ACO variants in solving Mobile Ad hoc Network routing

Mobile Ad hoc Network (MANET) is one of the most upcoming technologies in the field of wireless communication. As there is no predefined network configuration in MANET, routing, therefore, is much more difficult compared to that in a wired network. It is known that in MANET there is a continuous change in topology resulting in the change in adjacent nodes to a certain node. This subsequently may play a vital role in finding the path from source to the destination host. Meta-heuristics, like Ant Colony Optimization (ACO) are being used successfully in MANET routing. In our earlier work we made some variations of ACO techniques for routing in wired network. Here, in this paper, some modifications on those variants of ACO have been made considering the situations in MANET. Variations are related to selecting the next node to visit depending on the number of adjacent nodes to the current node and modification of the pheromone deposit formula on the basis of transmission time. In some variants a tabu list has been incorporated to enhance the performance remarkably. Using NS2 simulator the experiments have been made to compare the performance of six variants of ACO, where the various parameters have been adjusted optimally. It is observed that modified versions are better than the previous ACO variants in overall performance related to throughput and packet drop rate.