A novel closed loop power control for UMTS

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

“…The results of all three methods are represented in the The three curves (or their PCE standard deviations) present the common characteristics to converge towards the standard deviation value of the Rayleigh channel, (σ A =5.57dB) for high mobile velocity. This explains that for high doppler frequency the CLPC cannot track efficiently the fast fading [4]. Notice, same type of convergence was observed for shadowing [3].…”

“…In order to verify the results from both techniques under fast fading, we have also simulated the conventional CLPC (shown in the Figure 1) based on the UMTS standard, where the power control period (or PCG) chosen is 0.667ms and the step size is fixed to 1dB [4]. By setting the latter parameters, according to the UMTS standard, the Lyapunov and the Spectrum Integration Method results are also produced.…”

“…As mentioned before, the performance of the system is analyzed through the standard deviation of the PCE σ y . The simulation assumptions and results are identical to [4]. The results of all three methods are represented in the The three curves (or their PCE standard deviations) present the common characteristics to converge towards the standard deviation value of the Rayleigh channel, (σ A =5.57dB) for high mobile velocity.…”

“…Note, that in this performance the delay produced due to the extra number of bits used, is not affecting the gain obtained. However, as the mobile speed increases (from 10km/h to 100km/h) and the fading becomes faster, the fixed stepsize is not enough to compensate for the fading since bigger steps are needed [4]. In this case the quantized step size performs better since it can take bigger values as well.…”

“…The second section applies and proposes the analytical expression of the PCE under fast fading (Rayleigh channel). The results (expressed as the PCE std) obtained from the analytical methods are compared to those obtained from the simulation [4] in the third section. Finally a novel technique is introduced which consists of replacing the hard limiter by a quantizer.…”