Apparatus and method for uplink transmission in wireless communication system

• US 8,274,936 B2
• Filed: 05/05/2009
• Issued: 09/25/2012
• Est. Priority Date: 05/06/2008
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Yoo, Hee Chul
• Primary Examiner(s): Jaroenchonwanit, Bunjob
• Application Number:
  US12/435,674
• Publication Number:
  US 20090279495A1
• Time in Patent Office: 1,239 Days
• Field of Search: 370/329, 370/311, 370/350
• US Class Current: 370/329
• CPC Class Codes: H04L 5/0078 Timing of allocation
• CPC Class Codes: H04W 56/0045 compensating for timing error by altering transmission time
• CPC Class Codes: H04W 76/20 Manipulation of established connections

Abstract

An apparatus and method for uplink transmission in a wireless communication system are provided. The method comprises detecting an expiry of a time alignment timer in a MAC (Medium Access Control) layer, the time alignment timer being used to control how long the UE is considered uplink time aligned, notifying a release of PUCCH (Physical Uplink Control Channel) resources from the MAC layer to a RRC (Radio Resource Control) layer when the expiry of the time alignment timer is detected and keeping a part of the PUCCH (Physical Uplink Control Channel) resources in the RRC layer.

Claims

1. A method for uplink transmission in a wireless communication system, the method carried out by a user equipment (UE), the method comprising:

receiving a time alignment command from a base station;

starting a time alignment timer by applying the time alignment command so as to control how long the UE is considered uplink time aligned;

detecting whether the time alignment timer has expired;

when the time alignment timer has expired,

notifying a release of control resources used for transmission of control signals from a Medium Access Control (MAC) layer to a Radio Resource Control (RRC) layer, and

notifying a physical (PHY) layer by the MAC layer to suspend the control resources while the time alignment timer is not running;

upon a receipt of the release notification at the RRC layer, performing a random access procedure; and

resuming the control resources suspended in the PHY layer when the timer alignment timer is restarted.

2. The method of claim 1, further comprising:

applying default control configurations in the RRC layer.

3. The method of claim 1, wherein the control signals include a channel quality indicator (CQI), a sounding reference signal and a scheduling request.

4. The method of claim 1, further comprising:

when the time alignment timer has expired, releasing any downlink assignments and uplink assignments.

5. The method of claim 1, wherein the random access procedure comprises:

after the time alignment timer is expired, transmitting to the base station a random access preamble that is randomly selected from a set of random access preambles;

receiving a random access response as a response to the random access preamble, the random access response including a new time alignment command; and

restarting the time alignment timer by applying the new time alignment command.

6. The method of claim 5, wherein the random access procedure comprises:

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

7. A user equipment (UE), comprising:

a radio frequency (RF) unit configured to receive and transmit radio signals; and

a processor operatively connected to the RF unit, and configured to implement a radio interface protocol including a Medium Access Control (MAC) layer and a Radio Resource Control (RRC) layer,

wherein the processor is further configured to;

receive a time alignment command from a base station;

start a time alignment timer by applying the time alignment command so as to control how long the UE is considered uplink time aligned;

detect whether the time alignment timer has expired;

when the time alignment timer has expired,

notify a release of control resources used for transmission of control signals from the MAC layer to the RRC layer, and

notify a physical (PHY) lager by the MAC layer to suspend the control resources while the time alignment timer is not running;

upon a receipt of the release notification, perform a random access procedure; and

resume the control resources suspended in the PHY layer when the timer alignment timer is restarted.

8. The UE of claim 7, wherein the processor is configured to apply default control configurations in the RRC layer.

9. The UE of claim 7, wherein the control signals include a channel quality indicator (CQI), a sounding reference signal and a scheduling request.

10. The UE of claim 7, wherein the processor is configured to release any downlink assignments and uplink assignments when the time alignment timer has expired.

11. The UE of claim 7, wherein the random access procedure comprises:

after the time alignment timer is expired, transmit to the base station a random access preamble that is randomly selected from a set of random access preambles;

receive a random access response as a response to the random access preamble, the random access response including a new time alignment command; and

restart the time alignment timer by applying the new time alignment command.

12. The UE of claim 11, wherein the random access procedure comprises:

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

13. A method for maintaining, by a user equipment (UE), an uplink time alignment in a wireless communication system, the method comprising:

receiving, from a base station, a time alignment command;

starting a time alignment timer by applying the time alignment command, the time alignment timer being used to control how long the UE is considered uplink time aligned;

detecting whether the time alignment timer is expired;

when the time alignment timer is expired, notifying a release of control resources used for transmission of control signals from a medium access control (MAC) layer to a radio resource control (RRC) layer, and notifying a physical (PHY) layer by the MAC layer to suspend the control resources while the time alignment timer is not running;

transmitting, to the base station, a random access preamble which is randomly selected from a set of random access preambles after the time alignment timer is expired;

receiving, for the base station, a random access response as a response of the random access preamble, the random access response including a timing advance command; and

restarting the time alignment timer by applying the timing advance command.

14. The method of claim 13, further comprising:

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

15. The method of claim 13, further comprising:

applying default control configurations in the RRC layer on a receipt of the release notification at the RRC layer.