Executive Summary : | The IEEE 802.15.4 standard, the most widely adopted link-layer for Internet of Things (IoT) applications, has limitations that can hinder network performance in large deployments like smart cities. Issues like scheduling transmissions in multiple access networks and synchronization in peer-to-peer network topologies are not explored in the IEEE 802.15.4-2020 standard, limiting network scalability and affecting Quality of Service (QoS) parameters like throughput and latency. To improve network performance, several MAC-associated schemes are required. The proposed schemes include a distributed beacon and data-scheduling mechanism, a dynamic and adaptive multi-superframe parameter tuning mechanism for DSME-based networks, and an adaptive duty-cycling mechanism for dynamic channel conditions. These schemes aim to minimize the number of timeslots used while maximizing the usage of available channels, resulting in a QoS-efficient schedule. The proposed adaptive duty-cycling mechanism can be integrated into the MAC layer of the IEEE 802.15.4 standard, which is the most popular low-power long-range link-layer technology used by IP-based applications of IoT. By addressing these limitations, the proposed schemes can significantly improve network performance and increase network lifetime in large IoT network deployments. The physical testbed of 25-30 devices will be used to experiment with these proposed schemes and compare them with other related schemes from the literature. |