802.11ac: The Beginning
At some point, every modern freeway was a dream to drive. The pavement was fresh and the lanes were all but empty. But inevitably, congestion set in. People learned to hop on the freeway to quicken their daily travel needs. As populations steadily grew, so did the number of cars clogging the streets. What was once a breezy late afternoon jaunt eventually became today’s four-hour exercise in asthmatic gridlock.
Automotive analogy aside, we’re really talking about the 2.4 GHz Wi-Fi spectrum. In the first days of 802.11b (circa 1999), the freeway may have posted a paltry 11 Mb/s, but there was hardly anyone else on the road. Fast forward to the present. Despite evolving through 802.11g and 802.11n, the 2.4 GHz band became a congested mess clogged with notebooks, netbooks, wireless speakers, Bluetooth peripherals, smartphones, tablets, set-tops, TVs, consoles, appliances, and all manner of other devices. These gadgets compete for what boils down to essentially three (after considering bandwidth overlap) possible transmission channels under 802.11b. A 20 MHz-wide 802.11g/n network has four such channels, while a 40 MHz-wide 802.11n network has just two.
True enough, 802.11a, which resides on the 5.0 GHz band, offers more non-overlapping channels (23, to be exact). While 802.11a offered comparable 54 Mb/s speeds to 802.11g, the 2.4 GHz solution won out in the market thanks to the fact that longer wavelengths have better ability to pass through obstructions. With an oscillation roughly twice that of 2.4 GHz, a 5.0 GHz signal was more likely to die in less distance than its competitor, and so 802.11b/g went on to become the dominant public wireless communication standard. By the time 802.11n arrived supporting both radio bands, wireless had become so popular that interference and congestion was a significant problem for many users. While 802.11n employed several technologies to help improve wireless performance, it was clear that the 2.4 GHz band was becoming ever more bogged down. For a more thorough look at these problems and some of 11n’s answers to them, we strongly recommend reviewing our two-part series, Why Your Wi-Fi Sucks and How It Can Be Helped and What To Do About It.
Today, the successor to 802.11n, dubbed 802.11ac, is far enough down the road of standardization that vendors have the confidence to start releasing product. At present, 802.11ac is working under Draft 4.0. The 802.11 Working Group expects the standard to be finally approved by late 2013, although by then the technology will already be pervasive in the market.
The first 802.11ac chipset, from Quantenna, began shipping in November 2011. In April 2012, Netgear arrived with the first 802.11ac consumer router, fueled by Broadcom innards. Other vendors soon followed. By the end of 2013, we expect mid- to high-end consumer routers to have completely switched over from 802.11n.
But for now, 11ac is new, still relatively scarce, and priced accordingly. Is it worth it? We’ve seen pre-standard Wi-Fi advances that didn’t merit their price tags in the past. Are we in for another round of disappointment, or is today’s price premium for 11ac a bargain for the performance boost? We only know of one way to find out.
