Patent ID: 9078236
Filing Date: 2015-07-07
Classification: H04W

Abstract:
1. A method for performing random access to a base station by a terminal, the method comprising: transmitting a random access preamble to the base station; receiving, from the base station in response to the random access preamble, a random access response message including uplink grant information; and storing a Medium Access Control Packet Data Unit (MAC PDU) including uplink data and an identifier of the terminal in a message 3 (Msg3) buffer in response to the uplink grant information; copying the MAC PDU stored in the Msg3 buffer to a first Hybrid Automatic Repeat Request (HARQ) buffer associated with a first HARQ process, wherein the terminal comprises multiple HARQ buffers including the first HARQ buffer; transmitting the MAC PDU stored in the first HARQ buffer to the base station using the first HARQ process; starting or restarting a Contention Resolution (CR) timer; receiving, from the base station, a Physical Downlink Control Channel (PDCCH) signal; stopping a Timing Alignment Timer (TAT), if the received PDCCH signal or a Physical Downlink Shared Channel (PDSCH) signal associated with the received PDCCH signal does not match the identifier of the terminal or if the CR timer expires; and flushing the multiple HARQ buffers including the first HARQ buffer, when the TAT expires.