Hybrid Controlled User Association and Resource Management for Energy-Efficient Green RANs With Limited Fronthaul

Abstract

To alleviate the greenhouse effect, high network energy efficiency (EE) has become an important research target in wireless green communications. Therefore, an investigation for resource management to mitigate co-tier interference in a small-cell network (SCN) is provided. Moreover, with the merits of cloud radio access networks (C-RANs), small-cell base stations can be decomposed into central small cells (CSCs) and remote small cells (RSCs). To achieve coordination, split medium access control (MAC)-based functional splitting is adopted with a scheduler deployed at CSCs and retransmission functions implemented at RSCs. However, limited fronthaul has a compelling effect on RSCs owing to the requirements of user quality of service (QoS). In this paper, we propose a hybrid controlled user association and resource management (HARM) scheme to deal with the infeasibility of controlling all RSCs using a single CSC. A CSC performs the traffic-control-based user association and resource allocation (TURA) scheme for RSCs to mitigate intra-group interference within localized C-RANs, whereas the CSCs among separate C-RANs conduct cooperative resource competition (CRC) games to alleviate inter-group interference. Based on the regret-based learning algorithm, the proposed schemes are analytically proven to reach the correlated equilibrium (CE). The simulation results validate the capability of traffic control in the TURA scheme and the convergence of CRC. Moreover, a comparison of the proposed TURA, HARM, and CRC schemes with the benchmark is revealed. It is observed that the TURA scheme outperforms the other methods under ideal fronthaul control, whereas the HARM scheme can sustain EE performance considering practical implementation.

Keywords

• Cloud radio access networks
• functional split
• limited fronthaul
• energy efficiency
• green communication
• user association