【作者】 车小林；

【导师】 李勇；

【作者基本信息】 西北工业大学 ， 信号与信息处理， 2004， 硕士

【摘要】 近年来，智能天线已成为无线通信技术领域中的一个研究热点，该技术的应用可以提高无线通信系统的容量。本文首先介绍了阵列信号与无线信道模型和智能天线基本理论，阐述了向量信道模型和无线传播环境下天线阵列接收时的信道特征。其次，分析了天线阵列最优波束形成技术和恒模算法，深入研究了无线多径环境下自适应阵列的性能。论文重点讨论了CDMA系统的波束形成技术，在理论上详尽地推导了基于扩频码滤波的波束形成算法，对其收敛性、误码率等进行了计算机仿真；针对基于最小均方(LMS)误差的一种判决映射算法进行了改进。改进算法结合了归一化最小均方(NLMS)算法，仿真结果表明改进算法具有良好的收敛性、跟踪性能及较低的误码率。最后，在TMS320VC5402 DSK硬件环境下设计并实现了自适应波束形成算法。更多还原

【Abstract】 Recently, smart antenna has become a very promising technology for wireless communication, which could enhance the system capacity. This thesis begins with the introduction of the modeling of array signal and wireless channel, as well as the explanation of the fundamentals of smart antenna. Vector channel model is analyzed, and the features of the array receiver under wireless multi-path propagation are illustrated. Second, both the optimized beamforrnkig for antenna array and constant module algorithm are explored. We deeply study the performance of adaptive array under wireless multi-path environment. In addition, the beamforming techniques for CDMA systems are discussed emphatically. The algorithm based on code filtering is deduced in detail theoretically, and the performances such as convergence and bit error rate (BER) are simulated. Meanwhile, we improve a decision-projected algorithm based on Least-Mean-Square (LMS) error. The improved algorithm is combined with Normalized Least-Mean-Square (NLMS) algorithm. Computer simulations are presented detailedly to show the algorithm exhibits excellent convergence, tracking capability, as well as lower BER. Finally, the adaptive beamforming algorithm is designed and realized in TMS320VC5402 DSK board.更多还原