Linear detector length conditions for DS-CDMA perfect symbol recovery

Within the established framework of linear detection for multiuser DS-CDMA systems, we derive length conditions for perfect recovery of the transmitted symbols of all K in-cell mobile users. The analysis accounts for multiple access interference with arbitrary asynchronism as well as multipath interference with arbitrary delay spread. The results imply that linear detectors achieving perfect symbol recovery may require an observation interval much longer than a single bit. Moreover, we show that linear detectors employing oversampling and/or antenna arrays require less taps to achieve perfect symbol recovery than conventional non-oversampled, single antenna receivers. Simulation results are presented verifying the derived length conditions.