Optimal combining, partial cancellation, and channel estimation and correlation in DS-CDMA systems employing the generalized detector
Vyacheslav P. Tuzlukov · 2009
Abstract:- The symbol-error rate (SER) of a quadrature subbranch hybrid selection/maximal-ratio combining scheme for 1-D modulations in Rayleigh fading under employment of the generalized detector (GD), which is constructed based on the generalized approach to signal processing in noise, is investigated. At the GD, N dive-rsity branches are split into 2N in-phase and quadrature subbranches. Traditional hybrid selection/maximal-ratio combining is then applied over 2N subbranches. M-ary pulse amplitude modulation, including coherent bi-nary phase-shift keying (BPSK), with quadrature subbranch hybrid selection/maximal-ratio combining is investigat-ed. The SER performance of the GD under quadrature subbranch hybrid selection/maximal-ratio combining and hybrid selection/maximal-ratio combining schemes are investigated and compared with the conventional hybrid selection/maximal-ratio combining receivers. The obtained results show that the GD with quadrature su-bbranch hybrid selection/maximal-ratio combining and hybrid selection/maximal-ratio combining schemes out-perform the traditional hybrid selection/maximal-ratio combining receiver. Procedure of selecting the partial cancellation factor for the first stage of a hard-decision partial parallel interference cancellation of the GD emp-loying in direct-sequence code-division multiple access (DS-CDMA) systems is proposed. A range of the opti-mal partial cancellation factor, where the lower and upper boundary values can be explicitly calculated from the processing gain and the number of users of the DS-CDMA system, is derived based on the Price’s theorem. Co-