Novel Fronthaul Control Method to Address the Fronthaul/Air Interface Tradeoff

In 5th Generation (5G) virtualized Radio Access Networks (vRAN), where the protocol stack is split across three different elements (Radio Unit (RU), Distributed Unit (DU), and Centralized Unit (CU)), and data is transmitted across the transport network (fronthaul (FH) and midhaul) between these units, the capacity of the fronthaul pipe can become a limiting factor for packet transmission. To address this challenge, state-of-the-art approaches have introduced several fronthaul control methods, designed to limit the sending rate, to ensure that it does not exceed the available capacity. However, it is important to avoid potential conflicts between the decisions of such fronthaul control methods and those of the Medium Access Control (MAC) scheduling schemes, as they might impact one another. In this context, we provide a thorough analysis of the trade-off between the fronthaul and the air interface limitations and we propose a new FH Control method to limit packet transmissions without altering the decisions made by the MAC scheduler. An extensive simulation campaign in a 3GPP defined scenario with Virtual Reality (VR) and Cloud Gaming (CG) services is conducted, for air-limited and air/fronthaul capacity-limited conditions. The results demonstrate that the proposed fronthaul control method efficiently coordinates the MAC scheduler decisions with the constraints imposed by the fronthaul capacity.