Dual Band Wifi for Dense RF areas?

[mgraves]

I recently had a pretty bad experience with wifi at a trade show exhibition hall. There details are here:

http://www.mgraves.org/2011/04/when-the-wifi-blows-experience-at-nab-2011/

Which leads me to ask a question: would making use of 5 GHz by way of a dual band AP and some USB clients been a sensible solution?

If so, any recommendations for a dual-band AP that won't break the bank?

Would the RF nightmare in the 2.4 GHz band impact a dual band AP if most of its clients were in the 5 GHz range?

Michael

 

[stevech]

"For our company the one major annoyance of NAB 2011 was the complete failure of wifi on the show floor. From the last day of setup to the close of the event wifi was essentially useless. This was not a huge problem, but a considerable inconvenience. In our case it meant that the many sales and executive staff present could only access email via a wired network connection."

Yes, somewhat. However, few client devices support 802.11a or 802.11n for 5.8GHz.

But what WiFi access device were these people attempting to use? Did you have your own cat5 to your booth, then put an access point/router on that?

 

[mgraves]

Yes, we pay a company for a wired net drop to the booth. Then we arrange our local network with a Netgear AP. The trouble is that dozens of other exhibitors so the same thing, and the venue itself provides wifi to attendees for a fee. That's a lot of APs in the same physical space.

 

[stevech]

Yeah, in 2.4GHz WiFi, about all you can do is try changing the access point/router to use either of channels 1, 6 or 11. But there may be just too many transmissions from others' WiFi.

The client devices probably lack 5.8GHz capability. Some few would have it.

The problem isn't range/proximity to YOUR access point. It's that WiFi does "listen before transmit" (clear channel assessment). In a dense venue, this is like a freeway on-ramp at rush hour with metered lights!

 

[mgraves]

I would happily provide a handful of dual-band USB wifi interfaces if I had some confidence that the 5 GHz band was not as crowded as the 2.4 GHz band. That overcomes the lack of clients with the exception of a few tablets & cell phones.

 

[tannebil]

5Ghz can't do any worse than 2.4 did. There's more spectrum, fewer products, and less range (which should help with density) so it's worth trying next time. 5ghz works with a lot of Apple products although not the iPhone.

2.4 is only going to get worse with the personal hotspot support becoming common so 5ghz might be a good place to hide out for a couple of years.

 

[stevech]

My experience using 5.8GHz in urban areas is that it is quite underutilized.
In a high-tech conference center, I'd expect of course more use, but still channels with light or no loads.

YOU must set your access point/WiFi router to a lightly loaded channel! An auto-scan is not good, as it's just a brief snapshot in time.

 

[hceuterpe]

I live next to an apt complex. It's only 2 stories as is my house. I only live in the suburbs and we aren't part of a major metro area. I still have my entire backyard between them and me. With that said, I have Intel 6300 card and I can probably see around 30 unique MACs for APs, many of them sharing the same name (like NETGEAR and Linksys). Yet I do not see a single 5Ghz AP.

I can imagine it's only worse in an urban area. Assuming your building doesn't have thick radio killing walls, you are probably better off with 5Ghz. Just bear in mind 5Ghz attenuates much more, so the range is much lower.

2.4Ghz is quite limited. If you set your AP to channel 6 and force 40Mhz, you overlap all 11 channels! Considering the default is so commonly set at 6, there is definite possibility one of your neighbors has already done this.

 

[stevech]

It's not the number of SSIDs you detect, it's the transmission duty cycle (channel utilization) over time that's important, by channel 1, 6 and 11 in 2.4GHz. Lots more channels in 5.8GHz.

But again, It's not the number of SSIDs you detect.