Mobile network operators are currently facing a tremendous increase in the level of data traffic. Although cell size reduction is one of the most common ways used to accommodate such traffic demand, densely deployed small cells also dramatically increase the level of intercell interference. By centralizing baseband signal processing at powerful computing infrastructures, called centralized unit (CU) pools, cloud radio access network (C-RAN) enables advanced coordination algorithms to be employed in dense small cell networks. In C-RAN, due to stringent bandwidth and latency requirements at the fronthaul links, the optical fiber, thanks to its bandwidth and latency characteristics, continues to be the most prevalent fronthaul medium option. Nevertheless, the optical fiber is one of the fronthaul options, while C-RAN (physical layer radio frequency [PHY-RF] split) is one of the functional splits that can be defined each coming with different fronthaul requirements.In this paper, we formulate and solve a dynamic CU placement problem for mobile networks as an integer linear programming (ILP) problem. In the considered network, CU pools are placed at the edges of the network, and a reconfigurable millimeter wave (MMW) wireless fronthaul links are used in order to provide decentralized units (DUs) with connectivity. We study the impact of different functional splits on the placement cost and on the acceptance ratio using different substrate networks. Lastly, we propose and evaluate a CU placement heuristic algorithm using a numerical simulator. The results reveal that the optimal functional split selection can lead to significant resource utilization benefits in the RAN.Int J Network Mgmt. 2020;30:e2086. wileyonlinelibrary.com/journal/nem to the distributed radio access network (D-RAN) architecture, in which coaxial cables are substituted by optical fibers, and a digital interface is used to carry the in-phase/quadrature (I/Q) samples between the baseband unit and the radio unit. However, since in the D-RAN architecture a Long-Term Evolution (LTE) base station, called eNB, cannot share its frequency resources with other eNBs. These scarce frequency resources will be underutilized most of the time in a day due to the spatiotemporally fluctuating traffic demand. In order to tackle the aforementioned problem, the cloud RAN (C-RAN) 3 architecture has been recently proposed. C-RAN is capable of reducing the total cost of ownership (TCO) of mobile networks while, at the same time, optimizing network capacity, coverage, and power consumption. Such goals are achieved in C-RAN by separating baseband units, termed centralized units (CUs) from the radio units, termed distributed units (DUs) and combining CUs in powerful computing infrastructures, termed CU pools. * CU pools can run on a number of general-purpose of-the-shelf servers deployed in centralized locations.The separation of the signal processing functionalities in the RAN protocol stack between the CU pool and the DU is known as functional split. 5 Traditionally, in the ...