Multiple-Symbol Differential Detection for Distributed Space-Time Coding
  Differential distributed space-time coding (D-DSTC) technique has been considered for relay networks to provide both diversity gain and high throughput in the absence of channel state information. Conventional differential detection (CDD) or two-symbol non-coherent detection over slow -fading channels has been examined and shown to suffer 3-4 dB loss when compared to coherent detections. Moreover, it has also been shown that the performance of CDD severely degrades in fast-fading channels and an irreducible error floor exists at high signal-to-noise ratio region. To overcome the error floor experienced with fast-fading, a nearly optimal "multiple-symbol" differential detection (MSDD) is developed in this paper. The MSDD algorithm jointly processes a larger window of received signals for detection and significantly improves the performance of D-DSTC in fast-fading channels. The error performance of the MSDD algorithm is illustrated with simulation results under different fading scenarios. 
M. R. Avendi, Ha H. Nguyen and Nguyen Quoc-Tuan
cs.IT math.IT