Novel Adaptive Step Power Control algorithm for 3G WCDMA cellular system

Abstract

Power control is an essential radio resource management method in CDMA cellular communication systems, where co-channel and adjacent-channel interferences are the primary capacity limiting factors. Power control intends to control the transmission power levels in such a way that required quality of service for the users is guaranteed with lowest possible transmission powers. In this paper, a modulation of power control algorithm is proposed for the 3G WCDMA system. The algorithm is figured on a modification of the transmitted power update step size. Instead of the fixed value presently suggested, the step size is modified dynamically in order to obtain more adapted power variations as well as the step is also represented as a function of the difference between the target and estimated SIR of the MS to obtain more stability of the system. A general form of this algorithm is presented and it is then studied in a simple simulation. Performance of the algorithm was evaluated with the outage percentage, which is the percentage of the number of MS's whose received SIR falls below the fixed threshold. The focused requirement, which had been tried to achieve by this algorithm, is the stability, which was studied and represented through simulation.

Joint power control in CDMA cellular wireless communication system

“…4. JOINT POWER CONTROL WITH VARIABLE STEP-SIZE BASED ON MARKOV STATE Traditional power control step-size and power update control step-size are fixed [9] , generally, it's 1DB and 0.5DB. In the cellular wireless communication system, channel fading is random, the difference of the current time slot's amplitude of fading and the last time slot's amplitude of fading is random, too.…”

“…Especially for the fast fading channel, the loss of the fast fading channel can't be compensated effectively if the power control step-size isn't a good choice, so it's necessary to take a predict compensation to the channel fading. A linear predictor that can predict the receiving power next moment is proposed in literature [9] . Then compensate for the channel fading, especially for the fast fading channel, by using variable step-size power control algorithm based on Markov state, so as to reduce the deviation between receiving power and optimal power.…”

Model Predictive Zooming Power Control in Future Cellular Systems under Coarse Quantization

“…Recent results, yet to be published, also show that delay compensated power control may induce worse limit cycles with larger amplitudes, which is a further reason for this research. As a result, there has been substantial interest in different mechanisms to compensate for the ±1dB impairment [4], [5]. For example, in [2] a modified fixed step power control algorithm was proposed.…”