Cognitive Radio and Dynamic TDMA for efficient UAVs swarm communications
Résumé
In the last decades, under technological progress in electronic and avionics systems, Unmanned Aerial Vehicles (UAVs) have known an increasing use in several military and civilian missions. Multiple UAVs can cooperatively carry out dangerous applications for human operators or missions where human intervention is not needed, such as surveillance and monitoring of areas of interest and physical infrastructures. Due to the lack of proper communication rules and standards, communication remains one of the most crucial design issues for UAVs swarm. Furthermore, UAVs generally operate in frequency bands shared with other users. Hence, these spectral bands become overcrowded and UAVs may face a spectrum scarcity issue. To address the above challenges, it is essential to define a reliable communication architecture for multiple UAVs coordination and efficient bandwidth sharing. A promising technology that can satisfy the spectrum requirements of the emerging UAVs Networks is Cognitive Radio Network (CRN). The goal is to opportunistically use spectral bands with minimum interference to other users or applications, i.e., primary users. In this paper, we consider the problem of spectrum scarcity encountered by UAVs. We present a centralized CRN-based communication approach for UAVs-Ground Control Station (GCS) communication. The GCS is used as a central coordinator to handle bandwidth usage for the UAVs swarm in its coverage zone. It selects, allocates, and shares available frequencies using CRN and Software Defined Radio (SDR). To share the available CRN-frequency between the different UAVs in its scope, the GCS uses dynamic Time Division Multiple Access (TDMA) technique. The performance of the proposed communication approach is evaluated in a surveillance context in terms of the total time required to transfer UAVs data, the total number of packets sent, and the achieved throughput.