Mobile Intelligence

1.1 INTRODUCTION

Mobile ad hoc networks (MANETs) have opened up many new possibilities in using computer networks in improvised scenarios where traditional networking infrastructure is unavailable. Mobile networks are usually based on wireless communication and hence many of the established technologies developed for wired networks are not directly applicable in mobile networks. In particular, nodes forming a mobile network are not tied to any infrastructure and can form a network on the fly and for a short period of time. The main difficulties in forming a mobile network are the mobility of the nodes, the nature of the wireless medium, the energy constraints of small mobile nodes, and the possibility that nodes may join or leave a network anytime during the lifetime of the network.

Since nodes are mobile, the routes in the network usually have a short life span. A route may or may not exist for the entire duration of a data communication session, unlike in wired networks, where nodes are usually present in fixed geographical positions. The wireless medium has the constraint that any communication by a node is done through broadcasting of a packet. Since the bandwidth in the wireless medium is much less compared to wired networks, this poses the problem that almost all communications take up large amount of bandwidth due to the flooding of packets. Moreover, the contention for limited bandwidth results in packet collisions and retransmissions, further wasting the available bandwidth. ...