EFFECT OF BEAMFORMING ON MULTI-ANTENNA TWO HOP ASYMMETRIC FADING CHANNELS WITH FIXED GAIN RELAYS

In this paper, we investigate the impact of beamforming (BF) on a multi-antenna two hop amplify-and-forward (AF) fixed gain relay network over Rician-Rayleigh and Rayleigh-Rician asymmetric fading channels, respectively. The network consists of a relay with single antenna used to assist the signal transmission from the source to the destination, both of which are equipped with multiple antennas. By using the channel state information (CSI), the maximal output signal-to-noise ratio (SNR) with optimal beamforming is first obtained. Then, the novel analytical expressions for the outage probability (OP), probability density function (PDF) and generalized moments of the maximal output SNR are derived. Moreover, the theoretical formulas of the Ergodic capacity and average symbol error rates (ASERs) with various modulation formats are also developed. To gain further insights, the asymptotic ASERs at high SNR are presented to reveal the diversity order and array gain of the multi-antenna relay network. Finally, computer simulations confirm the validity of the theoretical analysis and indicate the influence of antenna number and Rican factor on the system performance.