Abstract of thesis entitled ”Optimization In Linear Multiuser MIMO Systems”Submitted byGan Zheng for the degree of Doctor of Philosophyat The University of Hong Kongin November 2007Multi-antenna technologies, or widely known as multiple-input multiple-output(MIMO) antenna systems, have emerged as an attractive means of providing reliableand efficient communications in future-generation wireless systems. This thesis fo-cuses on linear transceiver design in multiuser MIMO systems, both with and withoutperfect channel state information (CSI).To satisfy individual users’ quality of service (QoS) requirements with minimumpower consumption is an important problem in multiuser communication systems.In this study, the feasibility issue is firstly studied in multiuser MIMO systems. Thecondition which is necessary and conjectured to be sufficient for the feasibility is pro-posed. The necessary part is proved in the general case while the sufficient part isproved only for two special cases. Assuming this problem is feasible, an iterative algo-rithm is proposed to jointly optimize the transmit and receive beamforming vectors,and power vector in order to minimize the total transmit power. The convergenceproof and the analysis of the steady-state solution are also given. Simulation resultsshow power reduction compared with existing schemes.The problem of throughput maximization with total power constraints is nextstudied in a multiuser MIMO-OFDM (Orthogonal Frequency Devision Multiplexing)downlink with multiple streams for each user. An iterative algorithm which takesturns to optimize the downlink power allocation, transmit antenna vectors and receiveantenna vectors, and the virtual uplink power allocation is proposed. It is proved that