Random access scheme for user equipment

• US 9,414,412 B2
• Filed: 05/11/2015
• Issued: 08/09/2016
• Est. Priority Date: 01/02/2009
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Park, Sung Jun, Yi, Seung June, Chun, Sung Duck, Lee, Young Dae
• Primary Examiner(s): LY, ANH VU H
• Application Number:
  US14/709,093
• Publication Number:
  US 20150245387A1
• Time in Patent Office: 456 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: H04W 28/04 Error control
• CPC Class Codes: H04W 48/08 Access restriction or access information delivery, e.g. discovery data delivery signalling during connection H04W76/00
• CPC Class Codes: H04W 74/006 in the downlink, i.e. towards the terminal
• 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 and terminal for use in a communication system are discussed. The terminal can transmit a random access preamble via a physical random access channel (PRACH) to a network. The terminal may monitor a random access response after transmitting the random access preamble during a specific time window. Furthermore, if no random access response containing a random access preamble identifier corresponding to the transmitted random access preamble is received within the specific time window and a specific random access response contains a backoff indicator subheader is received, a preamble transmission counter is incremented by 1. A subsequent random access preamble transmission is delayed by a backoff time selected using a backoff indicator in the backoff indicator subheader, if the random access preamble was selected by a medium access control (MAC) layer.

Claims

1. A method of a terminal in a communication system, the method comprising:

transmitting a random access preamble via a physical random access channel (PRACH) to a network; and

monitoring a random access response after transmitting the random access preamble during a specific time window,

wherein, if no random access response containing a random access preamble identifier corresponding to the transmitted random access preamble is received within the specific time window and a specific random access response containing a backoff indicator subheader is received, the method further comprises;

incrementing a preamble transmission counter by 1; and

delaying a subsequent random access preamble transmission by a backoff time selected using a backoff indicator in the backoff indicator subheader, if the random access preamble was selected by a medium access control (MAC) layer.

2. The method of claim 1, further comprising:

indicating to a layer higher than the MAC layer that there is a random access problem, if the preamble transmission counter reaches a predetermined maximum number.

3. The method of claim 1, wherein the specific time window comprises a random access response reception window.

4. A terminal for use in a communication system, the terminal comprising:

a transmitter configured to transmit a random access preamble via a physical random access channel (PRACH) to a network; and

a processor configured to monitor a random access response after transmitting the random access preamble during a specific time window,

wherein, if no random access response containing a random access preamble identifier corresponding to the transmitted random access preamble is received within the specific time window and a specific random access response containing a backoff indicator subheader is received, the processor is further configured to;

increment a preamble transmission counter by 1; and

delay a subsequent random access preamble transmission by a backoff time selected using a backoff indicator in the backoff indicator subheader, if the random access preamble was selected by a medium access control (MAC) layer.

5. The terminal of claim 4, wherein the processor is further configured to indicate to a layer higher than the MAC layer that there is a random access problem, if the preamble transmission counter reaches a predetermined maximum number.

6. The terminal of claim 4, wherein the specific time window comprises a random access response reception window.