Energy Aware Congestion Adaptive Randomized Routing in MANETs with Sleep Mode

MANETs are typically limited in resources like available wireless transmission bandwidth, available node battery power etc which makes the routing complex compare to the normal infrastructure based wireless network. Node mobility also makes the routing decision further hard. A packet drop in such network can be due to: Node Mobility, Congestion on network or node failure (energy drain or hardware failure). The MANETs nodes are typically running on battery power and energy issue is one major concern in MANET operation. If a node’s battery power drains completely, the node goes to power off state and thus the connectivity of the network is affected and network life time is reduced. The other concern in MANETs is Congestion. When a portion of a network has high incoming load then its capacity, packets start to drop and experience higher delay than normal, which reduces the throughput of the network and negatively affects the QoS parameters of the network. Congestion also causes low utilization of the network resources. In congestion, with each packet drop the energy used in transmission and reception is wasted. Thus higher energy efficiency can only be achieved, if energy issue and congestion issue are addressed together. This paper proposes a new Energy aware congestion adaptive randomized routing algorithm (EACAR-AODV) which addresses both the energy and congestion issue to achieve higher energy efficiency and QoS parameters. The proposed method is based on AODV and applies energy policy to include only high energy node, Random routing packet drop policy to control the RREQ flood to reduce energy consumption and congestion during path setup, and applies congestion policy based on current queue size of the node to find an alternate non-congested path. The proposed protocol is implemented in NS2 network simulator and compared with traditional AODV. The results show an improvement in both QoS parameters and Energy efficiency without introducing significant overhead.