Performance of SIR-based power control for UMTS

The performance of SIR-based closed-loop power control (CLPC) for the W-CDMA UTRA-FDD uplink has been evaluated. The evaluation work has been carried out using the standard deviation of the power control error (PCE) as the performance metric. Two power control algorithms (PCAs) that are currently specified by the 3rd Generation Partnership Project (3GPP) have been simulated in a vehicular environment. The results indicate that the first algorithm outperforms the second for the range of speeds considered. An optimized SIR (signal-to-interference plus noise ratio) estimation scheme is proposed. It is also shown that the multipath diversity gain that is generally observed in the wideband channel can be degraded when combining weak taps.