Overview of LTE-NR Dual Connectivity

The initial components of New Radio (NR) technology are being discussed within the 3GPP with the aim of not only satisfying the urgent needs of the 5G market but also the long-term requirements that network operators want to provide to customers. An expected solution to start delivering value immediately for the 5G systems is represented by LTE-NR tight-interworking, also known in the 3GPP specifications as EN-DC. With this new network architecture, existing LTE radio and core networks are used as a master entity for mobility management and coverage while adding a new secondary 5G carrier. In this article, we will illustrate the concepts and key features that 3GPP has specified for LTE-NR tight-interworking regarding the control and user plane domains. Our supporting performance evaluations highlight that EN-DC, at least in certain scenarios expected to exist in early deployments, is able to deliver better coverage and capacity compared to standalone LTE and NR technologies deployed alone.