# AODV-EOCW: An Energy-Optimized Combined Weighting AODV Protocol for Mobile Ad Hoc Networks
## 2 Related Work  
AODV is a widely accepted reactive and a priori routing protocol. In AODV, when the target node receives the first RREQ (routing quest) routing request message from the source node, the link is considered stable, and the RREP (routing reply) message is returned to establish a complete routing link. Then, if the RREQ message from another link from the same source node is received again within a certain time period, the destination node will discard it. This reduces the delay and message forwarding processing to a certain extent and achieves the goal of saving energy. However, the routing table of the AODV routing protocol only stores one routing path, which means that the link will be heavily used, and the energy of the nodes on the link will be rapidly exhausted. The early death of nodes will decrease the performance of the whole wireless network and shorten the lifetime of all nodes. In addition, AODV simply chooses the route by a single metric among many other routing metrics that can reflect the stability of links, which limits the ability of AODV to choose more stable routing links. In terms of improving the lifetime of ad hoc networks, many researchers have introduced the concept of energy and added corresponding fields in their implementations. [PERSON] [11] considered energy during routing selection to improve the routing performance. [PERSON] [12] proposed that the congestion problem is an indicator of the routing performance; the determination of whether to transmit RREQs is based on the relationship between the cache size and the threshold. [PERSON] [13] introduced the backup routing mechanism to estimate the energy of the routing node and the time at which the route path breaks. When the route breaks, the standby route can be started on time. [PERSON] [14] proposed a new routing protocol based on AODV, in which the most important concept is the energy threshold. When the energy level is lower than a certain threshold, the node can reject data packets to preserve its own energy. The results of the policy indicate that the corresponding changes to the forwarding mechanism of the AODV routing protocol can extend the network's lifetime. [PERSON] [15] proposed Dichotomic-AODV from the perspective of controlling the transmission of packets to reduce the energy consumption. Before the establishment of the routing path, it is most likely that the intermediate node will be required to forward the messages to be transmitted. The new method reduces the broadcast by increasing the probability of discovering the destination and using the dichotomy method to reduce the transmission of route discovery control messages during route establishment, thus reducing the energy consumption. [PERSON] [16] proposed an ant-colony-based algorithm to allow the discovery of the minimum number of MDR paths required to preserve the energy and balance the data traffic through the round-trip time-delay evaluation on the path from the source to the destination. [PERSON]'s algorithm is able to satisfy multiple metrics for multiobjective optimization, such as the end-to-end delay, load balancing, and energy saving. [PERSON] [17] proposed a new route improvement method by selecting paths using the temporal load on the intermediate nodes and by distributing the load among the free nodes during the transmission of data. [PERSON] [18] used a method similar to [PERSON] [15] to reduce the cost of control messages and extend the network's lifetime. The difference is that the scene of [PERSON]'s research is the Internet of Vehicles. Because the vehicles generally have unlimited energy, the method of directional flooding based on geographical coordinates is possible. In terms of reducing link congestion in ad hoc networks, the most common method is to introduce new routing metrics to measure the degree of congestion.