The emergence of Centralized-RAN (C-RAN) has revolutionized mobile network infrastructure, offering streamlined cell-site engineering and enhanced network management capabilities. As C-RAN gains momentum, the focus shifts to optimizing fronthaul links. While fiber fronthaul guarantees performance, wireless alternatives provide cost efficiency and scalability, making them preferable in densely urbanized areas. However, wireless fronthaul often requires expensive over-dimensioning to overcome the challenging atmospheric attenuation typical of high frequencies. We propose a framework designed to continuously align radio access capacity with fronthaul link quality to overcome this rigidity. By gradually adapting radio access capacity to available fronthaul capacity, the framework ensures smooth degradation rather than complete service loss. Various strategies are proposed, considering factors like functional split and beamforming technology and exploring the tradeoff between adaptation strategy complexity and end-to-end system performance. Numerical evaluations using experimental rain attenuation data illustrate the framework's effectiveness in optimizing radio access capacity under realistically variable fronthaul link quality, ultimately proving the importance of adaptive capacity management in maximizing C-RAN efficiency.

翻译：集中式无线接入网（C-RAN）的出现彻底改变了移动网络基础设施，提供了简化的基站站点工程和增强的网络管理能力。随着C-RAN的发展势头日益强劲，优化前传链路成为关注焦点。虽然光纤前传能保证性能，但无线替代方案具有成本效益和可扩展性优势，使其在高密度城区更具吸引力。然而，无线前传通常需要昂贵的过度配置来克服高频段典型的大气衰减挑战。我们提出了一个旨在持续协调无线接入容量与前传链路质量的框架以克服这种僵化性。通过逐步调整无线接入容量以适应可用前传容量，该框架确保服务平滑降级而非完全中断。研究提出了多种策略，综合考虑功能分割和波束成形技术等因素，并探讨了适配策略复杂性与端到端系统性能之间的权衡。利用实验性降雨衰减数据的数值评估表明，该框架能在实际可变的前传链路质量下有效优化无线接入容量，最终证明了自适应容量管理对于最大化C-RAN效率的重要性。