System and method for message acknowledgment feedback for device-to-device communication overlaid on a cellular network

A method of operating a user equipment (UE) in a group of user equipments (UEs) of a direct mobile communication (DMC) link, comprising:

• generating, by the UE, acknowledgment and negative acknowledgement (ACK/NACK) feedback for a group of hybrid automatic repeat request (HARQ) processes over the DMC link;
• aggregating, by the UE, the ACK/NACK feedback according to a length of a sliding window and an allocation of a first set of subframes for the DMC link received from a communication controller, wherein the aggregated ACK/NACK feedback includes individual ACKs and NACKs for respective HARQ processes within the sliding window;
• and
• transmitting, by the UE, the aggregated ACK/NACK feedback to other UEs in the group of UEs of the DMC link on a subframe from an allocation of a second set of subframes received from the communications controller,
• wherein the allocation of the second set of subframes is a subset of the allocation of the first set of subframes.

A communications controller, comprising:

• a transceiver;
• and
• a processor unit coupled to the transceiver, the processor unit, in conjunction with the transceiver, configured to cause the communications controller to:
• allocate a set of subframes to a group of user equipments (UEs) for a direct mobile communication (DMC) link,
• signal the set of allocated subframes to the group of UEs, and
• indicate a length of a sliding window to the group of UEs to:
• enable UEs in the group of UEs to aggregate acknowledgment and negative acknowledgement (ACK/NACK) feedback for communications over the DMC link according to the length of the sliding window, wherein the aggregated ACK/NACK feedback includes individual ACKs and NACKs for respective hybrid automatic repeat request (HARQ) processes within the sliding window, and
• enable the ACK/NACK feedback for the communications over the DMC link to be determined independently from ACK/NACK feedback for cellular transmission between the communication controller and the group of UEs.