After a quarter century, Wi-Fi nomenclature is becoming understandable to mere mortals. There will be no more “.XX” designations and made-up marketing names like Super Wi-Fi. Currently, 802.11n is Wi-Fi 4, 802.11ac is Wi-Fi 5, and Wi-Fi’s upcoming next generation is Wi-Fi 6 (rather than 802.11ax). However, the Wi-Fi Alliance apparently could not resist continuing to call Wi-Fi operating at 60GHz “Wi-Gig.” For consistency, Wi-Fi 7 might have been a better choice, mainly because Wi-Gig is different from any other Wi-Fi standard.
Using the previous naming convention, Wi-Gig is IEEE standard 802.11ad, the specification that launched in 2011. At the time, the Wireless Gigabit Alliance, which was championing the specification, merged with the Wi-Fi-Alliance to more effectively promote Wi-Gig and Wi-Fi in general. The goal of Wi-Gig is to deliver blindingly fast downstream data rates by taking advantage of the huge bandwidth available at millimeter-wave frequencies. It is the first time this spectral region has been used for Wi-Fi or any other commercial wireless application.
The propagation characteristics at millimeter wavelengths make the region useful only for short distances as almost anything, even drapes, can impede the signals. In fact, walls present a major challenge. But as Wi-Gig was designed for short-range applications—such as transferring files between a smartphone and a computer, a virtual reality headset, or a wireless monitor—long range isn’t the prime requirement.
The key metric is speed, and Wi-Gig delivers that at rates higher than any other wireless technology and “slower” only than the most formidable versions of Gigabit Ethernet. A good example of one of the few Wi-Gig routers available so far is TP-Link’s Talon AD7200 that delivers theoretical downstream data rates of up to 4.6Gb/s at 60GHz. At this point, it is an early-adopter product as it costs about $680.
Like other manufacturers of Wi-Gig routers, TP-Link also uses channels at 5GHz and 2.4GHz to provide coverage over distances comparable to those of traditional Wi-Fi. This effectively makes Wi-Gig a component of next-generation Wi-Fi routers rather than a stand-alone offering. It will be complemented by yet another Wi-Gig enhancement called 802.11ay, which is supposed to be released late in 2019. The 802.11ay enhancement can potentially deliver peak throughput of 100Gb/s; it uses channel bonding and channel aggregation to produce wider signal bandwidths.
Wi-Gig without 802.11ay uses a single 2.16GHz channel, but 802.11ay channel bonding lets a single waveform cover up to four adjacent 2.16GHz channels. The resulting bandwidth is 8.67GHz, a feat only possible at millimeter-wave frequencies where, in the unlicensed band used by Wi-Gig, 14GHz of spectrum is available.
To understand just how much spectrum this is, consider that a major cellular carrier typically has total spectrum assets of about 200MHz, and that 8.67GHz is 3GHz wider than the entire spectrum from near DC through all cellular bands and Wi-Fi. The 802.11ay standard also expands Multi-User MIMO (MU-MIMO) to support up to eight served devices. It also exploits the advantages of beamforming and the use of dual polarization antennas that can reduce interference while improving reception in less-than-optimum propagation environments.
Complicating things, however, is Wi-Fi 6, which will appear in 2019 operating at 2.4 and 5GHz with downstream rates 37% faster than 802.11ac and without the need to use the 60GHz band to achieve them. At 5GHz, Wi-Fi 6 can reach a peak rate of nearly 10Gb/s in ideal conditions using a channel bandwidth of 160MHz. The standard uses higher-order modulation schemes including 1024 QAM for spectral efficiency, MU-MIMO in the uplink as well as the downlink paths, and other capabilities. Many features within the Wi-Fi 6 specification may not be available at release but will be adopted as Wi-Fi 6 matures.
So we now have two Wi-Fi standards that are competing with rather than complementing each other, which makes things more difficult for the consumer. While the new “Wi-Fi and a number” naming convention is welcome, it will not mean much unless it is applied across the board. Fortunately for consumers, Wi-Gig, Wi-Fi 4, and Wi-Fi 5 are already integrated into the latest routers, and Wi-Fi 6 will probably be as well. The end products will follow, from TVs to set-top boxes, streaming devices, and eventually smartphones and tablets.
Barry Manz is president of Manz Communications, Inc., a technical media relations agency he founded in 1987. He has since worked with more than 100 companies in the RF and microwave, defense, test and measurement, semiconductor, embedded systems, lightwave, and other markets. Barry writes articles for print and online trade publications, as well as white papers, application notes, symposium papers, technical references guides, and Web content. He is also a contributing editor for the Journal of Electronic Defense, editor of Military Microwave Digest, co-founder of MilCOTS Digest magazine, and was editor in chief of Microwaves & RF magazine.