End-to-End Delay Performance Analysis of Industrial Internet of Things: A Stochastic Network Calculus Perspective

In a hybrid scenario of 5G and Industrial Internet of Things (IIoT), there is a lack of a theoretical tool to analyze probabilistic end-to-end (E2E) delay. In this article, we provide a comprehensive procedure, which is based on stochastic network calculus (SNC) with moment-generating functions (MGFs), for calculating the E2E delay violation probability for the target traffic in IIoT. The particularity of the scenario is that the E2E network is composed of two segments: 1) the industrial wireless link challenged by the complex fading channel and 2) the multinode wired network that supports common schedulers. An improved concatenation theorem is proposed to calculate the service capability of the E2E network, and a method based on Meijer G-functions is proposed to calculate the MGF for the service processes of various wireless fading channels. We investigate the impacts of various resource allocation strategies (on both wireless and wired networks) and parameters (e.g., bandwidth, weight, and cycle time) on probabilistic E2E delay and provide numerical performance bounds. We show that the capability joint adaptation of the wireless and wired networks is the key to E2E service guarantee. Moreover, related parameters such as the weights and message sizes should be carefully considered to improve E2E delay.

I. Introduction

Thanks to the deployment of 5G-based Industrial Internet of Things (IIoT) in Industry 4.0, the manufacturing industry at present is undergoing a fundamental change. Traditionally, the communication technologies used in factories are wired communication, such as dedicated Industrial Ethernet technologies and field buses. However, these wired communication technologies face many problems, e.g., poor mobility, inflexibility in networking, and cable laying difficulty in special environments. The design architecture of IIoT changes fundamentally with the development of Industry 4.0 and 5G, because wireless connectivity can provide the flexibility, mobility, and versatility that are required for future factories [1]. This has promoted the new research trend of integration of 5G and IIoT [2].