Performance evaluation of AODV and OLSR under mobility.

摘要

Wireless mobile ad hoc network is a infrastructureless network where each network node not only acts as a host but also acts as a router. Since the nodes are mobile, the environment is highly dynamic. For these networks to function properly a routing protocol is required that can respond to the rapid changes in the topology. Many routing protocols have been developed for accomplishing this task. The objective of this thesis is to study the impact of mobility on the performance of two mobile routing protocols, AODV, which is reactive routing protocol and OLSR, which is proactive routing protocol. Since not many MANETs have been deployed, most of the studies are simulation based. But for this thesis, experiments were conducted on national Open Access Research Testbed (ORBIT) for Next Generation Wireless Networks. We developed a basic framework to analyze the performance of routing protocols. We firstly evaluated the performance in a static environment where nodes are arranged in static linear topology and concluded that OLSR outperformed AODV. To study the mobility, we used Reference Point Group Mobility model that generates real life scenarios. It is clear that there is considerable cost associated with mobility. Both the protocols show decrease in throughput, higher standard deviation, more dead links and higher overhead when compared to their respective performance in static environment. However, the relative performance of AODV and OLSR depends on the mobility scenario. AODV performed better than OLSR for discrete scenario when time snapshots were taken at a lower frequency i.e. every 30 seconds. On the other hand, OLSR performed better in pseudo-continuous scenario when time snapshots were taken at higher frequency i.e. every 5 seconds.