Cooperative communications techniques
Techniques are disclosed involving communications between source and destination devices. Such communications may involve multiple cooperating devices that retransmit (e.g., simultaneously retransmit) transmissions sent by a source device. Thus, the delivery of transmissions from source devices to destination devices may involve two or more “hops” (e.g., a first “hop” comprising an initial transmission, and a second “hop” comprising two or more relay transmissions).
1. A method, comprising:
selecting a set of two or more cooperating devices;
sending a transmission from a source device to a destination device and to one or more of the two or more cooperating devices;
receiving an acknowledgement, a negative acknowledgement or no acknowledgement from the source device and the cooperating devices; and
determining one or more characteristics for two or more retransmissions, the two or more retransmissions from the source device and a corresponding one or more of the two or more cooperating devices that returned an acknowledgement when the destination device returned a negative acknowledgement or no acknowledgement.
2. The method of claim 1 , wherein the two or more cooperating devices includes one or more cooperating devices that have acknowledged receipt of the initial transmission from the source device.
3. The method of claim 1 , comprising modifying the set of cooperating devices and retransmission characteristics for different retransmissions.
4. The method of claim 1 , wherein said determining the one or more characteristics comprises allocating one or more resources for the two or more retransmissions.
5. The method of claim 1 , wherein said determining the one or more characteristics comprises selecting a distributed space-time coding technique for the one or more retransmissions.
6. The method of claim 1 , wherein said determining the one or more characteristics comprises selecting a distributed beamforming technique for the one or more retransmissions.
7. The method of claim 1 , further comprising:
sending the one or more characteristics to the two or more cooperating devices in a portion of a subframe.
8. An apparatus, comprising:
a selection module to select two or more cooperating devices;
a radio module to send a transmission to the two or more cooperating devices; and
a determination module to determine one or more characteristics for two or more retransmissions, each of the two or more retransmissions from a corresponding one or more of the two or more cooperating devices that returned an acknowledgement of the transmission;
wherein each of the two or more retransmissions is of an initial transmission sent by a source device for which a negative acknowledgement or no acknowledgement is received from one or more of the two or more cooperating devices or from a destination device.
9. The apparatus of claim 8 , further comprising a transceiver to send to the two or more cooperating devices an indication of their selection.
10. The apparatus of claim 9 , wherein the transceiver is to send the indication in at least one of a DL-MAP and a UL-MAP and/or using MAC management messages.
11. The apparatus of claim 9 , wherein the transceiver is to send an indication of the one or more characteristics to the two or more cooperating devices.
12. The apparatus of claim 11 , wherein the transceiver is to send the indication in at least one of a DL-MAP and a UL-MAP and/or using MAC management messages.
13. The apparatus of claim 8 , wherein the initial transmission and each of the retransmissions are uplink data burst transmissions.
14. The apparatus of claim 8 , wherein the initial transmission and each of the retransmissions are downlink data burst transmissions.
15. The apparatus of claim 8 , wherein the retransmissions employ a distributed space-time coding transmission technique.
16. The apparatus of claim 8 , wherein the retransmissions employ a distributed beamforming technique.
17. The apparatus of claim 8 , wherein the selection module may change the set of cooperating devices and the determination module may change the retransmission characteristics across different retransmissions.
18. A system, comprising:
a source device to send an initial transmission; and
two or more cooperating devices to each simultaneously send a retransmission of the initial transmission to a destination device when they each receive the initial transmission if no message is sent from the source device to the destination device or a negative acknowledgement or no acknowledgement is received from one or more of the two or more cooperating devices.
19. The system of claim 18 , wherein the source device or the destination device is to select the two or more cooperating devices and determine one or more characteristics for each of the retransmissions.
20. The system of claim 18 ,
wherein two or more cooperating devices includes the source device; and
wherein the source device is to resend the initial transmission when the two or more cooperating devices fail to acknowledge receipt of the initial transmission.