Noncoherent Receiver for Amplify-and-Forward Relaying with M-FSK Modulation

This paper develops a detection scheme based on implicit pilot-symbol-assisted architecture for non-coherent amplify-and-forward (AF) relay networks. The networks use M-ary frequency-shift-keying (FSK) modulation and multiple relays to assist communication from a source to a destination. Built on the fact that every transmitted symbol from the source to the destination can be considered as a pilot symbol, the destination combines the signals from the source and the relays to perform detection by using the estimated channels obtained from the implicit pilot symbols. A tight upper bound on the bit-error-rate (BER) of the developed scheme is obtained and used to show that the proposed scheme achieves a full diversity order. Moreover, simulation results reveal that the proposed scheme can significantly improve the BER performance when compared to previously proposed schemes in a temporally-correlated fading environment.