Heterogeneous Cloud Radio Access Networks: A New Perspective for Enhancing Spectral and Energy Efficiencies

TL;DR

H-CRANs integrate cloud computing with heterogeneous networks to address interference and improve spectral and energy efficiencies through advanced cooperative techniques.

Contribution

This survey highlights recent advancements, key techniques, and challenges in H-CRANs, emphasizing their potential to enhance network performance.

Findings

H-CRANs improve spectral efficiency via cloud-based coordinated transmission.

Energy efficiency gains are achieved through cooperative radio resource management.

Major challenges include fronthaul constraints and standardization issues.

Abstract

To mitigate the severe inter-tier interference and enhance limited cooperative gains resulting from the constrained and non-ideal transmissions between adjacent base stations in heterogeneous networks (HetNets), heterogeneous cloud radio access networks (H-CRANs) are proposed as cost-efficient potential solutions through incorporating the cloud computing into HetNets. In this article, state-of-the-art research achievements and challenges on H-CRANs are surveyed. In particular, we discuss issues of system architectures, spectral and energy efficiency performances, and promising key techniques. A great emphasis is given towards promising key techniques in H-CRANs to improve both spectral and energy efficiencies, including cloud computing based coordinated multi-point transmission and reception, large-scale cooperative multiple antenna, cloud computing based cooperative radio resource management, and cloud computing based self-organizing network in the cloud converging scenarios. The major challenges and open issues in terms of theoretical performance with stochastic geometry, fronthaul constrained resource allocation, and standard development that may block the promotion of H-CRANs are discussed as well.