SPC11-4: On the Design of Practical Reduced-Rank DS-CDMA Receivers

A class of linear interference-suppression schemes is proposed that maximize the empirical SINR at the output of a DS-CDMA receiver under unknown multiuser interference conditions. We build upon well-known reduced-rank MVDR/MMSE solutions based on the Krylov-subspace spanned by the covari- ance matrix of the observations and the spreading sequence of the desired user. Only the effective signature of the intended user is assumed to be known at the receiver side. The optimum coefficients of the resulting polynomial expansion receiver are obtained by approximating the output SINR in the asymptotic regime defined when both the processing gain and the number of observations grow together without bound at the same rate.