Research And Implementation Of On-Demand Multicast Routing Protocol Based On Ant Colony Optimization

Mobile Ad Hoc network is a kind of acentric, multi-hop, temporary, self-organizing wireless network, which is consisted by mobile terminals with wireless communication transceiver devices, and can build a network at any time and any place quickly. Because of the fast and flexible features of mobile Ad Hoc network, it is widespread applicated in emergency rescue and disaster relief, emergency services, military communication, mobile meeting, etc., which makes it get more and more in-depth research, in which the routing protocols of meeting some QoS constraint are becoming one of the hot spots and difficulties in network research area.ODMRP is a typical on-demand multicast routing protocols in MANET, which uses the mesh structure to forward data packet with good robustness. But nodes forward packet in the way of flooding to all the neighbor nodes of the network, when the network has more nodes leading to more redundant paths, and invalid redundancy packets take up too much bandwidth resources in network, causes channel resources competition and network conflict.To address the issues mentioned above, this thesis introduces a kind of Ant Colony Optimization based On-Demand Multicast routing protocol, abbreviated ACODM. ACODM makes improvements mainly from the following aspects:first, it builds a tree structure by utilizing ant colony optimization on the mesh architecture built by ODMRP to ensure multicast data packet delivering rate, and through the artificial ant pheromone update rules which takes into consideration the energy of node, the time delays of nodes and links and the hops to the receiving nodes to meet certain QoS requirements. The energy, delay and hop constraints reflect to pheromones global update rules and local update rules. Second, in the stage of route establishing, a node chooses next node by probability formula constituting by pheromone and cost function to bulid stable route. Third, the primary mesh will be used as backup paths, when the mobile node frequent move and destruction the tree structure, nodes can forward packet by the mesh structure, not leading to the reconstruction of the network.Finally, this paper makes multi-scenario performance comparison on ACODM and ODMRP based on the NS2network simulation software. The simulation Results Shows that ACODM outperforms ODMRP in average end-to-end delay and routing overhead, and has a good performance in data packet delivering rate.