| Along with the rapid development of informatization process, the demand for wire-less communication is increasing continuously. On the one hand, this increasing demand for wireless communication has put forward higher requirements on the performance of wireless communication. On the other hand, there are many huge challenges to be over-come to further enhance the performance of wireless communication system, which in-clude the limited bandwidth, the increasingly serious interference, the limited power and the sustainability requirements by our society, etc. Because of its huge potential on spec-tral efficiency improvement, interference reduction and energy efficiency improvement, multiple-input multiple-output (MIMO) is the most promising technology to satisfy the demands of future wireless communications, and it has been recognized as one of the key technologies for the future communication systems. As a consequence, the typical future wireless communication scenarios can be envisaged to be multiuser MIMO net-works, and the transmission performance of which is limited by multiuser interference. Therefore, it becomes a hot topic currently to study transceiver designs for interference cancellation in MIMO multiuser networks. Meanwhile, more new applications, as repre-sented by energy harvesting, will be integrated into the wireless communication systems, which brings new changes in the system architecture. The traditional transceiver design methods, which have been developed for single user systems, has been unable to adapt to the multiuser MIMO systems and new system architecture. By summing up, this disser-tation aims to investigate transceiver designs for suppressing multiuser interference and adapting to the requirement of new applications represented by wireless energy harvesting in multiuser wireless communications.Focusing on multiple antennas technology, aiming at spectral efficiency and energy efficiency improvement, taking the interference alignment, interference suppressing and energy harvesting as the key points of breaking through, the work in this thesis mainly study transceiver designs for interference suppression and energy harvesting in multius-er MIMO system by utilizing the space dimensions and improving the efficiency of re-sources. The work in this thesis is carried out for several types of typical future multiuser MIMO networks, including the interference channels (IC), the broadcast channels (BC) and the interfering broadcast channels (IBC), etc. The main contributions are summarized as follows:1) The achievable rate of MIMO IC networks with interference alignment has been analyzed. The impact of channel error on the achievable rate of MIMO linear interference alignment (IA) networks has been studied. For uncorrelated channels, the upper and lower bounds of the ergodic mutual information are derived analytically with the assumption of orthonormal transmit precoders and receive filters designed from imperfect channel state information (CSI), and the tightness of the derived bounds is proved. Based on the derived bounds, the impact of channel error on the degrees of freedom (DoF) and the DoF persistence conditions are also investigated. For correlated channel, the impact of channel error on the achievable rate of one channel realization has been investigated, and the lower and upper bounds of the achievable rate of the channel realization are derived. The results of significance in theoretical guidance for practical interference alignment system designs.2) The robust transceiver designs for MIMO IC networks with imperfect CSI have been investigated. Based on the innovation work in 1), robust transceiver design schemes have been proposed based on the stochastic approach and the probabilistic constrain-t method, and the transceiver optimization algorithms are derived correspondingly. In the first case, utilizing the reciprocity between downlink and uplink channels, a robust scheme is proposed by maximizing the average SINR. The propsoed average SINR maximization robust scheme can be classified as the stochastic approach, which is of low computational complexity, but achieves rather conservative performance. To further improve the perfor-mance of the system, a probabilistic constraint robust transceiver design algorithm is also proposed by maximizing the average received signal while constraining the probability of large interference plus noise, both in downlink and uplink. Compared with traditional non-robust designs, the proposed robust transceiver designs can improve the achievable rate of MIMO IC networks significantly.3) The interference alignment transceiver designs for MIMO IBC networks have been studied. For the typical future MIMO multi-cell multi-user wireless communica-tion systems, an interference alignment transceiver design scheme has been investigated by taking into the user fairness into consideration. With the objective to optimize the worst user MSE in the whole network, an interference alignment scheme is proposed to minimize the maximum MSE of the received symbols. An alternative optimization algo-rithm is then developed to optimize the transceivers based on second order cone program (SOCP). The convergence of the proposed algorithm is proved, which shows its feasi-bility. Simulation results show that the proposed Min-Max MSE scheme can achieve IA when the antennas are configured to be strong IA proper and the users in the network are of the same MSE, which verifies that the user fairness can be improved by the pro-posed scheme. Furthermore, a robust Min-Max-MSE algorithm is proposed to counter the channel uncertainty. Simulation results show that the proposed robust design algorithm provides better performance when lacking perfect CSI.4) The simultaneous wireless information and power transfer (SWIPT) schemes for multiuser MIMO networks have been studied. For MIMO BC networks, a joint transceiv-er design and power splitting optimization scheme is proposed by considering both the MSE and energy harvesting (EH) QoS requirements. For MIMO IC networks, SWIPT schemes based on MSE optimization criterion have been proposed and studied. Two joint transceiver design and PS ratio optimization schemes are formulated by minimizing ei-ther the sum MSE or the worst user MSE subject to the given EH constraints and transmit power constraints. In order to solve the proposed joint transceiver design and power s-plitting optimization problems, the alternatively iterative optimization algorithms are then developed based on semidefinite programming (SDP) relaxation techniques. Theoretical analysis and simulation results show the effectiveness of the proposed schemes in achiev-ing SWIPT for multiuser MIMO systems.
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