Some results on power control in wideband CDMA cellular networks
Alessandra Giovanardi, G. Mazzini, Velio Tralli, Michele Zorzi · 2002
A general setup for simulating a WCDMA cellular system has been developed to estimate the performance, in terms of both the signal-to-interference ratio (SIR) and error burst statistic. Here, the analysis has been focused on closed loop power control in order to characterize the performance as a function of the control delay and the step size in different conditions. The simulator takes into account a hexagonal geometry with spatially uniform user distribution and a propagation channel characterized by distance attenuation, log-normal slow fading, and Rayleigh fast fading. The system is based on a wideband CDMA radio interface with RAKE receiver, convolutional coding with Viterbi decoding, and interleaving to counteract burst error occurrences. A relationship between the power control loop and the Doppler frequency trend is underlined in the numerical investigation. In particular, a power control delay increase could be related to an "equivalent" Doppler frequency increase. Furthermore, the sensitivity of the performance to the power control step size as a function of the Doppler frequency is shown.