Middle-Band Spectrum Seen as Sweet Spot for Wi-Fi Congestion Solution

The solution to increasingly congested Wi-Fi networks in dense urban areas lies primarily in middle-band spectrum, particularly in the 5.9 GHz band and potentially the 6 GHz band, said Wi-Fi Alliance CEO Ed Figueroa Wednesday. Having 80 MHz and 160 MHz channels is paramount, but that kind of channelization is tough to find in low bands, while high-frequency bands carry propagation limitations, he said at a Microsoft/New America’s Wireless Future Project panel.

Growth in Wi-Fi devices, connection speeds and data volumes will exceed the spectrum currently available in the 5 GHz band by 2020, said an alliance-commissioned study by Quotient Associates released earlier this year. Figueroa said the U.S. could need an additional 600 MHz by 2020, and 1500 MHz by 2025 to meet anticipated growth. He said Wi-Fi is successful because of global harmonization, and that, while the 6 GHz band has incumbents, it has opportunity for worldwide harmonization. "It's an area ripe for leadership," Figueroa said.

Spectrum frontiers opened up 64-71 GHz to unlicensed use, but there still are large spectrum needs for Wi-Fi given the increased densification of networks, Figueroa said. Given the amount of mobile traffic regularly offloaded to Wi-Fi, any hampering of the Wi-Fi experience "would have a domino effect on connectivity generally," he said.

Wi-Fi channels also aren't wide enough for many users of some high-bandwidth applications like video chatting, said Dynamic Spectrum Alliance President Kalpak Gude. Having 80 MHz and 160 MHz Wi-Fi channels would enhance video performance and beef up hot spot coverage, and the 5.9 GHz proceeding could yield 45 MHz that could be used to help create an 80 MHz and 160 MHz channel, he said. He said preliminary talks are underway about the 6 GHz band, which has ITU mobile designation.

The approach the FCC took on the 3.5 GHz shared band "is a great look at what the future can be," Gude said. He said it's "almost irresistible" to look at a similar if not identical approach that blurs the lines between unlicensed and licensed, and the 6 GHz band could be "an excellent opportunity" for a similar dynamic sharing solution.

For wireless ISP use, the 2.4 GHz band is largely restricted, and access to 3550-3700 MHz would be useful, but uncertainty remains about rules for that band, said Wireless Internet Service Provider Association FCC Committee Chairman Mark Radabaugh. He said wireless ISPs would welcome access to the 5 GHz band and 3.7-4.2 GHz band.

Much of the event focused on unlicensed spectrum applications driving that need. Paul Garnett, director-affordable access initiatives, said Microsoft is using TV white spaces spectrum for last-mile connectivity in unserved and underserved areas globally. An advantage of that spectrum is that it's globally harmonized and several countries, including the U.S., allow unlicensed use of it, while some others allow commercial licenses, Garnett said. He said the FCC needs to ensure sufficient TV white spaces spectrum is available nationwide since tech companies won't manufacture devices without a sufficient U.S. market. Microsoft Senior Director-Government and Regulatory Affairs Paula Boyd pointed to uncertainty about the TV white spaces band and its availability through the incentive auction, and said there's hope to see three swaths of usable channels in every market for unlicensed use at 700 MHz and below.

Facebook's Terragraph project under development uses small nodes on urban furniture to create a 60 GHz wireless network as a complement in urban settings to copper, fiber and cellular, said Public Policy Director Alan Norman. One strength of that high-band spectrum is that its propagation characteristics keep interference in check, he said. One of the company's chief pushes now is working out the municipal regulatory issues of deployment, Norman said.