The preferred method of installing multiple wireless access points in a large house or office, is to use the same SSID for all of the access points whilst separating them onto different channels as much as possible. However, not all wireless clients will automatically switch to the strongest signal as you roam around the environment. I recently discovered a setting on Intel wireless cards that does just that, and has increased my connection significantly. My laptop no longer stays connected to an access point with poor signal, it switches to the nearest one very quickly.
The setting is called roaming aggressiveness, and can be found on the Advanced settings or your network adapter. Just change this up to 5:
See the following on the Intel site for more details:
I am also interested in how IOS devices (iphones and ipads) handle WiFi roaming, in my experience the answer is not very well. There is a support on the Apple site
iOS and OS X: Recommended settings for Wi-Fi routers and access points http://support.apple.com/kb/HT4199
This recommends setting the same SSID on all routers, but doesn’t mention what settings to use on the client (there aren’t any).