Architectural aspects of mm-wave radio access integration with 5G ecosystem

Abstract

The following white paper discusses a range of architectural aspects that are crucial for the integration of mm-wave Radio Access Technology (RAT) in 5G mobile networks. While radio spectrum above 6 GHz offers contiguous high bandwidth resources for high capacity radio links; it gives rise to new challenges in terms of user mobility and reliability due to the harshness of the mobile radio environment, necessitating the deployment of highly directional links. To overcome these challenges, we propose architectural solutions based on tight integration of mm-wave RAT with RAT(s) operating in frequencies below 6 GHz with the intention to diversify the control plane and data split, and the duplication of the user plane.

The paper outlines initial architectural concepts envisioned for 5G mm-wave systems designed to operate in frequencies between 6-100 GHz, and discuss some crucial aspects of its integration within the 5G networks. The proposed concepts include: i) network slicing to address needs of 5G use cases with highly divergent requirements, ii) multiconnectivity with multiple mm-wave base stations and as a way to integrate multiple RATs; iii) mobility related aspects such as mm-wave cell clustering to make small scale mobility of the UE transparent to the CN, and the introduction of a novel inactive RRC state, iv) multi-RAT multi-layer management scheme which introduces abstraction at different layers of the protocol stack for flexible and scalable multi-RAT management, vi) control and user plane aspects for low-band integration, and finally vii) architectural aspects of self-backhauling.