A Novel Adaptive TDMA Protocol for Enhanced Collision Avoidance and Latency Reduction in LoRaWAN Networks

LoRaWAN networks are highly vulnerable to densenode deployments, as the ALOHA-based MAC implementation of these networks has high packet collision rates, high latency variability, and is also energy inefficient.The current set of solutions, including key collision-elimination methods such as static TDMA, is not adaptable to dynamic traffic and is unsuitable for simple IoT devices.In contrast, hybrid and AIbased methods introduce excessive overhead or complexity in computations.This paper, therefore, suggests an Adaptive Time Division Multiple (TDMA) protocol by dynamically assigning time slots depending on nodal condition (event-driven vs. normal) and distance to the gateway.The protocol combines priority-based scheduling, distance-based selection of spreading factor, and a realistic physical-layer model with full AES-CCM security compliance.With the help of massive simulations of an urban setting with 30 nodes in a 5 km urban setting, the protocol presents a zero-collision rate and a 100% packet delivery ratio (PDR).It has a mean latency of 361.7 seconds (7.1 packets/joule), which is 7.1 seconds (1.9 percent) lower than the standard LoRaWAN and is significantly faster than a static TDMA by 27.9 percent and uses less energy by 208.7 percent (7.1 packets/joule).Most importantly, it provides complete delivery of events, which is 1900 percent better than motionless TDMA.These findings show that the MAC layer solution is robust and adaptive to IoT applications with high reliability and low latency and energy consumption during dynamic conditions and is more effective compared to traditional or newer state-of-the-art techniques.