A Low Complexity Receiver for Noncoherent Amplify-and-Forward Cooperative Systems

A maximum energy selection (MES) receiver scheme is proposed for noncoherent amplify-and-forward (AF) cooperative diversity systems. An expression for the symbol error probability of this system when deployed with M-ary frequency shift keying (FSK) modulation is derived. It is shown that a noncoherent AF system employing the proposed MES scheme achieves full spatial diversity, while requiring neither instantaneous nor statistical channel gain information at the destination, but only knowledge of the average source-relay link signal-to-noise ratio (SNR) at the corresponding relay. The average source-relay link SNR information can be locally obtained at each relay using conventional practical estimation techniques, which in turn allows fully distributed implementation of the proposed scheme.