Research On QoS Routing In Ad Hoc Networks

Ad Hoc networks composed of mobile nodes with wireless communication device are typically characterized by their multi-hop, temporary and un-center. As a special wireless network without any fixed network infrastructure, it has extensive application prospectes in military and civilian field. It has been a research focus on current network research.With the prevalence of multimedia application, it has gradually become an important research field 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, which all cause in to provide QoS become more complex, it has brought the new challenge for the network researcher.This thesis is the extensive research on how to provide routing protocols with QoS guarantee in mobile Ad Hoc networks by referring to current relevant research contributions.Firstly, this thesis introduces the concept, characteristic and application of Ad Hoc networks.Then it introduces the two kinds of routing protocols of Ad Hoc networks including the table driven protocols and on-demand driven protocols. We research deeply in the routing protocols such as DSDV, DSR, and AODV. 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. This thesis introduces the QoS routing protocols and researches deeply in some typical QoS routing protocols. Then the network simulation and NS2 software are presented in detail. On the NS2 platform, the three classic Ad Hoc protocols are simulated.We draws the conclusion that the performance of the on-demand driven protocol is better than the table driven protocol. So the more effective QoS route protocol can based on on-demand driven protocol.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,When the stream in the network which has bandwidth and delay constraints arrived, the protocol issues route discovery process. When the node receives the reply, the protocol chooses the best route to sending the data.So the QOS-AODV can provides QoS guarantee.Secondly, in order to reduce in the route discovery process the nonessential route expenses, we revised the delivery frequency of hello package which match with the node moving speed, when the node moves quick, the hello package of delivery frequency is high; Otherwise, the hello package of delivery frequency is low, in certain degree reduced the route expenses. In this thesis, the author design this protocol on the NS2 platform,and compares its performance with AODV. The result shows that QOS-AODV which based on bandwidth and delay can provide good quality of service and appropriately reduce the routing cost. The simulation result indicated that, QOS-AODV based on the bandwidth and delay restraint chooses the QoS route, enhanced the packet delivery rate, reduced the delay, the route load in the suitable scope, may provide the good quality of service guarantee.Finally the conclusions of this thesis and suggestions for future research of the field are given.