Enhancing WCDMA Power Control Mechanism with Channel Prediction
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Date
2016
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Publisher
ABACUS, The Journal of the Mathematical Association of Nigeria
Abstract
A good power control algorithm is very essential in a Wideband Code Division Multiple Access (WCDMA) system. This is to prevent Near - Far effect or Multi - Access Interference (MAI) and its associated effects, which include degradation of channel capacity and signal quality, as well as significant drain of the user equipment (UE) battery power. To solve these problems, there is the need for an effective and efficient power control mechanism to compensate for the fading fluctuations in the transmit power level of the mobile stations (MS) such that the signal power from multiple UE's (Near or far) is made equal at the Base Station. The conventional power control algorithm, based on SIR, may lead to positive feedback or power escalation when the far away MS increases its transmit power to compensate for the interference from the near MS. This paper proposes a method, based on predicting the state of the transmission channels to develop an improved power
control mechanism in WCDMA systems. The proposed method uses Kalman filtering and Linear Quadratic Gaussian (LQG) control for channel prediction. Some conventional methods of power control in WCDMA such as Fixed Step size method, Quantized Step size method and Ideal Method are examined. The proposed method is then compared with the conventional methods using MATLAB. Analysis of the simulations show that the proposed method recovers faster from deep fades and provides a more steady performance than the conventional methods.
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Keywords
Power control mechanism, Kalman Filtering, Linear Quadratic Gaussian