Noncoherent Decode-and-Forward Cooperative Systems with Maximum Energy Selection

This paper investigates the performance of a maximum energy selection receiver of an adaptive decode-and-forward (DF) relaying scheme for a cooperative wireless system. In particular, a close-form expression for the bit-error-rate (BER) is analytically derived when the system is deployed with binary frequency-shift keying (BFSK) modulation. The thresholds used at the relays to address the issue of error propagation are optimized to minimize the BER. While finding the optimal thresholds requires information on the average signal-to-noise ratios (SNRs) of all the transmission links in the system, the approximate threshold at each relay that requires only information on the average SNR of the source-corresponding relay is investigated. It is also shown that the system achieves a full diversity order with the approximate thresholds. Both analytical and simulation results are provided to validate our theoretical analysis.