Cloud RAN Architectures with Optical and mm-Wave Transport Technologies

Cloud RAN has been regarded as a promising architecture for 5G mobile networks in terms of combination of implementing the very tight radio coordination schemes and sharing baseband processing and cooling system resources. However, the high capacity and stringent delay requirement for the fronthaul, the segment of the network between Baseband Units (BBU) and Remote Radio Heads (RRH) is one of the biggest barriers to larger deployments. To relax these constraints, physical layer functions can be split and centralized partially. In this paper, under one specific case scenario with the fixed number of LTE base stations, we calculate the transport capacity requirement for different physical layer function splitting solutions and adopt different transport technologies, i.e. Ethernet Passive Optical Network (EPON), Time-Wavelength Division Multiplexing PON, (TWDM-PON) and millimeter Wave (mm-Wave). We develop an end-to end power consumption model where the total power consumption is calculated by adding up the power utilized by RRHs, transport network and baseband processing. TWDM-PON shows better energy performance as fronthaul network when the capacity requirement is high, compared to EPON. The mm-Wave fronthaul is a better solution in terms of saving fiber and flexibility of deployment but comparatively more energy consuming.