# An Energy-Balanced Geographic Routing Algorithm for Mobile Ad Hoc Networks
## 1 Introduction  
A mobile ad-hoc network is a self-organized multi-relay wireless communication network which is composed of a number of mobile nodes with limited volume [1; 2; 3]. Mobile ad-hoc networks complete the information transmission with multiple hops. With the rapid development of computing, sensor, communication and network technology, mobile ad-hoc networks will play a new role in military and civilian applications, such as search and rescue operations, target detection, prevention of attacks, wind speed estimation, etc [4; 5; 6; 7; 8]. Due to the limited energy of nodes, the wide application of mobile ad-hoc networks is restricted. Therefore, the optimization of energy use and network load balancing has been a hot topic in the industry and academia [9]. With the increasing demand for multimedia applications, the energy consumption of nodes increases sharply in particular. If mobile nodes run out of energy, it will directly lead to data transmission interruption. The failure or exit of nodes may split the network and affect the quality of service of the network [10], which leads to higher requirements for the load-handling of the network. Therefore, an efficient energy balance and an accurate and timely perception of the nodes' remaining energy are crucial for mobile ad-hoc networks to move from theory to practice. Traditional routing protocols in mobile ad-hoc networks usually use the clustering algorithm to reduce energy consumption. In the cluster structure, nodes with lower energy are used for sensing near the target, while nodes with higher energy are selected as cluster heads for processing and sending information [11]. In Reference [12], the authors propose a hierarchical clustering algorithm (HCAL) and a corresponding protocol for hierarchical routing in large-scale mobile ad-hoc network. HCAL jointlyutilizes table-driven and on-demand routing using a combined weight metric to search the dominant set of nodes. Motivated by an energy-efficiency policy for the optimal selection of cluster-heads in the wireless sensor networks, in Reference [13], a modified stable election protocol, named Prolong-SEP (P-SEP), is presented to prolong the stable period of fog-supported sensor networks by maintaining balanced energy consumption. In cluster-based routing algorithms, data aggregation and fusion are performed to reduce the amount of messages sent to the base station (BS), which greatly improves the extendability of the whole system and effectively reduces the energy consumption. However, the throughput and the packet loss rate of cluster-based routing are not good enough [14]. To gain a better performance for clustered multihop mobile wireless networks, routing must take radio channel access, code scheduling, and channel reservation into account. In Reference [15], the authors propose heuristic routing schemes for clustered multihop mobile wireless networks. Considering that existing active clustering mechanisms require a periodic refresh of neighborhood information and introduce a significantly large amount of communication maintenance overhead, [PERSON] et al. [16] introduce a passive clustering scheme which is mostly supported/maintained by user data packets instead of explicit control packets. In Reference [17], it has been shown that if the queue lengths are observed at both servers, the optimal decision is to route jobs to the shorter queue, while if the queue lengths are not observed, it is best to alternate between queues, providing that the initial distribution of the two queue sizes is the same. Reference [18] presents a loop-free, distributed routing protocol for mobile packet radio networks. The routing algorithm adapts asynchronously in a distributed fashion to arbitrary changes in topology in the absence of global topological knowledge. [PERSON] et al. [19] present an energy- and delay-aware routing method which combines Cellular automata (CA) with a Genetic algorithm (GA).