oa Interference Cancellation of Hop-By-Hop Beamforing for Dual-Hop MIMO Relay Networks

Cooperative communication relaying systems are gaining much interest because they can improve average link signal to nose ratio by replacing longer hops with multiple shorter hops. The method of relaying has been introduced to enable a source (i.e. mobile terminal) communicate with a target destination via a relaying (i.e. mobile terminal). Furthermore, multiple-input multiple output (MIMO) communication systems have been considered as powerful candidates for the fourth generation of wireless communication standards because they can achieve further performance improvements including an increase in the achievable spectral efficiency and the peak data rates (Multiplexing), and robustness against severe effects of fading (transmit beamforming). In this work, we consider hop-by-hop beamforming relaying system over Rayleigh fading channels. In wireless communication environments, it is well known understood that the performance of wireless networks can be limited by both fading and co-channel interference (CCI). In this work, the multiple antennas at each node of relaying systems can be used to adaptively modify the radiation pattern of the array to reduce the interference by placing nulls in the direction of the dominant interferers. In this paper, we investigate the effect of CCI on the performance of hop-by-hop beamforming relaying system. First, we derive exact closed-form expressions for the outage probability and average symbol error rates. Moreover, we look into the high signal to noise ratio (SNR) regime and study the diversity order and coding gain achieved by the system.