METHOD OF PERFORMING UPLINK SYNCHRONIZATION IN WIRELESS COMMUNICATION SYSTEM

• US 20080310396A1
• Filed: 06/18/2008
• Published: 12/18/2008
• Est. Priority Date: 06/18/2007
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Park, Sung Jun, Lee, Young Dae, Yi, Seung June, Chun, Sung Duck
• Granted Patent: US 8,107,456 B2
• Time in Patent Office: Days
• US Class Current: 370/350
• CPC Class Codes: H04W 56/0005 synchronizing of arrival of multiple uplinks
• CPC Class Codes: H04W 56/0015 one node acting as a reference for the others
• CPC Class Codes: H04W 56/0045 compensating for timing error by altering transmission time
• CPC Class Codes: H04W 74/008 with additional processing of random access related information at receiving side
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access

Abstract

A method of performing uplink synchronization in a wireless communication system includes transmitting a random access preamble which is randomly selected from a set of random access preambles, receiving a random access response, the random access response comprising a random access preamble identifier corresponding to the random access preamble and a time alignment value for uplink synchronization, starting a time alignment timer after applying the time alignment value, starting a contention resolution timer after receiving the random access response, wherein contention resolution is not successful when the contention resolution timer is expired, and stopping the time alignment timer when the contention resolution timer is expired.

Claims

1. A method of performing uplink synchronization in a wireless communication system, the method comprising:

transmitting a random access preamble which is randomly selected from a set of random access preambles;

receiving a random access response, the random access response comprising a random access preamble identifier corresponding to the random access preamble and a time alignment value for uplink synchronization;

starting a time alignment timer after applying the time alignment value;

starting a contention resolution timer after receiving the random access response, wherein contention resolution is not successful when the contention resolution timer is expired; and

stopping the time alignment timer when the contention resolution timer is expired.

2. The method of claim 1, further comprising:

transmitting a scheduled message, the scheduled message comprising a unique identifier; and

stopping the contention resolution timer when receiving a contention resolution message, the contention resolution message comprising a contention resolution identifier corresponding to the unique identifier.

3. The method of claim 2, wherein the contention resolution timer is started when transmitting the scheduled message.

4. The method of claim 2, wherein the random access response further comprises uplink radio resource assignment, and the scheduled message is transmitted in the uplink radio resource assignment.

5. A method of performing uplink synchronization in a wireless communication system, the method comprising:

transmitting a random access preamble which is randomly selected from a set of random access preambles;

receiving a random access response, the random access response comprising a random access preamble identifier corresponding to the random access preamble;

starting a time alignment timer after receiving a random access response; and

stopping the time alignment timer when contention resolution is not successful.

6. The method of claim 5, further comprising:

processing a time alignment value for uplink synchronization, wherein the time alignment value is received through the random access response.

7. The method of claim 5, wherein the contention resolution is not successful when a contention resolution timer is expired.

8. The method of claim 7, wherein the contention resolution timer is started after receiving the random access response.

9. The method of clam 5, further comprising:

transmitting a scheduled message after receiving the random access response, the scheduled message comprising a unique identifier.

10. The method of claim 9, wherein the contention resolution is not successful when a contention resolution message is not received, the contention resolution message comprising a contention resolution identifier corresponding to the unique identifier.

11. The method of claim 10, further comprising:

starting a contention resolution timer when transmitting the scheduled message, wherein contention resolution is not successful when the contention resolution message is not received until the contention resolution timer is expired.

12. The method of claim 10, further comprising:

starting a contention resolution timer when transmitting the scheduled message, wherein contention resolution is not successful when the contention resolution message indicated by physical downlink control channel (PDCCH) addressed by temporary C-RNTI which is included in the random access response includes the contention resolution identifier which does not match with the unique identifier before the contention resolution timer is expired.