Neurofuzzy Controller for Closed Loop Power Control of Reverse Link DS-CDMA System over Rayleigh Fading Channel

This paper presents the Direct Sequence-Code Division Multiple Access (DS-CDMA) model and the strength based power control algorithm to control the power of reverse link DS-CDMA cellular system by using neurofuzzy controller (NFC). The Radial Basis Function (RBF) network is implemented as an NFC. The controller's parameters are selected and adjusted on line by Genetic Algorithms (GAs). The controller's inputs are the error between the received power of each user (P-th) and the target (P*) at base station and the difference of this error. The controller's output is the increasing or decreasing power. The controller was then tested to control DS-CDMA model which designed in synchronous transmission. In the test, NI sequence code used in spread spectrum was utilized under Rayleigh fading. The experimental results by comparing the operation characteristic of the designed and implement NFC and conventional power controller show that the NFC gives the power level tracked to the target and gives a lower outage probability and Bit Error Rate (BER).