Wireless CDMA system having a unique forward configuration control channel

• US 6,381,235 B1
• Filed: 05/29/1998
• Issued: 04/30/2002
• Est. Priority Date: 05/29/1998
• Status: Expired due to Term

• Current Assignee: RPX Corporation
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Kamel, Raafat E., Mizikovsky, Semyon B., Kuo, Wen-Yi, Koo, Yuen-Yin L.
• Primary Examiner(s): Ton, Dang
• Assistant Examiner(s): NGUYEN, TOAN D
• Application Number:
  US09/086,485
• Time in Patent Office: 1,432 Days
• Field of Search: 370/342, 370/335, 370/320, 370/208, 370/209, 370/441, 370/479, 370/524
• US Class Current: 370/342
• CPC Class Codes: H04J 13/0048 Walsh
• CPC Class Codes: H04J 13/18 Allocation of orthogonal codes
• CPC Class Codes: H04W 28/06 Optimizing the usage of the radio link, e.g. header compression, information sizing , discarding information system modifying transmission characteristic according to link quality by modifying frame length H04L1/0007; dynamic adaptation of the packet size for flow control or congestion control H04L47/365
• CPC Class Codes: H04W 36/18 for allowing seamless reselection, e.g. soft reselection
• CPC Class Codes: H04W 48/08 Access restriction or access information delivery, e.g. discovery data delivery signalling during connection H04W76/00
• CPC Class Codes: H04W 56/00 Synchronisation arrangements
• CPC Class Codes: H04W 72/00 Local resource management
• CPC Class Codes: H04W 74/0866 using a dedicated channel for access
• CPC Class Codes: H04W 8/20 Transfer of user or subscriber data

Abstract

The wireless CDMA system includes a base station which generates a configuration channel as one of the forward control channels. The message slots in the configuration channel only include overhead messages. The base station also generates at least one other forward control channel, but these other forward control channels do not need to include overhead messages in any of their message slots. The mobiles in the system determine the location of the configuration channel from information in a sync channel generated by the base station. By camping onto the configuration channel, a mobile can quickly obtain the overhead parameters in the overhead messages. Because obtaining overhead parameters and keeping an updated version of the overhead parameters is an important factor in overall performance, the significant decrease in overhead message access time provided by the provision of the configuration channel greatly improves performance.

Claims

1. A method of transmitting forward control channels from a base station in a wireless CDMA system, each forward control channel being assigned a separate orthogonal code, comprising:

first generating at least one forward control channel having a first plurality of slots, at least one of said first plurality of slots including a mobile specific message;

second generating a configuration channel as an other forward control channel having a second plurality of slots, said second plurality of only including overhead messages; and

transmitting said forward control channels including said configuration channel.

2. The method of claim 1, wherein said overhead messages include a neighbor list message, and overhead parameters in said neighbor list message list pilot channel offset indices for base stations of neighboring cells and indicate whether each listed base station transmits a configuration channel and a location of said transmitted configuration channel.

3. The method of claim 1, wherein said first plurality of slots does not include overhead messages.

4. The method of claim 1, wherein said second generating step sets a predetermined Walsh code for said configuration channel.

5. The method of claim 1, wherein said second generating step sets a Walsh code for said configuration channel as a highest Walsh code of said forward control channels generated in said first generating step plus one.

9. The base station of claim 4, wherein said forward control channel generator sets a predetermined Walsh code for said configuration channel.

6. A base station of a wireless CDMA system, comprising:

a pilot channel generator generating a pilot channel having a predetermined offset index;

a forward control channel generator generating at least a first paging channel having a first plurality of slots and configuration channel having a second plurality of slots, said configuration channel being assigned an orthogonal code different from an orthogonal code assigned to other paging channels, said second plurality of slots only including overhead messages, and at least one of said first plurality of slots including a mobile specific message; and

a controller controlling operation of said pilot channel generator and said forward control channel generator.

7. The base station of claim 6, wherein said overhead messages include a neighbor list message, and overhead parameters in said neighbor list message list pilot channel offset indices for base stations of neighboring cells and indicates whether each listed base station transmits a configuration channel and a location of said transmitted configuration channel.

8. The base station of claim 6, wherein said first plurality of slots does not include overhead messages.

10. The base station of claim 6, wherein said forward control channel generator sets a Walsh code for said configuration channel as a highest Walsh code for one of said paging channels plus one.

11. The base station of claim 6, further comprising:

a sync channel generator generating a sync channel associated with said pilot channel, said sync channel indicating a location of said configuration channel.

12. A method of initializing a mobile in a wireless CDMA system, comprising:

camping onto a sync channel associated with a received pilot channel, said sync channel including information indicating a location of a configuration channel, said configuration channel having a separate orthogonal code from paging channels;

camping onto said configuration channel based on said information in said sync channel, said configuration channel including a plurality of slots, said plurality of slots only including overhead messages; and

obtaining overhead parameters in said overhead messages from said configuration channel.

13. The method of claim 12, wherein

said overhead messages include a channel list message indicating a number of paging channels associated with said received pilot channel, and further including the steps of,

determining a paging channel containing a mobile specific message slot for said mobile based on said number of paging channels indicated by said obtained overhead parameters in said channel list message; and

hashing onto said determined paging channel.

22. The method of claim 12, wherein said orthogonal code is a Walsh code.

14. A mobile in a wireless CDMA system, comprising:

a pilot channel search engine camping onto a pilot channel;

a sync channel processor camping onto a sync channel associated with said pilot channel, said sync channel including information indicating a location of a configuration channel, said configuration channel having a separate orthogonal code from paging channels;

a forward control channel processor for camping onto a paging channel; and

a control unit controlling operation of said pilot channel search engine, said sync channel processor and said forward control channel processor, said control unit determining a location of said configuration channel from said information in said sync channel, and instructing said forward control channel processor to camp onto said configuration channel, said configuration channel including a plurality of slots, said plurality of slot only including overhead messages, and said control unit obtaining overhead parameters in said overhead messages from said configuration channel via said forward control channel processor.

15. The mobile of claim 14, wherein

said overhead messages include a channel list message indicating a number of paging channels associated with said pilot channel; and

said control unit determines a paging channel containing a mobile specific message slot for said mobile based on said number of paging channels indicated by said obtained overhead parameters in said channel list message, and instructs said forward control channel processor to hash onto said determined paging channel.

23. The system of claim 14, wherein said orthogonal code is a Walsh code.

16. A method of monitoring overhead messages at a mobile in a wireless CDMA system, comprising:

storing a message number associated with overhead parameters from at least one overhead message in a slot of overhead messages obtained from a configuration channel, slots in said configuration channel only including said overhead messages, said message number in a current slot of said configuration channel differing from said message number in a previous slot of said configuration channel if at least one of said associated overhead parameters in said overhead message in said current slot differs from said associated overhead parameter in said overhead message in said previous slot;

detecting a message number in a slot of a paging channel being monitored by said mobile;

determining if said stored message number matches said detected message number; and

obtaining at least said associated overhead parameters from said configuration channel if said stored message number does not match said detected message number.

24. The method of claim 16, wherein said configuration channel has a separate orthogonal code from paging channels.

17. A mobile of a wireless CDMA system, comprising:

a forward control channel processor camped onto a paging channel;

a memory storing a message number associated with overhead parameters from at least one overhead message in a slot of overhead messages obtained from a configuration channel, slots in said configuration channel only including said overhead messages, said message number in a current slot of said configuration channel differing from said message number in a previous slot of said configuration channel if at least one of said associated overhead parameters in said overhead message in said current slot differs from said associated overhead parameter in said overhead message in said previous slot; and

a control unit instructing said forward control channel processor to detect a message number in a slot of said paging channel, determining if said detected message number matches said stored message number, and instructing said forward control channel processor to camp onto said configuration channel and obtain said associated overhead parameters from said configuration channel if said detected message number does not match said stored message number.

25. The method of claim 26, wherein said orthogonal code is a Walsh code.

26. The system of claim 17, wherein said configuration channel has a separate orthogonal code from forward control channels.

27. The system of claim 26, wherein said orthogonal code is a Walsh code.

18. A method of initializing a mobile after an idle hand-off from a first base station to a second base station, comprising:

storing overhead parameters obtained from a configuration channel transmitted by said first base station, slots in said configuration channel only including overhead messages containing said overhead parameters, said overhead messages including a neighbor list message, said overhead parameters in said neighbor list message indicating at least a location of a configuration channel transmitted by said second base station;

camping onto said configuration channel transmitted by said second base station based on said location of said configuration channel transmitted by said second base station in said stored overhead parameters; and

obtaining said overhead parameters in said configuration channel transmitted by said second base station.

28. The method of claim 18, wherein said configuration channel has a separate orthogonal code from forward control channels.

29. The method of claim 28, wherein said orthogonal code is a Walsh code.

19. A mobile in a wireless CDMA system, comprising:

a forward control channel processor for camping onto a forward control channel;

a memory storing overhead parameters obtained from a configuration channel transmitted by a first base station, slots in said configuration channel only including overhead messages containing said overhead parameters, said overhead messages including a neighbor list message, said overhead parameters in said neighbor list message indicating at least a location of a configuration channel transmitted by a second base station;

a control unit determining said location of said configuration channel transmitted by said second base station from said stored overhead parameters when said control unit causes an idle hand-off from said first base station to said second base station, and instructing said forward control channel processor to camp onto said configuration channel transmitted by said second base station based on said determined location and obtain said overhead parameters in said configuration channel transmitted by said second base station.

30. The system of claim 19, wherein said configuration channel has a separate orthogonal code from forward control channels.

31. The method of claim 30, wherein said orthogonal code is a Walsh code.

20. A method of monitoring overhead messages at a mobile in a wireless CDMA system, comprising:

storing a message number associated with overhead parameters from at least one overhead message in a slot of overhead messages obtained from a configuration channel, slots in said configuration channel only including said overhead messages, said message number in a current slot of said configuration channel differing from said message number in a previous slot of said configuration channel if at least one of said associated overhead parameters in said overhead message in said current slot differs from said associated overhead parameter in said overhead message in said previous slot;

camping onto said configuration channel;

detecting said message number in a slot of said configuration channel;

determining if said stored message number matches said detected message number; and

obtaining said associated overhead parameters from said configuration channel if said stored message number does not match said detected message number.

32. The method of claim 20, wherein said configuration channel has a separate orthogonal code from forward control channels.

33. The method of claim 32, wherein said orthogonal code is a Walsh code.

21. A mobile in a wireless CDMA system, comprising:

a forward control channel processor camped onto a paging channel;

a memory storing a message number associated with overhead parameters from at least one overhead message in a slot of overhead messages obtained from a configuration channel, slots in said configuration channel only including said overhead messages, said message number in a current slot of said configuration channel differing from said message number in a previous slot of said configuration channel if at least one of said associated parameters in said overhead message in said current slot differs from said associated overhead parameter in said overhead message in said previous slot;

a control unit instructing said forward control channel processor to camp onto said configuration channel and detect a message number in a slot of said configuration channel, determining if said detected message number matches said stored message number, and instructing said forward control channel processor to obtain said associated overhead parameters from said configuration channel if said detected message number does not match said stored message number.

34. The system of claim 21, wherein said configuration channel has a separate orthogonal code from paging channels.

35. The system of claim 34, wherein said orthogonal code is a Walsh code.