15. This section provides context on international developments in the 6 GHz band.
16. It is recognized internationally that access to additional licence-exempt spectrum is needed to meet the exponentially increasing demand for innovative wireless services operating in licence-exempt spectrum. Globally, the 6 GHz band has traditionally been used for fixed services (FS) and fixed satellite services (FSS), among other services and applications. Spectrum regulators in many regions of the world have released or are planning to release the 6 GHz band or portion of the band for licence-exempt use, alongside the licensed incumbents currently using this band.
17. In the U.S., the 6 GHz band is heavily used with approximately 50,000 stations deployed across four services: fixed services, fixed satellite services, mobile services and radio astronomy. While recognizing the current use of the band, the Federal Communications Commission (FCC) decided to open up 1200 MHz of the 6 GHz band for licence-exempt use. In April 2020, the FCC published Report and Order (FCC-20-51) (the Report and Order) titled Unlicensed Use of the 6 GHz Band; Expanding Flexible Use in Mid-Band Spectrum Between 3.7 and 24 GHz, which allows licence-exempt use of the 6 GHz Band. The FCC permitted two types of licence-exempt devices, commonly referred to as access points (APs), to operate under different technical rules to minimize the potential of interference to incumbent services: (1) low-power (maximum equivalent isotropically radiated power (e.i.r.p.) of 30 dBm) indoor only APs across all 1200 MHz of the band, and (2) standard-power APs (maximum e.i.r.p. of 36 dBm) for indoor and outdoor use. Standard-power APs are only permitted in two sub-bands (5925-6425 MHz and 6525-6875 MHz) and must be under the control of Automated Frequency Coordination (AFC). The Report and Order’s accompanying Further Notice of Proposed Rulemaking (FNPRM) also proposed to permit very low-power (max e.i.r.p. of 14 dBm) devices to operate both indoors and outdoors across the entire band.
18. In the European Union (EU), the European Conference of Postal and Telecommunication Administrations released a report in May 2020 on the introduction of wireless access systems (WAS) including radio local area networks (WAS/RLAN) in the frequency band 5945-6425 MHz, with low-power (max e.i.r.p. of 23 dBm) for indoor use only and very low-power (max e.i.r.p. of 14 dBm) portable use both indoor and outdoor. The report concluded that WAS/RLAN with specified power limits could coexist with incumbent services. For example, lower-power, indoor-only WAS/RLAN could coexist with incumbent fixed-satellite services, fixed services, Communication Based Train Control systems, and Road Intelligent Transport Systems. The Electronic Communications Committee is expected to formally respond to the European Commission by November 2020.
19. In the United Kingdom (U.K.), Ofcom issued a decision in July 2020, enabling the use of Wi-Fi in the 6 GHz band. The decision makes the lower 6 GHz band (5925-6425 MHz) available for Wi-Fi and other licence-exempt technologies, enabling low-power (max e.i.r.p. of 23 dBm) indoor use and very low-power (max e.i.r.p. of 14 dBm) outdoor use.
20. In July 2020, South Korea’s Ministry of Science and ICT announced that low-power (maximum e.i.r.p. of 24 dBm) licence-exempt devices will be permitted to operate indoors across the entire 1200 MHz of the 6 GHz band. Very low-power (maximum e.i.r.p. of 14 dBm) devices will be permitted to operate outdoors in the 5925-6425 MHz frequency range. Furthermore, by 2022, outdoor use with a form of database-driven spectrum sharing, similar to the FCC’s AFC system, will be allowed over the entire 1200 MHz of the band.
21. While some countries are introducing licence-exempt use in the 6 GHz band, the International Telecommunications Union (ITU) is currently studying (as agenda item 1.2 of the 2023 World Radiocommunication Conference (WRC-23)) whether parts of the 6 GHz band could be identified for International Mobile Telecommunications (IMT) to support commercial mobile broadband services. The WRC-23 agenda item will consider identifying spectrum for IMT in the 6425-7025 MHz band for Region 1 and in the 7025-7125 MHz band globally.
22. As mentioned above, the FCC has allowed licence-exempt use of the 6 GHz band through technical and operational rules to protect incumbent services operating in the band. The technical rules took into account extensive comments from stakeholders, studies submitted by various stakeholder groups and internal studies performed by the FCC.
23. The FCC divided the 6 GHz band into four sub-bands designated as:
The different sub-bands and use types mandated in the U.S. are shown in figure 1.
24. Standard-power outdoor devices: Indoor and outdoor standard-power operation under the control of an AFC system is permitted in portions of the band, namely the 5925-6425 MHz (U-NII-5) and 6525-6875 MHz (U-NII-7) sub-bands, which are primarily in use by licensed fixed systems and FSS. The standard-power devices may operate at a maximum e.i.r.p. of 36 dBm and a power spectral density (PSD) of 23 dBm/MHz. The AFC system would protect the following services:
25. Fixed microwave systems and radio astronomy: The FCC concluded that protection of fixed microwave systems by AFC will be done through exclusion zones around the fixed systems operating in the band. The AFC system will calculate these exclusion zones and provide a list of available channels for a standard-power AP, including the permissible operating power of the AP on each of those channels. The FCC decided that the AFC system would also incorporate exclusion zones to protect radio astronomy stations in the U.S. The FCC mandated several technical interference protection criteria to be incorporated in the AFC system, which include:
26. Fixed satellite systems: The FCC concluded that fixed satellite receivers aboard orbital platforms would have a low likelihood of interference from RLAN operations given the low-power levels and large separation distances involved as well as the building attenuation applicable to indoor access points. In order to provide extra protection, the FCC mandated a vertical elevation mask (from the horizon) with a maximum e.i.r.p. limit of 125 mW above a 30 degree elevation angle, to protect satellite receivers. The FCC did not apply the AFC approach to the protection of satellite receivers since these receivers typically cover the majority of North America and span the entire band, and therefore, there would be no alternate frequencies for an RLAN to tune to.
27. Broadcast auxiliary systems: In the U.S., the Broadcast Auxiliary Service (BAS) and Cable Television Relay Service (CTRS) operate in the 6425-6525 MHz (U-NII-6) sub-band on a mobile basis, and in the 6875-7125 MHz (U-NII-8) sub-band on both a fixed and mobile basis. These services (analogous to television auxiliary services in Canada) are used for electronic news gathering (ENG), local television transmission and low-power auxiliary stations such as portable cameras and wireless microphones. The FCC did not allow licence-exempt standard-power operation in the 6425-6525 MHz and the 6875-7125 MHz sub-bands on the basis that the AFC system would not be able to effectively determine exclusion zones given the mobile nature of these broadcasting auxiliary services.
28. Low-power indoor devices: As set out in the final U.S. rules, low-power indoor operation is permitted across the entire 5925-7125 MHz band. The low-power indoor-only devices may operate at a maximum e.i.r.p. of 30 dBm and a PSD of 5 dBm/MHz, without the control of an AFC system. However, the low-power devices are required to implement a contention-based protocol (e.g. listen-before-talk) to protect licensed incumbents. Such a protocol consists of procedures for determining the state of the channel (available or unavailable) to avoid colliding with the active transmission of a co-located licensed incumbent system. In addition to protection of incumbent licensees, the contention-based protocol facilitates co-existence amongst licence-exempt devices.
29. Very low-power devices: In its Further Notice of Proposed Rulemaking (FNPRM), the FCC also proposed the introduction of very low-power devices operating over the entire 1200 MHz at a maximum e.i.r.p. of 14 dBm and a PSD of -8 dBm/MHz.
30. A viable equipment ecosystem has already emerged for RLAN technologies in the 6 GHz band. Two RLAN technologies are currently considered candidates for use in this band, namely Wi-Fi 6E and 5G New Radio-Unlicensed (NR-U), while other technologies could also be developed to operate in the band. The new Wi-Fi 6 (IEEE 802.11ax) standard introduces wider channel bandwidths (up to 160 MHz), and provides higher performance in the form of lower latency higher throughput rates. Many Wi-Fi device manufacturers are already shipping Wi-Fi 6 equipment for operation in the 2.4 GHz and 5 GHz bands, and the low-power variant of Wi-Fi 6E IEEE 802.11ax compliant devices for operation in the 6 GHz band could become available by the end of 2020. Meanwhile, the 3rd Generation Partnership Project (3GPP) standards development body has standardized licence-exempt NR-U technology in its Release 16 published in July 2020. The ecosystem availability for NR-U devices is yet to be confirmed by major device vendors.
31. With the introduction of an AFC requirement, the availability of standardized and certified AFC solutions and devices is another important element to consider for the overall 6 GHz ecosystem. In the U.S., the development of AFC solutions for the 6 GHz band is under way, while multi-stakeholder discussions are continuing to refine and standardize AFC system parameters and operation. It is expected that AFC required for the operation of standard-power devices could be approved by the end of 2021, with AFC-enabled devices potentially available starting in 2022.
ISED is seeking comments on the timelines for the availability of: