Effect of tracking error on DS-CDMA partial parallel interference cancellation

Partial parallel interference cancellation in a DS-CDMA system with tracking errors is studied. The aforementioned work showed that by multiplying symbol estimates by a factor less than unity in the early stages of cancellation, the performance of parallel cancellation can be improved relative to full (“brute force”) cancellation. Shan and Rappaport (see IEEE GlobeCom´98, vol.3, p.2615-20, 1998) shows that the BER performance is a function of the factor and the “best factor” can be far less than one. In a practical system, tracking errors need to be considered. This paper considers the effect of timing errors on the selection of the “best factor”. We show that due to the timing error the interference cancellation is less reliable and a smaller factor of cancellation need to be employed