Method and apparatus for managing uplink time alignment

• US 9,265,018 B2
• Filed: 03/08/2012
• Issued: 02/16/2016
• Est. Priority Date: 03/29/2011
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Yi, Seung June, Chun, Sung Duck, Jung, Sung Hoon, Lee, Young Dae, Park, Sung Jun
• Primary Examiner(s): Jiang, Charles C
• Assistant Examiner(s): Kamara, Mohamed
• Application Number:
  US13/978,081
• Publication Number:
  US 20130279493A1
• Time in Patent Office: 1,440 Days
• Field of Search: 370/324, 370/350, 370/503, 370/338, 370/437, 370/447, 370/445, 370458-459, 370461-462, 455/51.5, 455/502, 455524-525, 455/450, 455/451, 455/452.1, 455/464
• US Class Current: 1/1
• CPC Class Codes: H04W 56/00 Synchronisation arrangements
• 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 74/004 in the uplink, i.e. towards network
• CPC Class Codes: H04W 74/006 in the downlink, i.e. towards the terminal
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access
• CPC Class Codes: H04W 92/10 between terminal device and access point, i.e. wireless air interface

Abstract

A method and apparatus of managing uplink time alignment in a wireless communication system is provided. A user equipment transmits a random access preamble to maintain an uplink time alignment to a base station and receives a random access response in response to the random access preamble from the base station.

Claims

1. A method of managing uplink time alignment in a wireless communication system, performed by a user equipment, the method comprising:

transmitting a random access preamble to maintain an uplink time alignment to a base station; and

receiving a random access response in response to the random access preamble from the base station,

wherein the random access preamble is a dedicated random access preamble used by the base station to determine whether to maintain the uplink time alignment,

wherein the random access preamble is transmitted while a prohibition timer is not running, and

wherein the prohibition timer is used to indicate a specific time period for prohibiting a triggering of a random access procedure to maintain the uplink time alignment.

2. The method of claim 1, further comprising:

starting a time alignment timer which is used to control how long the user equipment is considered uplink time aligned.

3. The method of claim 2, wherein the random access preamble is transmitted while the time alignment timer is running.

4. The method of claim 2, further comprising:

applying a timing advance command included in the random access response; and

restarting the time alignment timer upon receiving the random access response.

5. A user equipment for managing uplink time alignment in a wireless communication system, the user equipment comprising:

a radio frequency unit configured to receive a radio signal; and

a processor, operatively coupled with the radio frequency unit and configured to;

transmit a random access preamble to maintain an uplink time alignment to a base station; and

receive a random access response in response to the random access preamble from the base station,

wherein the random access preamble is a dedicated random access preamble used by the base station to determine whether to maintain the uplink time alignment,

wherein the random access preamble is transmitted while a prohibition timer is not running, and

wherein the prohibition timer is used to indicate a specific time period for prohibiting a triggering of a random access procedure to maintain the uplink time alignment.

6. The user equipment of claim 5, wherein the processor is further configured to start a time alignment timer which is used to control how long the user equipment is considered uplink time aligned.

7. The user equipment of claim 6, wherein the random access preamble is transmitted while the time alignment timer is running.

8. The user equipment of claim 6, wherein the processor is further configured to:

apply a timing advance command included in the random access response; and

restart the time alignment timer upon receiving the random access response.