Research On Key Theories And Technologies For MIMO Wireless Communication Systems

Multiple-input multiple-output (MIMO) technology is a significant breakthrough in the development of wireless communication technologies. It can get rid of the constraint of radio frequency resource and greatly increase the spectral efficiency of wireless systems, and thus is considered as the future development trend of wireless communication technologies. However, MIMO technology thoroughly breaks the mode of traditional wireless communications, since it requires multiple transmit and receive antennas to simultaneously transmit and receive data information in the same frequency, which challenges all the aspects of wireless communications including system architecture, analytical methods, modulation, coding, detection, channel estimation, multiple access, and so on.On the basis of international current research works, this thesis investigates some key theories and technologies for MIMO wireless communication systems in depth, and presents some new contributions in the following topics: MIMO channel capacity, signal detection for MIMO systems, CDMA for MIMO-OFDM systems, adaptive transmission for MIMO systems, and differential space-time coding.On the topic of MIMO channel capacity, two new theoretical contributions are presented. One is that the simple closed-form formula and asymtotic bound of MIMO channel capacity is derived. The other is that a nonstationary analysis method of MIMO channel capacity is proposed, and the capacity limits of time-varying MIMO channels are analyzed via the method. The above contributions have important significance of guiding the theoretical researches and pratical applications of MIMO systems.On the topic of signal detection for MIMO systems, three novel computationally efficient detection algorithms are proposed. The first two algorithms are the fast implementation methods of conventional vertical Bell Laboratories layered space-time (V-BLAST) detection algorithm, which not only have lower complexity than other existing algorithms but gurantee no performance degradation. The third algorithm is a simplified scheme of optimal maximum-likelihood detection (MLD)...