engaging the push-
to-talk
button, the station sends the information to the DAP, which quickly locates
the
serving cells) of the target stations by examining a dispatch visit location
register
(D-VLR) 112. The D-VLR works substantially similar to that of a visit location
register used in mobile telephone systems to keep a timely record of the
serving cell
in which each connected mobile station is presently located. This facilitates
quick
routing of dispatch calls to the cell or cells of the other stations which a
calling
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station is calling. As mobile stations change locations, their cell
affiliation is
updated in the D-VLR. The MDG may also be connected to outside networks
through, for example, an IP router 120, which connects the wireless system 100
with a data network such as, for example, the Internet 122, where there are
other
5 servers 124 and network chat client machines 126.
Referring now to FIG. 2, there is shown a flow chart diagram 200 of a
method of performing wireless instant messaging between mobile communication
devices, in accordance with the invention. The method is explained with
references
to FIG. 1. At the start 202, a first mobile station, such as mobile station
102, is
powered and connected to the wireless communication system over an air
interface
103. This means the mobile station 102 is registered for service, and its
present cell
location is recorded in the D-VLR 112. When the user of the first mobile
station
decides to send an instant message, the user uses the mobile station to
compose a
message. The mobile station comprises a keypad and display, as is well known
in
the art, to facilitate the entry of alphanumeric information, and the user
composes
an alphanumeric message (202). However, it is contemplated that the message
may
be composed by recording the users voice speaking a short message, and
digitally
encoding the recorded voice message for transmission. The user must also
select a
target (206); a second mobile station used by the person to whom the user
wishes to
send the instant message. The user may select a from a database of target
identifiers stored in a memory, preferably by selecting an alias associated
with the
target identifier, or the user may enter the target identifier directly. The
target
identifier is the identifier the communication system uses to identify to
which
mobile station the user intends to send the message, and my be, for example,
an
Internet protocol (IP) address. Then the user uses the mobile station to
transmit
(208) the message. This may be done by, for example, pressing a push-to-talk
button on the mobile station. The target identifier and subsequently, the
message,
are then transmitted to the fixed equipment network. The fixed equipment
network
includes all non-mobile components of the communication systems, including the
EBTS 104, BSC 106, MDG 108, DAP 110, and so on. In the preferred
embodiment, the air interface 103 is a time divisioned interface, meaning that
the
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mobile station transmits and receives data in specified time slots, as is well
known
in the art.
The fixed equipment first receives the target identifier. The information is
received in packets, such as packet 300 shown in FIG. 3, as is well known in
the
art, with a header 302 in each packet indicating what type of data is included
in the
payload 304 of the packet. Initially the information received from the mobile
station indicates to the fixed equipment network that the mobile station is
attempting to transmit an instant message by the designation in the header of
the
incoming packets. The fixed equipment network routes the incoming packets to
the
1VIL~G 108. The 1VIDG receives the information, sees that the mobile station
is
attempting to send an instant message, looks up the target identifier in the D-
VLR
to see if the target, a second mobile station, such as mobile station 118, is
presently
available (210), and if so, to which cell it is presently connected. The 1VIDG
then
routes the information to a second EBTS 116 (214), which is operating the
serving
cell in which second mobile station 118, the target, is located. The EBTS 116
pages the second mobile station to alert it to the outgoing data, and which
channel
the data will be transmitted (216). The second mobile station tunes to the
appropriate channel and begins receiving the instant message. While it is
receiving
the instant message, or shortly after receiving the message, the second mobile
station sends an acknowledgement back to the first mobile station (220), and
displays the received message in an alphanumeric capable display (222).
Preferably, the second mobile station alerts the user an audio or visual
alert, or
both, upon receiving the message. The message may be displayed at the users
request upon perceiving the alert, or it may be displayed automatically.
Presently,
the instant message is finished (224).
There are a few ways of handling the situation if the second mobile station
is not presently available when the first mobile station begins to send the
message.
For .one, the first mobile station may "ping" the second mobile station prior
to
sending the message, or even prior to the first user composing the message, as
illustrated in FIG. 4. For example, the first user may be curious as to
whether the
second mobile station is in use, and hence able to receive an instant message.
The
first user merely selects the identifier of the second mobile station from
within an
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appropriate operating mode of the first mobile station (400), and takes some
action,
such as pressing a push-to-talk button. The identifier is sent to the MDG
through
the fixed equipment network (402). The MDG then looks for the identifier in
the
D-VLR (404). If the 1VIDG finds no record of the second mobile station in the
D-
VLR, it may return a failure message (406) to the first mobile station. This
is the
same as would preferably happen in the previous case had the MDG not found the
second mobile station's identifier in the D-VLR when the whole message was
attempting to be sent to the second mobile station. If the target identifier
is found,
the MDG returns an acknowledgment (408), and the user can then proceed to
compose a message. In an alternative embodiment, the user can compose the
message and if the second mobile station is not available, the first mobile
station
may automatically repeat attempting to send the message at preselected
intervals.
An alternative method occurs when the second mobile station 118 is listed in
the D-
VLR, but does not respond, either when paged by the EBTS 116, or after the
message is transmitted. Preferably, when the first mobile station transmits
the
message, it begins a timer. If after a preselected period of time there has
been no
acknowledgement received, the first mobile station displays a fail message to
the
user. Because of the very low latency in transmitting a message from one
mobile
station to another with this method over such a fixed equipment network, it is
contemplated that no more than a few seconds will be needed to receive a
proper
acknowledgement. So if, for example, 5 seconds have elapsed and no
acknowledgement has been received, the first mobile station will fail the
transmission. .
It is also contemplated that the user of a mobile station may desire to send a
message with a fixed terminal, or other terminal or station over public
network,
such as the Internet. As shown on FIG. 1, the MDG is connected to a an IP
router
120, which connects the wireless communication system to the Internet 122.
Also
connected to the Internet is, for example, a chat server 124, and a computer
running
a chat client application program 126. The chat client application program
allows
the user of the client program to log onto the chat server,preferably as soon
as it is
turned on, over the Internet using a unique name or identifier. Other users
can log
onto the chat server with similar programs and exchange messages over the
server
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with the each other. The server receives message from one client, queues the
message, then forwards the message to all designated targets, in turn. The
chat
server works as a first in, first out queue for messages received from client
machines.
In the first case, a mobile station 102 is used to send a message to a network
chat client 126. FIG. 5 shows a flow chart diagram of a method in accordance
with
the invention for accomplishing this. First, as before, the user composes a
message
(500), which may be a recorded voice message or an alphanumeric message, and
the chat client identifier, such as an IP address, or a unique name or other
identifier
used by the chat server. Of course, the network address of the chat server
will also
be included, although this may be provided by the messaging application
program
on the mobile station. The mobile station sends the message to the fixed
equipment
network, which recognizes the designation as being to a target outside the
wireless
communication network, and routes (502) the message to the IP router 120. The
IP
router forwards the message to the chat server 124 over the Internet, which
receives
the message (504). Upon receiving the message, the chat server looks up the
designated chat client to see if the particular chat client is presently
logged onto the
chat server (506). If not, a fail message is returned, and routed back to the
mobiles
station (508). If the chat client is online, the message is forwarded to the
chat
client.
FIG. 6 shows a flow chart diagram a method in accordance with the
invention of the reverse direction, when a chat client sends a message to a
mobile
station. First the chat client 126 logs onto the chat server 124 over the
Internet.
Then the user of the chat client composes and sends a message (602),
designating it
appropriately. This includes designating the particular wireless communication
system, although this may be done simply by use of an I address of the
particular IP
router/MDG. . The chat server recognizes the designation as one of a mobile
station, and routes the message to the lP muter, which forwards it to the
1VIDG
(604). The MDG then looks for the designated mobile station in the D-VLR
(606).
If the mobile station is not listed presently, a fail message rnay be returned
to the
chat client (608). Otherwise, the message is forwarded to the serving cell in
which
the designated mobile station is presently located (610), and the message is
received
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at the mobile station (612) as described hereinabove. It is also contemplated
that
the mobile station may generate an acknowledgement upon receiving the message,
and send it back to the network chat client over the network. It is still
further
contemplated that if no response is received upon sending a message from
either
the mobile station of the chat client, the device attempting to send the
message may
display a fail message within a period of time.
Thus, the present invention solves the problem of latency and the expense of
adding servers to avoid latency by sending message between mobile stations
similarly to dispatch calls, which are not queued. This is accomplished by the
use
of presently existing resources in a new way. Particularly, the use of the
mobile
station to compose a message, and transmit the entire message, for example, at
the
push of a button, without storing the message in the system. The message may
be
recorded voice or alphanumeric text. Furthermore the present invention allows
mobile station to exchange message with network chat clients, over the
Internet.
While the preferred embodiments of the invention have been illustrated and
described, it will be clear that the invention is not so limited. Numerous
modifications, changes, variations, substitutions and equivalents will occur
to those
skilled in the art without departing from the spirit and scope of the present
invention as defined by the appended claims.
What is claimed is:
