【作者】 章仁飞；

【导师】 曾孝平；

【作者基本信息】 重庆大学 ， 信号与信息处理， 2003， 硕士

【摘要】 围绕着CDMA无线蜂窝移动通信系统中的多址干扰（MAI）抵消问题，本论文在现有盲自适应多用户检测技术基础上，提出了一种新的基于干扰空间线性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C₁跟踪算法。数学分析和仿真结果表明：该检测器具有实现复杂度低、跟踪速度快和健壮性强的优点。 随着CDMA移动通信系统容量增大，同频信道中同时处于通信状态的用户数增多，单用户检测器抗多址干扰能力急剧下降。传统多用户检测在单用户检测技术基础上，充分利用造成多址干扰的所有用户的信息进行联合检测，从而具有良好的抗多址干扰能力，但存在一些缺陷：（1）不仅要求知道期望用户的地址PN码及其定时信息，还要求其他干扰用户的地址PN码及其定时信息；（2）不能消除其他相邻小区的多址干扰对本小区的影响；（3）不能直接应用在CDMA移动通信系统中的下行链路。在传统多用户检测技术基础上，自适应多用户检测利用训练序列在仅知道期望用户地址PN码及其定时信息条件下就可以进行检测，不足的就是训练序列占用了额外的频率资源。 研究结果表明：盲自适应多用户检测可以不需要训练序列，在仅知道期望用户地址PN码及其定时信息条件下自适应跟踪信道中用户地址PN码的变化，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，由此带来的子空间秩跟踪使得实现复杂度很高；另一方面，在跟踪算法中考虑一些实际情况而作出近似处理，从而引起误差积累和正交性误差，导致每次跟踪开始阶段跟踪速度变慢。为此，本论文提出基于干扰空间线性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C₁跟踪算法。仿真结果还表明，该检测器具有很好的健壮性。更多还原

【Abstract】 In this paper, a new Interference-space-Based blind adaptive MMSE linear detector and the corresponding tracking algorithm based interference correlation matrix is proposed for MAI in CDMA wireless celluar communication system. 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.With the increase of active user numbers in CDMA channels, single user detector cannot effectively suppress MAI. Traditional multiuser detector make good use of all signals which resuilt in multiple access interference so that it provides optimum MAI resistance. (1) Nevertheless, it assumes that the receiver can acquire the signature waveform and timing of desired user and the interfering users ; (2) It has no ability to suppress intercell multiple access interference; (3) It cannot be applied in downlink channels. Adaptive multiuser detector eliminates the need to know the signature waveforms and the timing of the interferes and has to need training data sequences for every active user. But the frequent use of training sequence is certainly a waste of channel bandwidth.Research shows that with the prior knowledge of only the signature waveform and timing of the user of interest, blind adaptive multiuser detector can effectively detect data symbol of the desired user without training data sequence for every active user . 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 tracking alrithgms, which result in high computational complexity. At the same time, approximation computation in tracking alrithgms also result in slow convergence. To overcome these shortcomes, a Interference-Space-Based blind adaptive MMSE linear detector and the corresponding tracking algorithm based interference correlation matrix is proposed. Simulation also show that the detector has strong robust.更多还原