Analysis of Distributed and Autonomous Scheduling Functions for 6TiSCH Networks

Francesca Righetti,Giuseppe Anastasi,Sajal K Das,Carlo Vallati

doi:10.1109/access.2020.3020153

Abstract

The 6TiSCH architecture is expected to play a significant role to enable the Internet of Things paradigm also in industrial environments, where reliability and timeliness are of paramount importance to support critical applications. Many research activities have focused on the Scheduling Function (SF) used for managing the allocation of communication resources in order to guarantee the application requirements. Two different approaches have mainly attracted the interest of researchers, namely distributed and autonomous scheduling. Although many different (both distributed and autonomous) SFs have been proposed and analyzed, a direct comparison of these two approaches is still missing. In this work, we compare some different SFs, using different behaviors in allocating resources, and investigate the pros and cons of using distributed or autonomous scheduling in four different scenarios, by means of both simulations and measurements in a real testbed. Based on our results, we also provide a number of guidelines to select the most appropriate SF, and its configuration parameters, depending on the specific use case.

Highlights

The Industrial Internet of Things (IIoT) is expected to revolutionize the way industrial systems are designed
Multi-path Ray-tracer Medium (MRM) implements ray-tracing techniques with various propagation effects, and associates a Packet Delivery Probability (PDP) to each link, which changes over time due to propagation effects and concurrent transmissions
In this article, we have performed a detailed performance comparison, based on both simulation and experiments on a real testbed, of three Scheduling Functions (SFs) for 6TiSCH networks that take a different approach in scheduling cells for communication

Summary

INTRODUCTION

The Industrial Internet of Things (IIoT) is expected to revolutionize the way industrial systems are designed. CLASSIFICATION AND RELATED WORK A significant number of SFs for 6TiSCH networks have been proposed to cope with the requirements of different use cases They can be broadly classified according to the paradigms considered by the 6TiSCH WG [19], namely, centralized, distributed, autonomous (or static), and hop-by-hop scheduling. In distributed scheduling [7]–[10], [20], nodes negotiate the allocation of TSCH cells with their neighbors, using the 6P protocol, and adapt the number of allocated cells, depending on traffic and network conditions. To allow ALICE to adapt to traffic changes, we exploited the FP mechanism provided by the underlying TSCH protocol [2] that allows the sending node to signal that it has more data to send (see Section II) Using this very simple mechanism, a node can transmit more data packets than the number of scheduled cells, facing temporary traffic peaks. In the implementation used for our experiments, downward traffic is managed through shared cells, as in E-OTF

EVALUATION METHODOLOGY

SIMULATION RESULTS

ONE-TO-ONE COMMUNICATION

INFLUENCE OF THE FRAME PENDING OPTION

CONCLUSION