Multicast Routing Algorithm Based On Particle Swarm Optimization In Ad Hoc Networks

Ad Hoc network is a kind of mobile multi-hop, self-organized and distributed wireless network. There is no static infrastructure such as base station as that was in cell mobile communication and they can be quickly built up in anywhere and at anytime. In Ad Hoc networks, all the nodes are equal and free to move. But the features of wireless channel and the mobility of node the routing strategies in Internet networks can not be directly used in Ad Hoc. Adaptive routing protocols must be designed to solve the routing question in Ad Hoc networks. Instead of sending via multiple unicast, multicast reduces the channel bandwidth, time of processing and delivery delay. In addition, multicast gives robust communication whereby the receiver address is unknown or modifiable without the knowledge of the source within the wireless environment. These characteristics are valuable for Ad Hoc network, because the bandwidth and system resource are limited in Ad Hoc network.The communication cost, bandwidth, delay and delay jitter are the major factors impacted the performance of Ad Hoc network multicast tree. To search for the Ad Hoc network optimal multicast tree for the study objectives, from two aspects analysis of particle swarm optimization principle and the characteristics of Ad Hoc network, the Ad Hoc Network multicast routing algorithm is researched deeply. The contents are as follows:1. A QoS multicast routing optimization algorithm of network is put forward aim at the disadvantage of improved standard particle swarm algorithm, which easily get into local extremum and is imprecise, with replace the linear descending inertia weight factor by the adaptive inertia weight factor. In the algorithm, the searching process of the particles in the solution space is mapped to the multicast tree transformation process. The model of QoS multicast routing in Ad Hoc networks is founded, and the fitness function is designed with penalty function for constraint condition. The realization process of solving QoS multicast routing problem with APSO algorithm is stated, and a new integer coding project is designed, which can translates QoS multicast routing problem into integer calculation problem. The simulation analyzes the change tends of cost, delay, delay jitter, and network scale of APSO algorithm. And the multicast trees of the traditional GA algorithm and the standard PSO algorithm are compared.2. According to the disadvantage of particle swarm algorithm and the excellence of simulated annealing algorithm, a QoS multicast routing algorithm based on simulated annealing particle swarm optimization is put forward, and the realization process is stated. The new solution of simulated annealing are produced with roulette strategy. In the network environment of twenty network nodes, one source node, and five destination nodes, the iteration number gotten the multicast tree is analyzed. And the multicast tree fitnesses of different network scales are computed. The simulation show that the optimal multicast tree satisfying the QoS requirement can be quickly found with this algorithm and this method has validity and reliability especially in large network scale.