Processing Radio Access Network Functions in the Cloud: Critical Issues and Modeling

Commoditization and virtualization of wireless networks are changing the economics of mobile networks to help network providers (e.g., MNO, MVNO) move from proprietary and bespoke hardware and software platforms toward an open, cost-effective, and flexible cellular ecosystem. Cloud radio access network is a novel architecture that perform the required base band and protocol processing on a centralized computing resources or a cloud infrastructure. This replaces traditional base stations with distributed (passive) radio elements with much smaller footprints than the traditional base station and a remote pool of base band units allowing for simpler network densification. This paper investigates three critical issues for the cloudification of the current LTE/LTE-A radio access network. Extensive experimentations have been performed based on the OpenAirInterface simulators to characterise the base band processing time under different conditions. Based on the results, an accurate model is proposed to compute the total uplink and downlink processing load as a function of bandwidth, modulation and coding scheme, and virtualization platforms. The results also reveal the feasible virtualization approach towards a cloud-native radio access network.