MAC Protocols And Routing Protocols Based On Burst Traffic In Ad Hoc Networks

Ad Hoc network is a dynamic distributed system consisting of temporarywireless nodes without support of fixed establishment. Each node which canmove freely is not only a host, but also a router in the network. Ad Hoc networkcan be self-organized and self-management with nodes adding and leaving. Theapplication field of Ad Hoc network includes urgent search, temporary meetingplace, wireless home network and so on. Recently the research on Ad Hocnetwork has been a hotspot.One of the most important obstacles for extensive application of Ad Hocnetworks is lack of simple MAC protocol and routing protocol suitable for realscenarios. Recent researches on Ad Hoc network always adopt Poissondistribution traffic model. Measurements of data traffic in real networks hadshown that the traffic in networks appears to be self-similar. The traffic inmulti-hop Ad Hoc network also possessed the character of self-similar anddifferent traffic models have heave impact on network performance. At present,the works related to Ad Hoc network only focus on qualitative simulation andanalysis without deep research. The major contributions of the dissertationinclude:Firstly, research on the impact of self-similar in Ad Hoc network. By theoryanalyzing the characteristic of self-similar in Ad Hoc network, this paperprovides network performance of delay and channel utilization ratio with phasictheory. Impact of self-similar in Ad Hoc network is found by simulation andresearch directions of routing protocol and MAC protocol were put forwardbased on simulation analysis.Secondly, a new backoff based on burst degree named BDB for Ad Hocnetwork is proposed. This algorithm employs burst degree as competitionparameter based on backoff of IEEE 802.11 wireless local area network takingtraffic burst into account. Nodes choose more reasonable backoff windowsaccording to traffic and competition. BDB suitable for different traffic model canreduce queue length, improve network performance suan as throughput anddelay. Thirdly, a new MAC protocol with packet fast forwarding named PFFMACis proposed. Middle nodes replies ACK with RTS in multicast way whenreceving no sengment or last sengment of data frame. Forward nodes with leastburst degree are choosed in order to reduce delay, improve channel utilizationratio and also alleviate intra-flow competition and queue head block. It is provedby both theory and simulation analysis throughput and delay have been improvedwhatever kind of traffic model.Fourthly, a new routing based on burst degree and node's degree namedBNBR is proposed. BNBR protocol inspects link quality and replace with betterbackup routing when the link quality becomes bad in order to finish routingswitch with less cost. Nodes choose routing according to burst degree and nodedegree along the routing path, while all the backup routings are keeped in therouting cache list. By taking traffic burst and node competition around intoaccount nodes can choose steady rounting as the best routing. BNBR routing suitwith different traffic model can decrease routing repair and rebuild, enhance datapacket delivery ratio and delay performance.