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Compare wireless: mimo, super 802.11 g, 802.11g

Posted on 2008-06-15
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I want to set up wireless in a medium size office (about 10 users in approx. 800 sg. ft. room).  I've only done 802.11g access points in the past, and that worked ok, but I want to know if the newer technologies are any better, especially super 802.11g and mimo wireless (netgear sells mimo, I'm not sure if this is a generic term or netgear proprietary).  Our main issue we are trying to correct is intermittent dropping of signal on the client computers and extending the range. Does mimo or super 802.11g help with this?  Also, does the client pc have to have a different card to take advantage of this?  They all have 802.11 g or n cards now.
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Question by:maharlika
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Frosty555 earned 125 total points
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"super 802.11g" is proprietary method of squeaking more throughput into the traditional wireless g standard. Manufacturers make their own proprietary devices. D-link makes the "Rangebooster" series, Linksys makes the "speedbooster" series. Both are just a cludgy attempt to "shotgun" two wireless G connetions side by side, and you need all proprietary equipment to do it. In my opinion it's a marketing technique to make you to use only one brand's equipment.  Not worth it in my opinion. It can theoretically have some detrimental effects to other, standard G equipemnt in the area. From wikipedia:

"Non-standard channel bonding extensions to 802.11g, such as Super G, have been criticized for creating interference on all Wi-Fi channels, potentially causing issues with other wireless devices in the band such as neighboring wireless networks, cordless telephones, baby monitors, and Bluetooth devices. However, Atheros claims that in real-world scenarios with physical separation and walls, closely located networks will not experience any interference from a Super G network."

http://en.wikipedia.org/wiki/Super_G_(wireless_networking)

It's a cludge. I would stay away from it.

MIMO means that the device has several antennae and can use them to try and get around some of the effects of signal reflection. The reflected signals are used to the devices advantage instead of hindering the signal. Little discussion here:
http://wireless.gumph.org/content/5/11/011-mimo-wireless-guide.html

MIMO is just the name of the technology used by wireless N. It looks to me like "wireless G with mimo" is the advertising term for what became "Wireless N", when the technology was brand new.  Wireless N is still in the works, and will be until 2009. So all the devices you see right now are "Draft N" or "Pre N" devices.  My guess is by the time the standard is finalized, these devices will no longer conform and need to be replacing. IEEE claims that the changes will be able to be done in software - e.g. a firmware upgrade - but would I trust it? No. I'm sure it probably WILL be the way of the wireless future, but I would not hop onboard just yet.

http://en.wikipedia.org/wiki/IEEE_802.11#802.11n

I think that wireless n devices can communicate with wireless G. E.g. your laptop with a wireless N card can operate in G mode and connect to a wireless G network. It will benefit slightly from the multiple antennae, but won't cause problems on the network.

Going the OTHER way around though, there seem to be issues with having a wireless G CLIENT connect to a wireless N ROUTER. The main reason being that now the router must function in a mixed mode. Serving both wireless g and wireless n at the same time. I believe that routers claim to do this okay, but in reality there are some problems, similar to the issues suffered when wireless B clients try to connect to a wireless G network.

Hope that clears some stuff up, and experts, please feel free to correct me. This is mostly what I've gathered from my own research.
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by:Darr247
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I really hope the IEEE gets rid of 2.4GHz 802.11n altogether, else 802.11g and 802.11b are going to become pretty useless in urban areas. When people set the 2.4GHz 11n routers to use 40MHz-wide channels (to get the advertised 270Mbps speeds) it uses channel 1 and channel 6 in the b/g band to make that 40MHz-wide channel. That leaves channel 11 as the only non-overlapped frequency in the americas for use with b/g. Europe and Japan have more channels, but they overlap channel 11's frequency so they gain no ground to get away from 11n interference by using those. On the other hand, there would be at least 6 non-overlapping 40MHz-wide channels in the 5GHz band, and their top speed is 300MBps. So a single 5GHz 11n router does NOT cause interference on 2/3rds of the 802.11a channels in a whole neighborhood, and offers higher speeds to boot.

> D-link makes the "Rangebooster" series, Linksys makes the "speedbooster" series.
> Both are just a cludgy attempt to "shotgun" two wireless G connetions side by side,
> and you need all proprietary equipment to do it.

In my experience that's not so. I've been able to get 108Mbps connections using a netgear USB adapter with a DLink Rangebooster DWL-7100AP and WRT54GS 'speedbooster', and 108Mbps connections using a DLink DWL-G650 and a Linksys WRT54GS and the DLink AP. I haven't tried any Linksys 108Mbps adapters.

Though to avoid compatibility issues it usually doesn't hurt to buy the same brand AP/router and wireless card, anyway... I have seen a test recently where the AP and wireless card from the same manufacturer actually got the worst scores. I don't remember what brand it was offhand - it was a 802.11n draft 2.0 test of at least 3 brand's products in Maximum PC, if I recall correctly.

I'm currently outfitting my laptops with A/B/G cards so when the 2.4GHz 11n APs/routers start showing up in the tiny burg where I live, I can just switch to 11a. A recent wardrive with my daughter's 11n Dell turned up only one 270Mbps out of a dozen APs within a 100 yard radius. Still, because they have only 1 (2.4GHz) radio, they're so much cheaper I can see them vastly outselling the technically better 2.4+5GHz routers (think VHS vs Betamax).
Semi-interesting factoids - almost half of those APs were still using WEP security, but I saw only 1 that was apparently wide open with no security...  they could have been using a MAC filter; the Site Monitor function on her notebook doesn't detect those, and I didn't try to actually connect to any of them... it was more of a sortie than 'war' drive.  ;-)

As for MIMO, I've read good things about the Ruckus MediaFlex and MetroFlex... they use 8 antennae - 6 horizontal, 2 vertical polarization - in a dynamic array to maximize throughput and range. Have not personally tried them yet, though.
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by:Frosty555
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>In my experience that's not so. I've been able to get 108Mbps connections using a netgear USB
>adapter with a DLink Rangebooster DWL-7100AP and WRT54GS 'speedbooster', and 108Mbps
>connections using a DLink DWL-G650 and a Linksys WRT54GS and the DLink AP. I haven't tried any
>Linksys 108Mbps adapters.

That's true. The Super-G implementation is theoretically supposed to work across different brands. I've had issues with it in the past since is doesn't seem to really be a well-enforced standard...

>Though to avoid compatibility issues it usually doesn't hurt to buy the same brand AP/router and
>wireless card, anyway... I have seen a test recently where the AP and wireless card from the same
>manufacturer actually got the worst scores.

I think I know the review you're talking about. It was a D-link Xtreme G 108mbps wireless laptop card and it got the worst pitiful scores with a D-link Xtreme G wireless router (5-10mbps), yet excellent scores with a... belkin router I think?

So when wireless N is full realized, it may not even operate in the same frequency as Wireless G. All the more reason to stay away from draft N devices for the moment.
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