Energy Efficient Routing Protocol in MANET

Energy Efficient Routing Protocol (EERP), a power aware routing protocol increases the network lifetime of MANET. EERP is an on demand source routing protocol which is basically an improvement on DSR. In EERP path is chosen based on energy unlike DSR where path is chosen based on minimum number of hops. In EERP, Initially source node generates a Route Request packet (RREQ) with Minimum Energy field (Emin) in the packet set to 100 %. An intermediate node on receiving RREQ overwrites minimum energy field of the RREQ packet with the residual energy of the node at the particular time if the residual energy of the node is less than the minimum energy field in the RREQ packet. Otherwise, Minimum energy field remains unchanged. Now, intermediate node forwards route request to its neighbors only if its residual energy is more than a threshold value. This process goes on until RREQ reaches to the destination. Thus, lowest hop energy of each path from source to destination is calculated. Finally, the path is then selected by the destination node by choosing the path with the maximum lowest hop energy and sends the RREP to through that path. EERP is dynamic distributed load balancing approach that avoids power-congested nodes and chooses paths that are lightly loaded. EERP achieves minimum variance in energy levels of different nodes in the network and maximizes the network lifetime.