Research On Anti-noise Performance And Resource Efficiency Of MIMO-OFDM System

Multiple-input multiple-output (MIMO) technology is a major breakthrough of smart antenna technique in wireless mobile communications. The technology exponentially improves the communication system capacity and spectrum efficiency without increasing the bandwidth,it must be one of the key technologies of the next generation mobile communication system.However, as a Multi-carrier modulation technique, orthogonal frequency division multiplexing(OFDM) utilizes sub-carriers of parallel, low-rate data transmission to achieve a high-speed data transmision, it can overcome the signal fading caused by multipath propagation and scattering,and the inter-symbol interference caused by symbol delay,and it is the key technique of the fourth generation. The MIMO-OFDM technique, combined with MIMO technique and OFDM technique,can improve the system spectral efficiency and the channel capacity.Meanwhile it can reduce the complexity at the receiver. So, it will be the key solutions of wireless communication system in the future. In orde to fully exert the superiority of MIMO-OFDM system,it is necessarry to research anti-noise performance and the signal processing at the receiver.In order to improve the transmission performance and lower bit error rate of MIMO-OFDM systems,this paper mainly studies anti-noise performance of MIMO-OFDM system. In order to compare and analyze the bit error ratio of MIMO-OFDM system at the receiver, this paper uses MLD,SIC and ICD algorithm method respectively. The main job is the following four aspects.Rirstly, the principle model of MIMO-OFDM system is ananlyzed.Secondly, the MIMO-OFDM system ber formula is derived theoretically.Thirdly,it uses MLD,SIC and ICD algorithm methods respectively at receiver. In case of equal number of sending and receiving antennas, this paper emulates the system ber curve and makes comparision and analysis of each other. In case of receiving antenna number exceeding antenna number, this paper emulates the system ber curve and makes comparision and analysis of each other. In case of different modulation mode, this paper emulates the system ber curve, and find out the general rule of reduced system ber.At the last, The last part of the article referenceds the overall resources efficiency measure of digital modulation and evaluates the overall resource efficiency of the OFDM systems and MIMO-OFDM system,and measures the resource efficiency at the receiver of different test methods. The results show that, MIMO-OFDM system achieves the best resource efficiency at the receiver using the maximum likelihood detection.