WCDMA 하향링크 시스템에서의 적응 하이브리드 채널 추정 기법

Abstract

The receiver performance of DS-CDMA system is significantly affected by the accuracy of channel estimate. In WCDMA downlink systems, the channel information is estimated using a pilot channel called common pilot channel (CPICH). Since both the data signal and pilot signal experience the same fading, the accuracy of channel estimate can be improved by using the dedicated physical channel (DPCH) together. However, erroneous data decision in the DPCH decoding process can deteriorate the estimation performance. In this paper, we analytically designed the coefficients that combine the two channel estimates from the CPICH and DPCH by considering the DPCH data decision error. For more accurate channel estimation, the adaptive channel estimation filters are designed for the DPCH part as well as the CPICH part. Numerical results show that the proposed channel estimator outperforms the conventional pilot channel aided estimator, particularly when the channel condition becomes worse.