Recursive structures and finite impulse response implementations of linearmultiuser detectors for an asynchronous CDMA system

We present order-recursive structures for implementing the linear decorrela ting and linear minimum mean square error (MMSE) detectors in a computation ally efficient manner. These infinite memory length, Linear time invariant, noncausal systems can be approximated by implementing them as K-input K-ou tput finite impulse response (FIR) filters. We developed a linear multiuser receiver architecture called a recursive linear multiuser detector which h as lower computational and memory requirements then an equivalent tap delay line FIR filter implementation. We establish the tradeoff between window l ength and bit error rate and find that relatively small window size yields performance indistinguishable from the ideal decorrelating detector and the ideal MMSE detector.