地理路由具有有效的传输性能和良好的可扩展能力,是当前移动Ad Hoc网络路由算法中的一个研究热点.在许多实际场合下,网络中的节点能量有限并且难以补充,所以合理调整节点之间的能量消耗成为提高网络寿命的一种重要手段.本文针对贪婪转发和空洞解决方案中存在的节点能量消耗不平衡的问题,提出了一种具有能量意识的无信标地理路由算法EBGR(Energy-Aware and Beaconless Geographic Routing).该算法包括两个模式:贪婪竞争策略和空洞解决策略.在贪婪竞争策略中,源节点或中继节点(即上游节点)广播数据包,位于数据包转发域内具有最小动态转发延迟的节点(即下游节点)转发数据包,其余候选节点侦听到该广播包后,自动放弃转发该数据包.当遇到节点空洞时,将角度和能量信息同时加入到转发节点的动态延迟计算中,从而在数据包转发过程中有效地避绕空洞和平衡节点间的能量消耗.仿真结果表明,与已有的BLR和GEAR等典型地理路由算法相比,平均投递率提高2%到4%;平均网络寿命提高了10%到20%.
Geographic routing has been widely hailed owning to its efficiency and scalability,and it is one of research hotspots for routing algorithms of Mobile Ad Hoc Network.Since node energy in such network is limited and cannot be supplemented easily in many cases,balancing energy consumption is one of the most important method to prolong network lifetime.To solve the problem of the energy-consumption imbalance of greedy routing and perimeter routing,we present an Energy-Aware and Beaconless Geographic Routing(EBGR).It operates in two strategies:contend-based greedy-forwarding strategy and void handling strategy.In the contend-based greedy-forwarding strategy,nodes forward data packets by competition.When receiving a data packet from upstream node,intermediate nodes within its forwarding area contend to relay it by waiting for a dynamic forwarding delay(obtained by energy and location information and called DFD).The intermediate node with minimum DFD transmits the data packet first and other nodes cancel their scheduled transmission for the same data packet by overhearing its packet forwarding.When there are no neighbor nodes in the forwarding area,a void handling strategy is employed.Applying angle progress and energy information to DFD,we can allow data packet to traverse the void and to balance energy consumption.Finally,simulation results show that EBGR exhibits 2%-4% packet delivery ratio higher and 10%-20% network lifetime longer than BLR and GEAR.