 as O-DU, O-CU, near-RT RIC, and 5G user plane function (UPF), are considered as virtualized network functions (VNFs) operating on VMs or containers. In order to specify the distribution of these entities on the cloud hierarchy, O-RAN alliance proposed six deployment scenarios in [42] that are based on regional cloud and edge cloud. The edge cloud is placed in the proximity of the cell site and communicates with a regional cloud hosted in data centers [2]. Among the six deployment scenarios of O-RAN, O-RAN planned to deploy scenario B, as depicted in Fig. 1.5. In this deployment scenario, the O-DU M. Alfaqawi et al. O-Cloud Service management and orchestration (SMO) Non real-time RIC Near real-time RIC xApp1 xAppN 5G Core (5GC) Cloud layer Open fronthaul M-Plane Edge layer ((())) (((a))) (((.))) O-RU 1 O-RU 2 O-RU n Cell-site layer Fig. 1.5 O-RAN 5G architecture and O-CU functionalities are processed at the edge, while the UPF and near-RT RIC are executed at the regional cloud. In order to process the E-UTRAN stack on the DU and CU, 3GPP proposed eight split options as presented in Fig. 1.6 [24]. Among these split options, O- RAN alliance adopted the split option 7.2 [2, 43]. For Option 7, 3GPP separates the physical (PHY) layer into high-PHY and low-PHY for the downlink (DL) and uplink (UL). However, low layer split options have been postponed by 3GPP due to the requirements for bandwidth (BW) larger than 100 MHz and larger antennas to transmit the in-phase and quadrature (IQ) samples from the DU to the CU [1, 24]. 1 A Comprehensive Study on 5G Centralized Unit (CU) eCPRI Distributed Unit (DU) 10-30 Gbps High- Option 2 Option 6 Option 7 Fig. 1.6 The separation options of E-UTRAN stack protocol for DL Cloud layer Controller layer Edge layer Device layer Fig. 1.7 5GPPP architecture for 5G with MEC 1.2.2.3 Multi-Access Edge Computing within 5G RAN Based on 5GPPP and 3GPP Unlike fog computing servers that can be placed anywhere in the network, MEC is owned by the mobile operators and installed near to the BSs [73]. 