Downlink RAKE receiver for WCDMA with Wiener filter

A simplified and sub-optimal wideband CDMA downlink RAKE receiver with Wiener combining is investigated. Pilot symbols in each slot are used for channel delay estimation and weighting calculation. Compared to conventional combining which uses MRC (maximum ratio combining), Wiener combining, which uses IRC (interference rejection combining), can get better MAI (multiple access interference) rejection. For an AWGN channel and R.H. Clarke´s Rayleigh fading channel (see Bell Syst. Tech. J., vol.47, p.957-1000, 1968) with four independent paths, we simulate the BER performance of the RAKE receiver with a Wiener filter. From the simulation result, although we get about 1.5 dB performance degradation in AWGN and 6 to 7 dB degradation in the Rayleigh fading channel as compared to the ideal performance, its simplified algorithm can be an advantage in implementation.