Trunking system for CDMA wireless communication

• US 7,453,837 B2
• Filed: 12/05/2002
• Issued: 11/18/2008
• Est. Priority Date: 08/15/2002
• Status: Active Grant

• Current Assignee: Yarnton Technologies LLC
• Original Assignee: ZTE USA, Inc. (ZTE Corporation)
• Inventors: Bhalla, Rajesh, Chion, Mary, Fang, Yonggang, Jiang, James
• Primary Examiner(s): Milord; Marceau
• Application Number:
  US10/313,943
• Publication Number:
  US 20040042438A1
• Time in Patent Office: 2,175 Days
• Field of Search: 370/320, 370/342, 370/327, 370/340, 370/335, 370/441, 370/337, 455/518, 455/519, 455/426.1
• US Class Current: 370/320
• CPC Class Codes: H04W 12/06 Authentication
• CPC Class Codes: H04W 12/08 Access security
• CPC Class Codes: H04W 12/76 Group identity
• CPC Class Codes: H04W 4/08 User group management
• CPC Class Codes: H04W 4/10 Push-to-Talk [PTT] or Push-On-Call services
• CPC Class Codes: H04W 52/12 Outer and inner loops
• CPC Class Codes: H04W 76/45 for Push-to-Talk [PTT] or Push-to-Talk over cellular [PoC] services
• CPC Class Codes: H04W 84/08 Trunked mobile radio systems

Abstract

Methods and systems for implementing trunking techniques in CDMA systems for handling group calls and push-to-talk services.

Claims

1. A CDMA communication system, comprising:

a plurality of base transceiver stations spatially distributed to communicate with mobile communication devices via radio links;

a plurality of base station controllers, each coupled to a plurality of base transceiver stations;

a mobile switching center connected to couple said base station controllers to a public telephone network;

a data communication system comprising (1) a plurality of packet control function devices respectively connected to said base station controllers to transmit data packets to and from the mobile communication devices via said base transceiver stations, and (2) a packet data serving node connected to said packet control function devices to provide packet data services to the-mobile communication devices; and

a trunking system comprising (1) a plurality of dispatching clients respectively connected to said base station controllers to transmit data packets of group calls to and from mobile communication devices of groups of subscribers where members of each group share a common trunking data link for transmission of data packets, and (2) at least one dispatching server connected to said packet data network to communicate with said dispatching clients, wherein said dispatching server and said dispatching clients are operable in combination to provide a push-to-talk function for a group call within each group.

2. The system as in claim 1, wherein said data communication system is coupled to share said packet data network with said trunking system.

3. The system as in claim 2, wherein said packet data network is an Internet Protocol network.

4. The system as in claim 2, wherein said packet data serving node is located in a communication path between a dispatching client and said dispatching server.

5. The system as in claim 1, wherein said data communication system is coupled to a second packet data network that is separate from said packet network.

6. The system as in claim 1, wherein said packet data network is an Internet Protocol network.

7. The system as in claim 1, wherein each dispatching client communicates with a connected base station controller via a first interface to provide a path for user data traffic and a second interface to provide a signaling connection, and communicates with said dispatching server via a third interface to provide a path for user data traffic and a fourth interface to provide a signaling connection.

8. The system as in claim 7, wherein said first, said second, said third, and said fourth interfaces are A8, A9, A10, and A11 interfaces, respectively.

9. The system as in claim 7, wherein said first, said second, said third, and said fourth interfaces are not A8, A9, A10, and A11 interfaces, respectively.

10. The system as in claim 1, wherein said trunking system further includes a group registration database to store information on trunking groups and group membership, a security server to authenticate group calls, and a dispatching location server to provide location information of group members in a group call, and wherein said dispatching server is in communication with said group registration database, said security server, and said dispatching location server, and is coupled to receive group call information for processing a group call.

11. The system as in claim 10, wherein said dispatching location server is coupled to said dispatching server via said packet data network.

12. The system as in claim 10, wherein said dispatching location server is integrated with and in direction communication with said dispatching server without going through said packet data network.

13. The system as in claim 10, wherein said trunking system is configured to support permanent trunking groups that are registered in said group registration database and temporary trunking groups that are not registered in said group registration database.

14. The system as in claim 13, wherein said trunking system is configured to authorize only a selected member of a permanent trunking group to change membership of said permanent trunking group by sending a message to said group registration database.

15. The system as in claim 13, wherein said trunking system is configured to authorize any member of a temporary trunking group to change membership of said temporary trunking group by sending said dispatching server a message with a list of phone numbers of members in said temporary trunking group, without sending a message to said group registration database.

16. The system as in claim 1, wherein said trunking system further comprising additional dispatching clients and an additional dispatching server in communication with said additional dispatching clients to handle group calls in additional base station controllers and additional base transceiver stations that are not connected to said dispatching clients and said dispatching server, and

wherein additional dispatching server is connected to said dispatching server.

17. The system as in claim 1, wherein said trunking system includes a message router to direct, according to a service category, a trunking message to said dispatching server through a corresponding dispatching client, a message for a packet data service to said packet data serving node, and a message for a normal voice or data call to said mobile switching center.

18. The system as in claim 1, wherein said trunking system is configured to provide a common trunking message link between each dispatching client and said dispatching server to transmit trunking messages.

19. The system as in claim 1, wherein said trunking system is configured to process trunking messages in the Short Data Burst format.

20. The system as in claim 1, wherein said trunking system is configured to include in each trunking message a data field for a group call service category, and address information for a trunking group and group members.

21. The system as in claim 1, wherein said trunking system is configured to have a protocol between each dispatching client and said dispatching server that does not have a point-to-point protocol layer.

22. The system as in claim 1, wherein said trunking system is configured to:

page members of a trunking group in response to a group call request from said trunking group in accordance with location information of said group members provided to said dispatching server;

authenticate said group call request by checking information on said trunking group, membership information, and information on network registration of each member; and

disable a slotted mode in a dormant state for each mobile communication device in said trunking group.

23. The system as in claim 22, wherein, in execution of the paging, said trunking system commands a corresponding dispatching client to send a paging signal to each base station controller which locates and pages group members.

24. The system as in claim 22, wherein said trunking system commands said dispatching server to check said information on said trunking group and said membership information.

25. The system as in claim 22, wherein said information on network registration of each member is received from said mobile switching center.

26. The system as in claim 1, wherein said dispatching server is configured to include an arbitration mechanism to prioritize group call requests.

27. The system as in claim 1, wherein said trunking system is configured to release a group call after receiving a release signal from a corresponding trunking group.

28. The system as in claim 1, wherein said trunking system is configured to release a group call prior to receiving a lease signal from a corresponding trunking group.

29. The system as in claim 28, wherein said group call is formed to release after said group call remains in a dormant state for a period of time.

30. The system as in claim 1, wherein said trunking system is configured to allow a group member to join a group call during said group call.

31. The system as in claim 1, wherein said trunking system is configured to allow said dispatching server to periodically page a group member absent from an on-going group call to join said group call.

32. The system as in claim 1, wherein said mobile switching center is configured to handle billing on a group call through said trunking system.

33. The system as in claim 1, wherein said trunking system is configured to establish forward channels in a group call, said forward channels comprising:

a forward dedicated control channel (F-DCCH) to carry signaling messages and power control information for each trunking group member, and

a forward supplemental channel (F-SCH) that carries user data of said group call and is shared by members of said trunking group.

34. The system as in claim 33, wherein both said F-DCCH and said F-SCH are configured to share a common long code sequence among group members.

35. The system as in claim 34, wherein a common Walsh code in said F-SCH is shared by group members in a common sector in a sectorized cell arrangement.

36. The system as in claim 34, wherein a unique Walsh code is assigned to each F-DCCH for each group member.

37. The system as in claim 34, wherein said trunking system is configured to have a first power control channel on said F-DCCH and a second, independent power control channel on said F-SCH.

38. The system as in claim 1, wherein said trunking system is configured to provide a single reverse dedicated control channel (R-DCCH) to each group member of a trunking group to carry signaling messages, power control information, and user data traffic.

39. The system as in claim 1, wherein said trunking system is configured to provide to each group member of a trunking group a reverse dedicated control channel (R-DCCH) to carry signaling messages and power control information, and a reverse supplemental channel (R-SCH) to carry user data traffic.

40. The system as in claim 1, wherein said trunking system is configured to support both soft and softer handoffs.

41. The system as in claim 1, wherein said trunking system is configured to provide a common frame offset to group members of a trunking group during a group call.

42. The system as in claim 1, wherein said trunking system is configured to monitor an activity of a group call and, after no data is transmitted in said group call for a period of time, set a group call into a dormant state in which at least one physical channel is released for other services.

43. The system as in claim 42, wherein said trunking system is further configured to set said group call into said dormant state prior to expiration of said period of time when there is a shortage in system resource.

44. The system as in claim 1, wherein said trunking system is configured to include a voice loop-back avoidance mechanism in processing group calls to prevent user data sent out by a group member from coming back to said group member.