ZeroJitter: An SDN Based Scheduling for CPRI over Ethernet
Tao Ruan Wan, Bill McCormick, Yufei Wang, Peter Ashwood-Smith · 2016
In the Cloud Radio Access Network (C-RAN)architecture, a fronthaul network carries digitized radio signals from Remote Radio Head (RRH) to centralized Baseband Unit (BBU) using the Common Public Radio Interface (CPRI), which has a one-way jitter requirement of several nanoseconds. It is widely believed that Ethernet cannot meet this stringent jitter requirement, thus today's fronthaul networks are primarily based on optical networks. In this paper, we propose ZeroJitter, an SDN based scheduling algorithm and a potential SDN application, for Ethernet to satisfy the CPRI jitter requirement. We implement ZeroJitter and test it in NS-3 with a realistic fronthaul network topology. Both our analysis and simulation results show that jitter incurred by Ethernet could be minimized or even completely removed with ZeroJitter under reasonable constraints. While technical challenges remain, our results suggest that SDN could enable Ethernet to be qualified for fronthaul networks, resulting in significant economic benefit.