On the capacity of a cellular DS/CDMA system under slow multipath fading and fixed step power control

In a cellular system, low mobility users' transmitted power can be very accurately controlled by a fixed step power control algorithm. This results in lowering the signal to noise ratio necessary to achieve a given frame error rate (FER). However, accurate tracking of multipath fading has the negative effect of increasing the other-cell interference level during periods of deep fades. In this work, we evaluate the capacity of a direct sequence CDMA system (DS/CDMA) assuming low mobility users and taking into account the increase in the other-cell interference due to perfect tracking of multipath fading. The effect of the number of fading resolvable paths on system capacity is determined and the increase in the capacity due to soft handoff is found for different soft handoff thresholds. Finally we investigate the effect of limiting the maximum transmitted power to compensate for multipath fading and find that a limit of 10 dB results in maximizing the system capacity.