On the Usefulness of Outer-Loop Power Control with Successive Interference Cancellation

It is well known that multiuser detection can obtain significant performance advantages over the conventional matched filter receiver in CDMA systems. Further, since optimal multiuser detection is exponentially complex, the majority of research has focused on sub-optimal approaches such as successive interference cancellation (SIC). SIC has been shown to require a geometric distribution of received powers to achieve equal performance for all received signals. In this letter we investigate the usefulness of outer-loop power control in CDMA systems to achieve this power profile. Specifically, we show that for unlimited mobile powers, outer-loop power control will drive the received powers to the appropriate power profile. Further, when we consider power limits for specific mobiles, we find that individual mobile limits will not affect the performance of other signals and based on limited simulation results, the system appears to be stable in the presence of such limits.