Patent ID: 8804632

Claim:
A method of performing a random access procedure by a user equipment (UE) in a multiple-carrier system, the method comprising: setting, by the UE, a common counter and a predetermined threshold for all configured uplink carriers, the common counter being used to count a number of preamble transmissions on all of the configured uplink carriers, the predetermined threshold being a maximum number of preamble transmissions or preamble retransmissions allowed for the UE, the setting of the common counter and the predetermined threshold being performed by a Medium Access Control (MAC) layer of the UE; transmitting, to a base station (BS), a first random access preamble on a first uplink carrier selected from all of the configured uplink carriers; transmitting, to the BS, a second random access preamble on a second uplink carrier selected from all of the configured uplink carriers when the first random access preamble is not successful to receive a corresponding random access response; counting, by the UE, a number of preamble transmissions on the first uplink carrier and the second uplink carrier, the common counter being incremented each time that both the first uplink carrier and the second uplink carrier transmit the first and second random access preamble; determining, by the UE, whether the number of preamble transmissions reaches the predetermined threshold; and indicating a random access problem to an upper layer if it is determined that the number of preamble transmissions reaches the predetermined threshold, wherein the indicating operation is performed by only considering the determining operation, wherein the random access problem is indicated to a Radio Resource Control (RRC) layer of the UE, and wherein the first uplink carrier and the second uplink carrier are aggregated.