Impact of Virtualization Technologies on Virtualized RAN Midhaul Latency Budget: A Quantitative Experimental Evaluation

In the next-generation radio access network (NG-RAN) defined by 3GPP for the fifth-generation mobile communications, the next-generation NodeB is split into a radio unit (RU), a distributed unit (DU), and a central unit (CU). The RU, DU, and CU are connected through the fronthaul (RU-DU) and midhaul (DU-CU) segments. If the RAN is also a virtualized RAN (VRAN), DU and CU are deployed in virtual machines or containers. Different latency and jitter requirements are demanded on the midhaul according to the distribution of the protocol functions between the DU and CU. This letter shows that in VRAN, the virtualization technologies, the functional split option, and the number of elements deployed in the same computational resource affect the latency budget available for the midhaul. Moreover, it provides an expression for the midhaul allowable latency as a function of the aforementioned parameters. Finally, it shows that the virtualized DUs featuring a lower layer split option shall be deployed not in the same computational resources, where other vDUs are deployed.