Study On MIMO Relay System Precoding Design And Optimization

Recent years, the multiple-input multiple-output (MIMO) relay technique is be-ing applied to increase the capacity, extend the coverage and improve the link re-liability of the network. Many research indicated that the proper linear precoding operation can further improve the overall system performance. This thesis mainly studies the precoding design for the single user non-regenerative MIMO relay system with direct link and multi user non-regenerative MIMO relay system. The main tasks of this thesis include3parts:We investigate the model of the non-regenerative MIMO relay communication system with the direct link. We propose a suboptimal joint source and relay beam-forming prccoding structure based on generalized singular value decomposition (GSVD) to diagonalize the mean-squared error (MSE) matrix in the cost function. The op-timization problem that involves matrix variables can be converted into a problem involves only scalar variables by using matrix diagonalization methods and optimiza-tion theory. Closed-form solutions can be obtained by using the proposed iterative water-filling algorithm which satisfies the KKT optimality conditions.We continue study the optimum linear precoding design for MIMO relay system under the minimum-mean-squared error (MMSE) criterion. We decompose the orig-inal problem into two sub-problems. The relay transceiver Wiener filter structure is first rigorously derived, then the source transmit and destination receive matrices are jointly designed by solving an equivalent dual problem. Through our proposed joint iterative algorithm, the closed-form solutions can be finally obtained.We propose a decentralized strategy to find out the linear precoding matrices for the two-hop multiuser MIMO relay system. From a game-theoretic perspective, we model the source alloeation process as a strategic non-cooperative game for fixing relay precoding matrix and the multiuser interference treating as additive colored noise, we then propose the simultaneous generalized iterative water-filling algorith-m (SGIWFA) to compute the NE points of game G. Alternately, from the global optimization perspective, we prove that the optimum relay precoding matrix has the transceiver Winner filter structure for giving a set of source transmit matrices. Closed-form solutions are finally obtained by using our proposed joint iterative SMSE algorithm.