Zero-Forcing Based Decode-and-Forward Cooperative Relaying Scheme over Doubly Selective Fading Channels

This paper evaluates the performance of a decode-and-forward scheme using orthogonal frequency-division multiplexing (OFDM) over both time-selective and frequency-selective fading channels. We consider a simple detection based on the zero-forcing (ZF) principle to eliminate inter-carrier interference (ICI) caused by high mobility and to combine signals received from the source and the relay for high spatial diversity at the destination. The symbol error rate (SER) of the ZF-based cooperative relaying scheme is derived and validated by computer simulations. Various results show the superiority of cooperative relaying to direct transmission under same transmission power and bandwidth efficiency for any relay position, signal-to-noise ratio (SNR), path-loss exponent, and normalized Doppler frequency.