Researches On The Energy Consumption In MAC And Routing Algorithm For Mobile Ad Hoc Networks

Mobile Ad Hoc Network (MANET), which consists of a group of mobile nodes equipped with transceivers, is a dynamic reconstructable multi-hop network without the support of fixed infrastructures. It can be rapidly deployed in places where the networking infrastructure neither available nor economical to build. It expands the using of mobile communication networks and can be used widely in tactical battlefield, civilian emergency communication, meetings or conventions. MANET has some characteristics such as distributed, self-organizing, multi-hop, dynamic topology, time-variant channels and limited resources etc., which pose lots of challenges on its protocols. The medium access control (MAC) and multi-hop routing are key technologies in MANET. The dissertation mainly does research on the following content: the energy consumption model of MAC protocol, Slot-Reservation Power Saving Mode (SR-PSM) algorithm, Energy-Efficient based Pseudo Gossip Routing (EEPGR) algorithm, Link Stability based Pseudo Gossip (LSPG) routing algorithm and a new local route repair algorithm.An energy consumption model of MAC protocol is presented for MANET in chapter 2. The MAC modeling includes all operation modes of nodes such as transmission, reception, idle and sleep states. Moreover, the energy consumed in overhearing state and retransmission due to collision is considered. The model takes into account the interference of nodes in the entire system. Based on the analytical model, a Slot-Reservation Power Saving Mode (SR-PSM) algorithm is proposed, in which the transmission will only cocure in the reserved time slots and nodes are just awake when they are a part of a transmission and turn into sleep mode during the remaining time. The mechanism can avoid collisions due to hidden terminal and exposed terminal problems and save more energy than Power Saving Mode (PSM).In routing protocols that use flooding, many routing messages are propagated unnecessarily. Gossiping can be used to significantly reduce the number of routing messages sent. Based on the energy consumption model in MAC protocol and gossip scheme, an Energy-Efficient based Pseudo Gossip Routing (EEPGR) algorithm is presented for MANET in chapter 3. In EEPGR, nodes with more residual energy take priority of participating in routing to balance the energy consumption over the network, meanwhile, the others are confined to save energy and bandwidth resource. The simulations show that EEPGR can decrease the routing overhead, reduce and balance energy consumption and then prolong the network lifetime, so it is feasible and preferable for MANET.When a route is broken for node mobility, route recovery and maintenance are executed. However, these procedures consume many resources and lead to increased delay. To minimize route breaking, it's important to find a route that lasts longer time. Shortest path route has short lifetime especially in highly dense MANET due to the edge effect. In chapter 4, the statistic results of link and path availability properties in MANET are derived. According to the analysis, a pseudo gossip routing algorithm based on the link stability is proposed. This routing algorithm can select reliable path that can last longer by using fewer routing messages as to be shown by the simulation results.If multi-hop route is failed, routing protocol should maintain it. The previous route repair mechanism causes high control overhead and long packet delay. The problem worsens when mobility is high and many real-time applications do not tolerate such long delays. In chapter 5, a new idea on local route repair which confine the repair to the vicinity of broken links is proposed to decrease the reaction time of route breakage and the overhead of route maintenance. Furthermore, the approach can repair failure links without taking into account of their relative position on the whole path. It improves obviously the ability of dealing with failure links in MANET. Simulations show that the new local route repair algorithm resulted in significant performance improvement, such as packet delivery ratio and end-to-end packet delay.Finally, chapter 6 summarizes the dissertation, reviews the above research work and presents the future research directions.