Research On Beamforming And Detection Algorithm For Full - Duplex MIMO Relay System

Full-duplex systems perform simultaneous transmission and reception in the same frequency band and time slot, hence and promise up to twice the data rate offered by half-duplex systems. However, in full-duplex systems, self-interference at the relay, due to the signal leakage from its transmitter to receiver, will lead to a significant degradation of the system performance. Therefore, one of the key challenges in full-duplex relaying systems is how to manage and control self-interference efficiently. In this paper, we consider a full-duplex multiple-input multiple-output (MIMO) relaying network with decoded-and-forward and amplify-and-forward strategies. And we mainly focus on the optimization of beamforming design and the detecting algorithms. This paper is organized as follows:1) To deal with the self-interference and enhance the system achievable rate in full-duplex MIMO relay systems with decoded-and-forward strategy, an iterative beamforming structure (IBS) at the relay is proposed. In this method, the received beamforming at the relay is optimized to maximize the received signal-to-interference-and-noise-ratio (Max-SINR), while the transmit beamforming at the relay is optimized to maximize the signal-to-leakage-plus-noise-ratio (Max-SLNR). Furthermore, in the presence of the residual self-interference, a low-complexity whitening-filter maximum likelihood detector is designed. From simulation results and analysis, it follows that the proposed IBS performs much better than the existing schemes. Also, the proposed low-complexity detector significantly reduces the complexity of conventional ML decetor (CMLD) while at the same time achieves a slightly better BER performance than the CMLD.2) For full-duplex MIMO relay systems with amplify-and-forward protocol, in order to improve the transmission rate, a new beamforming combination method for full-duplex MIMO relaying system is proposed. This method consists of singular value decomposition (SVD) beamforming at source and destination node, and Max-SINR receive beamforming, and transmit beamforming Max-SLNR at relay station, respectively. Similarly, an iterative structure are introduced to optimize the beamforming matrix at the relay jointly. Simulation results show the proposed combination method performs better than the existing beamforming combination schemes in terms of rate.