Patent ID: 8588834

Claim:
A method of performing a random access procedure in a mobile communication system, the method comprising: transmitting, by a mobile station (MS), a first random access preamble on at least one first uplink component carrier among a plurality of aggregated uplink component carriers to a base station (BS); receiving, by the MS, a random access response as a response to the first random access preamble on at least one downlink component carrier among a plurality of aggregated downlink component carriers from the BS; transmitting, by the MS, an uplink data on the at least one first uplink component carrier based on information on radio resource allocation contained in the random access response to the BS, the uplink data including an identity of the MS; monitoring, by the MS, the plurality of aggregated downlink component carriers for contention resolution; receiving a plurality of contention resolution messages on the plurality of aggregated downlink component carriers from the BS; deciding whether the contention resolution is successful or not for all of the plurality of aggregated downlink component carriers, wherein it is decided that the contention resolution is successful for a specific downlink component carrier if the contention resolution message on the specific downlink component carrier matches with the identity of the MS, wherein the specific downlink component carrier is being linked to the at least one first uplink component carrier among the plurality of aggregated uplink component carriers; and transmitting, by the MS, a second random access preamble on at least one second uplink component carrier, which has a higher priority than other uplink component carriers according to a preamble selection rule, among the plurality of aggregated uplink component carriers to the BS if the contention resolution is unsuccessful for all of the plurality of aggregated downlink component carriers.