Method of performing uplink synchronization in wireless communication system

• US 9,538,490 B2
• Filed: 04/16/2015
• Issued: 01/03/2017
• 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
• Primary Examiner(s): Abelson, Ronald B
• Application Number:
  US14/688,808
• Publication Number:
  US 20150223183A1
• Time in Patent Office: 628 Days
• Field of Search: 370/324, 370/350, 370/395, 370/62, 370/503, 370/509, 370/512
• US Class Current: 1/1
• 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, by a user equipment (UE), a first random access preamble to a network;

receiving, by the UE, a random access response comprising a timing alignment command from the network, wherein the random access response is identified by an identifier associated with a radio network temporary identity;

starting, by the UE, a time alignment timer after receiving the timing alignment command;

stopping, by the UE, the time alignment timer when contention resolution between the UE and the network is considered not successful; and

if the UE stops the time alignment timer, transmitting, by the UE, a second random access preamble to the network or reporting, by the UE, to a radio resource control (RRC) layer that the contention resolution is considered not successful.

2. The method of claim 1, wherein the random access response further comprises a temporary UE identifier.

3. The method of claim 1, further comprising:

starting, by the UE, a contention resolution timer after receiving the random access response.

4. The method of claim 3, wherein the contention resolution is considered not successful if the contention resolution timer is expired.

5. The method of claim 1, wherein the first random access preamble is selected by the UE from a set of random access preambles.

6. A user equipment (UE) of performing uplink synchronization in a wireless communication system, the UE comprising:

a transceiver; and

a processor coupled with the transceiver and configured to

transmit a first random access preamble to a network;

receive a random access response comprising a timing alignment command from the network, wherein the random access response is identified by an identifier associated with a radio network temporary identity;

start a time alignment timer after receiving the timing alignment command;

stop the time alignment timer when contention resolution between the UE and the network is considered not successful; and

if the UE stops the time alignment timer, transmit a second random access preamble to the network or report to a radio resource control (RRC) layer that the contention resolution is considered not successful.

7. The UE of claim 6, wherein the random access response further comprises a temporary UE identifier.

8. The UE of claim 6, wherein the processor is further configured to start a contention resolution timer after receiving the random access response.

9. The UE of claim 8, wherein the contention resolution is considered not successful if the contention resolution timer is expired.

10. The UE of claim 6, wherein the first random access preamble is selected by the UE from a set of random access preambles.