Energy aware cooperative routing in Mobile ad-hoc networks

A mobile wireless channel suffers from fading, meaning that the signal attenuation can vary significantly over the course of a given transmission. Spatial diversity is a technique used to combat fading, diversity is achieved by transmitting signals from different locations, thus allowing independently faded versions of the signal at the receiver. In wireless communication spatial diversity requires more than one antenna at the transmitter. However many wireless devices are limited by size and hardware complexity to one antenna. Recently cooperative communication has been proposed that enables single antenna mobiles in a multiuser environment to share their antennas and generate a virtual multiple-antenna transmitter that allows them to achieve spatial diversity. Cooperative communication generates this diversity by making use of the broadcast nature of the wireless environment. In this paper we have proposed a modified version of the AODV protocol for achieving cooperation in MANETs. We have further modified this protocol keeping energy efficiency in mind by making use of the concept of variable transmit power. We have also modified the data link layer protocol Automatic Repeat Request (ARQ) to work for cooperative networks.