ABSTRACT
This study is aimed at the development of a mechanism for black hole attack mitigation in Wireless Sensor Network (WSN) using a modified Bacterial Foraging Optimization Algorithm (BFOA). A total of 200 randomly generated bacterial sensor nodes with a communication range of 20m were deployed in a 100mx100m network coverage area, consisting of four base stations. The radii 20m, 30m and 40m were chosen for the black hole region. The algorithm was implemented in MATLAB R2015b. In all tests carried out, the results obtained at 40m radius showed the effect of the black hole attack better than those at 20m and 30m. Successful packet delivery probabilities of 83.52%, 95.78%, 97.26% and 99.78% respectively were achieved at 40m radius for one, two, three and four base stations respectively. Significant reduction in false positive was observed when the base stations were increased. A negligible value of about 0.003% false positive was observed with four base stations using 40m radius of black hole region. Average delivery times of 31sec, 37sec, 43sec and 49sec were achieved at 40m radius for one, two, three and four base stations respectively. The times indicated that the routing complexity increased as the number of base stations increased. The performance of the modified BFOA based method showed packet delivery probability improvement of 5.48%, 9.67%, 0.18% and 1.01% over the standard BFOA based method as the base stations were increased from one to four respectively. As the base stations were increased to five, six, seven and eight, successful packet delivery probabilities of 99.39%, 99.69%, 99.79% and 99.82% respectively were achieved using 40m radius of black hole region. The trend observed for packet delivery showed that optimum efficiency is achieved with quadrant placement of base stations. The results obtained indicated that optimal placement of the base stations minimized the effect of black hole attack and ensured successful packet delivery.