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802.11n: Fast Wi-Fi’s long, tortuous road to standardization


For a technology that’s all about being fast, 802.11n Wi-Fi sure took its sweet time to become a standard.

In fact, until September 2009, it wasn’t, officially, even a standard. But that didn’t stop vendors from implementing it for several years beforehand, causing confusion and upset when networking gear that used draft standards from different suppliers wouldn’t always work at the fastest possible speed when connected.

It wasn’t supposed to be that way. But, for years, the Wi-Fi hardware big dogs fought over the 802.11n protocol like it was a chew toy. The result: it took five drama-packed years for the standard to come to fruition.

The delay was never over the technology. In fact, the technical tricks that give 802.11n its steady connection speeds of 100Mbps to 140Mbps have been well-known for years.

Instead, the answer is the usual one behind standards wars: mud-wrestling among major vendors. They squared off over which approach would become the one, true, money-making standard. In this case, that wrestling match hit a new low point — several times, just when it seemed like agreement had been reached, it turned out that a new fight was brewing instead.

As Andrew Updegrove, a partner with the law firm Gesmer Updegrove LLP and well-known standards advocate, says, a major reason it took so long for 802.11n to be finalized was “the amount of money at stake and the number of vendors in the marketplace whose lives can be made easier or harder depending on the outcome.” In addition, the potential value of the technology kept growing “as Wi-Fi became more ubiquitous, in more and more devices, for more and more purposes.”

On top of that, Updegrove continues, while the basic technology was well understood, there were all kinds of small differences among approaches that could be debated. Among these: the number of channels, and their sizes, that a single 802.11n device could handle.

Another complication, he says, is that 802.11n attracted an “incredibly large number of submissions as candidates for the final gold star.” There were dozens of versions submitted to the deciding standards body, the IEEE (Institute of Electrical and Electronics Engineers), all with fairly minor variations.

Last, but not least, Updegrove explains, the IEEE “operates on consensus, which means, as a practical matter, that competing submitters have to cut deals and enter into alliances to get down to a single winner, often by successive mergers of competing groups of submissions. This alone is a very time-consuming process.”

It was indeed. In the beginning, in 2003, there were four major groups fighting to decide 802.11n’s fate. Two of these standardization efforts — a joint submission from Mitsubishi and Motorola and another from Qualcomm — quickly died off.

After some further consolidation, that left two major groups. The first was the Task Group ‘n’ Synchronization, or TGn Sync. It counted Intel, Atheros Communications and Nortel among its members. The other was World-Wide Spectrum Efficiency (WWiSE). Airgo Networks, the first company to deliver network chipsets that used MIMO (multiple-in, multiple-out technology), led this group.

Those two groups spent time battling with each other, but neither could gain the upper hand. With a 75% super-majority of the task force needed to approve the standard, the battle over whose version of the standard should prevail seemed unending.

Exhausted, in late 2005 the pair finally appeared to have hashed out their disagreements in the Enhanced Wireless Consortium and to have reached a compromise that would become the official IEEE standard, Updegrove says. But Airgo continued to hold out for its own take on the standard and it was able to block passage of the compromise version in mid-2006.

Adding insult to injury, even after delaying tactic, the authors and editors of the 802.11n standard had to wade through more than 12,000 comments on the 2005 “final” draft. As Bill McFarland, CTO at Atheros, a Wi-Fi chip vendor, and one of the editors and writers of the draft, observed at the time, “There were a lot of duplicate comments, and three people filed comments for each and every blank line in the document. The physical process of dealing with so many comments is tedious and time-consuming.”

In December 2006, Qualcomm purchased Airgo. With new ownership, Qualcomm/Airgo stopped fighting against the search for a consensus on the standard, and the first unified version, Draft 2, was passed in March 2007.

Further drafts were then passed in quick order, and it looked like 802.11n would finally be an established standard and that users could buy 802.11n equipment with certainty that it would interoperate by 2008. As Molly Mulloy, spokesperson of wireless OEM Broadcom, explained, “In 2008, we believed that draft 2.0 of the 802.11n specification was very solid. All of the major technical items had been resolved, and only relatively minor wording issues remained.”

Well, that was the plan. But, alas, there was one last major issue — a big, bad patent problem.

Before the IEEE will approve any given standard, everyone with a patent that touches that standard must sign a LoA (Letter of Agreement). The LoA states that the patent holder won’t sue anyone using his or her patent in a standard-compatible device. In this case, the holdout was CSIRO (Commonwealth Scientific and Industrial Research Organization), an Australian government research group that held a patent that concerned the development of a wirless LAN. CSIRO refused to sign the 802.11n-related LOA.

This led to a series of patent lawsuits. Apple, Dell, Intel, Microsoft, Hewlett-Packard and Netgear all attempted to overturn CSIRO’s 802.11n-related patents in court. They failed. Then, finally, in April 2009, the Wi-Fi vendors and allies gave up, paid up and signed patent licenses with CSIRO.

While the exact terms of all these deals are under nondisclosure agreements, the end result was that the 802.11n standardization process started moving quickly forward again. So it’s logical to assume that the settlement included an IEEE-acceptable LoA.

This means that, at long last, we will finally see interoperable 802.11n Wi-Fi access points, network routers and NICs (network interface cards). Vendors promise that customers will be able to update equipment build to the most recent draft 802.11n — 2008 and newer — to the new, final standard.

Some industry watchers don’t see the final standard as being that big a deal. Analyst Paul DeBeasi of the Burton Group, for example, believes that the real battle was won when Draft 2 was finally approved back in March 2007. In a blog posting, DeBeasai wrote, “The sorry fact is that the final ratification will have virtually no impact on the wireless industry. This is because what customers care about most is product interoperability. The Wi-Fi Alliance stepped into the standards void in 2007 and began certifying product interoperability based upon IEEE 802.11n draft 2.0. The fact of the matter is that the Wi-Fi Alliance did such a great job with their 802.11n certification program as to make the final IEEE standard a non-event.”

But other analysts predict that the standard is just now taking off. Victoria Fodale, an analyst with In-Stat, expects that 802.11n chipset revenue will surpass that of 802.11g this year, with a total Wi-Fi chipset revenue of over $4 billion by 2012. Overall revenue for products based on the most recent standard will be greater than that for 802.11g in 2012, she says.

It won’t just be computer networks zooming along at high speeds, though. Fodale also sees shipments of 802-11n-enabled TVs, set-top boxes, personal media players, digital still/video cameras and even mobile phones increasing quickly.

At that point, 802.11n may have finally caught up with itself.

SIDEBAR: The technology behind really fast Wi-Fi

Technically, 802.11n achieves its performance by adding MIMO (multiple-in, multiple-out) technology to the earlier 802.11g technology.

MIMO takes advantage of what has been one of radio communication‘s oldest problems: multipath interference. This occurs when transmitted signals reflect off objects and take multiple paths to their destination. With standard antennas, the signals arrive out of phase and then interfere with and cancel out one another.

MIMO systems employ multiple antennas to use these reflected signals as additional simultaneous transmission channels. In other words, MIMO knits the disparate signals together to produce a single, stronger signal.

In addition, 802.11n uses channel bonding to increase its throughput. With this technique, an 802.11n device uses two separate non-overlapping channels at the same time to transmit data. Thus, customers can send and receive multiple data streams at the same time.

As is the case with its predecessor, 802.11g, the new Wi-Fi operates in the 2.4GHz frequency range. Optionally, 802.11n can also operate at 5GHz. The new standard is backward-compatible with 802.11b and 802.11g.


802.11 through the years

Slowest: 802.11 — 1 to 2Mbps. Established in 1997 and ran at the 2.4GHz frequency range. Now obsolete.

Slow: 802.11b — maximum throughput of 11Mbps. Normal throughput in practice: 4Mbps. Made a standard in 1999 and runs on the 2.4GHz frequency range. Most Wi-Fi devices still support 802.11b.

Faster: 802.11a — maximum throughput of 54Mbps. Normal throughput in practice: 20Mbps. Made a standard in 1999 at the same time as 802.11b, but regulatory slowdowns kept 802.11a off store shelves until 2002. 802.11a, which is still supported on some devices, runs on the 5GHz range. (Yes, the naming happened out of order; 802.11b made it to market much, much faster than 802.11a. Long story made short: It was easier to make 2.4GHz silicon than it was to make 802.11a’s 5GHz chip sets.)

Faster still: 802.11g — maximum throughput of 54Mbps. Normal throughput in practice: 20Mbps. Approved as an IEEE standard in 2003. Like 802.11b, it operates in the 2.4GHz range. While it has the same speed as 802.11a, it has a greater range inside buildings and so has become the most widely deployed Wi-Fi protocol.

Fastest: 802.11n — maximum throughput of 450Mbps. Normal throughput in practice: 100Mbps+. Approved in 2009. It can operate on both the 2.4GHz and 5GHz frequencies and is expected to supersede 802.11g devices. At the 2.4GHz range, 802.11n devices can also support 802.11g devices at the cost of lowering 802.11n device connection speeds by half. So, for example, an 802.11n router supporting both 802.11g and 802.11n devices would deliver only 50Mbps throughput to a 802.11n-based computer.

A version of this story first appeared in ComputerWorld.

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