Radio Access Network (RAN) sharing, which often also includes spectrum sharing, is a strategic cooperative agreement among two or more mobile operators, where one operator may use another's RAN infrastructure to provide mobile services to its users. By mutually sharing physical sites, radio elements, licensed spectrum and other parts of the RAN infrastructure, participating operators can significantly reduce the capital (and operational) expenditure in deploying and operating cellular networks, while accelerating coverage expansion -- thereby addressing the spectrum scarcity and infrastructure cost challenges in the 5G era and beyond. While the economic benefits of RAN sharing are well understood, the impact of such resource pooling on user-perceived performance remains underexplored, especially in real-world commercial deployments. We present, to the best of our knowledge, the first empirical measurement study of commercial 5G spectrum and RAN sharing. Our measurement study is unique in that, beyond identifying real-world instances of shared 5G spectrum and RAN deployment "in the wild", we also analyze users' perceived performance and its implication on Quality of Experience (QoE). Our study provides critical insights into resource management (i.e., pooling) and spectrum efficiency, offering a blueprint (and implications) for network evolution in 5G, 6G and beyond.

翻译：无线接入网共享通常包含频谱共享，是两个或多个移动运营商之间的战略合作协议，允许一方使用另一方的RAN基础设施为其用户提供移动服务。通过共享物理站点、无线单元、授权频谱及RAN基础设施的其他组成部分，参与运营商能大幅降低部署和运营蜂窝网络的资本（及运营）支出，同时加速网络覆盖扩展——从而应对5G时代及未来频谱稀缺与基础设施成本的双重挑战。尽管RAN共享的经济效益已被充分认知，但此类资源池化对用户感知性能的影响仍缺乏深入探究，尤其在现实商用部署场景中。据我们所知，本研究首次对商用5G频谱与RAN共享开展实证测量研究。本测量研究的独特性在于：不仅识别了现实环境中共享5G频谱与RAN部署的实际案例，还深入分析了用户感知性能及其对体验质量的影响。本研究为资源管理（即池化）与频谱效率提供了关键见解，为5G、6G及未来网络演进提供了蓝图（及其启示）。