LAA as a Key Enabler in Slice-Aware 5G RAN: Challenges and Opportunities

The specification of 5G mobile and wireless communications is progressing at a rapid pace, where the early drop non-standalone version was already completed in December 2017 by 3GPP. 5G aims not only at mere performance enhancement relative to previous generations but also to be a key enabler for different services and business operations known as vertical industries. To this end, on one hand, 5G incorporates the framework of network slicing as a flexible and future-proof means to support vertical industries on a common infrastructure. On the other hand, 5G extends the notion of a conventional radio resource toward a native use of other available resources, namely, the unlicensed spectrum (varying from 1 to 100 GHz) in an LAA way, to respond to stringent and diverse service requirements. This article places the aforementioned key 5G features in focus, and proposes a new framework, namely LAA as a service, which aims to provide different LAA configurations to be used on demand in a service-oriented manner. First, the 3GPP standardization roadmap is presented, focusing on the challenges that need to be taken into consideration in order to allow for opportunistic complementary unlicensed spectrum usage for 5G assuming very demanding 5G services in terms of key performance indicators such as latency and reliability. The LAA configurations can be seen as different RAN configuration modes, that is, the RAN part of the end-to-end (E2E) network slice. Furthermore, as a particular 5G case study, a very dynamic and interference-limited scenario, which is a 5G ultra-dense network scenario with unplanned/dynamic small cells, is exemplified to show that dynamic radio topology coupled with LAA as a service is a promising and complementary enhancement.