Next Generation Wi-Fi and 5G NR-U in the 6 GHz Bands: Opportunities and Challenges

TLDR

Regulators in the US and Europe are opening up the 6 GHz bands for unlicensed use, adding 1.2 GHz in the US and potentially 500 MHz in Europe, which offers abundant spectrum for bandwidth‑intensive and latency‑sensitive applications but poses coexistence challenges with incumbents and other unlicensed RATs. This paper surveys the literature on unlicensed RAT operations in the 6 GHz bands, concentrating on next‑generation Wi‑Fi feature design and the foreseeable challenges for designers. The survey compiles research papers, standardization contributions, regulatory documents, and other venue presentations to provide a comprehensive overview of these issues. The authors highlight key research problems that must be addressed to ensure efficient use of the 6 GHz bands while protecting incumbent users from interference.

Abstract

The ever-increasing demand for unlicensed spectrum has prompted regulators in the US and Europe to consider opening up the 6 GHz bands for unlicensed access. These bands will open up 1.2 GHz of additional spectrum for unlicensed radio access technologies (RATs), such as Wi-Fi and 5G New Radio Unlicensed (NR-U), in the US and if permitted, 500 MHz of additional spectrum in Europe. The abundance of spectrum in these bands creates new opportunities for the design of mechanisms and features that can support the emerging bandwidth-intensive and latency-sensitive applications. However, coexistence of unlicensed devices both with the bands' incumbent users and across different unlicensed RATs present significant challenges. In this paper, we provide a comprehensive survey of the existing literature on various issues surrounding the operations of unlicensed RATs in the 6 GHz bands. In particular, we discuss how key features in next-generation Wi-Fi are being designed to leverage these additional unlicensed bands. We also shed light on the foreseeable challenges that designers of unlicensed RATs might face in the near future. Our survey encompasses key research papers, contributions submitted to standardization bodies and regulatory agencies, and documents presented at various other venues. Finally, we highlight a few key research problems that are likely to arise due to unlicensed operations in the 6 GHz bands. Tackling these research challenges effectively will be critical in ensuring that the new unlicensed bands are efficiently utilized while guaranteeing the interference-free operation of the bands' incumbent users.