  To meet the high demand for mobile data, the Third Generation Partnership
Project (3GPP) established a set of standards known as 5G New Radio (5G NR).
The architecture of 5G NR includes a flexible radio access network and a core
network. 3GPP has also been working on a new radio access technology, called 5G
NR Unlicensed (5G NR-U), which aims at extending 5G NR to unlicensed bands. In
this paper, we give an overview of the most recent 5G NR-U design elements and
discuss potential concerns, including fair coexistence with other unlicensed
technologies such as Wi-Fi. We use simulations to study coexistence between
Wi-Fi and 5G NR-U systems. Our evaluation indicates that NR-U often achieves
higher throughput and lower delay than Wi-Fi (802.11ac). The two systems
experience different buffer occupancies and spectrum utilization statistics. We
also discuss the improvements that NR-U offers over LTE Licensed Assisted
Access (LTE-LAA).
