Integrating Fairness in Current Consumption of End Devices in Time-Slotted LoRa-based Wireless Sensor Network

Abstract

LoRaWAN, a Low Power Wide Area (LPWA) networking protocol, allows devices to share a communication link and transmit data randomly. Its scalability is hindered by high collision rates and duty cycle restrictions, leading to uneven power usage and network instability. In contrast, time-slotted communications offer a solution by dividing time into fixed slots, ensuring fair and efficient network access. However, fairness in current consumption of end devices has been overlooked in previous studies, potentially causing network instability. This research introduces Group Acknowledgement Circular Shift (GACS) algorithm, combining group acknowledgment with a new Circular Shift method. Using MATLAB simulations and Jain's Fairness Index, two scenarios were tested: one with Group Acknowledgement (GA) without Circular Shift (CS) and another with GACS. Results on a network with ten devices and one gateway over ten cycles showed fairness improved from 98.32% with GA without CS to 99.75% with GACS. Even with 100 transmission cycles and varied parameters, GACS consistently outperformed GA without CS, highlighting its strong fairness index and ability to maintain uniform current consumption across nodes. Overall, the study emphasizes the robust fairness index of the GACS algorithm, irrespective of the number of nodes (SN) within each group slot, with nodes consistently exhibiting uniform current consumption at every SN^th cycle