# Practical Performance Analyses of 5G Sharing Voice Solution
## 1 Introduction  
With the continuous increase of data and devices in wireless networks, existing wireless networks face difficulty in increasing traffic load. Consequently, the next generation of mobile cellular communication and networking has emerged [1]. At the same time, global operators face many challenges in 5G network development, with insufficient coverage, difficult construction and high investment, and high operating expenses. By now, the global population using mobile services has reached 5.3 billion, accounting for 67% of the total global population. The number of 5G connections will increase from 8% of the total number of connections in 2021 to 25% in 2025, and it is expected that 5G connections will account for one-fourth of the total mobile connections in 2025. However, some developing regions and countries around the world still do not have mobile communication coverage. How to let more developing regions also enjoy mobile communications and experience the convenient life brought by 5G is a problem that the global communications industry needs to solve. In addition, operate and revenue will increase from USD 1.08 trillion in 2021 to USD 1.16 trillion in 2025, and operator expenses are expected to reach USD 620 billion from 2022 to 2025, 85% of which will be spent on 5G development [2]. In addition to the purchase of an expensive wireless spectrum, 5G construction uses higher frequency bands, greater bandwidth, higher base station construction densities, and higher power consumption and construction costs perstation. How to reduce the cost of 5G network construction and operation is a common and urgent problem for global operators. 5G wireless network sharing can effectively improve the utilization of spectrum resources, rapidly form advanced mobile networks, accelerate infrastructure networks, and promote the development of the digital economy [3]. Wireless network sharing has a long history, and since the 3G era, some European operators proposed demands for mobile communication network sharing. Network sharing among global operators has been occurring, and various forms of sharing have emerged [4; 5; 6]. The 3 rd-Generation Partnership Project (3 GPP) first developed the 3G network sharing standard in Release 6 [7]. TS 23.251 defines the Multi-Operator Core Network (MOCN) network-sharing architecture, including basic functions such as system information broadcast and network selection as well as basic requirements for UE, base station, core network, and other devices to support network sharing [7], Ref. [8] and others define interface protocols to support related network sharing requirements. 3 GPP successively clarified the 4G and 2G network-sharing specifications in Release 8 and Release 10. Release 15 started to support 5G MOCN radio access network sharing and standardized radio access network sharing in terms of network architecture, air interface, NG interface, and XN interface protocols. Ref. [9] defines the MOCN sharing architecture under 5G stand-alone (SA) networking. With the new demand for network sharing, 3 GPP standards continue to evolve, and new radio (NR) networks can evolve from non-stand-alone (NSA) networks to SA networks. The system model figure and specific solutions for 5G access network sharing are described in Section 3. The IP multimedia subsystem (IMS) is an all-IP system designed to assist mobile operators to deliver next-generation interactive and interoperable services over an architecture providing the flexibility of the Internet [10]. Voice is a real-time service with tight delay requirements; thus, it requires a robust underlying radio network to ensure an optimal user experience [11]. 3 GPP has adopted GSMA IR.92 IMS profile for voice and SMS [12] and GSMA IR.94 IMS profile for conversational video [13] to provide high-quality IMS-based voice services over NR radio access. 3 GPP Release15 has provided voice services for 5G users based on IMS.