Design issues in decision feedback MMSE multiuser receivers for high data rate indoor wireless CDMA networks

We consider multiple-access interference (MAI) and intersymbol interference (ISI) suppressing receivers for asynchronous direct-sequence spread-spectrum (DS/SS) code-division multiple-access (CDMA) networks operating over wireless multipath channels with background Gaussian noise. By varying the degree of connectivity in the feedforward filter (FFF), which linearly processes the samples at the output of a chip-matched filter, and feedback filter (FBF), which linearly processes previous decisions, we define a group of decision feedback (DF) minimum-mean-square-error (MMSE) receivers. A performance evaluation for coherent binary 10 Mb/s transmission with processing gains from 7-10 elucidates some of the performance/complexity tradeoffs present in the combined suppression of MAI, ISI, and noise.