Patent ID: 9655071
Date: 2017-05-16
CPC Classifications: H04W

Claim:
1. A method of performing an uplink synchronization by a base station (BS) in a wireless communication system, the method comprising: transmitting configuration information to a user equipment (UE), the configuration information including timing advanced group (TAG) information indicating serving cells in which a timing advanced value (TAV) is applied; transmitting random access preamble (RAP) allocation information to the UE, the RAP allocation information including a RAP index that indicates one preamble sequence selected from at least one dedicated RAP for a non-contention based random access procedure; receiving a message including the preamble sequence; and transmitting a random access response (RAR) to the UE, the RAR including a medium access control (MAC) protocol data unit (PDU), wherein the MAC PDU comprises a header and a MAC control element (CE), wherein the header includes a logical channel identifier (LCID) that indicates whether the MAC CE includes a timing advanced command (TAC) field, and wherein the MAC CE includes a TAC field indicating a TAV and a TAG index field identifying a TAG to control uplink timing adjustment identically with the TAV, the TAC field being a 6-bit value, and the TAG index field being a 2-bit value.