# SDN-Oriented 6G Industrial IoT Architecture Design and Application to Optimal RIS Placement and Selection

## TL;DR

This paper designs an SDN-based 6G architecture for industrial IoT, using RISs and graph theory to optimize network performance.

## Contribution

A novel SDN framework for 6G IIoT with RIS integration and graph-based RIS placement algorithms.

## Key findings

- The proposed SDN architecture supports IIoT requirements with RIS systems and OpenFlow compatibility.
- Graph-theory approaches for RIS placement improve coverage and reduce complexity in simulations.
- Network and host discovery protocols enable an updated global network view for SDN controllers.

## Abstract

This paper presents a high-level system architecture that integrates the Software Defined Networking (SDN) paradigm in 5G/6G networks with the aim of supporting the requirements expected for Industrial Internet of Things (IIoT) devices and services. To this purpose, we include multiple Reconfigurable Intelligent Surfaces (RISs) systems and provide for them an abstract representation consistent with the OpenFlow interface and messaging framework. The main contribution of this is firstly focused on designing a comprehensive framework that specifies the modules, components, interfaces, protocols, and message exchanges across the typical three layers SDN architecture. In addition, we characterize the Network Discovery (ND) and Host Discovery (HD) protocols that enable the SDN Controller to achieve a global and updated view of the network. Then, the RIS Placement and Selection Problem (RPSP) is formulated by using two graph-theory approaches, i.e., Set Covering (SC) and Minimum Spanning Tree (MST). Finally, we conduct an extensive simulation campaign that evaluates the performance of the discovery phases and the RIS placement/selection algorithms in realistic industrial environments. The results highlight the advantages achieved in terms of coverage and complexity.