Bit error probability of a rapidly-adapting rake receiver as a function of dwell time

Abstract

Implementable rake receivers have less correlators than there are propagation paths in the channel. In the case of slowly time-variant channels the rake receiver is able to adapt to the channel by selecting the paths with the maximum momentary power [Gue92a, Gue92b]. In practice, it is not possible to select the best paths for every modulation interval. The bit error probability of rake receivers is calculated for the situation that the path selection is maintained over fixed time periods, the dwell time. The results show that the degradation to an instantanous adaption is insignificant as long as the dwell time is less than five per cent of the inverse of the fading bandwidth.