Energy Efficiency of Downlink C-RAN With Edge Caching and Fronthaul Compression

In this letter, we study the impact of edge caching on the energy efficiency (EE) of a downlink cloud radio access network. The fronthaul compression strategy is introduced to tackle the problem of the limited fronthaul capacity. To reduce computational complexity, we resort to the large dimensional random matrix theory to derive the deterministic equivalent of the EE based on which the optimal cache capacity that maximizes the EE is derived. We compare the performance of the fronthual compression scheme with that of the data-sharing scheme and reveal the tradeoff between the EE and the transmit power. Simulation results show that the approximation is accurate and validate the dependency of the EE on the cache capacity.