Towards achieving an efficient ADR scheme for LoRaWAN: A review of the constrained optimisation approach

Abstract

Long Range Wide Area Network (LoRaWAN) is a networking technology that is rapidly growing in the Internet of Things (IoT) implementations under Low Power Wide Area Networks (LPWAN). The main goal of LoRaWAN is to optimise the coverage range, capacity, cost and battery life of the network. A vital LoRaWAN characteristic is the Adaptive Data Rate (ADR) algorithm that minimises energy utilisation and maximises throughput by regulating the bit rate, based on the link budget for individual end devices in the LoRaWAN. ADR regulates the transmission parameters, specifically Bandwidth (BW), Spreading Factor (SF), Transmission Power (TP) and Coding Rate (CR). The current spurt in IoT deployments has resulted in diverse QoS requirements, metrics, and implementation strategies. We present a comprehensive review of the constrained optimisation methods used to enhance ADR schemes for LoRaWAN technology. We highlight the strengths and drawbacks and computational complexity of the approaches. We provide a comparison of the optimisation techniques and identify research challenges and potential future study.