Patent ID: 9014180
Filing Date: 2015-04-21
Classification: H04L,H04W

Abstract:
1. A method of performing a random access procedure by a terminal in wireless communication system, the method comprising: receiving, at the terminal, a command for starting a time alignment timer that is used to control how long the terminal is considered uplink time aligned, wherein the command is a time advance command (TAC), and the command is received in a random access response message; determining, at the terminal, whether a random access preamble to be used by the terminal in the random access procedure was explicitly signalled and an index of the random access preamble was not 00000; and if it is determined that the random access preamble was explicitly signalled and the index of the random access preamble was not 00000, applying the time advance command, and starting or restarting the time alignment timer; and if it is determined that the random access preamble was not explicitly signalled and if the time alignment timer is not running, applying the time advance command, starting the time alignment timer, and stopping the timer alignment timer when a contention resolution is considered not successful, wherein the received command is ignored if it is determined that the random access preamble was not explicitly signalled and the time alignment timer is running.