Study on Routing Protocols in Wireless Ad-HOC Networks

Abstract

In computer communications Ad-hoc network is a great concept. A mobile ad-hoc network (MANET) is an autonomous system of mobile nodes connected by wireless links. Mobile ad hoc networks are networks without fixed infrastructure. The mobile nodes perform both as a host and a router forwarding packets to other nodes. Ad-hoc networks has several characteristics which imposes new demands on routing protocols. The most important character is dynamic topology, which is a consequence of node mobility. Nodes can change position quite frequently which means that we need a routing protocol which adapts topology changes quickly. The nodes in adhoc networks can consists of laptops and personal digital assistance and other often very limited in resources such as CPU capacity, storage capacity ,battery power and bandwidth. This means that routing protocol should try to minimize control traffic, such as periodic updates messages. Instead the routing protocol should be reactive, thus only calculate routes upon a receiving update requests. Because of the nature of ad hoc networks, there are special demands for ad hoc routing protocols. The performance of MANET is related to the efficiency of the routing protocols in adapting to frequently changing network topology and link status. This thesis paper provides the different categories of routing protocols: Destination-sequenced Distance Vector (DSDV), Ad-hoc Ondemand Distance Vector (AODV) and Optimized Link State Routing (OLSR) and the causes of packet losses and their solutions.