DyHSARW: A Dynamic GTS Scheduling Mechanism for Large IEEE 802.15.4 DSME-Based IoT Networks

The IEEE 802.15.4 standard is one of the widely adopted networking specifications for realizing different applications of the Internet of Things (IoT), One of its Medium Access Control (MAC) protocols, the Deterministic Synchronous Multi-channel Extension (DSME), enhances stringent QoS by allocating DSME-Guaranteed Time Slots (GTSs) between pairs of devices. However, the standard does not specify a mechanism for scheduling these DSME-GTSs, presenting numerous research opportunities in this area. In this paper, we propose a novel Dynamic Hierarchical Slot-Channel Allocation with Recursive Weighting (DyHSARW) scheme aimed at improving the scheduling of DSME-GTS in large-scale IEEE 802.15.4-based IoT networks. The proposed approach dynamically allocates non-overlapping time slots (using the HCF technique) across multiple channels (based on a device's association order), optimizing resource utilization while adapting to the hierarchical structure of the network. Specifically, the HCF condition checks if the transmission weights of a child-parent pair and the previous time slot's value are compatible, i.e., if their HCF is equal to 1. This condition indicates that the parameters are co-prime, which minimizes the likelihood of collision in the time slot allocation process. This method seeks to overcome the limitations of existing GTS scheduling algorithms, which face challenges in efficient resource allocation, increased latency, and higher energy consumption under dynamic traffic conditions.