Performance analysis of multistage BLUE/MMSE receivers for DS-CDMA in frequency selective fading channels

The multistage (MS) Wiener filter proposed in [1] is extended to meet the best linear unbiased estimator (BLUE) criterion in this research. The MS BLUE filter is shown to share the same structure of the MS minimum-mean squared error (MMSE)/minimum output energy (MOE) filter bank proposed in [2] for multipath channels modulo a scaling matrix. The limiting performance and the relationship between the output SINRs of MS-BLUE, MS-MMSE and MS-MOE multiuser receivers in a multi-path fading channel are derived and linked to the resultant bit error rate (BER). It is shown in our analysis that BERs and SINRs of the MMSE, MOE and BLUE receivers are, respectively, equivalent in flat Rayleigh fading channels.