Baseband unit cloud interconnection enabled by flexible grid optical networks with software defined elasticity

TLDR

5G networks demand higher data rates, low latency, and cost‑effective coverage, prompting RANs to centralize baseband units for statistical multiplexing and adopt advanced optical technologies for digital and analog transmission. This study targets BBU cloud interconnection using optical layer technologies. The authors employ flexible‑grid optical networks to create elastic, transparent, virtualized lightpaths, and introduce a software‑defined centralized control plane that coordinates heterogeneous BBU, radio, and optical resources. An experimental testbed demonstrates elastic lightpath provisioning for cloud radio over flexible‑grid optical networks.

Abstract

The evolution toward 5G mobile networks is characterized by supporting higher data rate, excellent end-to-end performance and ubiquitous user-coverage with lower latency, power consumption, and cost. To support this, the RANs are evolving in two important aspects. One aspect is “cloudification,” which is to pool baseband units to be centralized for statistical multiplexing gain. The other aspect is to use advanced optical technologies for digital and analog signal transmission in a cloud-based RAN. In this article, we focus on BBU cloud interconnection with optical layer technologies. Flexible grid optical networks with the enabling technologies are introduced to provide elastic, transparent, and virtualized optical paths between the BBU pools. To improve the elasticity and intelligence of C-RAN, we propose a software defined centralized control plane to coordinate heterogeneous resources from three domains: the BBU domain, radio domain, and optical domain. We report an experimental demonstration of elastic lightpath provision for cloud radio-over-flexible grid optical networks in a software-defined-networking-based testbed.