A general rule for IT departments is no matter how much bandwidth a network offers, users want more. So as soon as the Institute of Electrical and Electronics Engineers completed work on the 802.11b specification, which supports 11 Mbps wireless LAN transmissions, the 802.11 working group began to work on a higher-speed option, 802.11a, which operates at 54 Mbps.
However, migration to the high-speed option hit a few snags. Because of the way vendors designed the new standard, compliant products have been expensive and incompatible with the lower-speed option.
As a result, some suppliers went back to the drawing board and developed another 54 Mbps WLAN system, 802.11g, which is compatible with 802.11b. Each option has strengths and weaknesses, and which one of the two will emerge as the most popular is expected to become clearer as the year progresses.
A Banner Year for WLAN Gear
By most analyst estimates, this year is pivotal for high-speed WLANs because the low-speed option has been gaining so much acceptance. In the third quarter of 2003, worldwide revenue for WLAN access points reached US$427 million, an increase of 9 percent from the second quarter of 2003, according to market research firm the Dell’Oro Group. “WLAN use is exploding in every market segment: home entertainment, home office, small office and the enterprise,” noted Greg Collins, an industry analyst at the Dell’Oro Group.
Typically, a dramatic surge in use of a new networking technology will spark the development of new applications that lead to requirements for higher-speed connections. Users are now working with video and voice — as well as data — on their WLANs, and these transmissions require more bandwidth. Also, networks become saturated as more users work with them, and bottlenecks are arising on heavily used WLANs, such as hot spots at cafes or on college campuses.
When vendors began work on 802.11a, they did not want to stay in the 2.4-GHz range used with 802.11b products. The spectrum at 2.4 GHz is a shared frequency, so devices like cordless telephones and microwave ovens can create interference problems. Also, the vendors are able to squeeze out only about five channels — or simultaneous user connections — in this range, which relies on direct-sequence spread-spectrum technology, a signaling technique that places a premium on security and reliability while sacrificing efficient use of available bandwidth.
Keeping to Themselves
In the late 1990s, the Federal Communications Commission opened up a new frequency range — the 5-GHz range — that is only available for wireless LANs, so there is no outside interference. Also, it uses orthogonal frequency division multiplexing for modulation, which increases bandwidth efficiency so an access point can support about 10 simultaneous connections.
Despite its technical elegance, 802.11a hit a few bumps as it worked its way toward deployment. Because 802.11a products operate in a higher-frequency band — which means they are more complex and less forgiving — the transmission ranges available with 802.11a systems cover less distance than those found with 802.11b systems.
A rough rule of thumb used by vendors is that an 802.11b access point has a range of about 250 to 300 feet, while an 802.11a access point will reach about 90 feet. This means transmissions will have more trouble traveling through walls, floors, furniture and other obstructions on the faster LANs, and users will have to deploy more access points.
This necessity to deploy more access points is one reason why 802.11a products turned out to be expensive, costing as much as four times more than 802.11b systems.
Dotting the ‘I’ and Crossing the ‘T’
Also, 802.11a technology required access points with a more intricate product design than 802.11b access points. The products also required a bit more engineering time to complete than expected. Product deliveries that were initially slated for late 2001 slipped to 2002. This delay occurred as vendors tried to deliver access points that would run in dual mode — accepting both 802.11b and 802.11a transmissions.
“Users quickly made it clear to the suppliers that they weren’t going to rip out their existing networks to move to a higher speed, so vendors pulled back from developing 802.11a-only products,” Dell’Oro’s Collins told TechNewsWorld.
While networking vendors were a bit slow to support 802.11a products, consumer manufacturers were not. “Home entertainment devices from companies like Sony are coming out with integrated high-speed connections, and they were designed to work with 802.11a, not g,” said Michael Disabato, a senior analyst at the Burton Group.
Meanwhile, vendors also worked diligently on 802.11g — and the first wave of those products began to arrive in the second half of 2003. Because 802.11g products are compatible with 802.11b offerings, these higher-speed systems tend to cost less than 802.11a-based products.
“A growing number of companies and consumers are turning to 802.11g because it’s pretty cheap, a lot faster than 802.11b, and vendors have worked out most of its kinks,” said Gemma Paola, an industry analyst with In-Stat/MDR, a subsidiary of Reed Elsevier.
Pushing Top Speed
However, 802.11g products do not always deliver faster speeds. “If you have one user with an 802.11b connection, the entire network slows down to that speed,” Disabato told TechNewsWorld.
As the battle for market dominance begins in earnest, observers are split on which side will emerge victorious. Burton Group’s Disabato views 802.11a’s technical elegance as the key factor in its eventual dominance, while Dell’Oro Group’s Collins thinks 802.11g’s lower pricing will catapult it to the market’s top spot.
The winner has yet be determined, but in keeping with a well-known networking axiom, vendors are already examining ways to push wireless top speeds past the 100-Mbps mark.
Would like to initiate a discussion on what I think Intel direction ultimately will be with this whole WLAN business:
COnsider the following:
Intel is building WLAN capability to include:
1. Centrino new 802.11g as well as
2.a most recent announcement on placing an AP functionality on board Laptops and Desk Tops
3. this to include a Meshed network Functionality.
4.Now consider that Intel is a major player in the new 802.15.3a UltraWideband Forum (Teaming with Texas Instruments-MBOFDM) which will come out with a chip that will allow UWB (1-200Mbps over 10-20 Meters)to be placed on Laptops and even better all our desktops-GoodBye Ethernet LANS when combined with Meshed Networks.
5. Next step is their investment in the 802.16a WIMAX standard Fixed Broadband Wireless standard that will allow them to extend WLAN out in the MAN/WAN.
However, it is the prospect of having a UWB Meshed Network of PC’s (Set Top Boxes and or TV with UWB Chips in homes)that will eventually rule this whole market.
Then the FCC will be forced to open up the UWB spectrum to allow long reach MAN/WAN Networks to compete for Wireline and Wireless Carrier/Cell Nets.
Intel will rule
802.11a is not only NOT DEAD it will surface as an integrated dual band 802.11g & a chip that when placed on a Dual Radio (Dual Chip/Radio ) AP/Bridge will dominate the AP business. By combining these two standards on one chip we not only allow a diverse functionality (g is great for long reach limited to 3 channels and is interference prone)(a is great for more channels 12 vs 3, meaning more users can share the 54 mbps in congested high traffic areas).
The 5Ghz (802.11a) spectrum is also nowhere near as congested and therefore will be more clear (interference) for for high traffic areas.
This paragraph is inaccurate. Here’s the edited version:
"When vendors began work on 802.11a, they did not
want to stay in the 2.4-GHz range used with 802.11b [AND 802.11G]
Products. The spectrum at 2.4 GHz is a shared
Frequency [AS IS THE 5 GHZ U-NII BAND], so devices like cordless telephones and microwave ovens can create interference problems [MICROWAVE OVENS HAVE TO STAY IN THE 2.4 GHZ RANGE BASED ON THE RESONANT FREQUENCY OF WATER. THERE ARE 5 GHZ CORDLESS PHONES]. Also, the vendors are able to squeeze out only about five channels [IN THE US 2.4 GHZ BAND GOES FROM 2.4 TO 2.4835 GHZ, A BANDWIDTH OF 83.5 MHZ- 802.11B CHANNELS TAKE ABOUT 26 MHZ SO THERE ARE
3 NON-INTERFERING CHANNELS 1, 6, AND 11]– or simultaneous user connections [NO, NOT "USER CONNECTIONS", SEPARATE WLANS. MULTIPLE USERS SHARE A WIRELESS LAN]– in this range, which relies on direct-sequence spread-spectrum technology, a signaling ["RADIO TRANSMISSION"] technique that places a premium on security and reliability while sacrificing efficient use of available bandwidth."
[IN CDMA-BASED CELLULAR NETWORKS (E.G. SPRINT AND VERIZON), DSSS INCLUDES AN INTEGRATED ENCRYPTION SYSTEM BASED ON PSEUDO-RANDOM NUMBER (PN) CODES THAT RESULTS IN A HIGHLY SECURE RADIO LINK. THAT’S NOT DONE IN 802.11B. WLANS DEPEND ON ENCRYPTING THE SIGNAL BEOFRE IT’S MODULATED USING A TECHNIQUE LIKE WEP’S RC4 OR AES (I.E. 802.11i). IN ESSENCE, THE 802.11A/B/ AND G RADIO LINKS HAVE EXACTLY THE SAME INHERENT LEVEL OF SECURITY]
"In the late 1990s , the Federal Communications Commission opened up
A new [UNLICENSED] frequency range — the 5-GHz range — that is only available for wireless LANs, so there is no outside interference [WRONG- IT’S "UNLICENSED", ANYONE CAN USE IT]. Also, it uses orthogonal frequency division multiplexing for modulation [NO- THE "5 GHZ BAND" DOESN’T USE OFDM, THE 802.11A RADIO LINK DOES. YOU SEE. 802.11G ALSO USES THE SAME OFDM MODULATION IN THE 2.4 GHZ BAND], which increases bandwidth efficiency [THAT’S ACTUALLY CORRECT] so an access point can support about 10 simultaneous connections [IF YOU MEAN THAT THERE ARE 12 NON-INTERFERING WLAN CHANNELS IN THE 5 GHZ BAND YOU’RE ONLY OFF BY 20%. AN "ACCESS POINT" ONLY SUPPORTS ONE WLAN WHICH OPERATES ON ONE CHANNEL. THE NUMBER OF "SIMULTANEOUS USERS" DEPENDS ON THEIR TRAFFIC LOAD AND REQUIREMENT FOR PERFORMANCE].
The bottom line is that the advantage of 802.11a’s 12 channels (versus 3 for 802.11b or g) will be the critical factor for enterprise users. The 2.4 GHz options will remain the technology of choice for the residential market (i.e. Sony’s adoption is an anomaly), and the 5 GHz band will be used by enterprise users. The products will catch up- take it to the bank.