A study on multi-stage CCI cancellation algorithm incorporating redoing

摘要

It is well known that the system capacity of CDMA is limited by Co-Channel Interference so far as the receiver uses the single user matched filter. CCI is caused by the cross-correlation between the spreading sequences assigned to the simultaneous users. Many proposals for coping with the CCI have been made and investigated Among them a typical scheme repeatedly eliminates interference all together using replicas based on the single user decision for the simultaneous users. The performance of the method was found to deteriorate for the smaller signal dimension because of the error propagation. We already propose a cancellation scheme for CCI which eliminates in turn the replica of the user whose Orthogonal Matched Filter output looks the most reliable In this report, we introduced the hypothesis testing schemes for detecting erroneous cancellation. We first tried using a statistic derived from the likelihood ratio. It was found. however. the detectability was insufficient. Therefore we proposed another scheme based on the null hypothesis testing.