Error probability and near-far resistance of minimum mean squared error interference suppression schemes for CDMA

Interference suppression schemes for direct-sequence spread-spectrum (DS/SS) code division multiple access (CDMA) systems using the minimum mean squared error (MMSE) criterion are considered. When compared to other interference suppression schemes, such as maximum-likelihood decoding, this criterion has the advantage of being amenable to adaptive implementations that do not require knowledge of the interference parameters, such as their relative strengths and spreading sequences. These schemes are shown to be near-far resistant to varying degrees, depending on their complexity. That is, the error probability remains relatively low no matter how strong the interference. Numerical results showing error probability vs. interference power demonstrate that the proposed schemes offer substantial performance gains relative to the matched filter receiver