The Study of Multi-User Diversity Technology Over the MIMO-OFDM System

Recently, orthogonal frequency division multiplexing (OFDM) has become a popular technique for transmission of signals over wireless channels. Also, multiple-input multiple-output (MIMO) is one of the most promising technologies for assisting fading and improving link reliability without sacrificing bandwidth efficiency. The combination of OFDM and MIMO seems to be the key technology in next generation high-rate wireless mobile systems. First, this paper introduces the MIMO technology, point out that the combination of OFDM and MIMO seems to be very promising when aiming at the design of very high-rate wireless mobile systems. Secondly, describes the application of OFDM and outlines the block diagrams of an OFDM modulator and demodulator and a MIMO-OFDM system. Then, study several methods for combining the different diversity at the receiver, analyze the performances of diversity in OFDM-MIMO system with simulation results. Finally, achieves the conclusions.