Source-assisting strategy for differential distributed space time block codes

In this paper, a source-assisting differential distributed space time block coding (SA-DDSTBC) scheme is proposed for cooperative networks. Firstly, in most existing works on distributed space time block coding (DSTBC), the destination node is assumed to have perfect channel state information (CSI), thus, signal recovery is straight forward. In practice however, some scenarios exist whereby the destination node is unable to acquire CSI. Consequently, this work incorporates differential concepts with DSTBC to facilitate signal recovery in cooperative networks operating in environments where CSI acquisition is impractical. Secondly, different from most works on DSTBC which assume that the source-destination link is unavailable, the proposed scheme employs a source-assisting (SA) strategy that exploits the additional diversity path provided by the source-destination link. The numerical and simulation results obtained illustrate that compared to the conventional DSTBC schemes, the proposed SA-DDSTBC scheme achieves non-coherent signal recovery and improved BER and diversity performance with negligible increase in decoding complexity.