Performance analysis in AF/DF relay networks with beamforming

Beamforming (BF) performance is analyzed in amplify/decode and forward (AF/DF) fixed relay networks with a Rayleigh fading channel. Novel lower-bounds are presented for AF/DF relaying schemes such as selection relaying and relaying with known/unknown channel information of the relay link at the source and destination. We show that lower-bounds are achievable at the expense of a rate penalty. The optimal signal-to-noise ratio (SNR) threshold is analyzed for selection relaying. High SNR performance analysis is also done for AF relay networks. Finally, we show performance comparisons among strong-path BF and optimized BF with a corresponding lower-bound.