Correct, Efficient, and Realistic Wireless Network Simulations

GTNetS;Simulation;Wireless;802.11;Network measurements;NetBSD

Subbareddy, Dheeraj Reddy ; Electrical and Computer Engineering

University:Georgia Institute of Technology

Department:Electrical and Computer Engineering

关键词: GTNetS;    Simulation;    Wireless;    802.11;    Network measurements;    NetBSD;   

Others  :  https://smartech.gatech.edu/bitstream/1853/14558/1/subbareddy_dheeraj_r_200705_phd.pdf

美国|英语

来源: SMARTech Repository

【 摘 要 】

Simulating wireless networks accurately is a non-trivial task because of the largeparameter space that affects the performance of such networks. Increasing the amount ofdetail in the simulation model increases these requirements by many times. Hence thereis a need to develop suitable abstractions that maintain the accuracy of the simulationwhile keeping the computational resource requirements low. The topic of wireless networksimulation models is explored in this research, concentrating on the medium access controland the physical layers.In the recent years, a large amount of research has focussed on various kinds of wirelessnetworks to fit various application domains. Mobile Ad-Hoc Networks (MANETs), Wire-less Local Area Networks (WLANs), and Sensor Networks are a few examples.The IEEE802.11 Physical layer(PHY) and Medium Access Control (MAC) layer are the most popularwireless technologies in practice. Consequently, most implementations use the IEEE 802.11specifications as the basis for higher layer protocol design and analyses.In this dissertation, we explore the correctness, efficiency, and realism of wireless networksimulations. We concentrate on the 802.11-based wireless network simulations, although themethods and results can also be used for various other wireless network simulations too.While many simulators model the IEEE 802.11 wireless networks, almost all of them tend tomake some abstractions to lessen the computation burden and to obtain reasonable results.A comparitive study of three wireless simulators is made with respect to the correctness oftheir ideal behavior as well as their behavior under a high degree of load.Further, the physical-layer abstraction in wireless network simulations tends to be verysimplistic because of the huge computational requirements that are needed to accuratelymodel the various propagation, fading, and shadowing models. When mobility is taken intoaccount several other issues like the Doppler effect should also be accounted for.This dissertation explores an empirical way to model the physical layer which cumula-tively accounts for all these effects. From a network protocol designers perspective, it isthe cumulative effect of all these parameters that is of interest.Our major contribution has been the investigation of novel empirical models of thewireless physical layer, which account for node mobility and other effects in an outdoorenvironment. These models are relatively more realistic and efficient when implementedin a simulation environment. Our simulation experiments validate the models and pro-vide simulation results which closely match our outdoor experiments. Another significantcontribution is in understanding and design of wireless network simulation models.