Research On Coding In MIMO-OFDM

As one of the most important technologies, MIMO-OFDM has attracted a lot of attention. It can enormously improve the data-transmission rate and the reliability in complex environments of wireless communication without increasing the spectrum bandwidth and the transmission power. Space-time code is a way which can implement the performance of the MIMO-OFDM. Here, some work has been done according to the researches at home and abroad.Firstly, difficulties faced by modern communication and the advantages of MIMO compared with traditional communication technologies have been described. Then, several common code techniques have been introduced based on the established MIMO system. And then, there are some analysis and comparisons between them. As Alamouti code can't implement the high-rate transmission and quasi-orthogonal codes can't satisfy the full gain. Here, we bring the angle feedback to the space-time code based on the constellation rotation, which can achieve the high-rate and full gain. What' more, a new quantification scheme is proposed. It decreases the complexity of the design further through a simple selection between the real and imaginary part of the interference items. By this way, it only needs a little feedback at the transmitter to suppress the interferences. So, it is simpler to implement than others. Simulation shows that this new code can improve the system performance significantly. At the same time, the high-point that the improvement can achieve has been explored. As the limits of MIMO in the broadband, MIMO and OFDM are combined. After the introduction of STBC-OFDM,SFBC-OFDM and STFBC-OFDM, comparisons have been done through the chart analysis of communication resource, theoretical explanation and computer simulation in different channel environment. Then, we can get the result which is the better code in different communication conditions.