CRAN, H‐CRAN, and F‐RAN for 5G systems: Key capabilities and recent advances

Abstract

Summary The world of telecommunication is witnessing a swift metamorphosis towards fifth generation cellular networks. Particularly, the rapid shift from a user centric to a device centric communication has created a tremendous impact on service complexity and network requirements. The future networks present requisite needs in ubiquitous throughput, low latency, and high reliability. They are also envisioned to provide energy efficiency, spectrum reuse, network scalability, and robustness as well as improved quality of user experience, which proves to be of ultimate importance. Accordingly, government, academic, and industrial institutions are working together to fulfill these challenging goals. Their research efforts have been extensively reported in various topics and directions, such as heterogeneous small cell networks, millimeter wave communication, massive multiple input multiple output, network function virtualization, software‐defined network, and device‐to‐device communication. More interestingly, a revolutionary network architecture based on cloud computing and centralized processing is adopted as one of the best candidates for fifth generation. It is denoted Cloud Radio Access Network (CRAN) and (H‐CRAN) in heterogeneous networks. An upgraded version, namely, Fog RAN (F‐RAN), with caching and fog computing capabilities is also presented. Environmental friendly, it ensures flexibility and scalability with reduced expenditures. This paper presents the aforementioned key technological functionalities and surveys the benefits and challenges of CRAN, H‐CRAN, and F‐RAN.

A Survey on Low Latency Towards 5G: RAN, Core Network and Caching Solutions

“…Cloud radio access network (CRAN) (as illustrated in Fig. 6) is introduced for 5G in order to reduce the capital expenditure (CAPEX) and simplify the network management [138]. CRANs combine baseband processing units of a group of base stations into a central server retaining radio front end at the cell sides.…”

“…• The challenge of admission control in RAN for spectral and energy efficiency with latency constraint is not well explored [248]. CRAN/HRAN provides spectral and energy efficiency while aspects such as caching can ensure low latency [138]. Researchers can work for performance bounds regarding this issue.…”

A Survey of the Functional Splits Proposed for 5G Mobile Crosshaul Networks

“…This split has been known for several years and the literature in this area is very comprehensive. Therefore, several directions within using this split is investigated focusing on the CPRI transport interface: both the traditional CPRI transport, the option of transporting CPRI over the Ethernet network and the option of compressing [4], [5], [12], [19], [24], [25], [26], [27], [28], [29], [30], [31], [32], [33], [34], [35], [36], [37], [38], [39], [40], [41], [42], [43], [44], [45], [46], [47], [48], [49], [50], [51], [52] Simulations: [53], [54], [55], [56], [57], [58], [59], [60], [61], [62], [63], [64] Practical experiments: [65], [66],…”

Flying to the Clouds: The Evolution of the 5G Radio Access Networks

“…As such, SDN needs to be adapted to this new context. In the same way, virtualising the SDN controller in F-RAN architectures remains a challenge (Guizani and Hamdi 2017).…”