Performance Analysis Of Ad Hoc Networks Based On Queue Theory

Ad Hoc network is consists of a series of node that have the function of host and router.It represents a system of wireless mobile nodes that can freely and dynamically self-organize into arbitrary and temporary network topologies,allowing people and devices to seamlessly inter network in areas without any preexisting communication infrastructure.It applied widely in military affairs,emergency,earthquake,flood or succor in out-of-the-way place.And it also server as wireless access network and combination with wireless or wire network in existence.Therefore,it has a great future and it will become a crucial component in future communication technology.This thesis discuss the Markov chain model of single Ad Hoc network,the fact need consideration in modeling and the performance of single host and multi-receiver according to the media access protocol of Ad Hoc network.The first chapter of this thesis illustrates the concept,characteristic,important technique,and application fields of Ad Hoc network.Due to the MAC protocol in Ad Hoc network mostly use IEEE 802.11 DCF(Distributed Coordination Function),we introduced the series of IEEE 802.11 protocol.Then we present a Markov chain model for IEEE 802.11 protocol.This model take account of the characteristic of Ad Hoc network node,and based on the Markov chain state diagram it deduce the model of performance metrics including throughput and delay.In order to prove the validation of model,we take out the simulation for single-hop Ad Hoc network.The result shows that the analytical estimated throughput and media access delay and simulation are fairly accurate.Secondly,based on the introduction of communication network software OPNET Modeler,it detailed illustrates the simulation process of Ad Hoc network.By comparing the change discipline of delay and throughout in different moving speed and mode,the density of node and environment,it shows that the modeling process should considered these fact.Lastly,it presents the model and analysis for multi-radios and single-host node of Ad Hoc network.By abstracting the general character of multi-radios and multi-servers,based on the classical queuing system model,we import the multi-priority,multi-servers and AQM mechanism in the new and complicated queue system.it extend the node with single-host and single transmitter-receiver to multiple and deduce the analytical performance metrics model including average queue length, system throughput,probability of drop packet and average waiting time.Afterward,it illustrates the relationship between the above performance metrics and the number of servers.