Density Evolution Analysis of the Iterative Partial Multiuser Detector for CS-CDMA/CP

摘要

For the purpose of allowing a more bandwidth efficient CS-CDMA/CP system for more active users, an iterative partial multiuser detector (IPMUD) has been proposed for the case where the condition of multiuser interference-free (MUI-free) transmission is no longer satisfied. The IPMUD jointly detects data from the desired user and interfering users with varying degrees of accuracy and it has been shown that its performance depends on the detection quality for the interfering users. In this paper, we clarify the influence of the detection quality for the interfering users on the detection for the desired user by using the density evolution analysis approach. From the analysis, we see that the detection accuracy of data of the interfering users is essential for the detection of the desired user. Therefore, some modifications to the IPMUD, e.g. widened detection window or giving up iterative detection of some rather badly-detected interfering users, can be considered to offer better tradeoff between the system performance and detector complexity.