Research On QoS Routing Protocols Of Mobile Ad Hoc Networks

Mobile Ad Hoc networks composed of mobile terminal nodes with wireless communication device are typically characterized by their mufti-hop, temporary and un-center, can be quickly built up in anywhere and at anytime, and not necessary to be supported by basic network devices which have been constructed, e.g., emergency rescue or exploration missions, where cellular infrastructure is unavailable or unusable. In mobile Ad Hoc networks every terminal can move freely and equally and operates not only as a host but also as a router. Mobile Ad Hoc networks has extensive application prospect in military and civilian field and it has been a research focus in current network research.The routing protocols such used in traditional Internet can not be adapted to the need of mobile Ad Hoc networks in fact. At the same time, since the compute-capability of mobile nodes and storage-capacity are low and the energy sources are limited, the routing protocols have to be as simple as best. All those add the difficulty to the routing protocol design in mobile Ad Hoc networks. Because of the increasing of multimedia applications designing the QoS routing protocol has become a research and development hot issues of mobile Ad Hoc networks.In this thesis, firstly the recent research progresses are overviewed. Then the concept, characteristics and routing of the mobile Ad Hoc networks are introduced. The Dynamic Source Routing Protocol of mobile Ad Hoc networks is analyzed and improved. NS2 (Network Simulator V2) simulator software is introduced and has comparison between improved protocol and DSR in NS2.The Dynamic Source Routing protocol (DSR) is a simple and efficient routing protocol and has two processes of route discovery and route maintenance. As DSR is based on Source Routing, nodes needn't to save routing information and broadcast routing information periodically. DSR finds several paths in the route discovery, but it chooses path only because of shortest hop, and it didn't think about QoS parameter such as end-to-end delay of the paths, strong of the signal, stability of the paths, bandwidth and so on.In this thesis, route discovery of the DSR is improved. The source node adds QoS parameter to RREQ and the middle node looks over QoS parameter when receiving RREQ. The middle node forwards or drops RREQ due to QoS parameter. Multipath routing is used to send data. Packet delivery ratio, average end-to-end delay and route overhead three main parameters are selected to compare the performance of improved protocol and DSR for different node number, pause time and cbr. The stability and reliability is improved because of thinking about QoS parameter such as bandwidth and end-to-end delay. The quality of services is better than before.Finally, conclusions of this thesis and suggestions for future research are given.