Traffic capacity of CDMA systems is increased by implementing an appropriate power control scheme to equalize the performance of all subscribers in the system. The appropriate power control scheme reduces the interference to the other adjacent cells.
The less interference generated in the spectrum, the more users the CDMA system can support. As previously mentioned, the inaccuracy in power control is roughly a log-normal distributed function. Under different path loss situations, the average required Eb/(N0+I0) tends to fluctuate around the mean to maintain a desirable Frame Error Rate. The power control standard deviation varies according to the extent of fluctuations.
At relatively slow speeds or in static conditions (fixed), power control is effective in counteracting slow fades whereas at high speeds power control is not as effective in counteracting fast fading. At higher speed, the effects of interleaving become increasingly beneficial.