Research On A Variety Of Coding And Decoding Methods In MIMO-OFDM System

Without increasing bandwidth or transmitting power, MIMO technique can improve channel capacity greatly. The orthogonal-frequency-division-multiplexing (OFDM) system is a multi-carrier system which can be used to combat frequency selective fading and narrowband interference. MIMO-OFDM technique takes the advantages of both MIMO technique and OFDM technique, and becomes the hotpot in the study and industry field. MIMO-OFDM technique has been used in both WIMAX and LTE protocols as the key technique of the PHY Layer.Firstly a brief introduction on the key techniques and the principles of MIMO and OFDM techniques are given in this thesis. Subsequently, a brief summary about MIMO-OFDM used in LTE protocol is offered. Then the characters and models of the wireless channel are analyzed. Also, the capacity of the MIMO channel is studied and compared. Secondly, the algorithms of space-time code are studied, and the methods of OFDM techniques combined with the space-time code are assorted and their characters are compared and analyzed. Then, a lot of ameliorative algorithms about VBLAST-OFDM are advanced and analyzed. Also the ameliorative algorithm of Turbo-BLAST-OFDM system is advanced and analyzed in detail and compared with traditional principle. Finally in order to manage the space-time coding more freely and improve the compositive performance of system by choosing different combined coding according to different conditions, the conception of MIMO-OFDM space-time-frequency area mixed coding is advanced. Then its sorts, principles and structures are introduced and analyzed in detail. .