  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.
