Virtual Antenna Based Combining for Hybrid AF/DF Relaying Scheme over Multi-Antenna Broadband Channels

This paper focuses on turbo packet combining for hybrid AF/DF multi-relay systems operating over multipleinput–multiple-output (MIMO) broadband channels. We consider virtual antenna based combining strategy that has been widely studied for the point-to-point hybrid ARQ. However, the extension of this combining strategy to hybrid AF/DF cooperative communications is not straightforward. In this paper, we revisit this combining strategy. First, we build an appropriate system model to mask the cooperation. Then, we extend the turbo packet combiner inspired by virtual antenna concept to cooperative communications. Finally, block error rate (BLER) are investigated to demonstrate the gain offered by the studied turbo packet combiner.