5G networks aim to support a number of vertical industries that are characterized by diverse performance requirements. Network slicing is considered to be the key enabler to enhance cellular networks with the desired flexibility to achieve this target. During the past years, the network slicing concept has been thoroughly studied, and the main operational principles have been established. However, the added complexity introduced by network slicing creates some issues that are still under investigation. This article provides a comprehensive overview of solutions proposed by the research community and, more importantly, the latest status of the 3GPP standardization process. This survey covers solutions for all network domains (i.e., access, transport, and core) as well the management of network slices. The article also identifies key topics that need to be further addressed during the following years.

While there is clarity on the wide range of applications that are to be supported by 5G cellular communications, and standardization of 5G has now started in 3GPP, there is no conclusion yet on the detailed design of the overall 5G RAN. This article provides a comprehensive overview of the 5G RAN design guidelines, key design considerations, and functional innovations as identified and developed by key players in the field.1 It depicts the air interface landscape that is envisioned for 5G, and elaborates on how this will likely be harmonized and integrated into an overall 5G RAN, in the form of concrete control and user plane design considerations and architectural enablers for network slicing, supporting independent business-driven logical networks on a common infrastructure. The article also explains key functional design considerations for the 5G RAN, highlighting the difference to legacy systems such as LTE-A and the implications of the overall RAN design.

Network slicing addresses the deployment of multiple logical networks as independent business operations on a common physical infrastructure. The concept has initially been proposed for the 5^th Generation (5G) core network (CN) however, it has not been investigated yet what network slicing would represent to the design of the 5G radio access network (RAN). The paper explains how network slicing may impact several aspects of the 5G RAN design such as the protocol architecture, the design of network functions (NFs) and the management framework that needs to support both the management of the infrastructure to be shared among the slices and the slice operation.