A new lower cost UL split option for ultra-low latency 5G fronthaul

Next generation cellular networks are targeting higher bit rates, lower delays and enhanced inter-cell coordination. For that to happen, higher capacity and lower latency fronthaul solutions are required, among others. The use of Ethernet packet-switched networks for the fronthaul links with a Cloud-based Radio Access Network (C-RAN) architecture are nowadays considered. These will allow leveraging statistical multiplexing gains, infrastructure reuse and cost reduction. In the literature, different fronthaul split options are proposed. However, in order to satisfy latency requirements, most of these studies advocate the use of lower fronthaul split options like the eCPRI (evolved Common Public Radio Interface) I_U split, requiring huge fronthaul link capacity. In this paper, we propose and evaluate an alternative uplink physical split, denoted II_U. The objective is to reduce capacity requirements on the fronthaul while meeting latency constraints. The proposed split is analyzed for both fast and slow fading channel situations. Two variants are proposed for the II_U split: a subframe based and slot-based multiplexing. Performance results show that the proposed II_U split satisfies the stringent latency requirements of next generation mobile networks while reducing the deployment cost of links and Ethernet switches of the fronthaul.