Connectivity Maximization in Non-Orthogonal Network Slicing Enabled Industrial Internet-of-Things With Multiple Services

Industrial Internet of Things (IIoT) is a technological revolution that is profoundly reshaping the visage of industry. Facing the explosively increasing number of multi-service devices, traditional industrial network technology is no longer applicable. The advent of the fifth-generation (5G) wireless networks brings unprecedented possibilities for deploying the anticipated IIoT. To address the two main issues, i.e., connection density and multi-service requirements, in 5G empowered IIoT, we consider the non-orthogonal network slicing in this work. In particular, we jointly utilize network slicing to incorporate different types of services and exploit non-orthogonal multiple access (NOMA) to enhance the connection density. We formulate the connectivity maximization problem with joint sub-carrier association and power allocation as a mixed-integer nonlinear programming (MINLP). To tackle the intractable MINLP, we first transform it into a mixed-integer linear programming (MILP) and then simplify the MILP into an integer linear programming (ILP) by developing a simple yet effective pairing guideline. In order to further reduce the computational complexity, we then propose the alternating selection best-effort pairing (AS-BEP) algorithm with low complexity to solve the ILP effectively. Our analyses are supplemented by comprehensive simulation results that illustrate the performance superiority of the proposed algorithms to the benchmark schemes.

I. Introduction

Recently, the growing popularity of the Internet of Things (IoT) is providing an up-and-coming scheme not only for the development of various home automation systems but also for different industrial applications. By grasping the advantages, Industrial Internet of Things (IIoT) is becoming a buzz word. IIoT is a group of interconnected static/mobile objects, such as devices equipped with communication, networked sensors, and control modules, connected through the Internet. The concept of IIoT paves the way for a better understanding of the manufacturing process, allowing for more efficient and sustainable production [2]. To accelerate the growth of Industry 4.0, which primarily focuses on the manufacturing industry, IIoT urgently requires in possession of strong communication characteristics such as high density with multiple services, real-time performance, high reliability, and energy efficiency. Nevertheless, indeed because of these characteristics, it is challenging to deploy an IIoT.