Efficient Support for Deep Sleeping Modes in Embedded Systems: the Case of Zenoh-pico

The Internet of Things (IoT) is an ever evolving and ever growing field where plenty of devices communicate with each other and transfer data to/from the Cloud via an infrastructure, usually a pub/sub. In this extensive field comes to rescue Zenoh, a pub/sub/query middleware for Cloud and IoT applications. It supports many interesting functionalities but in this thesis we focus on its lightweight counterpart for embedded devices - Zenoh-Pico. Zenoh-Pico is entirely written using the C pro- gramming language thus making it extremely lightweight and efficient, perfect for an embedded device. In this work I focus on the support to deep-sleeping mode for Zenoh-Pico on UDP unicast communications. The deep-sleeping modes are typical of embedded devices such as ESP32 or Zephyr boards and they are used to put the board in a kind of energy saving state. In order to work with Zenoh-Pico I used PlatformIO, ESP-IDF, VSCode, and the board az-delivery-devkit-v4 ESP32. PlatformIO and ESP-IDF are used to manage the toolchain for the creation of a firmware to be put on the ESP32 starting from the code on VSCode. VSCode is used to program the code that will run on the board. I carried out many experiments from my support to deep-sleeping mode on the ESP32. The main and most interesting results being the time and space efficiency of my support to deep-sleeping mode, and the fact that with just 3 seconds of deep- sleeping on a low duty cycle programme (about 6 seconds of activity - 3 seconds of sleeping) with a 250mAh battery, the battery gains about 2 weeks of autonomy with 3 seconds of deep-sleeping. In conclusion, the deep-sleeping mode is of paramount importance for the embedded system world when those embedded devices are powered from an external battery limited in its capacity thus the importance of a middleware like Zenoh-Pico to support the deep-sleeping mode.