PERFORMANCE ANALYSIS OF GREEDY PERIMETER STATELESS ROUTING IN MOBILE ADHOC NETWORKS

Abstract

A Mobile Ad hoc Network (MANET) is an autonomous, self organized, wireless multi-hop packet network without any fixed infrastructure. Each node acts as a router in MANET. The routing protocols for MANETs, have to adapt quickly to frequent and unpredictable topology changes and must be parsimonious of communications and processing resources. In MANETs, routing with geographical information is more efficient and scalable than methods which rely only on node connectivity. Greedy Perimeter Stateless Routing (GPSR) is a geographic position assisted routing protocol. It uses the positions of routers and a packet's destination to make packet forwarding decisions. There are two modes to forward the packets; Greedy forwarding and Perimeter forwarding. When packet reaches a region where Greedy forwarding is not possible, the algorithm recovers by forwarding the packet in Perimeter forwarding mode. In this dissertation, GPSR has been simulated in MANETs. The performance of GPSR has been analyzed on the basis of packet delivery success ratio, routing overhead and path optimality. GPSR is suboptimal in performance because of Perimeter forwarding, as it makes the network vulnerable to congestion and incurs periodic computational overhead. Hence to optimize GPSR, Neighbor assisted forwarding is proposed in this dissertation. This is used instead of Perimeter forwarding, when Greedy forwarding fails in GPSR. Finally, the performance of GPSR with Neighbor assisted forwarding is compared with basic GPSR. The simulation of GPSR is done in Borland C++ on the Windows 9x platform.