Research On Beamforming And Antenna Selection For MIMO System

Wireless communication technology is one of the fastest growing and most dynamic sectors in the world. Along with the rapidly increasing of wireless communication users, arise the crucial challenge such as the high data rate, spectral efficiency, energy efficiency and so on. The solution to facing this challenge is the application of massive multi-antenna system and corresponding relaying techniques, but at the same time, in order to reduce the high cost of the radio frequency units and the hardware complexity while maintaining or improving the related system performance, the technology of joint beamforming and antenna selection is a potential research area. Based on the known channel state information, beamforming use a series of weighted value to improve the relevant system performance. Meanwhile, antenna selection technique is used to reduce the energy consume. This thesis focuses on beamforming and antenna selection algorithms in an MIMO communication system, the main researches as follows:First, we briefly introduced some existing classic antenna selection technology and beamforming technology. They are simulated and compared with numerical results, along with their advantages and disadvantages.Next, corresponding to a massive MIMO system, one-way amplify-and-forward MIMO relaying system, two-way decode-and-forward MIMO relaying system, we proposed a joint beamforming and antenna selection scheme respectively.Although transmit-receive beamforming is widely employed in general MIMO systems, much less is known about beamforming for massive MIMO communications. Even so, the literature focuses on receive beamforming, not transmit beamforming. We proposed a joint transmit beamforming and antenna selection algorithm. From the comparative simulation results, we concluded that our proposal has better performance in system capacity, achievable rate, output signal noise ratio, pairwise error probability.In existing literatures on MIMO relaying communication systems, the objection is often optimized by maximizing the channel capacity or the output single-to-noise ratio. In this thesis, we propose an energy-efficient antenna selection scheme for one-way amplify-and-forward MIMO relaying communication systems. The proposed algorithms can jointly optimize the transmit power, number of active antennas, and antenna subsets at the source, relaying and destination. We also derive the CDF of energy-efficient curve, which validated the simulation results.Traditionally, scholars usually assumes that the distance between relay node and two source nodes is symmetrical, while in the face of asymmetric situation, we proposed a joint beamforming and antenna selection for two-way decode-and-forward MIMO relaying communication system. First, performs antenna selection ensure that the high cost of RF chains can be reduced without iterations. Next, beamforming is employed for asymmetric condition. Extensive simulation results show that our algorithm have better performance in asymmetric cases, while have similar performance on the symmetric cases.Finally, summary conclusions are drawn, along with the advantages and deficiency of the proposed methods. Several possible future works are also discussed.