How to prepare WiFi for an on-stage demo?

Question

Today at WWDC, Steve Jobs gave his keynote and ended up having a failure on-stage when connecting to WiFi. Google had a similar issue a few weeks ago in the same conference center. Please reference the following article for more information.

http://news.cnet.com/8301-31021_3-20007009-260.html

I am looking for information on how to best prepare a demo which uses a closed wireless network in front of a large audience. Note that the network will be closed, and will not require internet access.

What steps can I take to prevent interference from existing WiFi, Bluetooth, etc? How can I best prevent curious/malicious people from trying to intrude on my WiFi network?

Using a wired network is not an option. A common scenario for me would be: PC server & one or more PC clients (Mac, Linux, Win, whatever) and one or more consumer mobile devices (iPhone, Nexus One, etc).

I am open to recommendations on specific models of routers.

Answer 1

Use a combination of proximity, directionality, less popular band, and increased transmit power:

• Put your wireless access point nearby your lectern or wherever your client device is going to be located, so you swamp other, more distant sources.
• Put a directional antenna on your AP, aimed toward your device and away from the preponderance of interfering devices. Also helps swamp the other sources. A directional antenna on your device will help too, if that's a possibility.
• Use -a or -n mode to limit the population of interfering and requesting devices.
• Use a firmware-modified AP that lets your boost its power (this last will help your AP's transmissions cut through the noise, but won't help your device's ability).

Answer 2

Use a wired network.

Seriously. You could lock down a Wifi router so that it only accepts one client's MAC, but that's not going to prevent connection requests from other clients in range. You could force people to give up their wifi-enabled devices at the door, and keep the devices physically out of range, but that will annoy your audience. You could use some proprietary frequency so that interference from Wifi or bluetooth is impossible, but that will require expensive or modified hardware.

Answer 3

It might be possible to use a directional Wi-Fi antenna to boost the reception within a limited area (i.e., the stage). And clearly the wireless network should be encrypted to help prevent malicious access. If there must be public Wi-Fi, then ideally the access points for this would be at the opposite end of the room, for what it's worth.

See also this related question at Server Fault.

Answer 4

You could use a not-so-common 802.11 A router or 5 GHz 802.11 N. Each are on the 5 GHz frequency and the more common 802.11 b g n on 2.4 GHz will not cause dramatic interference.

Make the network closed so that it will not answer for connection requests without credentials.

The issue then becomes whether your devices support it. Most recent laptops do; few cell phones do; iPads do.

Wikipedia 802.11