Research On QoS Routing Of Ad Hoc Networks

Ad Hoc networks composed of mobile nodes with wireless communication device are typically characterized by their multi-hop, temporary and uncentral, can be quickly built up in anywhere and at anytime, needn't be supported by pre-existing infrastructure, and every terminal can move freely and equally. So, as a special wireless network without any fixed network infrastructure, it has vast application prospect in military and civilian field.With the increasing need of Multimedia services in Ad Hoc networks, it has gradually become an important research field top provide QoS in mobile ad hoc networks. However, mobile ad hoc networks have a lot of characteristics such as multi-hop, limited bandwidth resource and dynamic network topology. How to design routing protocols which support QoS guarantee is challenging, and it has been the important content of Ad Hoc networks research.This thesis is the extensive research on how to provide routing protocols with QoS guarantee in Ad Hoc networks by referring to current relevant research contributions.Firstly, this thesis describes the concept, characteristic and application of Ad Hoc networks. Introduces the table driven protocols and on demand protocols of Ad Hoc networks routing protocols, and analyses and researches some typical QoS routing protocols of the two kinds of routing protocols. By comparing their function, come to a conclusion that with Ad Hoc networks developing fast, some applications need guarantee of the service quality. The research in the QoS support is just to solve the problem among which the QoS routing protocols are the important factors.And then, introduces QoS parameters and information entropy, then combines QoS with entropy, puts forward a stable QoS multicast routing based on entropy, and compares the new protocol with QoS Multicast routing protocol.Research on the AODV protocol, on the basis of AODV algorithms, this thesis puts forward a new protocol QOS-AODV, which can provide QoS guarantee. The protocol chooses the QoS routing path mainly based on the bandwidth and take the end-to-end delay of the link as optimization objective, use the memory and a new field called hopcount to cut down the opposite direction route in the process of routing choices. In order to reduce the route cost, data packet and hello packet are revised. In order to cut down the probability of the rebuilding route and the delay of end-to-end, add a back-up routing mechanism in the protocol of QOS-AODV.NS2 platform is used to analyze performance and problems of such protocol, in this thesis, we compare QOS-AODV protocol with AODV protocol through NS2. The result shows that QOS-AODV which based on bandwidth and delay can provide good quality of service and appropriately reduce the routing cost.Finally the conclusions of this thesis and suggestions for future research of the field are given.