Relay-dependent Path Replanning for Disconnected Drones Using Self-organized Communication Network

Drones are increasingly used in the delivery business. It is critical to ensure reliable and low-latency control and non-payload communication (CNPC) between delivery drones and the ground control station (GCS). Currently, delivery drones communicate with the GCS through Long Term Evolution (LTE) cellular network, but it is designed for ground users. Drones flying at low altitudes may suffer from poor communication with the GCS or even disconnect with the GCS, bringing huge pressure on social security. To ensure reliable drone-to-ground communication, a relay-dependent communication protocol is proposed to cope with situations when a drone loses connection with the GCS. Then we propose a path replanning algorithm that considers the low CNPC latency constraint during the whole fight. Experimental results show that our replanning algorithm is superior in terms of completion time. Moreover, we deploy the communication protocol on the Raspberry Pi equipped with a Long Range Radio (LoRa) module, and it works well in the outdoor environment.