# Communication Manager for Hyper-Connected RPAS Environments
## 1 Introduction
These technologies generally are not interchangeable, and each has its own field of application (e.g., long-distance point-to-point communications, networking, low energy consumption). However, given that they are increasingly being developed in lighter and smaller devices, it is possible to assume that an RPA could use several simultaneously, thus multiplying its versatility and complexity simultaneously. Finally, a highly volatile and dynamic environment, such as RPA operations, is also disruptive, not only from the intermittent availability of the transmissions themselves (e.g., coverage, obstacles, interference) but also from the intermittent availability of the transmission devices (e.g., transmission failures, RPA batteries running out, new devices, whether RPAs or RPSs that dynamically join or leave the communications network) which continuously forces network topology reconfigurations. This heterogeneity of such a broad spectrum of events, but also so focused on the discontinuity of the service, raises multiple challenges in the provision of these services, which in many cases are expected to reach extensive levels of robustness, reliability, and resilience (3R services), insofar as they are services that are very useful in all kinds of emergency operations or operations in challenging locations or even expensive operations that are difficult to be repeated. Figure 1 presents the reference scenario for this article, showing a network with multiple RPAs that may use different communication alternatives (not all vehicles are required to have or use the same communication links). However, to complete a successful mission, the RPA may have to cooperate for specific assignments (e.g., RPA1 uses RPA2 or RPS to report parameters to the air traffic control entity). This is the communication research framework that has been considered within the European project Labyrinth (Labyrinth, Ensuring drone traffic control and safety: [[https://labyrinth2020.eu/](https://labyrinth2020.eu/)]([https://labyrinth2020.eu/](https://labyrinth2020.eu/)) (accessed on 14 January 2023)) where different partners, including academia (Universidad Carlos III de Madrid), industry (such as Telefonica I + D, or ARQUIMEA), aeronautical research centres (such as the German Aerospace Center (DLR), or the Spanish National Institute of Aerospace Technologies (INTA)) will develop solutions that will be tested along the year 2023 by different relevant end users (the Municipal Emergency Assistance and Rescue Service--Civil Protection in Madrid, Spain (SAMUR); the Spanish General Directorate of Traffic (DGT); or the Italian Port Authority of the Eastern Ligurian Sea). This article presents the solution that has been developed to support communications in the context of the Labyrinth project that represents quite well all these frequent scenarios that we will be finding more and more in the RPAS field shortly. The solution involves the dynamic establishment of a network infrastructure that allows all those implicated in the communication to interconnect, extending the number of paths available to a given destination as far as possible. The proposed solution is also valid in use cases beyond traffic management, including road, air, and waterborne transport or supporting emergency services in natural disasters. A Communication Infrastructure Manager (CIM) will be responsible for this task. It will also manage all the complexity related to the assignment of flows to the multiple interfaces that may be present both in the RPA and the RPS. In a 3R (robustness, reliability, and resilience) environment, this task will imply the constant monitoring of the links in order to dynamically establish the proper metrics to be applied in each circumstance (e.g., path definition and flow assignments can be either based on delay metrics, or in allocated bandwidth, power consumption). For the CIM development, we started from a prior simple version [10], which has been upgraded to operate with Software-Defined Networking (SDN) technology. Figure 1: Motivating scenario.