  Mobile Ad hoc Network (MANET) is a distributed, infrastructure-less and
decentralized network. A routing protocol in MANET is used to find routes
between mobile nodes to facilitate communication within the network. Numerous
routing protocols have been proposed for MANET. Those routing protocols are
designed to adaptively accommodate for dynamic unpredictable changes in
network's topology. The mobile nodes in MANET are often powered by limited
batteries and network lifetime relies heavily on the energy consumption of
nodes. In consequence, the lack of a mobile node can lead to network
partitioning. In this paper we analyse, evaluate and measure the energy
efficiency of three prominent MANET routing protocols namely DSR, AODV and OLSR
in addition to modified protocols. These routing protocols follow the reactive
and the proactive routing schemes. A discussion and comparison highlighting
their particular merits and drawbacks are also presented. Evaluation study and
simulations are performed using NS-2 and its accompanying tools for analysis
and investigation of results.
