Network Load Balancing Routing Technology Based On Ant Colony Optimization Study

With several advantages, such as fast deployment and self-organization, Mobile Ad hoc Networks(MANETs) are suitable for applications involved in tactical battlefield and civilian emergency. However, due to their special form of organization, many protocols used in networks with pre-configured and centrally controlled infrastructure, cannot be directly applied to Mobile Ad-hoc Networks. Thus protocols need to be carefully designed for this kind of networks. Among them, routing algorithms are the main difficulty of design and research on self-organized networks. Considering the special characters and several limitations of MANETs in the design of routing protocols for MANETs, the idea of load balancing is largely introduced. This dissertation mainly focuses on the key techniques and algorithms involved in routing protocols of MANETs based on load balancing. The traffic load and congestion status of nodes in MANETs will play an important role in route selection, in hope of balancing load, alleviating the bottleneck and congestion problems, making the network stable and efficient, and optimizing the overall performance of the network.On the other side, the ant colony optimizing algorithm is a general distributed random optimization method, which can largely improve the stability, robustness of the system and increase the adaptability to unexpected situations, such as transmission failure and emergent traffic. It has already been applied to the solutions of combine optimization in communication networks. Based on the advantages of this algorithm, this dissertation proposed the Ant-colony Optimization based Load-balancing Routing protocol for MANETs(AOLR), which combines the algorithm of ant colony optimization with the idea of cross-layer design, in order to provide the mechanism for the evaporation of the pheromone strength and the its update mode triggered by different types of packets. Meanwhile, to further solve the load balancing problem of MANETs, AOLR introduced several mechanisms, such as the admission control mechanism, backward congestion restrain mechanism, shortcut enforcement mechanism, and the noise-encouraged route-selection mechanism, in order to dynamically perceive the load of nodes and increase the adaptability to it.This thesis elucidates and analyses the key techniques and rules of AOLR in detail, and introduces its simulation modeling of the integrated system infrastructure and each function modules. Through systematic simulation of AOLR in the performance of packet delivery rate, average end-to-end delay, average route set-up delay, routing overhead, and etc, the key techniques and algorithms are testified and can provide reference for practical system design and application. Simulation results show that, the system can improve several problems involved in MANETs, such as the congestion problem, the shortcut problem and the routing overhead problems. Meanwhile, compared to exist load balancing routing protocols, our system shows better performance of packet delivery ratio, end-to-end delay and routing overhead.