| Multiple-input multiple-output (MIMO) can increase channel capacity by many times and effectively resist wireless fading using spatial multiplexing and diversity technologies. Based on MIMO, cooperative relay (CR) by means of the broadcasting characteristics of wireless channels composes the virtual antenna array with the terminal, which can enlarge system covering range and lower transmit power. Therefore MIMO and CR are two important technologies in the next generation wireless communication systems. Combining with antenna selection, they can further increase system performance. In addition, more novel and practical service will be provided in the future. The services based on precise position information have great attraction to people. In order to improve the positioning accuracy and derive more precise position information, cooperative positioning taking fully advantage of existed wireless infrastructure is an effective solution. Hence this thesis has investigated the antenna selection and cooperative positioning technologies in the next generation wireless communication systems. The main working contents and research results are listed as follows:First, the analytical results of channel capacity for MIMO systems and MIMO antenna selection systems are summarized when the channel state information (CSI) is perfectly available at the receiver, but not at the transmitter. Regarding MIMO channel capacity, the statistical properties, approximate distributions and ergodic capacity bounds are presented. Then the capacity bounds of MIMO antenna selection systems are also presented.Second, antenna selection technologies in MIMO spatial multiplexing systems are studied. Above all, some antenna selection criterions, algorithms and important conclusions in narrowband MIMO systems are reviewed. Then receive antenna selection (RAS) in broadband MIMO systems is mainly investigated. In order to maximize system capacity, a suboptimal antenna selection criterion is proposed by exploiting the correlation between neighboring subcarriers. Utilizing the criterion, RAS is implemented combining with convex optimization method. Also the antenna selection algorithm is further analyzed and improved.Third, the performance of MIMO antenna selection systems using orthogonal space-time block codes is analyzed over Nakagami-m fading channels. When the channel fading parameter m is positive integer and more than two transmit (or receive) antennas are selected, the probability density function of system receive SNR is derived through approximate method. Thus the performance of system error probability (SEP) can be easily analyzed. Under arbitrary Nakagami fading channels, exact closed-form expressions of SEP are derived when one or two transmit antennas are selected.Finally, cooperative positioning technologies in CR systems are studied. Mathematical expressions of geometric dilution of precision (GDOP) are firstly deduced in Time-of-Arrival (TOA) and Angle-of-Arrival (AOA) positioning systems. The expressions obviously reveal that besides the measurement precision, the geometrical shape of base stations also makes a significant influence on positioning accuracy. Then the effect of cooperative relay assisted positioning on GDOP is mainly considered. Simulation results show that cooperative positioning can significantly lower GDOP. The best orientations of cooperative relay are also theoretically derived for TOA and AOA positioning systems. Based on the analytical process, a new indicator of geometry, geometry consistency factor (GCF), is defined. GCF can evaluate the geometrical shape of existed base stations from the view of CR. It relates the condition number of visibility matrix and GDOP together. An effective approach for acquiring additional measurements is also proposed, which can ensure best positioning accuracy with high probability.
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