Joint Beamforming Design and BBU Computational Resources Allocation in Heterogeneous C-RAN with QoS Guarantee

In this paper, we consider the joint transmission coordinated multi-point (CoMP) technique in a downlink heterogeneous cloud radio access network (C-RAN). The joint beamforming design and baseband unit (BBU) computational resources allocation problem in Heterogenous C-RAN is investigated. This problem is formulated as an optimization problem to minimize the overall system power consumption under per-user quality-of-service (QoS), fronthaul capacity, per-antenna transmit power and per-remote radio head (RRH) total transmit power constraints. The considered problem is a non-convex optimization problem due to the presence of the binary indicator in the fronthaul constraints. To address this challenge, we use the re-weighted $\boldsymbol{\ell}_{1}$-norm technique and reformulate the problem into a tractable form. Then, we transform the problem to a weighted sum mean square error (MSE) minimization problem and propose a weighted minimum mean square error (WMMSE) algorithm to solve it. Simulation results are provided to verify the effectiveness of the proposed algorithm.