Evaluating C-RAN Fronthaul Functional Splits in Terms of Network Level Energy and Cost Savings

Aleksandra Checko , Andrijana P. Avramova , Michael S. Berger and Henrik L. Christiansen

Abstract : The placement of the complete baseband processing in acentralized pool results in high data rate requirement and inflexibilityof the fronthaul network, which challenges the energy andcost effectiveness of the cloud radio access network (C-RAN). Recently,redesign of the C-RAN through functional split in thebaseband processing chain has been proposed to overcome thesechallenges. This paper evaluates, by mathematical and simulationmethods, different splits with respect to network level energy andcost efficiency having in the mind the expected quality of service. The proposed mathematical model quantifies the multiplexinggains and the trade-offs between centralization and decentralizationconcerning the cost of the pool, fronthaul network capacityand resource utilization. The event-based simulation captures theinfluence of the traffic load dynamics and traffic type variation ondesigning an efficient fronthaul network. Based on the obtained results, we derive a principle for fronthauldimensioning based on the traffic profile. This principle allows forefficient radio access network with respect to multiplexing gainswhile achieving the expected users’ quality of service.

Index terms : C-RAN, energy efficiency, functional split, multiplexing gain