MMSE correlator based RAKE receiver for DS-CDMA

This paper investigates the performance of a reduced rank MMSE correlator for a RAKE receiver in the context of CDMA in frequency selective multipath. The MMSE correlator based on the correlations subtractive architecture (CSA) is derived for frequency selective multipath. It is demonstrated that the standard multiuser limited RAKE receiver can achieve BER performance close to the MMSE receiver spanning multiple symbols by replacing its conventional correlator with an MMSE correlator. The CSA generates an MMSE correlator without requiring matrix inversion (thereby reducing computational complexity) and facilitates direct replacement of the standard RAKE correlator.