| Summary: | 碩士 === 明新科技大學 === 電機工程研究所 === 100 === Wireless Ad Hoc Networks composed of a crowd of mobile nodes are the dynamic and infrastructural-less wireless local area network (WLAN). Within the transmitting range, the mobile nodes communicate with each other and roam without any access point supporting. In wireless ad hoc network, the network congestion and failure links are caused by the migration of nodes and limited frequency bandwidth. The unstable communication links occasion packet loss. However, the channel environment quality and the kind of protocol affect the performance of network during the transmission process. In this study, the simulation and analysis are manipulated by Network Simulator ver. 2.29. We use NS 2 to evaluate the throughput of wireless Ad Hoc networks and to observe how these important factors impact on wireless Ad Hoc networks. These important factors are mutually mixed two routing protocols, i.e. DSDV and AODV, with two TCP versions, i.e. TCP NewReno and TCP Reno, and then which one is mixed with the speeds of mobile nodes while changing the path loss exponent and maximum congestion window (max-cwnd). Simulation results indicate that when path loss exponent increases the throughput drops sharply resulting from the link failure that is induced by channel environment quality degradation. The results presented in this thesis highlight the need for adapting the important factors of TCP, e.g. the value of maximum congestion window to improve the performance of wireless Ad hoc network.
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