采用串行干扰消除技术的多速率单小区CDMA系统性能分析

串行干扰消除(SIC)技术可以有效抑制多址干扰(MAI)，显著提高DS-CDMA系统容量。该文针对单小区DS-CDMA移动通信系统的上行链路，推导出在加性高斯白噪声信道条件下，采用匹配滤波器的传统单用户接收机双速率系统、线性SIC双速率系统以及理想SIC双速率系统的容量极限，并给出了数值结果。研究结果表明，在任何条件下，相对于传统的单用户接收机系统，采用线性SIC技术能显著提高系统容量。另外，随着系统中用户数目的增多，理想SIC和线性SIC的接收功率之间的差异越来越大，因此，对实际的多速率SIC系统进行功率分配时，不能简单地用理想SIC模型来替代实际的线性SIC系统，以免系统性能严重恶化。

Performance of Multi-rate Single Cell CDMA Systems with Linear Successive Interference Cancellation

Successive Interference Cancellation (SIC) can effectively mitigate Multiple Access Interference (MAI) and improve the capacity of Direct-Sequence Code-Division Multiple Access (DS-CDMA) systems. In this paper, for the uplink of a single cell DS-CDMA system, the capacity limits of a conventional single-user detection receiver, a system with linear SIC receiver, and a system with perfect SIC are derived for an Addictive White Gaussian Noise (AWGN) channel. The results show that the linear SIC system can provide a much larger capacity compared with the conventional system in all cases. Moreover, with increasing of the number of the users in the system, the difference between the whole power of the perfect SIC and that of the linear SIC increases. So, if the perfect SIC is used to guide the power allocation, the resulting performance will be significantly worse than predicted.