Wireless Mobile Ad Hoc Network And Its Simulation Study Based On NS-2

The Wireless Mobile Ad hoc Network (WMANET) is a special wireless mobile communication network. It is so due to that all mobile terminals in the network are equal and self-organized, there is no need to pre-deploy any infrastructure or centralized administration, the topology is dynamically changing, the bandwidth and energy are also limited, etc. Thus, the research on the WMANET, in particular, the research on its MAC and routing protocols has been immensely challenging. It is hard, however, to deploy a real network in the phase of researching. Generally, network simulation is one basic means to spread the research on the network technologies.This dissertation, at the very beginning, introduces the origin, characteristics, applications and current situations of the mobile ad hoc network. Then, contraposing the OSI (Open System Interconnect Reference Model) and TCP/IP Architecture, this dissertation analyzes in every layer the techniques and protocols WMANET currently adopts. Compared and analyzed with some other currently popular network simulator, the open-source NS-2 (Network Simulator V2) is chosen by this dissertation as a tool. Based on NS-2, this dissertation does simulations in depth upon three routing protocols (DSDV, DSR, AODV) of two different types (Proactive, Reactive) under a variety of situations including different network-scales, different topology ranges, different node receiving thresholds, different node movement scenarios and traffic scenarios. In the simulation, this dissertation employs many samples, extracts the data from the trace file and statistically analyzes three essential metrics (average end-to-end delay, delivery rate, routing overhead) of network routing protocols by using Shell and awk programs. The results show that proactive routing protocols like DSDV have comparatively shorter average end-to-end delay, while reactive routing protocols like DSR and AODV have comparatively better performances on delivery rate and routing overhead.As for routing protocol-oriented simulation, many a document simulates only with one routing protocol under some different situations, fewer with a few. Moreover, those documents often focus on one metric only. This dissertation, however, concentrates onmultimetric under different kinds of network situations. The facts show that this simulation measure is applicable.