Method for performing random access procedures and terminal thereof

Patent metadata

Field	Value
Publication number	US-2016353376-A1
Application number	US-201615231861-A
Country	US
Kind code	A1
Filing date	Aug 9, 2016
Priority date	Jun 18, 2008
Publication date	Dec 1, 2016
Grant date	—

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.

First claim

1 . A communications terminal configured to perform a random access procedure with a network, comprising:
a transmitter to transmit to the network a first type of random access preamble or a second type of random access preamble; a receiver to receive a random access response sent from the network in response to transmission of the first type of random access preamble or the second type of random access preamble; where the first type of random access preamble is based on a preamble selection by the communications terminal, the second type of random access preamble is not based on a preamble selection by the communications terminal, and the first type of random access preamble is a contention-based preamble for a contention-based random access procedure; a contention resolution timer; and processing circuitry to:
start operation of the contention resolution timer;
decode a downlink control channel while the contention resolution timer operates;
apply a back-off time when an indication of allocation of radio resources for a new transmission is not received by a time when the contention resolution timer expires;
stop decoding the downlink control channel during the back-off time; and
perform random access again after the back-off time.

2 . The communications terminal in claim 1 , wherein the processing circuitry is configured to:
increase power to monitor the downlink control channel after the back-off time expires.

3 . The communications terminal in claim 1 , wherein the random access response includes a random access preamble identifier, uplink channel grant information, timing adjustment information, and a temporary cell identifier, and wherein the processing circuitry is configured to:
when the random access response is intended for the communications terminal, control the transmitter to transmit data using the uplink channel grant information and including a communications terminal identifier allocated through a core network and different from the temporary cell identifier, wherein the processing circuitry is configured to start operation of the contention resolution timer after transmission of the data.

4 . The communications terminal in claim 3 , wherein the processing circuitry is configured to:
monitor for the downlink control channel using the temporary cell identifier of the communications terminal while the contention resolution timer is operating; when the downlink control channel is received using the temporary cell identifier of the communications terminal before the contention resolution timer expires, check data on a downlink shared data channel indicated by the received downlink control channel; and when the checked data includes a unique identifier for the communications terminal, terminate the random access procedure.

5 . The communications terminal in claim 1 , wherein the indication of allocation of radio resources is indicated by a Cell-Radio Network Temporary Identifier (C-RNTI).

6 . A communications terminal configured to perform a random access procedure with a network, comprising:
a transmitter to transmit a first type of random access preamble or a second type of random access preamble to the network; a receiver to receive a random access response sent from the network in response to transmission of the first type of random access preamble or the second type of random access preamble, the random access response including a random access preamble identifier, uplink channel grant information, timing adjustment information, and a temporary cell identifier; where the first type of random access preamble is based on a preamble selection by the communications terminal, the second type of random access preamble is not based on a preamble selection by the communications terminal, and the first type of random access preamble is a contention-based random access preamble, a contention resolution timer; and processing circuitry to:
when the random access response is intended for the communications terminal, control the transmitter to transmit data using uplink channel grant information and including a communications terminal identifier that is different from the temporary cell identifier, and
start the contention resolution timer after transmission of the data over the uplink.

7 . The communications terminal in claim 6 , wherein the processing circuitry is configured to:
monitor the downlink control channel using the temporary cell identifier of the communications terminal while the contention resolution timer is running; when the downlink control channel is received using the communications terminal before the contention resolution timer expires, check data on a downlink shared data channel indicated by information from the received downlink control channel; and when the checked data includes a unique identifier for the communications terminal, terminate the random access procedure.

8 . The method in claim 6 , wherein the processing circuitry is configured to:
apply a back-off time if the communications terminal identifier is not received upon expiration of the contention resolution timer; stop monitoring the downlink control channel; and perform random access procedures again after the back-off time.

9 . The method in claim 8 , wherein the processing circuitry is configured to:
resume monitoring the downlink control channel after the back-off time expires.

10 . The communications terminal in claim 6 , wherein the temporary cell identifier is a Cell-Radio Network Temporary Identifier (C-RNTI).

11 . The communications terminal in claim 6 , wherein the start of the contention resolution timer is associated with random access contention resolution.

Assignees

• Optis Cellular Tech Llc

Inventors

• Yi Seung-June
• Park Sung-Jun
• Lee Young-Dae
• Chun Sung-Duck

Classifications

• H04W72/23

  in the downlink direction of a wireless link, i.e. towards a terminal · CPC title

• H04W74/0833

  Random access procedures, e.g. with 4-step access · CPC title

• H04W74/0838

  using contention-free random access [CFRA] · CPC title

• H04W24/08

  Testing, {supervising or monitoring} using real traffic · CPC title

• H04W52/0216 Primary

  using a pre-established activity schedule, e.g. traffic indication frame · CPC title