Coherent receiver with channel estimator

摘要

The invention relates to an improved channel estimation technique for coherent CDMA systems. Traditionally channel estimators for coherent CDMA systems are based on a correlator. However, channel estimators based on this traditional approach are subject to the effect interpath interference, which caused performance to be degraded.The CDMA channel estimation technique eliminates the effects of interpath interference by using a cancellation technique. Therefore, estimate values output from a path searcher (30) respectively passed through a scaling unit (31) and a cross correlation calculator (32). The cross correlation term can be easily calculated since the path delay and the spreading sequence are known at the receiving side. The output signals of the cross correlation calculator (32) are respectively subtracted from the original estimation value alpha0 in a subtracting unit (33) to generate an improved estimation value to be supplied to an input terminal (27) of a RAKE combiner (26).