New Wireless Standards Challenge 802.11b
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The HomeRF Front
HomeRF is backed by the HomeRF Working Group, a consortium of companies that includes Proxim, Motorola, and Siemens. Intel jumped ship earlier this year, choosing 802.11b for its consumer wireless products.
An FCC ruling last August let the group finish spec 2.0 which brought its speed from 2 Mbps up to 10 Mbps. But devices using HomeRF have only recently been demonstrated at trade shows, and they're expected to begin to ship this summer.
HomeRF had previously been deprecated because of its lower speed and a paucity of cards and hubs. The spec's key advantage is the integration of voice and data into the baseline for data transmission: Voice packets are given a regular slot to make sure conversations aren't broken up. New HomeRF hubs should allow the use of cordless phone handsets side by side with computers transmitting data.
There is some concern that busy 802.11b networks might cut holes out of the hopping pattern of HomeRF devices, or that HomeRF devices could carpet-bomb Wi-Fi channels -- picture SUVs weaving around a highway careening into tractor-trailers occupying multiple lanes. Under their current designs, HomeRF and 802.11b aren't watching out for each other, and their transmissions could block each other, slowing down each protocol's effective throughput.
But the goal of HomeRF is truly "home," and it's unlikely you'll find both 802.11b and HomeRF networks at anyone's house except the most extreme technophile.
I've spoken to a variety of people inside and outside the HomeRF group, and a wait-and-see attitude prevails on HomeRF's chances once it's included in shipping equipment. The three main companies behind it will send out set-top cable boxes with embedded HomeRF hubs, handsets, consumer standalones like Internet radios, as well as PCI and PC cards. Time will tell.
Bluetooth coming in
Bluetooth has received considerably more attention than HomeRF, as the specification has been widely talked about for years. The goal of Bluetooth is low-bandwidth, short-range, low-power synchronization and data transfer, not full-blown networking. PDAs, laptops, cell phones, and other small devices could exchange information without requiring a full-blown TCP/IP stack or much configuration. (Note that I'm saying could; security settings might be Byzantine.)
Because Bluetooth is entering the market late, many companies and standards groups worried that 802.11b might completely drown it out. Or that Bluetooth would be a woodpecker in the 802.11b tree, reducing throughput on both systems.
Fortunately, the IEEE's Personal Area Network (PAN) working group, 802.15, had prioritized work on co-existence between Bluetooth and 802.11b, as well as future 802 wireless specs. The 802.15.2 task group recently approved a proposal that allows adaptive hopping, in which Bluetooth transceivers can avoid heavily trafficked frequencies, benefiting both systems.
Of course, the few Bluetooth devices shipping today and in the next months may not be able to take advantage of this new spec, as aspects of it will certainly require chipset modifications, not just a firmware update, even if firmware updates were available.
Bluetooth, with its lower power signature would have been the loser in those battles, anyway: imagine a relentless bulldozer crushing gnats dashing across its path.
Up in the spectrum! It's an "a"!
There's one more player in this new world order: IEEE 802.11a, which lives in a different band. 802.11a uses the 5-GHz band called U-NII (Unlicensed National Information Infrastructure) in the United States.
The "a" spec operates at 54 Mbps due to the higher frequency and greater bandwidth allotment. However, because the same power limits apply, "a" access points may only offer access within a few dozen feet. Because of this, a greater density of hubs is required, not just a combined "a," "b," and "g" hub.
In early 2001, many of the manufacturers and standards group members I spoke to thought that 802.11a wouldn't arrive until late 2001 or early 2002. They planned to push hard on 802.11b, and leave "a" as a future upgrade.
But the specification was approved more rapidly than expected (it uses the OFDM modulation) and chipmaker Atheros whipped out a chipset to manufacturers early this year. By summer, at least some 802.11a access points and cards are expected.
This caught folks by surprise. In the middle of a push for an 11-Mbps deployment, suddenly being tempted by 54 Mbps makes an IT purchaser sit up and take notice. The greater density of hubs and the high price tag on early equipment still make "b" - and ostensibly "g" - more affordable choices for the majority of office networking and public space use.
802.11a faces a separate challenge, too: provincialism. The Europeans have been working on a spec called Hiperlan in various forms for nearly a decade without pushing out working equipment. The Hiperlan2 Forum has a press release from early 2001 that suggests equipment will ship in volume by mid-2002.
The Europeans also haven't harmonized with the U.S. on frequency choices, making it even more difficult to meet in the middle. 802.11a may be relegated to the hinterlands -- the entire United States -- rather than make a worldwide splash. This might keep prices high for the long term.
Sorting out the wreckage
This summer is crunch time -- when you find yourself with an abundance of choices. But the ever-dropping price of 802.11b cards and hubs, along with ever-increasing options for equipping things other than computers (like Palm OS devices and printers) may continue to make 802.11b ideal even when faster options start shipping.
Bluetooth and 802.11b's détente is a great development, as Bluetooth plans to ship regardless of whether anyone is ready to buy. But HomeRF's future is less certain. And 802.11a throws a wrench in the work for enterprise planners trying to figure out how to spend their money on this new, useful technology.
My advice and strategy: buy into 802.11b. It's robust, tested, and cheap, and will be around for the long haul because of the massive current installed base that will grow by millions of users and hundreds of thousands of locations in 2001. Whatever comes after it will be faster, but it has to be compatible with the gold standard of "b" to make inroads.
Glenn Fleishman is a freelance technology journalist contributing regularly to The New York Times, The Seattle Times, Macworld magazine, and InfoWorld. He maintains a wireless weblog at wifinetnews.com.
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2002-11-07 06:45:56 praug1d [View]
802.11b range difficulties
2002-06-22 18:05:21 tdushane [View]