Detection schemes for distributed space-time block coding in time-varying wireless cooperative systems

In this paper, we investigate the influence of time-varying channels on the bit-error-rate (BER) performance for distributed space-time block coded system. We make use of pilot symbol assisted modulation (PSAM) to estimate the time-varying channel coefficients. We assess the performance of different reception methods, one of which is our newly considered receiver called cooperative maximum likelihood detector. The others are maximum likelihood detection in [12], Alamouti's receiver, zero-forcing detection and decision-feedback detection. Our results show that all detection methods, except cooperative maximum likelihood detection, achieve nearly the same BER performance over time-varying channels, unlike the results obtained in [12] by assuming perfect channel estimation. In many cases, cooperative maximum likelihood detection performs better by about 5dB due to the diversity gain. In addition, we have found that the time-varying nature contributes to the error flooring effect.