Additional 5 GHz Spectrum Opened Up for Wi-Fi in the US

While there has been a lot of activity across the world in opening up the 6 GHz band for Wi-Fi, work is still being done on the legacy 5 GHz Wi-Fi band. The FCC has voted in favor of new 5.9 GHz (i.e., 5.850 GHz to 5.925 GHz) rules, allowing Wi-Fi in most parts of the United States to utilize the low 45 MHz for Wi-Fi, offering new, license-free channels—including one 160 MHz channel, at the top of the 5 GHz range—and expanding the overall 5 GHz band. The FCC has stated that this part of the band, while limited in size, is in an important position, adjacent to the existing unlicensed 5 GHz Wi-Fi spectrum.

The upper 30 MHz will be reserved exclusively for automotive safety (CV2X) applications rather than Wi-Fi. These include providing direct communications between vehicles, cyclists, pedestrians, and road workers, ensuring that safety information is provided. In the past, this band has been largely unused, having been reserved for providing intelligent transportation systems such as dedicated short-range communications for the automotive industry. Any automotive applications still in the lower 45 MHz of the band have one year to vacate and move to the upper 30 MHz of the band to clear the way for Wi-Fi applications.

The COVID-19 pandemic in particular has highlighted a need to ensure that the Wi-Fi connectivity provided to homes and businesses is high quality, with an increasing number of users taking part in video conferencing, telehealth, and other critical applications. Offloading cellular data to Wi-Fi is helping to ensure that cellular networks do not become overwhelmed, but is also causing further strain on Wi-Fi. Increasing the amount of available spectrum has been determined as critical to help ensure that the growing connectivity needs are met.

The addition of this 45 MHz for 5 GHz Wi-Fi will impact the market, offering unlicensed gigabit services in the band. The FCC foresees this allocation being utilized in schools, hospitals, and small businesses, as well as by other consumers. It also sees mobile data offload as a driver for the need to increase the available spectrum within the 5 GHz band. Full-power indoor operations will be enabled in the 45 MHz portion of the band immediately. Outdoor unlicensed use on a coordinated basis following certain circumstances, such as the need for an existing occupant to leave the spectrum, is expected to follow. The expansion of the band is designed to provide faster, lower-latency, less congested Wi-Fi connectivity.

This development is not unexpected, with the FCC having made a number of announcements in the past:

• In September 2018, the FCC suggested reopening the case for the 5.9 GHz band to be used for Wi-Fi; however, the suggestion then took a back seat, with efforts being concentrated on the 6 GHz band. The suggestion was based on the fact that the 5.9 GHz band was not being utilized greatly by the automotive industry, as well as the increasing amount of Wi-Fi devices taking up large amounts of the currently available spectrum, causing a great amount of congestion.

• In May 2019, the FCC again announced its intention to reallocate the band for unlicensed Wi-Fi use, having determined that its location between the 5 GHz and 6 GHz band put it in a useful position. At this time, it was unknown what split would be provided between Wi-Fi and automotive, with suggestions including the one chosen, sharing the lower part between the two and the upper part reserved for automotive, and the entire band being offered for Wi-Fi.

The decision to provide the lower 45 MHz of the 5.9 GHz band for Wi-Fi has now been made by the FCC, allowing for new levels of spectrum to be offered in the 5 GHz band. This will help to address issues, such as increased congestion, which leads to lower speeds and higher latency, particularly as the use of Wi-Fi has increased throughout the COVID-19 pandemic. This additional spectrum within the band will allow legacy devices to have access to a greater amount of spectrum—unlike the 6 GHz band, which only supports new, compatible devices, meaning chipset providers and device OEMs have to develop new technologies and encourage consumers to purchase them. The development in the 5.9 GHz band will help to provide immediate relief for congested parts of the 5 GHz spectrum, ensuring that the increasing number of Wi-Fi devices using the legacy band are supported with little effort. Existing devices on the 5 GHz band are able to take advantage of the new spectrum immediately; however, some automotive applications may remain in the lower part of the band for up to a year.