Large-scale Antenna Operation in Heterogeneous Cloud Radio Access Networks: A Partial Centralization Approach

摘要

To satisfy the ever-increasing capacity demand and quality of service (QoS)requirements of users, 5G cellular systems will take the form of heterogeneousnetworks (HetNets) that consist of macro cells and small cells. To build andoperate such systems, mobile operators have given significant attention tocloud radio access networks (C-RANs) due to their beneficial features ofperformance optimization and cost effectiveness. Along with the architecturalenhancement of C-RAN, large-scale antennas (a.k.a. massive MIMO) at cell sitescontribute greatly to increased network capacity either with higher spectralefficiency or through permitting many users at once. In this article, wediscuss the challenging issues of C-RAN based HetNets (H-CRAN), especially withrespect to large-scale antenna operation. We provide an overview of existingC-RAN architectures in terms of large-scale antenna operation and promote apartially centralized approach. This approach reduces, remarkably, fronthauloverheads in CRANs with large-scale antennas. We also provide some insightsinto its potential and applicability in the fronthaul bandwidthlimited H-CRANwith large-scale antennas.