Method of handling random access response

1. A method of handling random access response for a network in a wireless communication system, the method comprising:

receiving a first random access preamble from a first mobile device of the wireless communication system at a first component carrier of a plurality of component carriers;

receiving a second random access preamble from a second mobile device of the wireless communication system at a second component carrier of the plurality of component carriers, wherein the second random access preamble is identical to the first random access preamble and is assigned by the network;

only responding to the assigned second random access preamble with a random access response including a timing advance command associated to the second mobile device, at the first component carrier, wherein after the second mobile device receives the random access response, the second mobile device checks an indicator to see if it is set to a predetermined value, and discontinues a contention resolution of a contention based random access procedure when determining that the indicator is not the predetermined value; and

responding no random access response to the first random access preamble selected and transmitted by the first mobile device.

2. The method of claim 1 , further comprising:

ignoring the first random access preamble from the first mobile device at the first component carrier.

3. A method of handling random access response for a network in a wireless communication system, the method comprising:

assigning a first random access preamble for a first mobile device in a first component carrier of a plurality of component carriers;

receiving a second random access preamble from a second mobile device at a second component carrier, wherein the second random access preamble is identical to the first random access preamble;

receiving no assigned first random access preamble from the first mobile device at the first component carrier during a period of time; and

responding no random access response to the first and second random access preambles;

wherein after the first mobile device or second mobile device receives the random access response, the first mobile device or second mobile device checks an indicator to see if it is set to a predetermined value, and discontinues a contention resolution of a contention based random access procedure when determining that the indicator is not the predetermined value.

4. A method of handling random access response for a mobile device in a wireless communication system, the method comprising:

transmitting a random access preamble of a contention based random access procedure to a network of the wireless communication system;

receiving a random access response, including a temporary cell radio network temporary identifier (T-CRNTI) and corresponding to the random access preamble, from the network; and

determining that the random access response is for the mobile device when the T-CRNTI is equivalent to a C-RNTI of the mobile device, and applying the timing advance command included in the random access response for an uplink synchronization; and

determining that the random access response is not for the mobile device when the T-CRNTI is not equivalent to a C-RNTI of the mobile device, and not applying the timing advance command included in the random access response for an uplink synchronization.

5. A method of handling random access response for a mobile device in a wireless communication system, the method comprising:

transmitting a first random access preamble of a contention based random access procedure, to a network of the wireless communication system;

receiving a random access response including an uplink grant from the network;

determining whether the received random access response is for the mobile device according to a size of the uplink grant, wherein the determining step comprises determining that the random access response is not for the mobile device when the size of the uplink grant is smaller than a threshold, wherein the threshold is determined according to a size of a message 3 of the contention based random access procedure; and

discontinuing a contention resolution of the contention based random access procedure when determining that the random access response is not for the contention based random access procedure.

6. The method of claim 5 , further comprising:

transmitting a second random access preamble of the contention based random access procedure, to the network of the wireless communication system.

7. A method of handling random access response for a mobile device in a wireless communication system, the method comprising:

transmitting a first random access preamble of a contention based random access procedure, to a network of the wireless communication system;

receiving a random access response including a temporary cell radio network temporary identifier (T-CRNTI), from the network;

determining whether the received random access response is for the mobile device according to validity of the T-CRNTI, wherein the determining step comprises determining that the random access response is not for the mobile device when the T-CRNTI is invalid or set to a predetermined value; and

discontinuing a contention resolution of the contention based random access procedure when determining that the random access response is not for the mobile device.

8. The method of claim 7 , further comprising:

transmitting a second random access preamble of the contention based random access procedure, to the network of the wireless communication system.