On the performance of a DS/SS system in a band-limited multipath environment

Direct sequence spread spectrum systems for band limited multipath channels are considered. The trade off between processing gain and intersymbol interference with various fixed bandwidths is investigated. Two chip waveforms, rectangular and raised cosine, are examined for both deterministic and random spreading sequences. The performance measure of interest is signal to interference ratio (SIR). A general expression for SIR that applies to a broad spectrum of cases is derived. The numerical results suggest that though a larger number of chips per bit results in more intersymbol interference due to bandwidth limitations, the increased interference suppression capability is able to overcome the degradation and yields a better performance