| Mobile Ad-hoc NETwork is used to meet the demand of emergency communications and military mobile communications, such as expeditionary operations, advance on the battlefield and rescue after earthquake or flood, etc. Because of the difference between Ad hoc network and wired network, how to design a suitable routing protocol for the Ad hoc network has become a very hot research topic. This paper begins with an introduction about the characteristics of mobile ad hoc networks and the existing routing protocols. Then an analysis of the operation scheme of AODV and its advantages and disadvantages in mobile ad hoc networks are represented and two improved schemes are provided.The SD-AODV establishes a latency model to forecasts the latency in the stage of route discovery. An improved local repairing scheme is used in the stage of route repairing to find and establish a route at the same time by broadcasting only one packet; The ES-AODV decides how to response to the RREQ based on the remaining energy in the stage of route discovery; In the stage of route maintenance, when the remaining energy of one route node is lower than the warning value, the node triggers an alarm message to ask the source node to find a new routing path in advance. Besides, there is an improvement on Hello packet to lower the overhead.At last, simulations are done using NS2 for the improved schemes. According to the result, the SD-AODV scheme reduces the delay of the routing in mobile ad hoc networks, the ES-AODV scheme can prolong the lifetime of the routing in mobile ad hoc networks. |
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