Differential Space-Time coding for partially-coherent Decode and Forward cooperative communication

In this paper, a Decode and Forward (DF) cooperative communication scheme, achieving full rate, is introduced. The scheme uses Minimum-Decoding complexity Quasi-Orthogonal Space-Time Block Code (MDC-QOSTBC), which uses a non-linear transmitter to obtain a linear decoding complexity at the receiver side. The transmitter has four transmitting antennas and the receiver uses more than four antennas to achieve a better performance. This technique acquires a differential full-diversity and linear complexity of the system in the first-hop. The channel used is a partially-coherent relay channel (PCRC), where the first-hop is non-coherent and the second-hop is coherent. In the second hop, Generalized Selection Combining (GSC) technique is used to select and combine part of these relays. The relay nodes selection decision is based on instantaneous signal to noise ratio (ISNR).