A fast converging algorithm for limited fronthaul C-RANs design: Power and throughput trade-off

This paper considers the downlink transmission of cloud-radio access networks (C-RANs) with limited fronthaul capacity. We formulate a joint design of remote radio head (RRH) selection, RRH-user association, and transmit beamforming for simultaneously optimizing the achievable sum rate and total power consumption, using the multi-objective optimization concept. Due to the non-convexity of per-fronthaul capacity constraints and introduced binary selection variables, the formulated problem is combinatorial and nonconvex, which is generally NP-hard. To deal with this difficulty, we develop a new framework which iteratively approximates the continuous non-convex constraints by convex ones in the form of second order cones. The problem arrived at each iteration is a mixed integer second order cone programming which can be solve optimally and efficiently. Numerical results show that our proposed algorithms converge rapidly and outperform the existing solutions.