Fixed Wireless Technology

Dual-Band Becoming Standard

802.11b, the bedrock of wireless networking, and its presumed successor, 802.11a, may be giving way to 802.11a/b or 802.11a/g.

by Ed Sutherland of Wi-Fi Planet. [January 7, 2003]

"802.11a has reached a dead end," says Will Strauss, analyst for the Tempe, Ariz.-based Forward Concepts research firm. While WLAN shipments in general have seen a 100 percent jump in 2002, Strauss says fewer than 100,000 802.11a-specific chipsets shipped in the same year. The slumping sales are causing some consternation to two leading 802.11a chip suppliers, Atheros and Resonext, he said.

Resonext, recently purchased by RF Micro Devices, produces 802.11a chipsets. The company has signed an agreement to provide 802.11a chips to Enterasys Networks for the firm's 5 GHz RoamAbout product to provide in building roaming on the WLAN.

Resonext touts an AccuChannel technology in its chips that the company claims provides a 32 percent greater range compared to standard 802.11a gear.

The 802.11a standard differs from the more widely known 802.11b specification. Where 802.11b shares the 2.4 GHz spectrum with cordless phones, garage door openers, and microwave ovens, 802.11a inhabits the more-sparsely used 5 GHz radio band. While 802.11b has a top speed of 11 Mbps, 802.11a can reach data rates of up to 54 Mbps.

However, 802.11a comes with equal disadvantages. Chiefly, 802.11a is incompatible with the more widely installed 802.11b specification becuase they use different radio frequencies. Furthermore, 802.11a signals cannot travel as far, so the number of access points needed is usually greater. Both factors have aided the popularity of dual band gear, which supports both 802.11a and 802.11b technology.

"Existing 802.11b infrastructure needs 802.11a/b," says Strauss.

Forward Concepts reports "the 5 GHz 802.11a market will have a very short life, giving way to combo 802.11a/b and 802.11a/g devices."

Strauss says Resonext is the only Wi-Fi chip company still offering an 802.11a-only product. Atheros has begun shipping 802.11a/b chips; Intersil 802.11g chips will be in products by January while Broadcom's 802.11g have is already on some store shelves.

Rich Redelfs, president and CEO of Atheros, says that although his company shipped over one million 802.11a chipsets in 2002, the year 2003 will see a shift toward combo boards. Redelfs says that over time, the market for 802.11a or 802.11b products will shrink as 802.11a/g combination chipsets dominate.

Atheros says both 802.11a and 802.11b will have new lives in embedded devices and as part of home multimedia networks.

Redelfs calls the current Wi-Fi chip market "brutal" and believes trying to support 40 Wi-Fi chip makers is "insane."

"There's going to be a shakeout," Redelfs says.

Gee, how sweet
Strauss believes 802.11g, with its 54 Mbps capability, will take the top spot. The new standard, set for final approval in 2003, will work in the 2.4 GHz band.

The 2.4 GHz band is favored "since it can penetrate walls and has greater distance," requiring fewer access points, according to Strauss. 802.11g is also backwards-compatible with the ubiquitous 802.11b.

"In short, there is little need for 802.11a, even as a combo solution, in the home," he concludes.

John Chang is another analyst saying WLAN chips are red hot, but the prospect for 802.11a-only is growing dim. Chang, a senior analyst for Allied Business Intelligence (ABI), says he sees only a niche market for 802.11a-only solutions. With the growing move toward dual-band chipsets, the analyst foresees "limited interest" in 802.11a-only products.

Why the gloom? Chang points to Microsoft. The shift away from 802.11a-only products crystallized when Microsoft said after Windows XP it would withhold certification from 802.11a-only devices.

"On the PC platform, at least, the prospects for 802.11a-only solutions are dim," Chang says.

In its report predicting a 2007 Wi-Fi chip market worth more than $1 billion, ABI says that by 2004 dual-band chipsets will outnumber 802.11b and 802.11g. 802.11g has the potential to become the preferred WLAN protocol "once there is no perceptible premium over 802.11b," says Chang.

Tom Mitchell heartily disagrees with those saying 802.11a-only products are destined to be just a footnote in the history of wireless networking.

Mitchell is the CEO of RadioLAN Marketing Group. Based in San Jose, CA, RadioLAN makes bridging equipment allowing campuses, carriers, and WISPs to provide long distance connections. The distances can reach up to four miles. RadioLAN recently unveiled its BridgeLINK-11a Wireless Bridge. Mitchell says that in bridging, compatibility is a bad thing. Companies don't want 802.11b gear to sniff out their wireless data.

Mitchell says 5 GHz reduces interference and is more controlled than the more prevalent 2.4 GHz band. The networking executive says dual-band devices will never deliver the performance his customers require.

RadioLAN says that while consumers may not have a problem with their 802.11b connection cutting out every time the fridge turns on, such interference cannot be tolerated by businesses.

What does the future hold for 802.11a-only applications? Analysts say the standard can maintain limited use in environments where compatibility is not needed: Allen Nogee, analyst for In-Stat/MDR, says 802.11a's large data pipe and multiple available channels makes it ideal for video streaming, conferencing, or education.

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