Traffic Characterization of the MAC-PHY Split in 5G Networks

In the 5G radio access network (RAN), the functions of the next-generation eNodeB (gNodeB) are split into a centralized and a distributed unit. Depending on how the split is performed, the amount of traffic generated between the units can be too high to be supported by the current infrastructure. Therefore, a careful characterization of this traffic is needed for every split option. Among the wide array of options, the MAC-PHY split proves to be both promising, as a balanced trade-off between centralization and decentralization, and difficult to characterize, due to the high amount of low level interactions between MAC and PHY layers. Indeed, the MAC-PHY split is frequently considered in the literature as a possible implementation option for the 5G RAN, yet there is no detailed study about the capacity it requires. This paper remedies that by offering a comprehensive analysis of the downlink traffic of a MAC-PHY split for 5G networks. This analysis is backed with both simulative data and measurements from a physical implementation.