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As mobile technology continues to evolve, it is the transmission rate and stability of the increasingly high demand. Multiple-input multiple-output (MIMO, Multiple Input Multiple Output) technology is considered to be a new generation of wireless communications technology revolution, MIMO wireless communications technology has become one of the key technologies through the continued development in recent years, MIMO technology will increasingly more and more used in various wireless communication systems. The space-time block coding technology is a coding system based on MIMO technology, owing to its simple structure and low decoding complexity and, in the cellular mobile communications and wireless LAN already has more in-depth study. This study includes the following three aspects: (1) describes the four elements of the orthogonal design and build a four element orthogonal polarization STBC (OSTPBC, Orthogonal Space Time Polarization Block Code), the Code satisfy orthogonal design relationships can be polarized antennas transmit and receive full rate. Number of transmit antennas is N = 3, respectively, using BPSK, QPSK and 8PSK modulation, orthogonal space-time block codes designed for performance simulation, when BER = 10 -3 , the designed code respectively, compared with the orthogonal code word to get 6dB, 5.5dB and 5.3dB gain; when BER = 10 -5 , the codeword designed, respectively, compared with the orthogonal codes obtained 8dB, 8dB and 7dB gain. The results show that the design of the four elements orthogonally polarized STBC without increasing the transmit and receive antennas circumstances can effectively reduce the error rate and improve the system believed to. (2) is proposed based on four elements of quasi-orthogonal STBC design the kind of quasi-orthogonal code designed to meet the relationship, can be polarized antenna for transmitting and receiving full rate. First, establish a channel model, and then design a number of transmit antennas N = 6 the four elements of quasi-orthogonal space-time block code, and using fast maximum likelihood decoding algorithm for decoding, and finally using BPSK modulation, it with the traditional quasi- Orthogonal STBC performance simulation were carried out comparing the spectrum utilization 1bit / (s · Hz), when BER = 10-3, the codeword designed and quasi-orthogonal codes obtained compared to the gain of 5dB When BER = 10-5, the codeword designed Compared with quasi-orthogonal codes obtained 8dB gain. The results show that the design of the four elements of quasi-orthogonal STBC designs without increasing the transmitting and receiving antennas in the case, you can reduce the bit error rate and improve system performance. (3) is proposed based on the angular coordinate interleaved orthogonal STBC design the code rate of 3/4, number of transmit antennas N = 8, the receiver decodes using paired. Were used BPSK, QPSK modulation, and orthogonal space-time block codes designed for performance simulation, when BER = 10-3, the codeword designed, respectively, compared with the orthogonal codes obtained 5dB, 5.2dB gain; When BER = 10-5, the codeword designed, respectively, compared with the orthogonal codes obtained 6.8dB, 6.5dB gain. The results show that, based on the angular coordinate interleaved orthogonal space-time block codes with orthogonal STBC has a lower error rate compared to, can significantly improve system performance.
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