Research On Performance Of MIMO Space-time Coding In Wireless Communication

With the rapid development of wireless communication in the communication industry, people's demand for high-speed and reliable data services is also increasing. In the face of limited radio spectrum resources, multiple-input multiple-output(MIMO) technology is regard as the key technology of the future mobile communication system. Because of its unique advantages that increasing the channel capacity significantly and improving the communication quality under the condition of without expanding the bandwidth. Space-time coding as the coding technology that is suitable for multi-antenna system combines with MIMO technology, which is very significant to the development of wireless communication.This paper emphatically analyzes space-time block coding(STBC) based on the spatial diversity technology and layered space-time coding(LSTC) based on the spatial multiplexing technology on the basis of analyzing the performances of existing space-time coding. Then a space-time coding scheme where the STBC is combined with the VLSTC is proposed. In the sending end, transmitting antennas are grouped and each group as a layer which proceeds orthogonal space time block code independently. Then the signals were launched by the transmitting antennas. At the receiving end, on the basis of the original algorithm that group interference suppression, this paper presents the parallel interference elimination iterative QR decomposition algorithm based on group interference suppression for decoding. This algorithm exploits the characteristic that parallel processing of parallel interference elimination method and the advantage that eliminating the error propagation of circulation iterative QR decomposition method to increase the reliability of signal detection and improve the performance of MIMO space-time coding system.Finally, the performances of STBC-VLSTC, STBC and VLSTC coding schemes are analyzed and compared by simulating. Analysis and simulation results show that the proposed space-time coding scheme combines the advantages of the STBC and VLSTC and obtains diversity gain and multiplexing gain at the same time. It reaches the trade-off for the performances of two kinds of codes in such aspects as coding rate, channel capacity and bit error rate. And compared with the original decoding algorithm, the improved decoding algorithm has higher performance of anti-fading.