Research Projects

The 6TiSCH (IPv6 over the Time Slotted Channel Hopping mode of IEEE 802.15.4e) protocol stack enables IPv6-based wireless communication for critical Internet of Things (IoT) applications such as smart healthcare, smart industry, and smart homes. 6TiSCH provides highly reliable, high throughput, bounded-latency, and energy-efficient communication compared to other resource-constrained IoT networks. Similarly, Deterministic Synchronous Multichannel Extension (DSME) -based IoT networks target time-critical IoT applications that require high throughput and low latency. Both 6TiSCH and DSME networks use the RPL (Routing Protocol for Low-Power and Lossy Networks) standard (RFC 6550) as the routing protocol. Using RPL, sensor-attached IoT nodes forward their data packets by selecting a preferred parent to reach the Border Router (BR) (aka PAN co-ordinator), which then transmits the packets over the Internet to the end-users. The nodes must schedule communication cells to send data to the BR with their RPL-parents. Cell scheduling refers to the process of allocating and de-allocating timeslot and frequency (together known as a cell) for data exchange. Cell scheduling is essential because resource-constrained IoT nodes, unlike WiFi devices, do not always keep their radios active to save energy. Again, it is challenging due to unpredictable traffic in IoT networks, IEEE 802.15.4e’s channel hopping feature against the interference and multipath fading issues on a single channel, and multi-channel communication. Allocating more cells than the networks’ actual requirements increases energy consumption, while allocating fewer cells leads to packet loss and increases latency and energy consumption. Current 6TiSCH cell scheduling approaches i.e., centralized or distributed, incur high energy consumption due to control packet overhead. Autonomous scheduling omits such overhead by assigning cells based on nodes’ EUI64 addresses. However, current autonomous schemes face challenges in terms of adaptivity (i.e., they do not allocate cells based on real-time requirements), high cell scheduling convergence time, and poor cell utilization. Consequently, these limitations lead to packet loss in large or dense IoT networks, increased energy consumption, and reduced network reliability and lifetime. In DSME-based IoT networks, similar issues persist, which is further complicated by dividing time into Contention Access Periods and Collision-Free Periods. This project initially aims to validate existing cell scheduling issues through analytical and testbed experiments. Then, it aims to design adaptive cell scheduling schemes to adjust cells in real-time dynamically, enhancing node energy efficiency and network reliability of 6TiSCH and DSME-based IoT networks. Additionally, the project will explore the interoperability of TSCH and DSME networks with long-range technologies like LoRaWAN in terms of cell scheduling to extend the communication range of these networks.