Method for performing random access procedures and terminal thereof

• US 7,933,243 B2
• Filed: 06/17/2009
• Issued: 04/26/2011
• Est. Priority Date: 06/18/2008
• Status: Active Grant

• Current Assignee: Optis Cellular Technology LLC (Brevet Capital)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Yi, Seung-June, Park, Sung-Jun, Lee, Young-Dae, Chun, Sung-Duck
• Primary Examiner(s): Trost, IV; William
• Assistant Examiner(s): Jiang; Charles C
• Application Number:
  US12/457,653
• Publication Number:
  US 20090316638A1
• Time in Patent Office: 678 Days
• Field of Search: 370310-350, 455403-466, 455 73-129
• US Class Current: 370/329
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 24/08 Testing, supervising or monitoring using real traffic
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 74/002 Transmission of channel access control information
• 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 74/0808 using carrier sensing, e.g. carrier sense multiple access [CSMA]
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A random access procedure between a mobile terminal and a network is performed based upon the characteristics of a RACH preamble. If the RACH preamble was explicitly signaled by the network, a downlink channel is monitored until a new transmission is indicated according to radio resource allocation information received from the network. If the RACH preamble was not explicitly signaled by the network, a contention resolution timer is started and the downlink channel is monitored until the contention resolution timer expires. Such monitoring of downlink channels in a more efficient manner, results in effective reduction in power consumption.

Claims

1. A method of performing a random access procedure between a communication terminal and a network, comprising:

transmitting, by the communication terminal, a RACH (Random Access CHannel) preamble to the network;

receiving, by the communication terminal, a RACH response from the network;

monitoring, by the communication terminal, a downlink channel according to a DRX (Discontinuous Reception) active time until a radio resource allocation for an initial transmission is indicated according to radio resource allocation information received from the network, if the RACH preamble was signaled by the network, wherein the DRX active time specifies a time until the radio resource allocation for an initial transmission is indicated if the RACH preamble was signaled by the network; and

starting, by the communication terminal, a contention resolution timer and monitoring the downlink channel until the contention resolution timer is expired, if the RACH preamble was selected by a MAC (Medium Access Control) entity of the communication terminal,

wherein the monitoring is not performed if the contention resolution timer is expired.

2. The method of claim 1, wherein the downlink channel is a PDCCH (Physical Downlink Control CHannel).

3. The method of claim 1, further comprising:

using the information included in the RACH response to determine whether the RACH preamble was either signaled by the network or selected by the MAC entity of the communication terminal.

4. The method of claim 1, wherein the radio resource allocation information is a C-RNTI (Radio Network Temporary Identifier).

5. A method of performing a random access procedure between a communication terminal and a network, the method comprising:

transmitting, by the communication terminal, a RACH (Random Access CHannel) preamble to the network;

receiving, by the communication terminal, a RACH response from the network;

determining, by the communication terminal, whether the RACH preamble was signaled by the network;

if the RACH preamble was signaled by the network, monitoring, by the communication terminal, a downlink channel according to a DRX (Discontinuous Reception) active time until a radio resource allocation for a new transmission is indicated according to radio resource allocation information received from the network, wherein the DRX active time specifies a time until the radio resource allocation for an initial transmission is indicated if the RACH preamble was signaled by the network; and

if the RACH preamble was not explicitly signaled by the network, starting a contention resolution timer and monitoring the downlink channel until the contention resolution timer is expired,

wherein the monitoring is not performed if the contention resolution timer is expired.

6. The method o claim 5, wherein the radio resource allocation information is a C-RNTI (Radio Network Temporary Identifier).

7. The method of claim 5, wherein the downlink channel is a PDCCH (Physical Downlink Control CHannel).

8. A communication terminal comprising:

a microprocessor configured to provide control operations;

an input/output means configured to operate based on the control operations provided from the microprocessor; and

a communications module configured to cooperate with the input/output means and operate based on the control operations provided from the microprocessor,

wherein the communications module is configured to transmit a RACH (Random Access CHannel) preamble to a network, receive a RACH response from the network, determine whether the RACH preamble was signaled by the network, monitor a downlink channel according to a DRX (Discontinuous Reception) active time until a radio resource allocation for a new transmission is indicated according to radio resource allocation information received from the network if the RACH preamble was signaled by the network, start a contention resolution timer if the RACH preamble was selected by a MAC (Medium Access Control) entity of the communication terminal and monitor the downlink channel until the contention resolution timer is expired if the RACH preamble was selected by the MAC entity of the communication terminal,

wherein the DRX active time specifies a time until the radio resource allocation for an initial transmission is indicated if the RACH preamble was signaled by the network,

wherein the communications module does not monitor the downlink channel if the contention resolution timer is expired.