To allow wireless communication where an access point is not available or access to a wired network is not required, IEEE 802.11 provides ad hoc mode. Stations on an ad hoc WLAN communicate directly with each other. To join an ad hoc WLAN, a wireless station must be configured for ad hoc mode, given the same SSID as all the other stations, given suitable security settings, and set to use the same channel as all the other stations.
AdHoc Mode Info
Typically, wireless stations will not connect automatically to an ad hoc WLAN. Once one station is configured, however, assuming it broadcasts its SSID and does not use encryption; other users can join with one or two clicks in their wireless configuration software's "site survey" or "available networks" display.