Research And Simulation On QoS Routing Protocols Of Ad Hoc Networks

Mobile Ad Hoc network is a multi-hop autonomous system which grouped by mobile nodes equipped with wireless transceivers and receivers.This system is no need of a fixed center cut-over point or basic point support.As a special wireless network which not only without any fixed network infrastructure but also taking flexibility,speediness and convenience as its advantages,it has an extensive application prospect in military and civilian field.So it has been a focus in current network research field.With the prevalence of multimedia application,QoS being provided in mobile Ad Hoc networks has become more and more important.However,Ad Hoc networks have a lot of characteristics such as multi-hop,limited bandwidth resource and dynamic network topology.These make QoS to be more complex and also take new challenges for researchers.By referring to the researches at home and abroad,this thesis aims to make further researches on how to provide routing protocol guaranteed by QoS in Ad Hoc networks.The flowing are the main researches and innovations of this thesis.1)Because that in Ad Hoc networks,different protocols have different advantages and disadvantages under different environment,and every protocol has its own application conditions,so it becomes very important to research and analyze the performance parameters of different protocols under different conditions.This thesis introduces the concepts and characteristics of Ad Hoc networks,concludes classic routing protocols,after analyzing the current routing protocol and simulations models on the base of relative references,makes a simulation under a node moving speedy and more thicker environment,and compares the performances of AODV,DSR, TOgA and DSDV on delay-time,jitter,packet delivery rate and efficiency.2)Due to the transfer requirement of Ad Hoc networks application environment and multimedia traffic flow that Ad Hoc networks must support QoS,so many QoS routing protocols have been presented now and to study these QoS design ideology, performances and characteristics will help to improve even present new QoS routing protocols in future.This thesis studies QoS techniques of Ad Hoc networks, compares the performances of the current routing algorithms,concludes the current QoS routing protocols of Ad Hoc networks and compares their performances by several aspect,such as routing system,QoS target,distributed operating system, unidirectional-link support and multicast support.3)According to the requirement of real time flow,this thesis presents RT_QRP protocol which is an improved AODV with real time delay constraint.In RT_QRP protocol,when the delay time limited flow appears,it will choose routing on the base of the least delay time to meet the needs of flow and take use of routing copy to cut down the unnecessary spending produced when reboot routing discovery in order to cover the needs of delay time and at the same time optimize resource distribution. The result of simulation shows that comparing with classic AODV protocol, RT_QRP reduced routing spending,boosted delivery ratio,decreased delay time and improved net service quality.4)The current QoS routing protocol of Ad Hoc networks mainly study how to find a useful path satisfying certain conditions between two nodes without thinking of the stability of this path,this thesis presents a kind of routing protocol,PS_QRP, which takes bandwidth as QoS limited parameter and path stability as base.Because of PS_QRP choosing routing on path stability basis,which reduces the link cracked times caused by mainframe moving and decreases the spending of routing control. Besides,because it takes primary and secondary reservation idea when reserve resource,so it greatly enhanced the stability of chosen path and further increased request succeed rate and sending succeed rate.This thesis is supported by National Natural Science Foundation of China (90304018,60773211,60672137),Hubei Province Scientific and Technological Research Project(2007AA101C63)and the Ph.D.Programs Foundation of Ministry of Education of China(20060497015).