Development of a C-RAN Fronthaul Simulator

Sammanfattning: Cellular networks have significantly transformed the way we communicate and access data and the data rates have only been increasing for the last 30 years. 5G is the current generation of cellular networks and enables faster data rates and lower latency. One of the cellular network architectures used to enable 5g is centralized radio access networks (C-RAN). C-RAN centralizes all the baseband units (BBU) into one or a few locations in contrast to traditional architectures where BBUs are separated. This centralization causes more demand on the fronthaul to transfer larger amounts of data. To mitigate this demand on the fronthaul, functional splits were developed to distribute the baseband functions dependent on the need. This thesis focuses on simulating several functional splits in C-RAN with packetized fronthaul. The objective is to study the impact the functional split options have on the network by investigating key metrics such as fronthaul link throughput, utilization, and, buffer usage. The thesis includes the development of a digital twin (DT) of C-RAN deployments. This digital twin is implemented in Python using the SimPy library to enable discrete event simulation. The DT was then used to simulate each split option over low, medium, and high traffic loads. The network that was simulated includes one BBU, fronthual link, one switch, and three remote radio units with 64 antennas. The fronthaul link is 1 km long and has a transfer rate of 100 Gbps. The results show that various functional split options have a significant impact on the network’s overall performance. This impact is mostly dependent on the split option choice and not on the load for this configuration. Overall, this thesis contributes to the understanding of functional splits in centralized radio access networks with packetized fronthaul.