【作者】 曹硕；

【导师】 谢红；

【作者基本信息】 哈尔滨工程大学 ， 通信与信息系统， 2007， 硕士

【摘要】 随着移动通信业务的发展，频谱资源日益紧张，如何高效地利用有限的通信资源成为无线通信新技术发展的焦点。空时编码是一种结合信道编码和分集技术的新型的编码和信号处理方法，它可以在不需增加带宽的情况下大幅度的提高无线通信系统的信息容量和传输速率，从而提供远高于传统单天线系统的频带利用率。空时编码主要分为空时格形码(STTC)和空时分组码(STBC)两种。在本文中，对这两种编码方式在设计准则、编码方法、译码方法进行了深入研究。采用两个以上发射天线的正交空时分组码的编码速率小于1，不能保证数据的全速率传输；对此，本文重点讨论了准正交空时分组码(QOSTBC)。然后，在此基础上提出了一种发射天线数是2的幂的新的准正交空时分组编码方法，通过仿真表明新的设计方法不增加译码复杂度，具有很强的通用性。准正交空时分组码的译码复杂度是影响其应用的一个重要原因，本文在深入研究球形译码算法的基础上，结合准正交空时分组码的准正交性，提出了一种应用于准正交空时分组码上的改进球形译码算法，缩小了检索范围，提高了系统的相应速度，降低了译码的复杂度。更多还原

【Abstract】 With the development of mobile communications services, frequency resources are becoming more and more scarce. To improve new technologies of wireless communications mainly focus on how to efficiently make use of the limited communication resources. Space-Time Coding (STC), which is a new coding/signal processing technique that combines channel coding with antenna diversity techniques, greatly increases data rate and the capacity of wireless communication system with no need of additional bandwidth and transmitting power, accordingly provides far more higher frequency band utilization than traditional single antenna system.Space-Time Codes mainly include two parts, Space-Time Trellis Code and Space-time Block Code. In this paper, we compare the performances of the two Space-Time Codes in many aspects, such as design criterion, coding and decoding methods. The coding rate is less than one for Orthogonal Space-Time Block Code with two or more transmit antennas, it can’t ensure the data transmission with full rate. In this paper, attention is paid to Quasi-Orthogonal Space-Time Block Codes. From which we propose an improved Quasi-Orthogonal Space-Time Block Code which the number of transmission antennas is two to some power. Simulation results demonstrate that the new method doesn’t increase the decoding complexity, therefore, it allows a wide latitude of generality.The complexity of quasi-orthogonal codes is an important cause of limiting its application to industry. Based on the thorough research on Sphere Decoding (SD) algorithm, a new improved method is introduced which combines Quasi-Orthogonal Space-Time Block Code with Sphere Decoding algorithm, which narrows detection range, increases respond speed and reduces the complexity to decode for systems with four or more transmit antennas, compared with the conventional SD algorithm.更多还原