A Novel Dynamic Stepsize Power Control Algorithm for UMTS W-CDMA Systems

摘要

Power control is an essential mechanism for wideband code division multiple access (W-CDMA) systems. In our earlier work [1], a combined power control and a greedy rate packing (GRP) allocation scheme employing conventional fixed stepsize power control (FSPC) is discussed and evaluated. In this paper, we extend the algorithm to apply a novel dynamic stepsize power control (DSPC) algorithm to improve system performance. The dynamic stepsize (DS) is determined by the difference between the target SIR and the received SIR. A larger stepsize is applied when the difference between the received SIR and the target SIR is large to enhance tracking ability, and vice versa to reduce granular noise. Simulation results show the effectiveness of the proposed DSPC algorithm, with around 2% gain of throughput, 6.5% average power consumption saving and 0.5 dB standard deviation (STD) reduction of the received SIR, when compared with the FSPC scheme.