一种基于跨层设计和蚁群优化的自组网负载均衡路由协议

A Cross-Layer Design and Ant-Colony Optimization Based Load-Balancing Routing Protocol for Ad Hoc Networks (CALRA)

针对大部分现有替代路径共同存在的替代路径老化和构建效率问题,本文提出了一种基于跨层设计和蚁群优化的负载均衡路由协议(CALRA),利用蚁群优化算法特有的信息素挥发方法实现对替代路径的老化问题,将蚁群优化和跨层优化方法结合起来解决自组网中的负载均衡问题,通过双向逐跳更新的方式较好的解决了替代路径构建效率问题,并将蚂蚁在所经过的各中间节点为路由表带来的信息素增量映射为蚂蚁离开源节点的距离、移动过程中所遇到的节点拥塞程度、节点当前信息素浓度和节点移动速度等各协议层的统计信息的函数,通过对各种信息所对应的参数赋予不同加权值的方法对概率路由表进行控制,改善了自组网中现有基于蚁群优化的路由协议中普遍存在的拥塞问题、捷径问题、收敛速度问题和引入的路由开销问题.仿真表明,CALRA在分组成功递交率、路由开销、端到端平均时延等方面具有优良性能,能很好地实现网络中的业务负载均衡.

In order to reduce the flooding overhead of alternate path construction, most existed alternate path routing protocols build their alternate path routes （APR） during route discover period, which leads to two limitations. As the topology of the ad hoc network evolves, links will be created and destroyed, resulting in route reduction or route failure. Additionally ,changes in network traffic （including the traffic introduced by the source itself） will have a significant effect on traffic-dependent route metrics. This motivates the need for a route-probing mechanism that could periodically re-assess the status of the APR route set. The results of those route probes could then be used to both construct a new APR route set and also adjust the route alternation policies. The alternate path route set is unidirectionally constructed from the source to the destination by flooding,which is inefficiency for bi-directional communication. In this paper,we present a cross-layer design and ant-colony optimization based load-balancing routing protocol for ad hoc networks （ CALRA）. In CALRA, ants deposit simulated pheromones as a function of multiple parameters corresponding to the information collected by each layer of each node visited,such as the distance from their source nodes,the congestion degree of the visited nodes, the current pheromones the nodes possess, the velocity the nodes move and so on, and provide the information to the visiting nodes to update their pheromone tables by endowing the above different parameters corresponding to different information with different weight values, which provides a new method to improve the congestion problem, the shortcut problem ,the convergence rate and the heavy overheads commonly existed in existing ant-based routing protocols for ad hoc networks. With the pheromones evaporation mechanism, CALRA can age and re-assess the APR set. The performance of the algorithm is measured by the packe, t delivery rate, the good-put ratio （routing overhead）, and the end-to-end delay. Simulation results show that CALRA performs well in decreasing the route overhead and balancing traffic load, as well as increasing the packet delivery rate, etc.