浙江大学博士学位论文 摘摘 要要 多天线系统是单天线系统的扩展。当通信系统的收发端同时使用多天线的时候，发射 机与接收机之间就构成 MIMO 信道。 信息论的结果表明， MIMO 信道具有更大的信道容量。 这意味着，在带宽和信噪比不变的情况下，多天线系统可以传输更高的数据率。因此对多 天线系统进行研究具有重要意义。 与单天线系统相同，多天线系统也要解决同步、均衡和信号检测等问题。本文的研究 主要集中在这些方面。本文第三章研究了多天线 QAM 系统的载波同步和信道均衡。第四 章研究了多天线 TD-SCDMA 系统的多用户检测。第五章研究了多天线 OFDM 系统的时钟 同步。在这些章节中，还简要介绍了接收机其他模块的实现方法，以使本章能够构成一套 完整的接收系统。 如今，用全数字的方法实现通信系统的每个模块已成为一种趋势。因此本文的研究以 全数字接收机为背景。另外，在本文的研究过程中，始终以低复杂度为目标。因此本文的 研究成果具有较强的实用性。 最后简要介绍本文的主要成果：针对多天线 QAM 系统提出一种可用于频率选择性衰 落信道的载波频偏估计算法，这种算法对时钟同步误差不敏感，并可以工作在多倍采样率 下；针对多天线 QAM 系统提出一种低复杂度载波频偏检测算法，这种算法可以与载波相 偏检测算法有机地结合在一起；针对多天线 QAM 系统提出活动抽头判决反馈均衡器的概 念，这种均衡器可根据信道情况调节抽头的位置，与传统结构均衡器相比，具有较低的复 杂度和较好的性能；针对多天线 TD-SCDMA 系统提出一种逐符号多用户检测算法，这种 算法与传统的联合检测算法相比，大大降低了复杂度；针对多天线 OFDM 系统提出一种可 用于频率选择性衰落信道的时钟频偏估计算法，这种算法可以在存在载波频偏的情况下工 作。 关键词：关键词： 多输入多输出（MIMO） ；正交幅度调制（QAM） ；时分同步码分多址（TD-SCDMA） ；正 交频分复用（OFDM） ；同步；均衡；多用户检测 董斌：多天线通信系统中的同步、均衡与信号检测技术研究 Abstract Multi-antenna systems are the spread of single-antenna systems. When the transmitter and the receiver use more than one antenna, MIMO channel is constructed. As information theory indicates, MIMO channel has larger capacity. This means multiple-antenna systems can transmit information with higher data rate when the bandwidth and signal-noise-ratio is fixed. So the study of multi-antenna systems is significant. Like single-antenna systems, synchronization, equalization, and signal detection are required in multiple-antenna systems. Our research work focuses on these topics. In chapter 3, carrier synchronization and equalization of multi-antenna QAM systems are studied. In chapter 4, signal detection of multi-antenna TD-SCDMA systems is studied. In chapter 5, clock synchronization of multi-antenna OFDM systems is studied. In these chapters, we also give a brief introduction to other modules in the receiver, which enables the chapter to construct a complete system. Nowadays, all-digital implementation of communication systems becomes popular. Therefore, our research work is based on all digital receivers. In addition, low complexity is pursued in our research work. Therefore, the algorithms presented in this paper are practical. Now introduce some fruits in this paper. For multiple-antenna QAM systems, a carrier frequency offset estimation algorithm that could work in frequency selective fading channel is presented. The algorithm is not sensitive to clock synchronization error, and can work under multiple sampling rate. For multiple-antenna QAM systems, a carrier frequency offset detection algorithm that has low complexity is proposed. The algorithm could be combined with carrier phase offset detection algorithm. For multiple-antenna QAM systems, a novel equalizer whose tap could be moved according to channel response is proposed. This equalizer has lower complexity and better performance than conventional ones. For multiple-antenna TD-SCDMA systems, a symbol by symbol multi-user detection algorithm is presented. The algorithm has lower complexity than block detection algorithm. For multiple-antenna OFDM systems, a clock frequency offset detection algorithm is presented. The algorithm can work before carrier frequency offset compensation. Key Words: Multiple Input Multiple Output (MIMO); Orthogonal Amplitude Modulation (QAM); Time Division Synchronous Code Division Multi Address (TD-SCDMA); Orthogonal Frequency Multiplexing (OFDM); synchronization; equalization; multi-user detection 浙江大学博士学位论文 目目 录录 第一章 无线通信技术概览 .1 1.1 无线通信的发展概况.1 1.2 无线通信的传输方式.1 1.2.1 无线通信的主要问题和解决方案.1 1.2.2 无线通信的传输方式.2 1.2.2.1 传输方式的多样性.2 1.2.2.2 线性调制.3 1.2.2.3 恒包络调制.4 1.2.2.4 扩频（SS）与码分多址（CDMA）.5 1.2.2.5 正交频分复用（OFDM） .9 1.3 无线通信的接收技术.11 1.3.1 接收机的任务.11 1.3.2 接收机设计的基本理论.12 1.3.3 全数字接收机的结构.13 1.4 本文的内容和贡献.