A bacterial foraging algorithm optimized fuzzy logic for power control of code division multiple access cellular systems

This research focuses on the application of the bio-inspired bacterial foraging algorithm (BFA)1, an effective computational tool among other bio-inspired optimization techniques1. The BFA mimics nature and checkmates the impending problems of local optimum associated with classical procedures like steepest descent and Conjugate methods. It was used here to optimize fuzzy logic controller parameters for control of power in the reverse link of DS-CDMA cellular system over the fading channel. The cellular structure assumed consists of 19 hexagonally shaped cells with BS at the centre of each cell having equal users while mobile units transmit equal power at 1watt maximum. A closed-loop feedback model of the communication link was designed and computer simulations conducted using Matlab-Simulink tool box. The developed model was used to compute and simulate the gain links, total system interference power and outage probability in the context of Energy per bit to interference ratio (E0/I0) and AWGN. The simulation results have shown that the BFA tuned fuzzy controller improved the signal reception with respect to steady state error, minimum peak overshoot and shows a slower rate outage probability with respect to increasing number of users. Doppler effects due to mobility of the mobile user have also been evaluated. These results have great impact generally on the improvement of system Quality of Service (QoS) in terms of system capacity and minimized outage probability rate.