A Novel Autonomous Adaptive Frame Size for Time-Slotted LoRa MAC Protocol

LoRa networks represent a promising technology for Internet of Things applications due to their long range, low cost, and energy efficiency. However, their ALOHA-based access method and duty cycle restrictions can limit their scalability and reliability in high-density networks. To address such a challenge, this article proposes the autonomous time-slotted LoRa (ATS-LoRa), protocol that allows LoRaWAN nodes to autonomously determine their optimal transmission parameters without extensive downlink transmissions from the gateway. ATS-LoRa utilizes the geographical coordinates of the nodes and their gateway in a novel way to allow them to determine their appropriate transmission parameters, such as the spreading factor, the channel frequency, and the slot ID. ATS-LoRa performance is evaluated through extensive simulations under different operating conditions showing an average throughput of around 47 times better than the adaptive data rate algorithm of LoRaWAN protocol.