A bidirectional congestion control transport protocol for the internet of drones

Wireless sensor networks (WSNs) are composed of energy constrained devices that autonomously form networks through which sensed information is transported from the region of interest to the central control station (sink), integration with unmanned aerial vehicles (UAVs) leads to enlarged monitoring area and to enhance overall network performance. Due to application specific nature of wireless sensor networks, it is challenging to design a congestion control protocol that is suitable for all types of applications in the Internet of Drones (IoD). Congestion avoidance and control in wireless sensor networks mainly aims at reducing packet drop due to congestion and maintaining fair bandwidth allocation to all network flows. In this research work, we propose a reliable and congestion based protocol, which provides both bidirectional reliability and rate adjustment based congestion control. It uses Technique for Order Preference by Similarly to Ideal Solution (TOPSIS) method to select optimal path for data transmission because TOPSIS selects an alternative such that it has shortest distance from the ideal one and greatest distance from negative ideal solution. Congestion is detected by using proportion of average packet service time over average packet inter-arrival time as congestion degree. Then, congestion is notified using implicit notification to save energy and reduce overhead. To mitigate congestion along with maintaining fairness, an equal priority index is assigned to all data sources and when congestion occurs, rate adjustment to optimal value based on priority value is used for congestion control. This approach helps to diminish packet drops, maintain fairness and get better energy efficiency. Finally, we compare the performance of the proposed protocol with that of existing protocols. Our simulation results show reduced average delivery overhead, drop packet ratio, queue length and delay with increased average delivery ratio. Moreover, our protocol provides better energy efficiency and fairness when compared with the existing competing protocols.