【摘 要】 摘 要码分多址通信系统中，多址干扰是影响系统性能和容量的主要因素。然而多址干扰不是不可避免的，可以通过采用多用户检测技术减小以致消除多址干扰的影响，改善系统性能，增大系统容量。本论文在总结现有码分多址通信系统中多用户检测技术的研究成果的基础上，重点集中于既不需要干扰用户扩频序列信息也不需要训练序列的盲自适应多用户检测技术的研究。盲自适应多用户检测可以更有效地抵消小区内和小区间多址干扰，很方便地应用在上行和下行链路。为实现盲自适应多用户检测，通常采用对接收信号样本矩阵进行特征值分解（EVD）或奇异... 更多 >> 摘 要码分多址通信系统中，多址干扰是影响系统性能和容量的主要因素。然而多址干扰不是不可避免的，可以通过采用多用户检测技术减小以致消除多址干扰的影响，改善系统性能，增大系统容量。本论文在总结现有码分多址通信系统中多用户检测技术的研究成果的基础上，重点集中于既不需要干扰用户扩频序列信息也不需要训练序列的盲自适应多用户检测技术的研究。盲自适应多用户检测可以更有效地抵消小区内和小区间多址干扰，很方便地应用在上行和下行链路。为实现盲自适应多用户检测，通常采用对接收信号样本矩阵进行特征值分解（EVD）或奇异值分解（SVD）后进行跟踪，由此带来的子空间跟踪使得实现复杂度很高；同时在跟踪算法中考虑一些实际情况而作出近似处理，导致每次跟踪开始阶段跟踪速度变慢。本论文首先研究基于子空间的线性MMSE盲自适应多用户检测器；然后提出一种新的基于干扰空间的线性MMSE盲自适应多用户检测器及其相应的基于干扰自相关矩阵 跟踪算法；最后数学分析和仿真结果表明：新的检测器具有实现复杂度低、跟踪速度快和稳健性强的优点。关键词：码分多址，多址干扰，盲自适应多用户检测，干扰子空间，干扰空间ABSTRACTIn code division multiple access systems(CDMA),multiple access interference(MAI) becomes the predominant factor that determines the system performance as well as capacity. However, MAI is not inevitable. It can be alleviated or even eliminated by using multiuser detection which thus improves system performance and enhances capacity. In this paper,on the basis of all previous work on multiuser detection in code division multiple access systems, we focus on the development of blind adaptive multiuser detection algorithms which require neither knowledge of the interfering users' spreading sequences nor training sequences. It is especially attractive for the downlinks and suppressing intercell MAI. When multiuser detector is adapted in blind mode, it usually adopts eignvalue decomposition or singularvalue decomposition of received sample correlation matrix and subspace tracking algorithm, which result in high computational complexity. At the same time, approximation computation in subspace tracking algorithm also result in slow convergence.In this thesis,firstly a Subspace-Based blind adaptive MMSE linear multiuser detector;Secondly an Interference-Space-Based blind adaptive MMSE linear multiuser detector and the corresponding tracking algorithm based interference correlation matrix is proposed;Finally analysis and simulation illustrate that the proposed blind multiuser detector has lower computational complexity, faster convergence and stronger robust with respect to imprecise knowledge of the received signature waveform of user of interest. Keywords:Code division multiple access,Multiple access interference,Blind adaptive multiuser detection,Interference subspace,Interference space << 收起
