基于循环平稳周期的交织差分最小均方误差多用户检测算法

以抑制宽带码分多址(wide code division multiple access, WCDMA)系统在快变信道中的多址干扰为目标，提出基于循环平稳周期的交织差分最小均方误差(interleaving differential minimum mean square error, IDMMSE) 多用户检测算法. 根据WCDMA系统特有的二级扩频结构，将差分最小均方误差(differential minimum mean square error, IDMMSE) 算法的权系数优化准则改为基于循环平稳周期，而不是基于简单的扩频因子. 该方法更准确地反映了多址干扰的变化规律，有利于抑制多址干扰. 另外，引入交织技术能使信源不相邻的具有相同综合扩频序列的符号在实际信道中相邻传输，从而保证DMMSE算法所需的快变信道中相邻两个符号周期内信道变化很小的假设成立. 仿真实验表明，IDMMSE算法能在一定程度上对抗多普勒频移，且误码性能优于现有自 适应MMSE算法.

Interleaving Differential MMSE Multiuser Detection Based on Cyclic-stationary Period

To suppress multiple access interference (MAI) in wide code division multiple access (WCDMA) systems in a fast fading channel, an interleaving differential MMSE multiuser detection method based on the cyclo-stationary period is proposed. According to typical characteristics of two-layered spreading modulation in WCDMA, the update criterion of coefficients is based on the cyclo-stationary period, instead of the spread factor. As the proposed method can characterize the pattern of MAI properly, improved performance can be achieved. Moreover, interleaving is involved to let the symbols with the same comprehensive spread sequence be transmitted consecutively to ensure that the channel gains of successive symbols keep constant in the fast fading channel. Simulation results show the performance is improved without increasing the system complexity, and Doppler shift is better dealt with.