METHOD OF PERFORMING UPLINK SYNCHRONIZATION IN RANDOM ACCESS PROCEDURE

• US 20110038361A1
• Filed: 10/21/2010
• Published: 02/17/2011
• Est. Priority Date: 03/14/2008
• Status: Active Grant

• Current Assignee: Optis Cellular Technology LLC (Brevet Capital)
• Original Assignee: Optis Cellular Technology LLC (Brevet Capital)
• Inventors: PARK, Sung Jun, Lee, Young Dae, Yi, Seung June, Chun, Sung Duck
• Granted Patent: US 9,008,072 B2
• Time in Patent Office: Days
• US Class Current: 370/350
• CPC Class Codes: H04B 7/2681 Synchronisation of a mobile station with one base station
• CPC Class Codes: H04J 11/003 at the transmitter transmission to multiple receive units in multiple input multiple output [MIMO] H04B7/0452; transmit antenna weighting H04B7/0615
• CPC Class Codes: H04J 2011/0096 Network synchronisation
• CPC Class Codes: H04W 56/0005 synchronizing of arrival of multiple uplinks
• CPC Class Codes: H04W 56/0045 compensating for timing error by altering transmission time
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 72/21 in the uplink direction of a wireless link, i.e. towards the network
• 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 88/16 Gateway arrangements

Abstract

A method and device for performing a contention based random access procedure by a mobile communication terminal in communication with a base station. The method according to an embodiment includes transmitting a random access preamble message to the base station; receiving a random access response from the base station, the random access response including a timing advance command; determining a status of a mobile communication terminal time alignment timer; and ignoring the timing advance command if the mobile communication terminal time alignment timer is determined to be running in the determining step.

Claims

1. A method of performing a random access procedure by a mobile terminal in communication with a base station, comprising:

transmitting a random access preamble to the base station;

receiving from the base station a random access response as a response to the random access preamble, the random access response including an uplink resource assignment and time alignment information;

determining whether an uplink is synchronized or not when the random access procedure is contention based; and

if the uplink is not synchronized, applying the time alignment information.

2. The method of claim 1, further comprising:

if the uplink is synchronized, ignoring the time alignment information.

3. The method of claim 2, further comprising:

initiating contention resolution with another mobile terminal trying the random access procedure by transmitting a scheduled message using the uplink resource assignment to the base station.

4. The method of claim 1, wherein the random access preamble is randomly selected from a plurality of available random access preambles when the random access procedure is contention based.

5. The method of claim 1, further comprising:

receiving a message from the base station before transmitting the random access preamble, the message comprising second time alignment information; and

applying the second time alignment information for uplink synchronization.

6. The method of claim 5, wherein the message is not a random access response.

7. The method of claim 1, further comprising:

applying the time alignment information when the random access procedure is non-contention based.

8. A mobile terminal configured to perform a random access procedure with a base station, the mobile terminal comprising:

a radio frequency (RF) unit; and

a processor operatively connected to the display and configured for;

transmitting a random access preamble to the base station;

receiving from the base station a random access response as a response to the random access preamble, the random access response including an uplink resource assignment and time alignment information;

determining whether an uplink is synchronized or not when the random access procedure is contention based; and

if the uplink is not synchronized, applying the time alignment information.

9. The mobile terminal of claim 8, wherein the processor is configured for ignoring the time alignment information if the uplink is synchronized.

10. The mobile terminal of claim 9, wherein the processor is configured for initiating contention resolution with another mobile terminal trying the random access procedure by transmitting a scheduled message using the uplink resource assignment to the base station when the uplink is synchronized.

11. The mobile terminal of claim 8, wherein the processor is configured for selecting randomly the random access preamble from a plurality of available random access preambles when the random access procedure is contention based.

12. The mobile terminal of claim 8, wherein the processor is configured for:

receiving a message from the base station before transmitting the random access preamble, the message comprising second time alignment information; and

applying the second time alignment information for uplink synchronization.

13. The mobile terminal of claim 8, wherein the processor is configured for applying the time alignment information when the random access procedure is non-contention based.