Design And Analysis On Interference Mitigation In MIMO Cellular System

Multi-antenna transmission and reception (known as MIMO)is a key technique in the futuremobile communication systems. MIMO technique could achieve higher spectral efficiency thantraditional systems without additional transmit power and frequency bandwidth. However, thecellular MIMO systems become interference-limited because of the existence of inter-cellco-channel interference as the reason of the high sensitivity of MIMO receivers to interference,spectral efficiency of the MIMO system will be greatly reduced as a result. Advanced technologyabout the suppression of interference should be adopted in order to ensure high enough spectrumefficiency which is the one of advantages of MIMO system.This article conducted an intensive research on interference management techniques of cellularMIMO system. This article introduced system models and interference suppression technologies ofpoint-to-point MIMO system and multiuser MIMO system and extends these technologies intocellular MIMO environment. This article compare and evaluate the system performance oftraditional interference suppression algorithms which are based on the receiver and transmitter incellular MIMO system and reach a conclusion that system-level interference reducing strategiesbased on cooperation will be important for overcoming interference in future spatial multiplexingcellular systems.This article proposed a distributed multi-user precoding method for interference suppressionwhich called leakage zero forcing block diagonalization (LZF-BD). The main idea of this methodis proactively suppressed the interference leakage to the out-of-cell users by the base station andguarantee the signals of intra-cell users are orthogonal to each other at the same time. Subspacesspanned by interference channels and other intra-cell users channels are zero-forced by using thismethod. The analysis of theory and simulation both indicate that the proposed method couldsuppress the interference more efficiently and keep the complexity lower than traditionalinterference suppression methods.