The effect of clock and carrier phase drifts on the performance of a direct sequence spread spectrum multiple-access system

Abstract

A direct-sequence spread-spectrum multiple-access network is discussed. The probability of symbol error in such a network is dependent on the carrier and spreading code chip phases of the interfering terminals with respect to the signal of interest. As a result, for a given total interference power the performance is worse for the case of one strong interferer when compared to the case of many weak interferers where the Gaussian assumption on the multiple-access interference holds. It is shown that if there is an offset between the carrier and spreading code frequencies of the signals, then the difference in performance between the cases of a set of balanced and a set of unbalanced interferers is drastically reduced.<>