# Research on Multi-Strategy Routing Protocol in Flying Ad Hoc Networks
###### Abstract
In [18], aiming at the topological structure in the dynamic change of an ad hoc network, the topological network structure of the recording platform was designed by using the random constant speed moving model (RCS), which made the simulation scene closer to the dynamic performance of the high-dynamic mobile node. In [19], a novel routing protocol inspired by the cuckoo search algorithm was proposed. The latest meta-heuristic cuckoo search algorithm (CSA) was used to improve the AODV routing protocol and identify the shortest path between two nodes. The authors of [20] proposed a FANET routing protocol, PSO-GLFR, based on greedy forwarding and limited flooding. Particle swarm optimization was used to solve the problem of greedy forwarding suboptimal selection and realize low delay and low power routing support. In [21], a geographic location-based routing protocol was proposed to reduce routing overhead using neighbor geographic location information. In [22], a multi-data rate mobility aware (MDRMA) protocol was proposed. The MDRMA protocol is the primary extension of a self-organizing distance vector in two-way mobile sensing with adaptive HELLO message protocol, which can quickly generate stable routes and reduce link failures. In [23], an adaptive greeting interval scheme (EE-HELLO) was proposed, reducing energy consumption under the same packet transmission rate. In [24], based on dynamic source routing (DSR), a continuous Hopfield neural network was used to optimize routing to adapt to the FANET network. The optimized DSR protocol improved the key performance of routing. In [25], an adaptive hybrid communication protocol was proposed,including position prediction-based directional MAC (PPMAC) and a self-learning method. The protocol provides a highly autonomous communication solution. Most three-dimensional geographic location routing protocols use two working modes simultaneously: the greedy mode (greedy routing) and the recovery mode (recovery routing, also known as bypass mode or bypass routing). The greedy mode ensures packets are forwarded in advance, while the recovery mode is mainly used to make packets jump out of routing holes or loops when the greedy mode encounters a local minimum or routing loops. The three-dimensional geographic location routing protocol will generally follow the following basic principles: Each node knows its 3D location information. In some cases, nodes can use a virtual location instead of an actual location to simplify the configuration. Currently, the sending node knows the location information of the surrounding neighbor node and the destination node. Each node needs to exchange location information with the neighbor node, which can be achieved by periodically sending beacon messages. The current routing decision of the sending node is based on local information and is fully distributed. Generally, the current sending node selects the next-hop forwarding node according to its own location, the neighbor node's location, and the destination node's location. The current sending node uses the greedy mode to decide on the next-hop forwarding node. The common way this is achieved is through greedy geographic forwarding (GGF) [26]. For the switch of the recovery mode, when the current sending node encounters a local minimum or routing loop, the greedy mode will not continue to work. At this time, the protocol needs to switch to the recovery mode to forward packets until it jumps out of the routing hole or loop and then switches back to greedy mode. According to the above principles, the three-dimensional geographical location routing protocol can be designed reasonably, which can efficiently complete the communication task of the flight ad hoc network. However, the structure of the 3D dynamic network is complex. Making 3D geographic location routing work efficiently with a reasonable switch routing strategy has become a hot and arduous task in the FANET.