# Research on Multi-Strategy Routing Protocol in Flying Ad Hoc Networks
###### Abstract  
In this paper, a multi-strategy routing protocol, reactive-greedy-face (RGF), is proposed based on the advantages of reactive forwarding, greedy forwarding, and projected face forwarding strategies. This protocol improves and unites the strategies through a reasonable selection and switching mechanism to make up for the deficiencies of the existing three-dimensional routing protocols in the flight self-assembly network and improve the rapid recovery of packet forwarding after topology changes. The simulation validation shows that this routing protocol can be used to recover packets after a topology change. Simulation verification indicates that the routing protocol significantly improves the packet delivery rate and the average end-to-end delay performance, and can better adapt to the flight self-assembly network's three-dimensional high-dynamic and low-density characteristics. unmanned aerial vehicle; flying ad hoc networks; routing protocol; three-dimensional high-dynamic network; reactive mechanism +
Footnote †: journal:  
0000-0001-6500-0000-0000-0000-0000-0000-0000-0000-0000-0000-0000-  
memoryless routing algorithm in a three-dimensional space that can ensure the delivery of data packets [7], which also means that the uncertain recovery routing algorithm can ensure that data packets jump out of the routing hole. Therefore, the design of an efficient three-dimensional geographic location routing protocol is still facing great challenges. Many researchers have studied the operation of traditional ad hoc network routing protocols in the FANET and have achieved some results, but they still need to improve and develop new routing protocols according to the characteristics and requirements of the FANET. In [8], the traditional ad hoc on-demand distance vector routing (AODV) protocol can be improved by adding the location and heading information of the source node as well as a minimum expected connection time (minCT) and maximum risk value to the RREQ packet as a joint measure to select the best route. The reactive green reactive (RGR) protocol proposed in [9] combines a reactive routing mechanism with greedy geographic forwarding. Once the reactive path is interrupted, the existing packets will be saved by greedy geographic forwarding during the re-routing. The RGR protocol effectively reduces the delay while maintaining the overhead of the conventional routing level. In the literature [10; 11; 12], the AntHocNet protocol, based on the ant colony algorithm, and the BeeAdHoc protocol, based on the bee colony algorithm, were analyzed. Simulation results showed that the heuristic algorithm based on swarm intelligence is more suitable for the flight ad hoc network characterized by high-speed data transmission and high node mobility. The authors of [13] proposed a predictive routing algorithm for the flight ad hoc network based on the clustering structure. The algorithm uses the improved Dijkstra algorithm to calculate the minimum end-to-end delay path, which avoids link loss in the transmission process. In [14], an adaptive beacon scheme called ABPP (adaptive beacon and position prediction) was proposed for the geographic location routing protocol. ABPP uses historical location information to predict the future location of UAVs through a weighted linear regression model, which effectively reduces the channel overhead. In [15], a greedy location-assisted routing scheme based on fountain code was proposed, which was called FGPA (fountain code-based green position assisted routing). FGPA takes the relative motion trend between two UAV nodes as a new measure. The authors of [16] proposed an adaptive forwarding protocol (AFP) in a 3D space. AFP can reduce unnecessary replay and conflict between neighbor nodes based on forwarding probability and region standards. In [17], the hybrid routing protocol HSRP (hierarchical space routing protocol) was proposed based on the ZRP protocol. The HSRP protocol uses the flow rate mechanism to select table-driven or on-demand routing protocols.