System and method for terminal-group based HARQ for cellular integrated D2D communications

1. A method for supporting two-level terminal-group based hybrid-automatic repeat request (HARQ) signaling, the method comprising:

receiving, at a cooperating user equipment (CUE) within a virtual multi-point (ViMP) node comprising a plurality of UEs, a data packet for a target UE (TUE), within the ViMP node, that is broadcasted from a base station (BS) to the ViMP node;

successfully decoding the data packet;

in an absence of an acknowledgement (ACK) message or a negative ACK (NACK) message from the TUE, broadcasting, by the CUE, the data packet within the ViMP node; and

subsequent to the broadcasting, and in an absence of the NACK message from the TUE, rebroadcasting, by the CUE, the data packet within the ViMP node until either the CUE receives a subsequent broadcast of the data packet from the BS, or the CUE receives the ACK message from the TUE or the ViMP node.

2. The method of claim 1 further comprising:

receiving the broadcasted data packet from one or more UEs in the ViMP node.

3. The method of claim 2 , wherein the data packet is rebroadcasted within the ViMP node until the CUE receives the subsequent broadcast of the data packet from the BS.

4. The method of claim 2 , wherein the data packet is re-broadcasted until the ACK message is received from the TUE, a beacon UE, or any of the UEs in the ViMP node.

5. The method of claim 1 further comprising receiving the subsequent broadcast of the data packet from the BS in response to a timer pre-established by the BS expiring.

6. The method of claim 1 , wherein the data packet is rebroadcasted within the ViMP node without using scheduling within the ViMP node and without synchronization with the BS.

7. The method of claim 1 , wherein the data packet rebroadcasted to the UEs in the ViMP node comprises a network coded version of the same received and decoded data packet, additional coded symbols in case of a concatenated low-density parity check (LDPC) coding, or a given redundancy version in case of turbo coding.

8. The method of claim 7 , wherein the network coded version comprises a linear combination of successfully decoded packets, and wherein the decoded packets are combined using coefficients that are sent to the TUE with information on which packets were network coded.

9. The method of claim 7 , wherein the network coded version comprises a linear combination of successfully decoded packets, and wherein the decoded packets are combined using coefficients that are known beforehand by the TUE.

10. The method of claim 1 further comprising:

receiving, from the BS, data packets with different HARQ redundancy versions, low-density parity check (LDPC) codewords, or both for different TUEs, wherein the different HARQ redundancy versions and LDPC codewords are mapped to orthogonal signatures; and

rebroadcasting the data packets to the UEs in the ViMP node.

11. A method for supporting two-level terminal-group based hybrid-automatic repeat request (HARQ) signaling, the method comprising:

receiving, at a cooperating user equipment (CUE) within a virtual multi-point (ViMP) node comprising a plurality of UEs, a data packet for a target UE (TUE), within the ViMP node, that is broadcasted from a base station (BS) to the ViMP node;

successfully decoding the data packet;

in an absence of an acknowledgement (ACK) message or a negative ACK (NACK) message from the TUE, broadcasting, by the CUE, the data packet within the ViMP node;

subsequent to the broadcasting, receiving, by the CUE, the NACK message from the TUE;

rebroadcasting, by the CUE, the data packet within the ViMP node in response to receiving the NACK message; and

subsequent to the rebroadcasting, receiving either a subsequent broadcast of the data packet from the BS or the ACK message from the TUE.

12. The method of claim 11 further comprising:

receiving the broadcasted data packet from one or more UEs in the ViMP node.

13. The method of claim 12 , wherein the data packet is rebroadcasted within the ViMP node until the CUE receives the subsequent broadcast of the data packet from the BS.

14. The method of claim 12 , wherein the data packet is rebroadcasted until the ACK message is received from the TUE.

15. The method of claim 11 further comprising receiving the subsequent broadcast of the data packet from the BS in response to a timer pre-established by the BS expiring.

16. The method of claim 11 , wherein the data packet is rebroadcasted within the ViMP node without using scheduling within the ViMP node and without synchronization with the BS.

17. The method of claim 11 , wherein the data packet rebroadcasted within the ViMP node comprises a network coded version of the same received and decoded data packet, additional coded symbols in case of a concatenated low-density parity check (LDPC) coding, or a given redundancy version in case of turbo coding.

18. The method of claim 17 , wherein the network coded version comprises a linear combination of successfully decoded packets, and wherein the decoded packets are combined using coefficients that are sent to the TUE with information on which packets were network coded.

19. The method of claim 17 , wherein the network coded version comprises a linear combination of successfully decoded packets, and wherein the decoded packets are combined using coefficients that are known beforehand by the TUE.

20. The method of claim 11 further comprising:

receiving, from the BS, data packets with different HARQ redundancy versions, low-density parity check (LDPC) codewords, or both for different TUEs, wherein the different HARQ redundancy versions and LDPC codewords are mapped to orthogonal signatures; and

rebroadcasting the data packets to the UEs in the ViMP node.