【作者】 张国强；

【导师】 马社祥；

【作者基本信息】 天津理工大学 ， 信号与信息处理， 2010， 硕士

【摘要】 TD-SCDMA作为由中国自主提出的第三代移动通信网络标准,它是以TDD和CDMA技术为基础,充分结合了智能天线、联合检测、功率控制等先进技术,具有极高的频谱利用率与频谱灵活性。联合检测技术作为TD-SCDMA系统的关键技术之一,它能够抑制或完全消除多址干扰、多径干扰以及信号在传输过程中产生的噪声影响,同时还能够简化功率控制,降低功率控制精度,消除远近效应为系统带来的消极影响。因而,联合检测技术的研究对于改善系统性能、提高系统容量有着关键的作用。本文首先介绍TD-SCDMA系统的网络结构以及其物理信道结构、时隙结构等。同时结合TD-SCDMA系统的信道特点建立了系统上行链路的离散传输模型,并对系统矩阵的生成进行推导。接着推导了几种线性联合检测算法的基本原理,并对解相关匹配滤波器(DMF)法、迫零线性块均衡器(ZF-BLE)法、最小均方误差线性块均衡器(MMSE一BLE)法三种线性联合检测算法的复杂度及性能进行比较。由于联合检测算法中涉及到系统矩阵的求逆运算,其计算量十分巨大,因而寻求一种快速的系统矩阵求逆算法对于提高联合检测性能至关重要。基于此,本文提出了两种基于改进矩阵求逆算法的联合检测技术：近似Cholesky分解系统矩阵求逆算法,该算法只需要对系统矩阵左上角的一个或两个矩阵块做Cholesky分解,即可得出系统矩阵的近似Cholesky分解逆矩阵。以及Block FFT系统矩阵求逆算法,该算法首先对系统矩阵进行了块扩展,使之满足块右循环,通过在频域内求解方程组,从而获得系统矩阵的逆矩阵,很大程度上降低了运算量。计算机仿真表明,基于这两种改进求逆算法的联合检测算法,能够有效地消除TD-SCDMA系统中的多址干扰和多径干扰,在与原算法的误码率基本保持一致的前提下,可以极大的降低运算复杂度。更多还原

【Abstract】 TD-SCDMA, as proposed by China’s own third-generation mobile communication network standards, It is based on TDD and CDMA technology, fully integrated smart antenna, joint detection, power control and other advanced technologies, wich has a very high frequency spectrum utilization and spectrum flexibility. This study focus on joint detection technology as one of the key technologies of the TD-SCDMA system, It can inhibit or completely eliminate the multiple access interference, multipath interference and signal transmission noise generated in the process, It also can simplify power control, reduce the power control precision, eliminate the negative effects of near-far effect for the system. Thus, the joint detection technology research have a key role for improving system performance, increase system capacity.This paper first introduces the TD-SCDMA system’s network structure and its physical channel structure, and slot structure. Consider the TD-SCDMA system’s channel characteristics of uplink to establish a system of discrete transmission model, and to generate the system matrix. Introduction a number of linear joint detection algorithm’s basic principle, And comparison DMF, ZF-BLE, MMSE-BLE three kinds of the principle of linear joint detection algorithm and performance. Joint detection algorithm, however, the bottleneck is the inverse system matrix computation is huge, looking for a fast system matrix inversion algorithm is essential for improving the performance of joint detection.Based on this, this paper presents two improved matrix inversion algorithms:approximate Cholesky decomposition of the system matrix inversion algorithm. The algorithm requires only the upper left corner of the system matrix of one or two blocks to do Cholesky matrix decomposition can be derived system matrix of the approximate Cholesky decomposition of the inverse matrix. As well as the Block FFT system matrix inversion algorithm, which carried out the first block of the system matrix expansion, so as to meet the right blocks loop, through the solving of equations in the frequency domain in order to obtain the system matrix of the inverse matrix, largely reduces the computing volume. Computer simulation shows that, based on these two kinds of inversion algorithms to improve the joint detection algorithm can effectively eliminate the TD-SCDMA system with multiple access interference and multipath interference, the original algorithm with the bit error rate remained the same premise, can greatly reduce the computing complexity.更多还原