Impact of packetization and functional split on C-RAN fronthaul performance

Cloud-RAN (CRAN) is considered as one key en-abler for beyond 4G networks, offering multiplexing gains, and advanced cooperation and coordinated signal processing. However, a key obstacle in the adoption of the CRAN architecture is that it requires very high capacity and low latency fronthaul (FH) links to carry raw I/Q samples between remote radio heads (RRH) and the baseband units (BBUs). These capacity requirements could be reduced by a more flexible split of baseband processing between BBUs and RRHs. Nevertheless, while moving some of the processing back into the RRH is expected to reduce FH rates, the amount of reduction mainly depends on the split, cell load, scenario and it might also introduce some delays. To this end, this paper studies the impact of different functional splits on the FH capacity for representative scenarios. Furthermore, we propose the use of a packet-based fronthaul network and study the joint impact of different packetization methods and RRH-BBU functional splits on the FH rate and latency. Based on this study, we provide some insights on the feasibility and optimality of different combinations, and the potential multiplexing benefits in terms of numbers of RRHs one could support over a single Ethernet-based FH network.