optical fiber with common public radio interface (CPRI) protocol or wireless link. The C-RAN is categorized into fully and partially centralized C-RAN, as depicted in Fig. 1.2. In the fully centralized C-RAN, the operation and management (O&M) as well as all the E-UTRAN stack layers are processed on the BBU pool, including L1, L2, and L3.2 Meanwhile, in the partially centralized C-RAN, O&M, L2, and L3 are processed by the BBU, while L1 and the radio functionalities are managed by the RRH [1, 3]. Thanks to the shared resources in C-RAN architecture, the 5G eco-system is foreseen to gain several benefits in terms of capital and oper- ational expenditure (CAPEX/OPEX) reduction, boosting the network performance, enhancing the spectrum and energy efficiencies, supporting several protocols and standards, and SO on [3, 37, 56, 57]. Despite these benefits, several challenges and issues are facing C-RAN including security, privacy, and low latency [3]. A shared BBU pool demands a universal security and privacy mechanism. In this context, the security challenges and 2 L2 represents the MAC, radio link control (RLC), and packet data convergence protocol (PDCP). In addition, L3 represents the radio resource control (RRC). M. Alfaqawi et al. BBU pool Cloud layer Fronthaul Fronthaul (((.))) ((())) ((())) Edge layer RRH 1 RRH 2 RRH 3 Device layer Fig. 1.1 C-RAN architecture L1/L2/L3/O&M Cloud layer L2/L3/O&M BBU pool BBU pool Cloud layer Fiber or Fiber Fronthaul Fronthaul Microwave (((-))) (((-))) ((())) L1((c)()) Li(c-)) L1((i))) Edge layer Edge layer RRH RRH 2 RRH 3 RRH RRH 2 RRH 3 Fig. 1.2 (a) Fully centralized C-RAN and (b) partially centralized C-RAN solutions for C-RAN have been investigated in [6]. Another challenging issue for C- RAN is the demand for efficient frameworks for BBU resource allocations in order to achieve high QoS for the end-users. This challenging issue has been explored in depth in [5]. On the other hand, the high data traffic generated from the massive number of end-user devices might overwhelm the fr