A flexible 5G RAN architecture with dynamic baseband split distribution and configurable optical transport

In a Cloud Radio Access Network (C-RAN) architecture, different baseband processing functions (BPFs) splits options are available on the interface between the central unit (CU) and the radio units (RUs) [1]. A lower layer split, e.g., low-physical (PHY), can support advanced radio coordination techniques, for example Joint Reception (JR) Coordinated MultiPoint (JR-CoMP) [2]. However, the interface between low-PHY and the rest of the BPF chain (i.e., referred to as enhanced Common Public Radio Interface - eCPRI [3]) requires a high-capacity transport. With a higher layer split, e.g., between the Packet Data Convergence Protocol (PDCP) and the Radio Link Control layer (RLC), the transport capacity required on the interface between RLC and PDCP (i.e., referred to as F1 [1][4]) is lower than for eCPRI. However, with this split it is difficult to implement advanced radio coordination functions. The choice of BPF split and consequently the transport capacity requirements are determined by the RUs' radio coordination needs [1][5].