Introduction
The 2.4GHz radio frequency band is a popular place these days. Some cordless phones and several varieties of wireless communications networks are all vying for a place in this radio frequency spectrum. The main reason for its popularity is the fact that this part of the spectrum is unlicensed and thus suitable for short-range wireless devices. Indeed, most wireless local area network ( LAN) products operate in this 2.4GHz unlicensed band. The wireless LAN products can interfere with other 2.4GHz products, such as some cordless phones. (900MHz cordless phones should not be affected).
In addition, devices using the 2.4GHz band can suffer interference from appliances that radiate in this band, such as microwave ovens. Yes, these new devices employ the same 2.4GHz frequency range as that used by microwave ovens to heat food. Fortunately, there is little or no evidence that the low level of wireless radiation emitted by wireless communications devices is harmful to us. And we have not heard of wireless network users having trouble with interference from their microwave ovens -- or vice versa.
"Having the PC card in the laptop allows me to roam around, my house, my yard and conference rooms at the office. I do not know how I lived without them."
-- Paul Bender, commenting on his 802.11b wireless networking system on a Usenet forum
IEEE 802.11b
By far the most popular wireless LAN standard is IEEE 802.11b, now endowed by marketing types with the more mellifluous sounding moniker "Wi-Fi." If you are looking for a product with the greatest interoperability with other 802.11 wireless cards, we suggest that you get a product that is compliant with the 11Mbps DSSS standard, not the older FHSS ("Frequency Hopping Spread Spectrum") standard. Direct Sequence Spread Spectrum DSSS devices can access older FHSS networks, but the reverse is not true. As a consequence, the older FHSS cards are cheaper -- a pair of Aviator cards from WebGear (www.webgear.com) can be had for around US$150.
DSSS cards, such as Apple's AirPort, are a little more expensive. AirPort cards sell for US$99 each. An optional base station provides connections to the Internet via its integrated Ethernet and phone jacks. It sells for US$299.
More business-oriented 802.11b compatible devices from vendors such as Intel are considerably more expensive, but provide additional security via 128-bit encryption capabilities missing from Apple's low-cost (40-bit encryption) AirPort. (AirPort also relies on the host Mac to provide the required antenna, further lowering the cost.)
There are multiple vendors that make products that are compliant with the 802.11b specification. To name a few:
Paul Bender, writing in the microsoft.public.win2000.hardware forum, offers some sage advice:
"Be sure that it is 802.11b compliant, not just 802.11 compliant. 802.11b has a peak rate of 11Mbps, while 802.11 has a peak rate of 2Mbps. (There's another high-end variant, dubbed 802.11a, as well, that delivers a whopping 72Mbits of data per second in its "turbo mode." -- Ed.) If you do get 802.11 rather than 802.11b, be sure it is DSSS not FHSS. DSSS will interoperate with 802.11b and FHSS will not."
You can, he notes, operate 802.11 products products in either infrastructure mode or ad-hoc mode. Infrastructure mode requires an access point (also known as a base station). Generally, access points point have a greater feature set, including SNMP/WBEM for management, quality of service control for voice over IP ("VoIP"), etc. As a result, they are more expensive than other element of the network, such as PC cards. However, access points can be plugged directly into an Ethernet, acting as a wireless extension of the subnet. As a result, they are convenient.
Most, if not all these vendors sell both access points (AKA base stations) and PC card products. Many also sell PCI cards for desktop PCs.
802.11g
There's also a new variant of the standard, typically designed as a "combo card" that will support transfer rates up up to 54 megabits/sec, while maintaining backward compatibility with existing 802.11b equipment. Apple is said to be currently in the process of selecting a supplier for such a product, with the aim of delivering an updated version of its AirPort wireless system in upcoming Macs. Betanews.com has additional details on the recently ratified standard, approved on Nov. 15 by the Institute of Electrical and Electronics Engineers (IEEE) after a reportedly difficult arbitration finally led to an agreement on 802.11g between Texas Instruments and Intersil. Betanews notes that 802.11a is not compatible with either 802.11b or the new 802.11g standard, given that it operates within the 5 gigahertz range rather than 2.4 gigahertz like its uniformly labeled cousins. (Read more at ZDNet UK....)
HiperLAN
Back in 1999, a then-new standard called HiperLAN was lauded by Network Magazine and others as "the most sophisticated wireless LAN technology so far defined." At the time, it was fast. The variant known as HiperLAN1 promised wireless data transmission rates up to 25Mbps; HiperLAN2 would theoretically deliver more than double that much at "peak" rates but, perhaps more importantly, was able to achieve a not-too-shabby 20 Mbps in sustained throughput rates.
Proxim (which, as we noted in part one of this feature, is owned in part by Intel) was the first company to release a HiperLAN product. Proxim's Product Manager Jeff Orr, in 2000 stated that HiperLAN, 802.11 and HomeRF would all have their place in the market. HomeRF's four channels of audio data, he says, while not exploited by the first generation products Proxim had OEMed to Intel and Compaq, were uniquely suitable for use in mobile phones -- a technology currently being developed by HomeRF consortium partners Siemens and Motorola.
However, as we've seen since these statements were made, the market didn't shape up the way Proxim or other HomeRF or HiperLAN backers hoped. By Dec. 2001, the momentum behind HiperLAN had all but collapsed, leaving 802.11a as its most likely successor in the WLAN wars. Products based on the fast wireless network standard are expected to hit the market in mid-2002.
HomeRF 2.0
At Comdex Fall 2000, proponents of the competing Wi-Fi standard tried to rain on the HomeRF parade, characterizing the HomeRF group as "behind the times" and a "dying organization." Indeed, when one looks at the relative speeds and the momentum behind each of the two standards, it is hard not to agree, despite comments in publications such as Electronic Buyers' News that suggests that HomeRF not expected to disappear despite 802.11. It's also worth noting that HomeRF is supported (very nicely!) in Windows XP, as is 802.11b.
Even Intel, which recently released a Windows XP-compatible software update to its HomeRF-based AnyPoint Wireless network, says it is dropping plans to further develop HomeRF products, although it remains an active member of the HomeRF Working Group. Despite these setbacks, the HomeRF group has asked the government to approve a faster 2.0 version of its technology. The FCC approved this enhanced specification in March 2001.
This approval by the commission will allow the sale of an enhanced class of HomeRF 2.0 devices, which boost network performance tenfold by increasing the range of "hops" in the technology from the current 1 MHz range to 5MHz. This will, explained Intel Home Networking Product Manager Dan Sweeney in an interview before Intel cancelled its HomeRF plans, boost wireless connections to speeds of 10Mbps, delivering more than enough bandwidth for data-intensive applications such as the delivery of full-motion video (typically requiring at least 3Mbps) over wireless networks and improved network gameplay. These second-generation HomeRF products are expected to hit the market in before the end of 2001 at prices comparable to those of the company's existing 1Mbps products, which will, unfortunately, not be flash-upgradeable. Around this time, expect to see other products exploiting other enhanced features in the HomeRF 2.0 spec, notably, support for isochronous support for up to eight channels of voice data. Motorola and Siemens requested a change from the 1.0 spec's limit of four channels.
Sooner or later, we're bound to see a new generation of wireless, multi-channel mobile phone devices with built-in Internet access, thanks to this currently unexploited feature of HomeRF.
The Future
Further down the road, expect home and business-oriented technologies to converge when the inevitable demand from greater throughput drives vendors to move from current 2.4GHz-band products to faster 5 GHz-range products. In mid-2001, Intel's Dan Sweeney predicted that the first 802.11a products, based on 5GHz radio technology, would arrive in mid-2001. He wasn't far off -- several manufacturers showed 802.11a products at Comdex that fall. They were quite expensive initially, although silicon integration efforts quickly brought the price down and by the Spring of 2003, 802.11a cards were selling for less than C$200.
Expect to see pressure coming from satellite providers and the military to discourage the use of the 5GHz frequency range for WLAN activity. Despite this pressure, we think 802.11a will soon establish itself as the dominant next-generation WLAN standard -- first in North America, and later in Europe. There are other, roughly comparable technologies -- Apple's "AirPort Extreme" initiative (including 802.11g-based backward compatibility with existing Airport networks) is a wild card -- but at this point, 802.11g is the only other contender with a decent shot at becoming a dominant standard... and some worry that 802.11g, which boosts the speed of wireless LANs on the 2.4GHz wave band, could be declared obsolete before it is delivered. This hasn't stopped Microsoft and several other industry heavyweights from jumping onboard the 802.11g bandwagon.
At this writing, several new 802.xx specs are on the drawing boards. Microsoft promises a "seamless" upgrade to 802.11i will follow its latest (currently Windows XP-only) Wi-Fi security update, Intel, Nokia and Proxim and others are pushing WiMax, and 802.11n promises high throughput, not just fast wireless. Members of the working group predict 2005 or 2006 for completion.
Wireless Glossary (and archives)
Bluetooth - A wireless technology based on a short-range 2.4GHz signal, designed for creating "personal area networks."
802.11b - Also known as "Wi-Fi," this is a popular (perhaps the most popular) wireless networking standard for PCs and Macs. Not interoperable with BlueTooth, but also based on a short-range 2.4GHz signal. With speeds up to 11Mbps, it is considerably faster than HomeRF.
GPRS (General Packet Radio Switching) - A wide-area wireless standard, not yet in common use but expected to gain in popularity in 2001 and beyond.
HomeRF Yet another wireless networking "standard," endorsed by Intel, Compaq, Proxim and a handful of others. Version 1.0 promises throughput up to 1.6Mbps. Version 2, approved in March 2001 and expected to show up in products in mid-year, boosts speed to 10Mbps.
QuoteUnquote
"There are multiple standards in Canada. Manufacturers have to decide which standard they want to use. They essentially have to place their bets on one set of standards. In these early days of wireless data, this makes it seem risky to bring a device like the WA3050 to Canada."
-- Adam Anger, business manager, Mobile Devices Group, Microsoft Europe, Middle East and Africa (EMEA).
For Further Reading:
Post new comment