A method and a system for wireless terminals registering a communication
system, comprising wireless terminals, public land mobile network (PLMN),
wireless local area network (WLAN), Wherein the wireless terminals are
able to communicate with both the PLMN and the WLAN. The PLMN coverage
overlaps the WLAN coverage linking the two together. First, the wireless
terminal obtains an ID, attaches to a PLMN, and then transmits the ID to
PLMN to authenticate and register. After authentication, the PLMN
generates an authentication code and transmits the code to a wireless
terminal. Additionally, the PLMN transmit the authentication code to at
least one WLAN. The wireless terminals must communicate with at least one
WLAN.