The cloud-RAN (C-RAN) may be viewed as an architectural evolution of the distributed base station system (Fig. 1.1). It takes advantage of many technological advances in wire- less and optical communication systems. For example, it uses the latest CPRI specifications, Common Public Radio Interface, http://www.cpri.info/. 4G systems 5G systems Distributed RAN Cloud RAN SDN, NFV, MEC Network slicing Center node with network network dedicated Applications Applications Dedicated Applications Central cloud (NFV/) Applications equipment 5G core CP 5G core CP 5G core CP equipment Distributed VM), commercial 4G core 4G core 5G core UP 5G core CP 5G core UP 5G core UP core (CP) 5G core UP servers and virtualization Backhaul Distributed app server Backhaul Backhaul Backhaul Backhaul Backhaul Distributed core (UP) Central Central Dedicated Cache office office equipment Network connectivity 5G core UP 5G core UP 5G core UP Redefinition of Baseband unit CU/DU functions Central unit among VMs, SDN Central unit Central unit Central unit Central unit Baseband Fronthaul Functional split (PHY) Fronthaul Fronthaul Fronthaul Fronthaul Fronthaul Cell site/eNB Baseband unit with dedicated H Edge cloud (NFV/VM), equipment Radio unit/ commercial server and virtualization Radio High data Voice Massive loT Mission-critical loT rate services services services services Figure 1.1 Network architecture evolution from 4G to 5G 60]. . 5G Network Architecture low-cost coarse/dense wavelength division multiplexing (CWDM/DWDM) 3 technology, and mmWave to allow transmission of baseband signals over long distance, thus achieving large-scale centralized base station deployment. It applies recent data center network tech- nology to allow a low cost, high reliability, low latency, and high bandwidth interconnect network in the BBU pool. In the run up to 5G networks, the C-RAN utilizes open platforms and real-time virtualization technology rooted in cloud computing to achieve dynamic shared resource allocation and support of multi-vendor, multi-technolo