【作者】 杜娜；

【导师】 陆传赉；

【作者基本信息】 北京邮电大学 ， 应用数学， 2006， 硕士

【摘要】 未来移动通信系统要求在高速移动条件下提供非常高的频谱效率。李道本教授基于分组零相关窗序列设计理论和MIMO信息论中的并行思想，提出了超高频谱效率的并行，分组随机多地址编码理论。它一方面将地址码的编码空间，从固定的数值推广到了随机元素，即时间，空间，频率元素，使得编码的自由度更大，同时还可以利用这些元素，通过合理的设计获得充分的分集增益，提高系统性能，另一方面，通过增加组内并行的子信道数，通过在并行子信道之间引入可控的干扰，使得系统的频谱效率可以大大的提升，完全可以满足未来移动通信高频谱效率的要求。这套理论不仅丰富了地址码理论的内容，更重要的是给未来的移动通信指明了方向。 本文正是基于李道本教授提出的并行，分组随机地址编码理论，分别从和频谱效率息息相关的地址码设计，接收机技术，信道估计等方面进行了较为深入的研究和探讨，具体包括： 1．第二章是并行分组随机地址编码理论的充分展开。在这章中，我们考虑的是以时间和空间两个随机元素作为地址码编码元素。本章以两个发射天线为例，研究了时空地址码如何获得发射分集增益，以及如何尽可能多的提高传信率的问题。 2．在第三章中，我们则以时空地址码系统为基础，对多码检测算法进行了较深入的研究。我们将传统多用户检测算法和我们的系统进行了结合。提出和比较了基于chip和符号级的ZF算法，对于SIC算法，我们提出了一种改进算法，它可以在对性能损失较小的情况下，大大降低复杂度。 3．无线移动通信中，信道估计是关系到系统性能的关键技术之一。在第四章中，我们根据LAS-CDMA技术信道估计的特点研究了连续导频和插值信道估计在LAS-CDMA系统中的应用。对于连续导频，为了平滑噪声对系统性能的影响我们提出了一种基于回归算法的新方法。当选用合适的回归长度时，这种新方法要比传统的连续导频方法有2dB的增益，接近理想信道估计性能。而对于插值信道估计中的插值密度，由于它在平滑噪声和模拟信道时变特点方面的作用是相反的，因此，对于系统而言通常有最佳值的存在。不仅如此，当把LAS-CDMA推广到多天线系统的时候，信道估计又有了新的特点。我们通过仿真和分析分别给出了导频长度，导频间隔，车速，系统天线数之间的关系。更多还原

【Abstract】 The future mobile communication system is characterized with its high spectral efficiency even in high speed environment. Based on the GZCW (Group Zero Correlation Window) spreading codes and the theory of MIMO, Professor Daoben Li provided a famous theory system on the design of generalized, parallel, group zero correlation window spreading codes, with the elements of which being random, i.e. GPRGZCW. The most attractive character is its super high spectral efficiency. This theory on one hand enlarges its elements from the numeric one to those random ones on the description of time, space and frequency. With the proper design, these elements not only broaden the freedom of design on spreading codes, which means there could be more spreading codes available in the system, but also can provide gains of diversity, which would improve system performance. On the other hand, with allocating more parallel sub-channels within one group and introducing the controllable interference between these sub-channels, it can improve system spectral efficiency greatly, which can satisfy the requirements of the future mobile communications. This theory not only enriches the content of the theory on spreading codes design, but also shows the right way for the future mobile communications.Based on this theory, my thesis focuses on the design of the proper spreading codes that are with high spectral efficiency and diversity gain at the transmitter. And the low complexity, good performance receiver also interests me, which means the better MCD (Multi-Code Detector) that is fit for those special codes. What is more, I have also payed much attention to the methods of channel estimation, which plays an important role in the mobile communication system.1. In the following, we give a sufficient discussion of space-time GZCW. Based on the system with two transmitters, how to get more transmitting diversity gains and how to improve spectral efficiency are studied. We altogether compare the performance, capacity of four schemes. The results show that our space-time GZCW surely provides much higher spectral efficiency than the LS-MIMO system, and with the proper design, system performance can also be improved. Besides, a new method for LAS-MIMO which would be close to the upper bound of MIMO system capacity is provided.2. In chapter 3, based on the space-time system, we focus on the MCD. Firstly, we provide the ZF method on chip level and symbol level respectively, and the one on chip level performs better. As it for SIC, we provide a new method that can simplify the SIC process while the performance degrades little. When MLD is employed, we provide a rule that can be used to judge how the design of space-time spreading codes will perform.3. Channel estimation plays a very important role in mobile communication system. In LAS-CDMA, the most often used channel estimation methods are continuous pilots and linear interpolation method. As for continuous pilots method, because of the IFW of spreading codes for data symbol and pilot symbol, the main error comes from the noise. Based on this, we provide a new channel estimation method which combines continuous pilot methods with regression to suppress the noise degradation. The results show that it will provide 2dB gain and will perform as well as the ideal channel estimation does. As for the linear interpolation methods, after analyzing, it is found that for the same interpolation更多还原