Performance analysis for CDMA distributed antena systems in an imperfect multipath environment

Most of the previous study in CDMA distributed antenna (DA) systems only provides the performance analysis based on the ideal channel estimation assumption in a flat fading environment. In this paper, the impact of imperfect channel estimation on the forward-link outage performance of CDMA DA systems in a multipath fading environment is investigated. A detailed analytical model based on a hybrid signal combining method is presented and the exact outage probability expression is derived. Our investigation shows that the effect of imperfect channel estimates varies with system load. Furthermore, we find that for forward-link of DA systems, if simulcasting is employed, macrodiversity can decrease both the sensitivity of performance to channel estimation errors and the outage probability, which is contrary to the conclusion drawn based on the ideal channel estimation assumption.