Draft 802.11n ‘causes interference’
Spanner in the works
According to Airgo, the draft version of the new 802.11n wireless standard will cause interference with legacy 802.11b and g networks. Airgo, maker of the True MIMO chipsets featured in kits including those from Belkin, Netgear and Buffalo, has made an incredible statement about version 1.0 of draft IEEE standard, approved by the IEEE 802.11 working group on March 10 in Denver. The timing is designed to be devastating for the standard. Netgear has publicly declared it’s intention to release draft 802.11n kit in the first half of this year, while others will be similarly timed. In a statement released to us, Airgo claims that if draft 1.0 kits are released “they will severely degrade – or even disable – nearby 802.11b and 802.11g networks.” Airgo is clearly hoping to start a fight with the release of this statement, which comes despite an 87 per cent approval rate for the draft at the meeting. “A few chipset companies are attempting to develop chip designs based on early, less stable versions of the draft and are resisting all proposed improvements to the specification because they do not wish to ‘respin’ their chips,” the statement continues.
The problem centres around a 40MHz channel bonded mode of the draft standard which uses MIMO technology. Think of this as a turbo mode that may not be on all the routers being released. 40GHz has a problem since there are just three channels in the 2.4Ghz band that don’t already have a problem with overlapping. Craig Reid, Product Specialist for Buffalo Technology explains the draft: “It is mandatory to have 20MHz channels and 40MHz is optional. Only if the chipset vendors like Atheros, Broadcom and Marvell use this 40MHz option…[the draft will] inhibit the 802.11b/g networks that currently exists. The truth is that if you use a 40MHz channel bonded solution then there is simply no room available for anything else in the channel spectrum.” Buffalo isn’t planning to go this route. “As Buffalo is a Japanese company we are pushing for 20MHz channel bonding because in Japan it is not legal to use 40MHz channels in the 2.4GHz frequency,” explains Reid.
Atheros’ CTO Bill McFarland told us that changes to the 1.0 draft are possible, but unlikely: “Any new changes will have to receive 75 per cent approval. Additionally, companies have already been discussing the best techniques for the 802.11n standard for several years now. It’s very unlikely that a new technique would be introduced at this stage….” An ad-hoc group, led by Motorola and Cisco, has been created to look at the 40MHz issue, something that Airgo refers to in its statement as a ‘deficiency’ in the draft standard. This group will report in May. “Atheros’ position is that the implementation of avoidance technologies should be clearly defined and mandatory,” says McFarland. His company is clearly planning to release channel-bonded kit but says this will not cause interference problems.
“Atheros-based devices intelligently select 40 MHz mode only when adjacent channels are free. Silicon based on the 1.0 draft does contain elements to mitigate interference with legacy devices. Atheros will guarantee that its chips include avoidance technologies,” he says. It’s known that the third generation of Airgo’s MIMO chipset, as featured in products including the Netgear RangeMax 240 and Linksys SRX 400 range does have the ‘bad neighbour’ syndrome that Airgo is referring to. “Don't forget, the first company that launched product with the unsocial 40MHz channel bonding technology was Airgo,” continues Reid.
McFarland looks ready for a fight. “We find it rather ironic that Airgo is on one hand promoting its third-generation chipsets, which do cause interference with legacy devices, and on the other hand warning the public regarding the 1.0 draft specification,” he states. “It is a fact that Airgo’s third-generation chipsets are not upgradeable to the 1.0 draft. As a result, one could assume that Airgo is trying to slow down the momentum for the 802.11n standard or otherwise cast doubts on the 1.0 draft specification. In a desperate attempt to preserve MIMO market share, Airgo is trying to create confusion in the market so they can continue to sell their own proprietary third-generation chipsets while creating FUD about competitors’ chipsets.”
According to Airgo, the draft version of the new 802.11n wireless standard will cause interference with legacy 802.11b and g networks. Airgo, maker of the True MIMO chipsets featured in kits including those from Belkin, Netgear and Buffalo, has made an incredible statement about version 1.0 of draft IEEE standard, approved by the IEEE 802.11 working group on March 10 in Denver. The timing is designed to be devastating for the standard. Netgear has publicly declared it’s intention to release draft 802.11n kit in the first half of this year, while others will be similarly timed. In a statement released to us, Airgo claims that if draft 1.0 kits are released “they will severely degrade – or even disable – nearby 802.11b and 802.11g networks.” Airgo is clearly hoping to start a fight with the release of this statement, which comes despite an 87 per cent approval rate for the draft at the meeting. “A few chipset companies are attempting to develop chip designs based on early, less stable versions of the draft and are resisting all proposed improvements to the specification because they do not wish to ‘respin’ their chips,” the statement continues.
The problem centres around a 40MHz channel bonded mode of the draft standard which uses MIMO technology. Think of this as a turbo mode that may not be on all the routers being released. 40GHz has a problem since there are just three channels in the 2.4Ghz band that don’t already have a problem with overlapping. Craig Reid, Product Specialist for Buffalo Technology explains the draft: “It is mandatory to have 20MHz channels and 40MHz is optional. Only if the chipset vendors like Atheros, Broadcom and Marvell use this 40MHz option…[the draft will] inhibit the 802.11b/g networks that currently exists. The truth is that if you use a 40MHz channel bonded solution then there is simply no room available for anything else in the channel spectrum.” Buffalo isn’t planning to go this route. “As Buffalo is a Japanese company we are pushing for 20MHz channel bonding because in Japan it is not legal to use 40MHz channels in the 2.4GHz frequency,” explains Reid. Atheros’ CTO Bill McFarland told us that changes to the 1.0 draft are possible, but unlikely: “Any new changes will have to receive 75 per cent approval. Additionally, companies have already been discussing the best techniques for the 802.11n standard for several years now. It’s very unlikely that a new technique would be introduced at this stage….” An ad-hoc group, led by Motorola and Cisco, has been created to look at the 40MHz issue, something that Airgo refers to in its statement as a ‘deficiency’ in the draft standard. This group will report in May. “Atheros’ position is that the implementation of avoidance technologies should be clearly defined and mandatory,” says McFarland. His company is clearly planning to release channel-bonded kit but says this will not cause interference problems.
“Atheros-based devices intelligently select 40 MHz mode only when adjacent channels are free. Silicon based on the 1.0 draft does contain elements to mitigate interference with legacy devices. Atheros will guarantee that its chips include avoidance technologies,” he says. It’s known that the third generation of Airgo’s MIMO chipset, as featured in products including the Netgear RangeMax 240 and Linksys SRX 400 range does have the ‘bad neighbour’ syndrome that Airgo is referring to. “Don't forget, the first company that launched product with the unsocial 40MHz channel bonding technology was Airgo,” continues Reid.
McFarland looks ready for a fight. “We find it rather ironic that Airgo is on one hand promoting its third-generation chipsets, which do cause interference with legacy devices, and on the other hand warning the public regarding the 1.0 draft specification,” he states. “It is a fact that Airgo’s third-generation chipsets are not upgradeable to the 1.0 draft. As a result, one could assume that Airgo is trying to slow down the momentum for the 802.11n standard or otherwise cast doubts on the 1.0 draft specification. In a desperate attempt to preserve MIMO market share, Airgo is trying to create confusion in the market so they can continue to sell their own proprietary third-generation chipsets while creating FUD about competitors’ chipsets.”
posted by Unknown @ 12:55 PM
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