Research On Key Technologies Of Grean Communicaiton Based On The Distributed MIMO Multiple Antennas System

Along with the rapid development of wireless communication, the energy consumption produced by communication systems also increases dramatically. Therefore, achieving energy saving and environment-friendly communications have caused widespread public concerns. Distributed MIMO multiple antennas system has attracted much attention because of its unique advantages. RAU (Remote Antennas Unit) in this system is located in different positions, so that the direct access distance between the system and the user is shortened which reduces the signal attenuation during the transmission. The Green ICT (Information & Communication Technology) based on the distributed MIMO multiple antennas system is studied in this thesis.Firstly, the basic concept of distributed MIMO multiple antennas system and Green ICT is overviewed, also the current research on the status quo of distributed MIMO multiple antennas system and Green ICT is introduced. The channel model of wireless communication is analyzed and the appropriate models under different scenarios is given out. Four metric to evaluate the energy efficiency of system and the application scenes of each metric is introduced. Also, the energy efficiency of distributed MIMO multiple antennas system and centralized MIMO multiple antennas system are analyzed and simulated simultaneously.Secondly, the energy efficiency of distributed MIMO multiple antennas system is analyzed in this paper and the energy efficiency optimization problem is transformed into the problem of finding optimum location of RAU under the situation that the number of RAU and the transmit power are constant. The RAU deployment in single cell system and multi-cell system is discussed respectively in this paper. In single cell system, the location of RAU is determined based on the norm of maximize the lower bound of the expected SNR (Signal and Noise Ratio) and the closed-form solution is found. In the situation of multi-cell, the mutual interference between different cells is considered. The location of RAU is determined based on the norm of maximize the lower bound of the expected SLR (Signal and Leakage Ratio) and the relevant iterative procedure is designed.Finally, the preprocessing technology of energy efficient down-link distributed MIMO multiple antennas system is studied. In the case of single cell, the energy efficient beamforming algorithm is designed by anal-ysis. The algorithm consists of two sub-algorithms. First, the original fractional problem is first transformed into an equivalent subtractive-form problem by equivalence algorithm. Then the equivalence problem is fur-ther transformed into attractable form. The superiority relative to the WMMSE (Weighted Minimum Mean Square Error) algorithm is proved through simulation analysis. In the case of multi-cell, a binary power con-trol algorithm is designed, which means that we stop providing service for some mobile users in the system when they are in poor communication quality so that the system energy efficiency is improved.The perfor-mance between binary power control algorithm and average power allocation algorithm is compared in this paper. It is proved that system energy efficiency is improved by the binary power control algorithm.