# Research on Multi-Strategy Routing Protocol in Flying Ad Hoc Networks
###### Abstract
However, previous FANET routing protocols have focused on selecting the best path through joint metrics, although they use greedy and recovery modes. Although some researchers have considered network topology dynamics, most researchers have determined routing paths with the idea of studying the UAV location or trajectory prediction, for example. With the rapid changes in the routing environment brought about by the highly dynamic motion of UAVs, few researchers have conducted studies. At this stage, there is a lack of routing protocols for fast strain in different topological situations caused by highly dynamic flying UAVs. We have built on previous research to design routing switching strategies to adapt to highly dynamic changing UAV networks based on different network scenarios brought about by highly dynamic UAV flights. The previous study also improved the routing strategy to make it more suitable for the FANET. According to the characteristics of a three-dimensional network, when routing protocols encounter different network environments, routing forwarding can be effectively completed by selecting different routing strategies. Compared with the previous scheme, the proposed three-dimensional geographic location routing protocol, RGF, can complete the communication task of the FANET more effectively. The overall idea of the protocol is to provide a low overhead and scalable location services through the routing discovery process of the HELLO packet active flooding strategy and reactive fisheye technology, and to effectively improve the location acquisition ability of the 3D network. The reactive path in the 3D network is easily interrupted. At this time, the improved greedy forwarding can immediately transmit data packets and improve the link duration of the 3D network. However, greedy forwarding easily falls into local minima and forms routing holes in three-dimensional networks. Multi-path projection face forwarding can help packets jump out of routing holes. Projection face can easily generate path expansions, which can avoid potential path expansions by switching to reactive mechanism forwarding. The simulation results show that RGF can effectively improve the routing and forwarding capability of the FANET. The main contributions of this paper are summarized as follows:  
1. We propose a multi-strategy routing RGF protocol to solve the topological high-dynamic problem of the FANET by reasonably selecting and switching different forwarding policies. 2. We propose a hybrid location service strategy that can achieve the low overhead, scalable location services required by the RGF protocol. 3. We improve the traditional reactive path-building mechanism and greedy geographic forwarding mechanism to make the selected path or next-hop node more reasonable. 4. We propose a multi-path projected face forwarding policy and directionally adaptive forwarding rules to avoid routing loops, reduce path sprawl, and improve the efficiency of jumping out of routing holes. The research scheme is shown in Figure 1. The rest of this paper is arranged as follows: Section 2 introduces the relevant research content, Section 3 is the location service design of the routing protocol, Section 4 is the forwarding strategy selection and handover method, Section 5 is the specific forwarding strategy design, and Section 6 is the simulation analysis of the experiment.