Method and apparatus for providing downlink acknowledgements and transmit indicators in an orthogonal frequency division multiplexing communication system

1. A method for providing downlink acknowledgments corresponding to uplink transmission using hybrid automatic repeat request to a plurality of users in an Orthogonal Frequency Division Multiplexing communication system wherein a frequency bandwidth comprises a plurality of frequency sub-carriers, the method comprising:

spreading each acknowledgment of a plurality of acknowledgments with a selected spreading sequence of a plurality of spreading sequences to produce a plurality of spread acknowledgments;

using a first resource unit assigned to a user equipment in an uplink scheduling grant and for an uplink transmission to select a downlink acknowledgment channel number for the user equipment; and

distributing the plurality of spread acknowledgments across the plurality of frequency sub-carriers.

2. The method of claim 1 , wherein the plurality of spreading sequences are associated uniquely with a plurality of users.

3. The method of claim 1 , further comprising choosing a transmission power of the spread acknowledgement sequence for a user based on a received Channel Quality Information of the user.

4. The method of claim 1 , wherein each spreading sequence of the plurality of spreading sequences is orthogonal to the other spreading sequences of the plurality of spreading sequences.

5. The method of claim 1 , wherein each spreading sequence of the plurality of spreading sequences comprises a CAZAC sequence.

6. The method of claim 1 , wherein a first set of spreading sequences are used for individual user equipment and a second set of spreading sequences are used by members of a group of user equipment.

7. A wireless network element that provides downlink acknowledgments corresponding to uplink transmission using hybrid automatic repeat request to a plurality of users in an Orthogonal Frequency Division Multiplexing communication system wherein a frequency bandwidth comprises a plurality of frequency sub-carriers, wherein the wireless network element comprises:

a processor that is configured to use a first resource unit assigned to a user equipment in an uplink scheduling grant and for an uplink transmission to select a downlink acknowledgment channel number for the user equipment, spread each acknowledgment of a plurality of acknowledgments with a selected spreading sequence of a plurality of spreading sequences to produce a plurality of spread acknowledgments, and distribute the plurality of spread acknowledgments across the plurality of frequency sub-carriers.

8. The wireless network element of claim 7 , wherein the plurality of spreading sequences are associated uniquely with a plurality of users.

9. The wireless network element of claim 7 , wherein the processor is further configured to choose a transmission power of the spread acknowledgement sequence for a user based on a received Channel Quality Information of the user.

10. The wireless network element of claim 7 , wherein each spreading sequence of the plurality of spreading sequences is orthogonal to the other spreading sequences of the plurality of spreading sequences.

11. The wireless network element of claim 7 , wherein each spreading sequence of the plurality of spreading sequences comprises a CAZAC sequence.

12. The wireless network element of claim 7 , wherein a first set of spreading sequences are used for individual user equipment and a second set of spreading sequences are used by members of a group of user equipment.

13. A user equipment (UE) that receives an acknowledgment corresponding to uplink hybrid automatic repeat request transmission in an Orthogonal Frequency Division Multiplexing communication system wherein a frequency bandwidth comprises a plurality of frequency sub-carriers, the user equipment comprising:

a processor that is configured to monitor a downlink control channel informing the UE of an uplink grant, determine that the UE is scheduled to transmit data during a given time period based on the uplink grant, transmit data during the time period, receive an acknowledgment corresponding to the UE's uplink transmission via a plurality of sub-carriers, wherein the acknowledgment comprises a spreading sequence associated with the UE and wherein the spreading sequence is distributed over the plurality of sub-carriers in the frequency bandwidth, and decode the acknowledgment using a selected acknowledgment sequence number, wherein the processor is configured to determine the acknowledgment spreading sequence number based on a first resource unit assigned to the user equipment in the uplink grant and wherein the resource unit is assigned to the user equipment for an uplink transmission.

14. The user equipment of claim 13 , wherein the spreading sequence is orthogonal to spreading sequences used to convey acknowledgments to other user equipment via the same multiple sub-carriers.

15. The user equipment of claim 13 , wherein the spreading sequence comprises a CAZAC sequence with a time shift that is different than time shifts applied to acknowledgments conveyed to other user equipment via the same multiple sub-carriers.

16. The user equipment of claim 13 , wherein the spreading sequence used depends upon whether or not the user equipment is a member of a group.

17. The user equipment of claim 13 , wherein the selected acknowledgment sequence number is based on the resource unit of the plurality of resource units assigned to the user equipment.