# A Flexible Infrastructure-Sharing 5G Network Architecture Based on Network Slicing and Roaming
###### Abstract  
The sharing of mobile network infrastructure has become a key topic with the introduction of 5G due to the high costs of deploying such infrastructures, with neutral host models coupled with features such as network function virtualization (NFV) and network slicing emerging as viable solutions for the challenges in this area. With this in mind, this work presents the design, implementation, and test of a flexible infrastructure-sharing 5G network architecture capable of providing services to any type of client, whether an operator or not. The proposed architecture leverages 5G's network slicing for traffic isolation and compliance with the policies of different clients, with roaming employed for the authentication of users of operator clients. The proposed architecture was implemented and tested in a simulation environment using the UERANSIM and Open5 GS open-source tools. Qualitative tests successfully validated the authentication and the traffic isolation features provided by the slices for the two types of clients. Results also demonstrate that the proposed architecture has a positive impact on the performance of the neutral host network infrastructure, achieving 61.8%-higher throughput and 96.8%-lower packet loss ratio (PLR) in a scenario sharing the infrastructure among four clients and eight users when compared to a single client with all the network resources.  
5G; network sharing; neutral host; roaming; network slicing +
Footnote †: journal: Information  
From the CSPs' perspective, the reliability of these networks may not be optimal due to challenges in network management and commercial agreements, among other factors. The NSPs can use infrastructure virtualization to surpass those challenges, with techniques such as network slicing [4]. These advancements make neutral hosts more appealing and reliable; however, resource management and ensuring customer policy control are still challenges when using network slicing [5]. In this context, this paper proposes an infrastructure-sharing architecture that enables neutral hosts to provide their tenants a network slice with a set of 5G network services, being capable of offering CSPs the ability to provide a 5G service to their customers regardless of whether they are an MNO or not and ensure network services to provide control over their customers.  
This paper's main contributions are as follows: the design of an infrastructure-sharing 5G network architecture that accommodates both types of tenants--MNOs and non-MNOs; the selection of a set of 5G network functions (NFs) to provide the tenants with all the necessary services, improving NSPs' scalability and resource management while ensuring CSPs' traffic isolation and policy control over their customers; the implementation of the proposed architecture in a simulation environment using open-source tools; and the execution of multiple tests to validate the proposed architecture.  
The remainder of this article is organized as follows: Section 2 presents the background and related work. Section 3 describes the proposed solution and its implementation, whereas Section 4 presents the results and discussion. Finally, the conclusions and suggestions for future work are presented in Section 5.