随着数据通信与多媒体业务需求的发展，4G时代的到来成为必然，对通信技术的发展也就提出了更高的要求。不仅要求现代数字无线通信能够提供高的传输质量，同时还要提供大的传输容量。无线MIMO系统中的空时编码（STC）技术是一种利用多天线发送和接收来提高系统频带利用率的编码技术，由于它将信道编码与分集技术结合起来，充分利用了分集技术的可靠性和所隐藏的信道容量，可以同时获得分集增益和编码增益，从而成为宽带移动通信系统中传输高速数据的有效编码方案。低密度奇偶校验 (LowoensityParityCheCk)LDPC码以具有非常逼近容量限的优异性能在通信编码领域引起了广泛关注，并且已被应用于各个方面，包括太空及卫星通信，无线通信，磁记录和网络包传输等。 本文介绍了无线衰落信道和MIMO信道建模的相关理论，分析了MIMO信道容量；在研究LDPC码基本编译码理论和空时分组码(STBC)算法的基础上，提出了LDPC编码与STBC码相结合的编码方法，通过仿真验证得出此方法可以提高编码的性能，并分析了码重、接收天线数目对LDPC-STBC系统性能的影响；在 LDPC-STBC系统中，发送天线上分配功率相同导致各天线上的衰落信息没有充分利用，针对此问题，提出将发送功率分配方案应用于LDPC-STBC系统的改进方案，新方案中总发送功率保持不变，各天线上的发送功率随信道质量而变化，充分利用了信道信息，仿真结果证明系统性能有了进一步的改善。

With the development of data communication and multimedia business, the arrival of 4G era becomes inevitable. It requirements the modern digital wireless communications can not only provide high quality transmission of mass, but also provide large transmission capacity. Space-time coding (STC) technique in a wireless MIMO system improves spectral efficiency with multi-elements antenna array, as combining channel coding and diversity techniques and making the best use of the reliability of diversity technique and the hidden channel capacity, it can obtain diversity gain and coding gain, thus it becomes an effective high-speed data transmission encoding scheme in the broadband mobile communication system. Low Density Parity Check codes have attracted considerable attention in the coding community as they can achieve near-capacity performance, and they have been applied in various aspects, such as deep space and satellite communications, wireless communications, magnetic storage, Internet packet transmission, etc. This thesis introduces the correlation theory of wireless fading channel model and MIMO channel modeling, and analyzes the MIMO channel capacity；then based on the encoding and decoding theories of LDPC and space-time block code (STBC) , this thesis proposes an encoding method which combines the STBC with LDPC . The simulations show that the concatenation scheme can improve the performance .The impact of different LDPC code weight and receiving antennas number to the performance of LDPC-STBC is discussed. In LDPC-STBC system, transmitting antenna with the same distribution power results in less use of channel attenuation information. In order to solve this problem, an improved scheme using transmission power distribution scheme to LDPC-STBC system is presented. In the new scheme, total transmitting power remain unchanged , each antenna transmitting power changes with channel quality and channel information is fully utilized. Simulation results indicate that this scheme can make further improvement of the coding performance.