Cost-constrained delay minimization of C-RAN and its multiplexing gain

Abstract

The recently-proposed centralized cloud radio access network (C-RAN) promises to deal with the ever-increasing traffic volume and reduce network cost by centralizing the baseband operation and simplifying radio access points. However, compared with traditional radio access network, whether it always has performance gain, and how large the gain will be are still open questions. This paper presents and analyzes a simple stochastic model for C-RAN wherein dynamic resource sharing is allowed in the centralized pool. Based on this, a cost-constrained delay minimization framework for C-RAN is proposed to optimize its capacity configuration. With the same network cost and traffic load, the multiplexing gain of C-RAN over traditional access network is analyzed under this framework. Bounds of the multiplexing gain are obtained, and the conditions under which C-RAN performs better are derived. Besides showing the optimal delay and multiplexing gain performance under homogeneous traffic scenario, numerical results also extend to heterogeneous arrivals, where the impact of traffic heterogeneity on the multiplexing gain is explored.