Random access channel response handling with aggregated component carriers

1. A method for mobile communication using carrier aggregation, the method comprising:

transmitting, from a user equipment to a network access node in a carrier aggregation network, a random access preamble in a time and frequency resource allocated for preamble transmission on any one of a plurality of component carriers, the plurality of component carriers comprising a primary component carrier and a plurality of secondary component carriers, the one of the plurality of secondary component carriers being selected by the user equipment;

receiving, at the user equipment, a random access response to the random access preamble, the random access response being aggregated with other random access responses in a time and frequency resource of the primary component carrier regardless of on which component carrier among the plurality of component carriers the random access preamble was transmitted,

wherein the aggregated random access response comprises responses to a plurality of random access preambles from individual ones of a plurality of user equipments.

2. The method of claim 1 , wherein the random access response is received on a physical downlink shared channel.

3. The method of claim 1 , wherein the aggregated random access response is for a first type of user equipment and for a second type of user equipment, the aggregated random access response comprising at least one random access response for the second type of user equipment placed at a location to be ignored by the first type of user equipment, the aggregated random access response comprising an indicator for indicating whether the aggregated random access response contains the at least one random access response for the second type of user equipment.

4. An apparatus comprising:

a wireless receiver;

a wireless transmitter; and

a controller configured to utilize the wireless receiver and the wireless transmitter, the controller further configured to:

transmit, via the wireless transmitter, a random access preamble to a network access node in a time and frequency resource allocated for preamble transmission on one of a plurality of component carriers, the plurality of component carriers comprising a primary component carrier and a plurality of secondary component carriers, the one of the plurality of secondary component carriers being selected by the user equipment, the network access node being in a carrier aggregation network; and

receive, via the wireless receiver, a random access response to the random access preamble, the random access response being aggregated with other random access responses in a time and frequency resource of the primary component carrier regardless of on which component carrier among the plurality of component carriers the random access preamble was transmitted,

wherein the aggregated random access response comprises responses to a plurality of random access preambles from individual ones of a plurality of user equipments.

5. The apparatus of claim 4 , wherein the random access response is received on a physical downlink shared channel.

6. The apparatus of claim 4 , wherein the aggregated random access response is for a first type of user equipment and for a second type of user equipment, the aggregated random access response comprising at least one random access response for one of the second type of user equipment placed at a location to be ignored by the first type of user equipment, the aggregated random access response comprising an indicator for indicating whether the aggregated random access response contains the at least one random access response for the second type of user equipment.

7. A non-transitory computer-readable storage medium storing instructions that, when executed on a processor, cause an apparatus to perform:

transmitting, from a user equipment to a network access node in a carrier aggregation network, a random access preamble in a time and frequency resource allocated for preamble transmission on one of a plurality of component carriers, the plurality of secondary component carriers comprising a primary component carrier and plurality of secondary component carriers, the one of the plurality of secondary component carriers being selected by the user equipment; and

receiving, at the user equipment, a random access response to the random access preamble, the random access response being aggregated with other random access responses in a time and frequency resource of the primary component carrier regardless of on which component carrier among the plurality of component carriers the random access preamble was transmitted,

wherein the aggregated random access response comprises responses to a plurality of random access preambles from individual ones of a plurality of user equipments.

8. The non-transitory computer-readable storage medium of claim 7 , wherein the random access response is received on a physical downlink shared channel.

9. The non-transitory computer-readable storage medium of claim 7 , wherein the aggregated random access response is for a first type of user equipment and for a second type of user equipment, the aggregated random access response comprising at least one random access response for the second type of user equipment placed at a location to be ignored by the first type of user equipment, the aggregated random access response comprising an indicator for indicating whether the aggregated random access response contains the at least one random access response for the second type of user equipment.