Efficient acknowledgement messaging in wireless communications

1. A method for acknowledging message reception in a wireless OFDM/OFDMA system, comprising:

receiving, at a subscriber station, a message having a medium access control layer header and an unsolicited medium access control (MAC) management message as payload;

operating the subscriber station to generate an acknowledgement (ACK) signal when the subscriber station receives the message from a base station;

receiving a pre-allocated uplink resource for the subscriber station to transmit the ACK signal to the base station without making a request to the base station for sending the ACK signal; and

sending the ACK signal consisting of a MAC header transmitted at the pre-allocated uplink resource, the MAC header including acknowledgement information associated with the received message and a message type of the received message.

2. The method as in claim 1 , comprising:

configuring the MAC header to include a transaction ID to identify different versions of received message of the same message type, wherein the transaction ID is set to a transaction ID retrieved from the message being acknowledged.

3. The method as in claim 2 , comprising:

compressing the transaction ID by including only the least significant bits in the MAC header.

4. The method as in claim 1 , comprising including a confirmation code in MAC header to indicate an operation of subscriber station in response to the message being acknowledged.

5. A method for acknowledging message reception in a wireless OFDM/OFDMA multi-hop relay system, comprising:

receiving, at a relay station, a message having a medium access control layer header and an unsolicited medium access control (MAC) management message as payload sent from a base station or a superordinate relay station;

operating the relay station to generate an acknowledgement (ACK) signal when the relay station receives the message sent from the base station or the superordinate relay station;

receiving a pre-allocated uplink resource for the relay station to transmit the ACK signal to the base station or the superordinate relay station without making a relay station request for sending the ACK signal; and

sending the ACK signal consisting of a MAC header transmitted at the pre-allocated uplink resource, the MAC header including acknowledgement information associated with the received message and a message type of the received message.

6. The method as in claim 5 , comprising including a transaction ID in the MAC header to identify different versions of received message of the same message type, wherein the transaction ID is set to a transaction ID retrieved from the message being acknowledged.

7. The method as in claim 6 , comprising compressing the transaction ID by including only the least significant bits in the MAC header.

8. The method as in claim 5 , comprising including a confirmation code in the MAC header to indicate an operation of relay station in response to the message being acknowledged.

9. A method for acknowledging message reception in a wireless OFDM/OFDMA system, comprising:

receiving, at a subscriber station or a relay station, a plurality of messages having a medium access control layer header and an unsolicited medium access control (MAC) management message as payload;

operating the subscriber station or the relay station to generate an acknowledgement (ACK) signal to acknowledge the plurality of messages received by the subscriber station from a base station;

providing a pre-allocated uplink resource for the subscriber station or the relay station to transmit the ACK signal to the base station without making a subscriber station request to the base station for sending the ACK signal; and

comprising sending the ACK signal consisting of a MAC header transmitted at the pre-allocated uplink resource, the MAC header including acknowledgement information associated with the received message and a message type of the received message.

10. The method as in claim 9 , comprising:

operating the base station to, after sending out the message to the subscriber station or relay station, allocate the pre-allocated uplink resource for the subscriber station or relay station to send the ACK signal.

11. The method as in claim 9 , comprising including a transaction ID in the MAC header to identify different versions of received message of the same message type, wherein the transaction ID is set to a transaction ID retrieved from the message being acknowledged.

12. The method as in claim 11 , comprising compressing the transaction ID by including only the least significant bits in the MAC header.

13. The method as in claim 9 , comprising including a confirmation code in the MAC header to indicate an operation of relay station in response to the message being acknowledged.

14. The method as in claim 1 , comprising operating the base station to start a timer after sending the message received at the subscriber station, wherein the timer is indicative of a time for the base station to wait for the ACK signal from the subscriber station before retransmitting the message to the subscriber station.

15. The method as in claim 5 , comprising operating the relay station to start a timer after sending the message received at the base station or the superordinate relation station, wherein the timer is indicative of a time for the relay station to wait for the ACK signal from the base station or the superordinate relay station before retransmitting the message to the base station or the superordinate relay station.

16. The method as in claim 9 , comprising operating the base station to start a timer after sending the message received at the subscriber station or the relay station, wherein the timer is indicative of a time for the base station to wait for the ACK signal from the subscriber station or the relay station before retransmitting the message to the subscriber station or the relay station.