Method of performing random access procedure in multiple component carrier system

1. 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.

2. The method of claim 1 , further comprising transmitting a failure message from the upper layer to the BS.

3. The method of claim 2 , wherein the upper layer is a radio link control (RRC) layer and the failure message is a RRC connection reestablishment request message.

4. The method of claim 1 , wherein the predetermined threshold is common for the first uplink carrier and the second uplink carrier.

5. A method of performing a random access procedure by a base station (BS) in a multiple-carrier system, the method comprising:

receiving, from a user equipment (UE), a first random access preamble on a first uplink carrier selected from all of the configured uplink carriers;

receiving, from the UE, 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 by the UE; and

receiving a failure message from the UE, the failure message indicating a random access problem,

wherein a common counter and a predetermined threshold for all of the configured uplink carriers are set by the UE,

wherein the common counter is used to count a number of preamble transmission on all of the configured uplink carriers,

wherein the predetermined threshold is a maximum number of preamble transmissions or preamble retransmissions allowed for the UE,

wherein the setting of the common counter and the predetermined threshold are performed by a Medium Access Control (MAC) layer of the UE,

wherein a number of the preamble transmission on the first uplink carrier and the second uplink carrier is counted by the UE,

wherein the common counter is incremented arbitrarily each time that the both first uplink carrier and second uplink carrier transmit the first and second random access preamble,

wherein the UE determines whether the number of preamble transmissions reaches the predetermined threshold,

wherein a random access problem is indicated to an upper layer if it is determined by the UE that the number of preamble transmissions reaches the predetermined threshold,

wherein the indicating the random access problem to the upper layer is performed by only considering the determination by the UE,

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.

6. The method of claim 5 , wherein the failure message is a RRC (Radio Resource Control) connection reestablishment request message.

7. The method of claim 5 , wherein the threshold is common for the first uplink carrier and the second uplink carrier.