On the Capacity of Cellular CDMA with Controlled Power Disparities

In a cellular CDMA system, the received powers from mobiles that are close to the base station form a dominant factor in the interference presented to mobiles that are farther away. Conventional power control techniques try to eliminate this problem by maintaining equal received powers for all users. However, recent research has produced successive interference cancellation schemes that rely on controlled disparities between the powers of users. In this work, we study capacity gains in cellular CDMA from ideal successive interference cancellation. Our studies show that power control with disparate powers can approximately double the capacity when compared with a conventional system. The idea of disparities among users also appears naturally when diierent users can transmit at diierent rates. We study the capacity regions for the multi-rate case under equal power control and disparate power control.