Ask Slashdot: Overcoming Convention Hall Wi-Fi Interference?

bbowman writes "One of my job responsibilities is to set up the small network for our company's exhibit at the trade shows we attend. The mobile demo devices we use depend upon a reliable Wi-Fi connection to a router I have in the exhibit. In the days leading up to the opening of the trade show, W-iFi connections are reliable and work as expected. However, as soon as the show opens none of our devices can reliable maintain a Wi-Fi connection to the router. The devices we use at the trade shows are Windows-based laptops, iPods/iPads, Android tablets, and a variety of Wi-Fi enabled cell phones. I have tried using channels 1, 6, and 11 (as well as the others) and used different routers (Linksys, D-Link, Netgear) without success. I'm sure it is likely that there are poorly insulated electrical cabling, fluorescent lighting, and other issues that would contribute to Wi-Fi interference in the convention hall. A quick scan shows dozens and dozens of discoverable Wi-Fi networks nearby. If I take the router back to my hotel room, I have zero connection problems. How can I overcome this so that Wi-Fi works reliably in the convention hall?"

Comments

Just ask What would Jobs do?

[arcite]

Then stand up and announce on the loud speaker in a polite English accent to everyone; "So you guys have a choice: Either turn off your Wi-Fi (devices) or I give up. Would you like to see the demos?" ......"Then all you bloggers need to turn off your notebooks. Go ahead, just shut the lids. I'll wait," he said.

I'm sure everyone will understand.

Get ye some 802.11a.

[FooAtWFU]

802.11a has a lot more spectrum. Aside from that, hoping that you can drown out everyone else's screaming really isn't going to work.

Alternatively, install a giant metal Faraday cage. (Good luck with that.)

New Frequency?

[BadPirate]

If your devices are 802.11n compatible, you could put your router in n only mode... The 5.4ghz band may be less crowded.

FYI Steve Jobs routinely uses out of spec channels

[tlambert]

FYI Steve Jobs routinely uses out of spec channels. For WWDC, this used to be channel 13, which is not licensed for use in the US, but is in Japan.

This got to be a problem (leading to the famous "you've got a choice..." speech) when enough Japanese Mac developers attended without changing their locale, and all the Japanese machines ended up on channel 13 because it was "less crowded" (for obvious reasons).

-- Terry

Wrong assumptions

[mrmagos]

Given this:

In the days leading up to the opening of the trade show, W-iFi connections are reliable and work as expected. However, as soon as the show opens none of our devices can reliable maintain a Wi-Fi connection to the router.

I doubt it's this:

I'm sure it is likely that there are poorly insulated electrical cabling, fluorescent lighting, and other issues that would contribute to Wi-Fi interference in the convention hall.

...and more likely this:

A quick scan shows dozens and dozens of discoverable Wi-Fi networks nearby.

I would recommend trying a few things:
- Reduce your RTS threshold, if your AP supports it.
- Reduce the fragmentation threshold, if your AP supports it.
- Play with data rates, reducing them if your AP supports it.

If your AP does not support any of those options, go out and get a real AP.

Re:Wrong assumptions

[Anonymous Coward]

I'll go with Upgrade The Access Point...

Quoting a post to the SoCal FreeNet list on July 21, 2011 by Matt:

Just an interesting tidbit. I was asked to help out with the soccer game at Qualcomm Stadium last night. They had a special area on the field for the photographers and wanted to be able to have the photographers connected to the net to upload their pictures to their respective news agencies without leaving the field. Just off the tunnel that the players come out is the "media room" where we have just a little Netgear wireless router/access point for the photographers to use during Chargers games, so I just grabbed that, ran 280 ft of CAT-5 out to the field plunked down the Netgear, and set it to WPA2 encryption. I tested it thoroughly the day before the game. The next day, a few minutes after the game started, I got called down to the field because the wireless wasn't working. Everyone was associated with the SSID, but it wouldn't pass any traffic. So I power cycled it, and went back upstairs, and was called back down within minutes. With all the fans in attendance, many of them with wireless enabled smartphones, keeping track of all the wifi in the air must have been too much for the little Netgear, the thing couldn't pass traffic for more than 5 minutes between reboots.

So, plan B, went up to the media booths which weren't really being used for this game, and snagged a crusty old Cisco Aironet 1121B (yes, 802.11b) and put it in place of the Netgear on the field, even left it unsecured as I didn't have time to much about with it. Long story short, not a peep out of it the rest of the game.

I had been told many years ago, that what happens is the mac table of the cheaper wifi gear gets full trying to keep track of all the mac addresses it sees flying around the air, but I haven't confirmed this. Long story short, an old crusty Aironet is better than a fancy new consumer grade AP for large events any day of the year.

Directional antenna

[Scutter]

Why not simply use a narrow-field directional antenna for your demo? If you're just feet away from it, it seems unlikely that other nearby networks would be strong enough to drown out the signal.

Dish Antenna

[jmcharry]

Perhaps the router could be connected to a dish above the booth pointed straight down like a street light. This could overpower other signals in your booth and reduce your interference to other users. Dishes at wifi frequencies aren't large.

Re:Nicolas Cage

[clyde_cadiddlehopper]

http://en.wikipedia.org/wiki/Nicolas_cage