Transmitting a physical downlink shared channel after losing uplink synchronization

1. A method comprising:

transmitting information indicating a first physical random access channel preamble used to indicate a hybrid automatic repeat request acknowledgment;

transmitting a physical downlink control channel order;

transmitting a physical downlink shared channel transmission, wherein the physical downlink control channel order and at least a portion of the physical downlink shared channel transmission are transmitted after a remote unit loses an uplink synchronization and before the remote unit completes a physical random access channel procedure; and

receiving feedback information corresponding to the physical downlink shared channel transmission, wherein the feedback information comprises the first physical random access channel preamble that indicates the hybrid automatic repeat request acknowledgment or a second physical random access channel preamble that indicates a hybrid automatic repeat request negative acknowledgement, and wherein the second physical random access channel preamble is:

derived from the information indicating the first physical random access channel preamble.

2. The method of claim 1 , wherein the feedback information is multiplexed with a physical uplink shared channel transmission.

3. The method of claim 1 , wherein the feedback information is received as part of a physical random access channel transmission.

4. The method of claim 1 , wherein the feedback information is received by a first set of resources indicating an acknowledgement and a second set of resources indicating a non-acknowledgement.

5. The method of claim 4 , wherein predetermined rules are used to identify the first set of resources and the second set of resources.

6. The method of claim 1 , wherein transmitting the physical downlink shared channel transmission comprises transmitting the physical downlink shared channel transmission a predetermined number of times.

7. The method of claim 6 , wherein receiving the feedback information comprises receiving the feedback information after the physical downlink shared channel transmission is transmitted the predetermined number of times.

8. The method of claim 6 , wherein receiving the feedback information comprises receiving the feedback information only in response to the remote unit failing to decode the physical downlink shared channel transmission.

9. The method of claim 1 , wherein transmitting the physical downlink shared channel transmission comprises transmitting a plurality of transport blocks, and receiving the feedback information comprises receiving a hybrid automatic repeat request identity for each transport block of the plurality of transport blocks.

10. The method of claim 9 , wherein transmitting the plurality of transport blocks comprises transmitting an indication with a last transport block of the plurality of transport blocks, and the indication indicates that no transport blocks are to be transmitted after the last transport block.

11. An apparatus comprising:

a transmitter that:

transmits information indicating a first physical random access channel preamble used to indicate a hybrid automatic repeat request acknowledgment;

transmits a physical downlink control channel order; and

transmits a physical downlink shared channel transmission, wherein the physical downlink control channel order and at least a portion of the physical downlink shared channel transmission are transmitted after a remote unit loses an uplink synchronization and before the remote unit completes a physical random access channel procedure; and

a receiver that receives feedback information corresponding to the physical downlink shared channel transmission, wherein the feedback information comprises the first physical random access channel preamble that indicates the hybrid automatic repeat request acknowledgment or a second physical random access channel preamble that indicates a hybrid automatic repeat request negative acknowledgement, and wherein the second physical random access channel preamble is:

derived from the information indicating the first physical random access channel preamble.

12. A method comprising:

receiving information indicating a first physical random access channel preamble used to indicate a hybrid automatic repeat request acknowledgment;

receiving a physical downlink control channel order;

receiving a physical downlink shared channel transmission, wherein the physical downlink control channel order and at least a portion of the physical downlink shared channel transmission are received after a remote unit loses an uplink synchronization and before the remote unit completes a physical random access channel procedure; and

transmitting feedback information corresponding to the physical downlink shared channel transmission, wherein the feedback information comprises the first physical random access channel preamble that indicates the hybrid automatic repeat request acknowledgment or a second physical random access channel preamble that indicates a hybrid automatic repeat request negative acknowledgement, and wherein the second physical random access channel preamble is:

derived from the information indicating the first physical random access channel preamble.

13. The method of claim 12 , wherein the remote unit comprises a mapping linking the first random access channel preamble to the second random access channel preamble.

14. The method of claim 12 , wherein the feedback information is transmitted using resources allocated by a radio resource control message.

15. An apparatus comprising:

a receiver that:

receives information indicating a first physical random access channel preamble used to indicate a hybrid automatic repeat request acknowledgment;

receives a physical downlink control channel order; and

receives a physical downlink shared channel transmission, wherein the physical downlink control channel order and at least a portion of the physical downlink shared channel transmission are received after a remote unit loses an uplink synchronization and before the remote unit completes a physical random access channel procedure; and

a transmitter that transmits feedback information corresponding to the physical downlink shared channel transmission, wherein the feedback information comprises the first physical random access channel preamble that indicates the hybrid automatic repeat request acknowledgment or a second physical random access channel preamble that indicates a hybrid automatic repeat request negative acknowledgement, and wherein the second physical random access channel preamble is:

derived from the information indicating the first physical random access channel preamble.