Performance evaluation of TSCH-minimal and orchestra scheduling in IEEE 802.15.4e networks

Abstract

Having been considered as a key enabler for the Internet of Things (IoT), the IEEE 802.15.4 standard is, now, emerging as a main pillar of the evolving Industrial IoT (IIoT), thanks to its Time Slotted Channel Hopping (TSCH) mode. TSCH allows nodes, in an IIoT network, to hop between the 16 channels of the IEEE 802.15.4 standard within specified timeslots in order to meet the reliability and real-time requirements of industrial applications, while saving nodes energy. A TSCH schedule dictates to each node what to do in each timeslot, that is: send, receive or sleep. However, the IEEE 802.15.4-TSCH specification does not provide mechanisms on how to build or maintain such a schedule. To address this issue, many solutions have been recently proposed, including a standard minimal schedule (TSCH-Minimal) by the Internet Engineering Task Force and a promising advanced solution dubbed Orchestra. This paper presents a comprehensive study and a performance evaluation of these state-of-the-art solutions in order to extract their advantages and drawbacks. Obtained results from extensive realistic simulations conducted in dedicated IIoT platforms, show that, overall, Orchestra outperforms TSCH-Minimal in reliability and energy aspects. On the latency and complexity aspects, however, TSCH-Minimal has shown noticeable performance. Based on such results, this study concludes the need for a hybrid TSCH scheduling mechanism that benefits from both worlds.