RE-SYNCHRONIZATION OF TEMPORARY UE IDS IN A WIRELESS COMMUNICATION SYSTEM

• US 20100189071A1
• Filed: 10/02/2007
• Published: 07/29/2010
• Est. Priority Date: 10/03/2006
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Kitazoe, Masato
• Granted Patent: US 8,374,150 B2
• Time in Patent Office: Days
• US Class Current: 370/331
• CPC Class Codes: H04W 74/002 Transmission of channel access control information
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access
• CPC Class Codes: H04W 74/0866 using a dedicated channel for access

Abstract

Techniques for re-synchronizing Cell Radio Network Temporary Identifiers (C-RNTIs) in a wireless communication system are described. In one design, a user equipment (UE) sends a random access preamble for random access. A base station receives the random access preamble, assigns a Temporary C-RNTI to the UE, and sends a random access response including the Temporary C-RNTI. The UE uses the Temporary C-RNTI as a C-RNTI for itself if a valid C-RNTI is not already available. The UE discards the Temporary C-RNTI and uses the valid C-RNTI if available. The UE sends a transmission after receiving the random access response, and the transmission may include the valid C-RNTI if available. For handover, the base station (a target base station) receives a handover request from a source base station, assigns the valid C-RNTI to the UE, and sends the valid C-RNTI to the source base station for forwarding to the UE.

Claims

1. An apparatus for wireless communication, comprising:

at least one processor configured to send a random access preamble for random access by a user equipment (UE), to receive a random access response comprising a Temporary Cell Radio Network Temporary Identifier (C-RNTI), to use the Temporary C-RNTI as a C-RNTI for the UE if a valid C-RNTI is not already available, and to discard the Temporary C-RNTI and use the valid C-RNTI if available; and

a memory coupled to the at least one processor.

2. The apparatus of claim 1, wherein the at least one processor is configured to send a transmission after receiving the random access response, the transmission comprising the valid C-RNTI if available.

3. The apparatus of claim 1, wherein the at least one processor is configured to send a transmission after receiving the random access response, the transmission not including the Temporary C-RNTI if used as the C-RNTI for the UE.

4. The apparatus of claim 1, wherein the at least one processor is configured to receive the valid C-RNTI from a source base station prior to the random access, to send the random access preamble for handover from the source base station to a target base station, and to receive the random access response from the target base station.

5. The apparatus of claim 4, wherein the valid C-RNTI is assigned by the target base station, sent to the source base station, and forwarded by the source base station in a handover command.

6. The apparatus of claim 1, wherein the at least one processor is configured to send the random access preamble for timing synchronization update when the valid C-RNTI is available, and to discard the Temporary C-RNTI and continue to use the valid C-RNTI.

7. The apparatus of claim 1, wherein the at least one processor is configured to send the random access preamble for initial system access when the valid C-RNTI is not available, and to use the Temporary C-RNTI as the C-RNTI for the UE.

8. The apparatus of claim 1, wherein the at least one processor is configured to send the random access preamble for transition from an idle state to an active state when the valid C-RNTI is not available, and to use the Temporary C-RNTI as the C-RNTI for the UE.

9. A method for wireless communication, comprising:

sending a random access preamble for random access by a user equipment (UE);

receiving a random access response comprising a Temporary Cell Radio Network Temporary Identifier (C-RNTI);

using the Temporary C-RNTI as a C-RNTI for the UE if a valid C-RNTI is not already available; and

discarding the Temporary C-RNTI and using the valid C-RNTI if available.

10. The method of claim 9, further comprising:

sending a transmission after receiving the random access response, the transmission comprising the valid C-RNTI if available.

11. The method of claim 9, further comprising:

receiving the valid C-RNTI from a source base station prior to the random access, wherein the sending the random access preamble comprises sending the random access preamble for handover from the source base station to a target base station, and wherein the receiving the random access response comprises receiving the random access response comprising the Temporary C-RNTI from the target base station.

12. The method of claim 9, wherein the sending the random access preamble comprises sending the random access preamble for timing synchronization update when the valid C-RNTI is available, and wherein the Temporary C-RNTI is discarded and the valid C-RNTI is used.

13. The method of claim 9, wherein the sending the random access preamble comprises sending the random access preamble for initial system access or for transition from an idle state to an active state when the valid C-RNTI is not available, and wherein the Temporary C-RNTI is used as the C-RNTI for the UE.

14. An apparatus for wireless communication, comprising:

means for sending a random access preamble for random access by a user equipment (UE);

means for receiving a random access response comprising a Temporary Cell Radio Network Temporary Identifier (C-RNTI);

means for using the Temporary C-RNTI as a C-RNTI for the UE if a valid C-RNTI is not already available; and

means for discarding the Temporary C-RNTI and using the valid C-RNTI if available.

15. The apparatus of claim 14, further comprising:

means for sending a transmission after receiving the random access response, the transmission comprising the valid C-RNTI if available.

16. The apparatus of claim 14, further comprising:

means for receiving the valid C-RNTI from a source base station prior to the random access, wherein the means for sending the random access preamble comprises means for sending the random access preamble for handover from the source base station to a target base station, and wherein the means for receiving the random access response comprises means for receiving the random access response comprising the Temporary C-RNTI from the target base station.

17. A machine-readable medium comprising instructions which, when executed by a machine, cause the machine to perform operations including:

sending a random access preamble for random access by a user equipment (UE);

receiving a random access response comprising a Temporary Cell Radio Network Temporary Identifier (C-RNTI);

using the Temporary C-RNTI as a C-RNTI for the UE if a valid C-RNTI is not already available; and

discarding the Temporary C-RNTI and using the valid C-RNTI if available.

18. An apparatus for wireless communication, comprising:

at least one processor configured to receive a random access preamble for random access by a user equipment (UE), to assign a Temporary Cell Radio Network Temporary Identifier (C-RNTI) to the UE, to send a random access response comprising the Temporary C-RNTI, to use the Temporary C-RNTI as a C-RNTI for the UE if a valid C-RNTI is not already available at the UE, and to release the Temporary C-RNTI and use the valid C-RNTI if received from the UE; and

a memory coupled to the at least one processor.

19. The apparatus of claim 18, wherein the at least one processor is configured to receive a transmission from the UE after sending the random access response, the transmission comprising the valid C-RNTI if available at the UE.

20. The apparatus of claim 18, wherein the at least one processor is configured to receive a handover request from a source base station for the UE, to assign the valid C-RNTI to the UE in response to the handover request, to send the valid C-RNTI to the source base station for forwarding to the UE, and to receive the random access preamble from the UE for handover from the source base station to a target base station.

21. The apparatus of claim 18, wherein the at least one processor is configured to receive the random access preamble from the UE for timing synchronization update when the UE already has the valid C-RNTI, to receive a transmission comprising the valid C-RNTI from the UE after sending the random access response, and to release the Temporary C-RNTI and use the valid C-RNTI for the UE.

22. The apparatus of claim 18, wherein the at least one processor is configured to receive the random access preamble from the UE for initial system access, and to use the Temporary C-RNTI as the C-RNTI for the UE.

23. The apparatus of claim 18, wherein the at least one processor is configured to receive the random access preamble from the UE for transition from an idle state to an active state, and to use the Temporary C-RNTI as the C-RNTI for the UE.

24. A method for wireless communication, comprising:

receiving a random access preamble for random access by a user equipment (UE);

assigning a Temporary Cell Radio Network Temporary Identifier (C-RNTI) to the UE;

sending a random access response comprising the Temporary C-RNTI;

using the Temporary C-RNTI as a C-RNTI for the UE if a valid C-RNTI is not already available at the UE; and

releasing the Temporary C-RNTI and using the valid C-RNTI if received from the UE.

25. The method of claim 24, further comprising:

receiving a transmission from the UE after sending the random access response, the transmission comprising the valid C-RNTI if available at the UE.

26. The method of claim 24, further comprising:

receiving a handover request from a source base station for the UE;

assigning the valid C-RNTI to the UE in response to the handover request; and

sending the valid C-RNTI to the source base station for forwarding to the UE, wherein the random access preamble is received from the UE for handover from the source base station to a target base station.

27. The method of claim 24, wherein the receiving the random access preamble comprises receiving the random access preamble from the UE for timing synchronization update when the UE already has the valid C-RNTI, wherein the method further comprises receiving a transmission comprising the valid C-RNTI from the UE after sending the random access response, and wherein the Temporary C-RNTI is released and the valid C-RNTI is used for the UE.

28. The method of claim 24, wherein the receiving the random access preamble comprises receiving the random access preamble from the UE for initial system access or for transition from an idle state to an active state, and wherein the Temporary C-RNTI is used as the C-RNTI for the UE.

29. An apparatus for wireless communication, comprising:

means for receiving a random access preamble for random access by a user equipment (UE);

means for assigning a Temporary Cell Radio Network Temporary Identifier (C-RNTI) to the UE;

means for sending a random access response comprising the Temporary C-RNTI;

means for using the Temporary C-RNTI as a C-RNTI for the UE if a valid C-RNTI is not already available at the UE; and

means for releasing the Temporary C-RNTI and using the valid C-RNTI if received from the UE.

30. The apparatus of claim 29, further comprising:

means for receiving a transmission from the UE after sending the random access response, the transmission comprising the valid C-RNTI if available at the UE.

31. The apparatus of claim 29, further comprising:

means for receiving a handover request from a source base station for the UE;

means for assigning the valid C-RNTI to the UE in response to the handover request; and

means for sending the valid C-RNTI to the source base station for forwarding to the UE, wherein the random access preamble is received from the UE for handover from the source base station to a target base station.

32. A machine-readable medium comprising instructions which, when executed by a machine, cause the machine to perform operations including:

receiving a random access preamble for random access by a user equipment (UE);

assigning a Temporary Cell Radio Network Temporary Identifier (C-RNTI) to the UE;

sending a random access response comprising the Temporary C-RNTI;

using the Temporary C-RNTI as a C-RNTI for the UE if a valid C-RNTI is not already available at the UE; and

releasing the Temporary C-RNTI and using the valid C-RNTI if received from the UE.