Analytical performance of closed loop power control quantized under fast fading for CDMA techniques

The performance of SIR (signal to interference ratio)-based closed loop power control (CLPC) is analytically analysed. The evaluation work has been carried out using the standard deviation of the power control error (PCE) as the performance metric. A non-linear control theory method is applied to the feedback system under fast fading. An analytical expression of the CLPC under fast fading is also produced. Finally a quantized-step size power control algorithm, replacing the hard limiter is considered. The proposed method is found to work considerably better for high speed MS as well as being a powerful tool to optimise the loop performance.