Cellular telephone with datagram and dispatch operation

• US 5,475,689 A
• Filed: 07/14/1994
• Issued: 12/12/1995
• Est. Priority Date: 12/06/1990
• Status: Expired due to Term

• Current Assignee: Hughes Electronics Corporation (Rtx Corporation)
• Original Assignee: Hughes Aircraft Company (Rtx Corporation)
• Inventors: Mehta, Ashok D., Kay, Stanley
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): Hom, Shick
• Application Number:
  US08/275,161
• Time in Patent Office: 516 Days
• Field of Search: 370/95.3, 370/95.1, 370/79, 370/109, 370/61, 370/100.1, 370/80, 370/110.1, 375/107, 379/59, 379/63, 379/61, 455/11.1, 455/33.1, 455/33.2, 455/33.3, 455/33.4
• US Class Current: 370/337
• CPC Class Codes: G10L 19/012 Comfort noise or silence coding
• CPC Class Codes: H04B 7/26 at least one of which is mobile
• CPC Class Codes: H04B 7/2643 using time-division multiple access [TDMA] H04B7/2615, H04B7/2618 take precedence
• CPC Class Codes: H04J 3/172 Digital speech interpolation, i.e. DSI
• CPC Class Codes: H04L 9/40 Network security protocols
• CPC Class Codes: H04W 88/16 Gateway arrangements
• CPC Class Codes: H04W 88/181 Transcoding devices; Rate adaptation devices
• CPC Class Codes: H04W 92/20 between access points
• CPC Class Codes: H04W 92/22 between access point controllers

Abstract

A cellular system supports dispatch and datagram operations. The architecture of a conventional cellular system, such as the GSM system, is modified by adding a local area network (TIL) where nodes on the network include various base switching controllers (BSC). The BSC has a Switching Interface Module (SIM) which provides an interface to the TIL. The TIL may also include one or more gateways (40) to landline based networks. The datagram operation uses an appropriate gateway to complete a data path which includes an RF segment to or from the BSC. Dispatch operations provide for switching by the BSC so that switching is at a level below the Mobile Switching Center (MSC). For example, compressed voice traffic received by the BSC may be transmitted over the TIL to another BSC from where it is sent over an RF segment to a mobile receiver (MS).

Claims

1. A cellular radio telephony system for communication of data, voice or data and voice messages between remote stations, a switched telephone network and a data network comprising:

a plurality of base stations, each base station having a radio frequency interface to said remote stations, there being at least one radio frequency interface for each cell of said cellular system;

a mobile switching center coupled to said switched telephone network and to said base stations for use in transmitting said data, voice or data and voice messages as telephone communications between said remote stations and said switched telephone network over said radio frequency interface; and

a local area network, said base stations being coupled to said local area network as nodes for use in transmitting said data, voice or data and voice messages to and from said remote stations over said radio frequency interface.

2. A system as recited in claim 1 wherein said radio frequency interfaces of said base stations operate exclusively within one cell of said cellular system.

3. A system as recited in claim 1 wherein said radio frequency interfaces further include at least one transceiver station, each transceiver station having a radio frequency transceiver for communicating with remote stations operating exclusively within a cell of said cellular system.

4. A system as recited in claim 1 wherein:

said base stations include a codec to compress voice traffic from said switched telephone network for transmission to said remote stations and to expand compressed voice traffic from said remote stations for transmission to said switched telephone network, and

wherein said base stations include an interface for transmitting compressed voice traffic onto said local area network.

5. A system as recited in claim 1 in which said base stations include an interface for transmitting compressed voice traffic onto said local area network.

6. A system as recited in claim 1 which further includes a gateway coupled to said local area network with an interface to a switched data network.

7. A system as recited in claim 1 in which said base stations include an interface to said local area network, said interface including means for monitoring messages on said local area network and means for copying those messages addressed to a remote station registered with the base station of the interface.

8. A system as recited in claim 1 wherein said base stations includes a switching interconnection module coupled to said local area network for receiving messages from said local area network for transmission to remote stations and for transmitting messages received from remote stations to said local area network.

9. A system as recited in claim 8 wherein said base stations include a channel access processor for registering remote stations in association with a cell of said cellular system and allocating radio frequency resources to said registered remote stations through said radio frequency interfaces.

10. A system as recited in claim 8 wherein said base stations include a channel access processor for registering remote stations in association with a cell of said cellular system and allocating radio frequency resources to said registered remote stations through said radio frequency interface, said channel access processor being in communication with said interconnection module for regulating the reception and transmission of messages by said interconnection module.

11. A system as recited in claim 10 wherein said channel access processor include a dispatch pool register for associating remote stations with a dispatch pool, said channel access processor regulating the receipt and transmission of dispatch messages received from remote stations by said interconnection modules through said radio frequency interface.

12. A method of providing communication of voice or data or voice and data messages in a cellular radio telephony system having a plurality of remote stations for communicating through a radio frequency interface with a plurality of base stations, said base stations being connected as nodes to a local area network and connected through a switching center to a switched telephone network, there being at least one radio frequency interface for each cell of said cellular system, the method comprising:

receiving registrations through said radio frequency interfaces from said remote stations at corresponding ones of said base stations, said registrations identifying said remote stations for access to said local area network or to said switched telephone network;

recording said registrations at said corresponding base stations;

receiving a message from a registered remote station;

routing said message alternately to said local area network or to said switched telephone network based on said recorded registration.

13. A method as recited in claim 12 wherein said step of receiving a message further includes,

receiving a reverse allocation request from said remote station;

transmitting a reverse assignment to the remote station; and

receiving said message on said allocated reverse channel.

14. A method of providing communication of voice or data or voice and data messages in a cellular radio telephony system having a plurality of remote stations for communicating through a radio frequency interface with a plurality of base stations, said base stations being interconnected by a local area network, there being at least one radio frequency interface for each cell of said cellular system, the method comprising:

receiving registrations through said radio frequency interfaces from said remote stations at corresponding ones of said base stations;

recording said registrations at said corresponding base stations;

receiving a message for communication to one or more remote stations and, associated with said message, an identification of said remote stations to which said message is to be communicated;

transmitting said message and said associated remote station identification to each of said base stations using said local area network;

at each base station, comparing said associated station identification to said recorded remote station registrations; and

if said associated station identification matches a recorded remote station registration, transmitting said message to the corresponding registered remote station through said corresponding radio frequency interface.

15. A method as recited in claim 14 wherein said step of receiving a message comprises receiving a message from a remote station through a radio frequency interface.

16. A method as recited in claim 14 wherein said cellular system further comprises a gateway connected to said local area network and wherein said step of receiving a message comprises receiving a message from an external source through said gateway.

17. A method as recited in claim 14 including the further steps of:

initiating a dispatch setup by receiving an identification of remote stations to be included in a dispatch pool from a dispatch initiator;

registering an identification for the dispatch pool along with the identification of remote stations to be included in the dispatch pool, and

wherein said step of receiving a message comprises receiving a message for transmission to members of the pool by receiving said message from the dispatch initiator.

18. A method as recited in claim 17 including the further step of receiving a second message from a member of said dispatch pool for transmission to members of said dispatch pool said member from which said second message is received not being said dispatch initiator.

19. A method as recited in claim 17 wherein said step of receiving an identification of remote stations in a dispatch pool comprises receiving said identification at a given base station from a remote station, wherein said step of registering said identification comprises registering in said given base station an identification for the pool and wherein said step of receiving a message comprises receiving said message at said given base station.

20. A method as recited in claim 17 wherein said step of receiving an identification of remote stations in a dispatch pool comprises receiving said identification at a gateway connected to said local area network from an external source, wherein said step of registering said identification comprises registering in said gateway an identification for said dispatch pool and wherein said step of receiving a message comprises receiving said message at said gateway.

21. A method as recited in claim 17 including the further step of transmitting said identification for said dispatch pool along with said identification of remote stations to be included in said dispatch pool to each of said base stations using said local area network wherein said associated station identification comprises an identification of a dispatch pool and wherein said step of comparing said associated station identification comprises comparing said associated dispatch pool identification with said identification of said pool.

22. A method as recited in claim 14 including the further step of:

at a station other than said given station, copying said message for transmission to a mobile station registered with said other station.

23. A method as recited in claim 22 wherein said associated station identification includes an identification of the source of said message, and said step of transmitting said message at said other station includes identifying the dispatch pool associated with said message by the correlation between the dispatch pool and the source of said message.

24. A cellular radio telephony system for communication of voice or data messages between remote stations, a public switched telephone network, and a public data network comprising:

a plurality of base stations, each base station having at least one radio frequency interface to said remote stations for each cell in said cellular system, each radio frequency interface comprising a forward radio channel for communications from the base station to the remote station and a reverse radio channel for communications from the remote station to the base station;

a mobile switching center coupled to said public switched telephone network and in direct communication with each of said base stations, said mobile switching center capable of directly routing a message from one of said base stations to another of said base stations independent of said public switched telephone network; and

a local area network interconnecting the plurality of base stations, said local area network allowing at least one of said base stations to communicate with another of said base stations independent of said public switched telephone network.

25. A method of providing dispatch operations in a cellular telephone system comprising the steps of:

receiving a dispatch setup message at a first base station over a reverse radio channel from a dispatch initiator, said dispatch setup message including an identifier for a dispatch pool, said dispatch pool includes a plurality of mobile stations, and an identifier for each mobile station to be included in the dispatch pool, said mobile stations including a first mobile station registered with said first base station and a second mobile station registered with a second base station;

storing the dispatch pool in a memory in said first base station, said dispatch pool including said dispatch pool identifier and said mobile station identifiers;

transmitting said dispatch pool to said second base station over a local area network, said local area network inter-connecting said first and second base stations;

storing said dispatch pool in a memory in said second base station;

receiving a dispatch transaction message at said base station from said dispatch initiator over a reverse radio channel, said dispatch transaction message comprising a voice traffic burst and said dispatch pool identifier;

comparing said received dispatch pool identifier recovered from said transaction message with said dispatch pool identifier previously stored in said first base station memory;

determining that said first mobile station is registered in said first base station and is a member of said dispatch pool;

transmitting said voice traffic burst to said first mobile station;

determining whether said second mobile station is registered in said first base station;

transmitting over said local area network a message containing said dispatch pool identifier and said voice traffic burst to said second base station;

comparing said dispatch pool identifier with said dispatch pool identifier previously stored in said second base station memory;

determining that said second mobile station is registered in said second base station; and

transmitting said voice traffic burst to said second mobile from said second base station via a forward radio channel.