In a little over three years after the United States Federal Communications Commission (FCC) made 1,200 megahertz of spectrum available in the 6 GHz band for unlicensed Wi-Fi use, we are seeing significant momentum. Hundreds of Wi-Fi 6E devices have been certified, a full ecosystem of Wi-Fi 7 products has been launched, and the Wi-Fi Alliance is expected to launch the Wi-Fi 7 Certification within the next half year. The seventh generation of Wi-Fi technology is designed from the ground up with the 6 GHz band in mind, and promises larger channel sizes and multilink operations, which together bring deterministic low latencies, greater capacity and higher throughput. But the regulatory work is not yet done.
Next steps for Wi-Fi in the U.S., explained Director of Product Marketing for Broadcom’s Mobile Connectivity Division Chris Szymanski, are to enable portable device operations, certify standard-power devices that operate under the control of an automated frequency coordination system and, perhaps most critically, expand the 6 GHz unlicensed spectrum designation up to at least 7250 MHz.
Szymanski told RCR Wireless News that there are several reasons Broadcom finds the 7125-7250 MHz portion of the 6 GHz band so attractive. First, this frequency range already has a mobile allocation within the World Radio regulations and some of the services are largely the same as those in the 6 GHz band, meaning that at least low-power indoor operations are likely to coexist with existing users. Existing equipment can be easily tuned to the proposed bands. “If I get up to 7250 MHz, existing radios can all be extended right now, providing immediate benefit to consumers and enterprises,” clarified Szymanski. “If a new radio is required, that would impede adoption. That’s why 6 GHz was so appealing and why 6E was adopted so quickly.” One radio in existing client devices can cover both the 5- and 6-GHz range, he explained.
A smart spectrum strategy
Despite its push for more spectrum to be allocated for Wi-Fi use, Broadcom is clear that it wants a “smart” spectrum strategy that includes mobile. “We want [cellular], we want spectrum for the G’s, but we see the most immediate capacity crunch for Wi-Fi,” Szymanski emphasized.
For instance, according to the DSA, less than 10% of all Internet traffic goes over a cellular network — a very small percentage compared to the data going over fixed networks. And the vast majority of that traffic terminates over Wi-Fi. Further, very few devices beyond a mobile phone have cellular at all, while nearly all connected devices have Wi-Fi connectivity.
Of course, Szymanski acknowledged that cellular capacity remains critical for outdoor use, roaming and high-speed networks. “Wi-Fi and cellular networks need to keep pace with each other because consumers expect their applications to work on whatever network they are connected to,” he said, adding that if people are mostly indoors, Wi-Fi capacity needs to be the primary focus for wireless broadband to drive new applications that operate indoors.
“We are designing Wi-Fi to meet 5G KPIs, and expect to do the same for 6G KPIs once they come out. From a Broadcom view, we’re designing around the bottleneck — we’re not going to get to the next broadband chip… if you can’t terminate that broadband wirelessly. We’ve got to have end-to-end connectivity from the data center to the end-user,” he continued.
As a clear example of why Wi-Fi capacity should be the priority, Szymanski pointed to recent data collected by the University of Toronto School of Cities. This study showed that in the U.S. there has been a significant reduction in urban cellular traffic since COVID-19. In some instances, cities were operating at around 40% of what their 2019 capacity was.
As a result, Szymanski sees excess 5G capacity for many urban centers that operators are able to use for fixed wireless use. They are deprecating older low capacity networks and replacing them with 5G fixed wireless networks. “It’s an excellent use of excess resources, but this solution is temporary — fixed wireless does not have anywhere near the capability of a fiber or DOCSIS 4.0 network.” Bottom line, there’s plenty of capacity for cellular networks in urban areas right now. With new applications, there will be an increase in cellular data demand, “but there is time,” argued Szymanski. “We see large demand [for Wi-Fi] now.”
The spectrum crunch
Szymanski described the stadium scenario as the most acute need for spectrum. Looking at data transmitted over the past few Super Bowls, you can see a massive increase in data consumed, but a limit is also being reached on the wireless capacity available per user in the 5 GHz band. Fans have an insatiable appetite for wireless broadband; they want to share their experiences with friends and family. Immersive experiences, such as instant replay, will add even more demand.
Stadiums achieve more capacity per user by serving a smaller number of users per access point, and/or using wider bandwidths for transmissions. “I expect that it is possible to achieve more than 5x increase in capacity per user if access points can be configured to use 80 MHz channels in the 6 GHz band along with the current 20 MHz channels being used in the 5 GHz band,” said Szymanski.
It is currently possible to run fourteen 80 MHz channels, which is the minimum number of channels for a stadium deployment. However, if the unlicensed spectrum designation was extended up to 7250 MHz, this would add two more channels providing additional flexibility for larger stadiums. If up to 7625 MHz were opened in the future, there could be up to twenty channels. This would be sufficient spectrum to cover some of the largest venues with significant capacity per user.
