Research On QoS Routing Protocols Of Ad Hoc Networks And NS2 Simulations

QoS-Based routing technique is the key to apply multimedia operations in Ad Hoc networks. However, so far there remain many problems still expecting to be solved in the field of QoS-based routing in Ad Hoc networks. Surrounding the two themes, multiple path and QoS-based multiple path, this thesis undertakes an in-depth study of some key issues in Ad Hoc networks, including simulation of Ad Hoc networks, single path, QoS constraints, and multiple QoS constraints etc.The following work is accomplished in this thesis.1. At first, two kinds of structures of wireless networks are introduced in this thesis,then some themes in Ad Hoc networks are researched as key parts such as the characteristic, the architecture, and the routing protocols. At last, we research the two kinds of routing protocols of Ad Hoc networks including the table driven protocols and on demand protocols, and make the corresponding comparison to their performances among the typical routing protocols.2. NS2 is a network simulation platform which is universally acknowledged in the world. It's important to master and skillfully use NS2. This thesis makes a further study on NS2, and then introduces the work principle and structure of NS2. More over, the wireless networks module is introduced in detail as a special part in this thesis. Through appending a newly developed data transmitting protocol, we elaborate how to simulate protocols and analyze data by NS2.3. Multi-path routing, as a kind of important measure of reducing congestion, has attached the attention in Ad Hoc networks research field. However, there're still some flaws existing in the current multi-path algorithms. For example, some algorithms are too complicated to realize, some routings' spending so high that increase congestion. This thesis puts forward a new multiple path routing protocol named MPDSR. MPDSR has improved the routing mechanism of DSR, and can obtain several routing messages which nodes disjointed at the same time. We append several fields in the RREQ in order to get the message of multi-path, and properly extend the routing cache to accelerate routing. Simulation shows that the performance of MPDSR is as full and complete as we expected.4. With the development of Ad Hoc, it is more and more important to provide QoS guarantee for multimedia application. Although QoS-based routing is an available method to provide QoS guarantee, most of present QoS-based routing based on single path, which do not take full advantage of resource of Ad Hoc networks. Thus, on the base of MPDSR, this thesis puts forward a QoS-based multiple path routing protocol named QMPDSR. QMPDSR can find several paths provided QoS guarantee. Also, it can disassemble QoS demands to transmit application data stream using different node disjointed path simultaneously. Simulation shows that QMPDSR protocol is better than QoS-MSR.Its packet delivery ratio is higher,time delay is lower,even the increased routing spending caused is not outstanding.Finally, some conclusions for this thesis are made and some suggestions for future research on this field are given.This thesis is supported by National Natural Science Foundation of China (60672137, 60773411) ,the Ph.D. Programs Foundation of Ministry of Education of China (20060497015) and Hubei Province Key Scientific and Technological Project(2007AA101C63).