Method and apparatus for reporting statistic information associated with random access in a wireless communication system

• US 9,107,225 B2
• Filed: 08/13/2012
• Issued: 08/11/2015
• Est. Priority Date: 08/12/2011
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Lee, Ki Dong
• Primary Examiner(s): Chriss, Andrew
• Assistant Examiner(s): Ahmed, Atique
• Application Number:
  US13/584,354
• Publication Number:
  US 20130039274A1
• Time in Patent Office: 1,093 Days
• Field of Search: 370/328, 370/311, 370/252, 370/329, 455/450, 455/561, 455/456.6
• US Class Current: 1/1
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access

Abstract

A method and apparatus for reporting statistic information associated with random access procedure and back-off process are provided. The method proposes a number of back-off interval reporting modes. The reporting modes include the first mode in which a sequence indicating every back-off interval applied during the back-off process is reported, the second mode in which a total sum of the every back-off interval applied during the back-off process is reported, the third mode in which an average of the every back-off interval applied during the back-off process is reported, and the fourth mode in which a variance of the every back-off interval applied during the back-off process is reported. The reporting information is transmitted via RRC signaling.

Claims

1. A method of reporting data related to random access procedure in a wireless communication system using a number of orthogonal frequency division multiplexing (OFDM) symbols, the method performed by a user equipment (UE) and comprising:

performing a first random access procedure by transmitting a random access preamble to a base station (BS);

when contention resolution for the first random access procedure is not successful, performing at least one back-off process based on at least one of back-off indexes, which are received in a random access response, wherein each of the back-off indexes indicates a back-off interval of the UE;

performing a second random access procedure by retransmitting the random access preamble;

when the second random access procedure is successful, establishing a radio resource control (RRC) connection;

after establishing the RRC connection in response to the success of the second random access procedure, receiving from the BS via the RRC connection, a first RRC message including a UE information request message which includes bitmap information indicating at least one mode among plural modes for the UE to report the back-off interval; and

transmitting, in response to the UE information request message, a second RRC message including a UE information response message to the BS,

wherein the UE information response message of the second RRC message includes back-off interval report information configured based on the at least one mode.

2. The method of claim 1, wherein the at least one back-off process is performed base on a random value selected from a uniform distribution between zero and an upper bound, the upper bound being indicated by the at least one back-off index.

3. The method of claim 1, wherein the UE information response message includes a data field indicating a number of preambles sent for a last successfully completed random access procedure.

4. The method of claim 1, further comprising:

performing an access class barring procedure before transmitting the random access preamble.

9. The method of claim 1, wherein the plural modes include:

a first mode in which a sequence indicating every back-off interval applied during the at least one back-off process is reported to the BS,

a second mode in which a total sum of the every back-off interval applied during the at least one back-off process is reported to the BS,

a third mode in which an average of the every back-off interval applied during the at least one back-off process is reported to the BS, and

a fourth mode in which a variance of the every back-off interval applied during the at least one back-off process is reported to the BS.

5. A user equipment (UE) for reporting data related to random access procedure in a wireless communication system using a number of orthogonal frequency division multiple (OFDM) symbols, the UE comprising:

a processor configured to;

perform a first random access procedure by transmitting a random access preamble to a base station (BS),

when contention resolution for the random access procedure is not successful, perform at least one back-off process based on at least one of back-off indexes, which are received in a random access response, wherein each of the back-off index indicates a back-off interval of the UE,

perform a second random access procedure by retransmitting the random access preamble,

when the second random access procedure is successful, establish a radio resource control (RRC) connection,

after establishing the RRC connection in response to the success of the second random access procedure, receive from the BS via the RRC connection, a first RRC message including a UE information request message which includes bitmap information indicating at least one mode among plural modes for the UE to report the back-off interval, and

transmit, in response to the UE information request message, a second RRC message including a UE information response message to the BS,

wherein the UE information response message of the second RRC message includes back-off interval report information configured based on the at least one mode.

6. The user equipment of claim 5, wherein the at least one back-off process is performed base on a random value selected from a uniform distribution between zero and an upper bound, the upper bound being indicated by the at least one back-off index.

7. The user equipment of claim 5, wherein the UE information response message includes a data field indicating a number of preambles sent for a last successfully completed random access procedure.

8. The user equipment of claim 5, wherein the processor is further configured to:

perform an access class barring procedure before transmitting the random access preamble.

10. The user equipment of claim 5, wherein of the plural modes include:

a first mode in which a sequence indicating every back-off interval applied during the at least one back-off process is reported to the BS,

a second mode in which a total sum of the every back-off interval applied during the at least one back-off process is reported to the BS,

a third mode in which an average of the every back-off interval applied during the at least one back-off process is reported to the BS, and

a fourth mode in which a variance of the every back-off interval applied during the at least one back-off process is reported to the BS.