Wi-Fi Alliance seeks to crack down on 'pre-standard' 802.11 n claims

Rethink IT, Dec, 2004 by Adrian Drury

802.11n is anticipated to generate the same frenzy to cash in on pre-ratification chipsets and hardware as 802.11 g did in early 2003. Last week, Belkin did not disappoint by launching a 'Pre-N' router and PC card, a full two years before the standard is scheduled for ratification.

With 61 separate company submissions to the 802.11n task group received in August, there is virtually no visibility, as to what the final standard will look like, except that it will incorporate Multiple In Multiple Out (MIMO) smart antenna technology. Belkin is likely to be followed by a host of 'me-too' vendors, and non-interoperability is a very real risk for enterprise users.

The Wi-Fi Alliance has moved early to try and stem shipments of draft 802.1 In hardware, but it is fighting an impossible uphill battle against powerful market forces. The next two years will see a flood of draft-802.1 In hardware, and much of it is likely be non-interoperable. Belkin has fired the first round in tile much anticipated 802.11n wars. The consumer after-market PC hardware vendor has launched a router and a notebook PCMCIA card that it is marketing as "Pre-N", delivering "4x greater speed than standard 802.11g" and four times the range.

The engine behind Belkin's Pre-N hardware is the core technology that is likely to be at the heart of the 802.11n standard when it eventually receives ratification, Multiple In Multiple Out (MIMO) smart antennas. MIMO is set to be one of the next big things in wireless. It presents a new model for wireless digital signal processing, using multiple smart antennas to transmit multiple data streams using a single radio channel to multiply throughput rates, while simultaneously extending range. The new Belkin kit is the first set of products to bring this smart antenna technology to the mass market, as well as being the first hardware to be marketed as pre-802.11n--though Broadcom and Conexant have hinted at offering pre-standard 802.11 n chips.

For all MIMO's technical advantages, ratification of" tile 802.11 n standard is at least two years away. In August, the IEEE's 802.11 n task group received submissions from 61 different companies, and there are currently some major points of dissent between three main groups. Belkin's move is nothing if not controversial. At stake is the credibility of tile 802.1 in standard, and potentially the Wi-Fi brand itself. Belkin is using Airgo Network's True MIMO solution, and by virtue of Airgo's involvement, its router and PC card are manifestations of the high profile WWiSE (Worldwide Spectrum Efficiency) submission to the IEEE task group. In addition to Airgo, supporting WWiSE members are Broadcom, Conexant, Texas Instruments, Reahek, and STMicroelectronics.

The WWiSE proposal calls for a mandatory requirement within the 802.11 n standard that hardware must be able to operate in a 20MHz channel using a 2x2 MIMO antenna system, as well as having a robust, efficient, small form factor, that will deliver a 100Mbps mode. The ability to operate using a 20MHz channel will provide a basis for compatibility with 802.11 b and 802.11g. The WWiSE proposal also includes the optional caveat for tire inclusion of a 40MHz channel mode, using an additional one to two antennas, delivering a theoretical maximum data rate of 540Mbps. The theoretical maximum data rate of Belkin's Pre-N gear is reportedly 135Mbps.

Challenging the WWiSE submission are two rival groups. One, backed by Atheros, Intel, Matsushita, Philips, and Sony, is proposing that all the 802.11 n specification should be based on a 40MHz channel. The other, fronted by Agere, is calling for 540Mbps to be the required speed for the standard, eschewing entirely a 100Mbps mode (this one is likely to take a back seat with Agere's decision to quit the 802.11 n development race).

It is impossible to call, at this point, which approach will win, but with the example of Broadcom's huge success from anticipating the 802.11 g standard, vendors and chipmakers are unlikely to wait for the final 802.11n before leaping in. At least Broadcom was only a few months in advance and products based on its pre-g silicon could usually be firmware upgradeable. The risks with products that are two years ahead of 802.11 n are far higher.

This creates the possibility that hardware will proliferate into the market--particularly the consumer market--that is pitched as "Pre-N" and Wi-Fi compatible, but that will actually be noninteroperable in their fast, supposed 802.11 n modes, or worse, bring entire networks down.

To its credit, the Wi-Fi Alliance has reacted quickly to the Belkin product announcement. It has threatened to strip 802.11a, b or g Wi-Fi certification from any products that claim to incorporate enhancements based on 802.11 n, and which adversely affect interoperability of other Wi-Fi products. The Alliance's view is straightforward. In a statement it has said, "No 802.11 n products currently exist, and none are expected to exist until tile standard is completed in approximately two years [November 2006] ."