Abstract: A location update method, and a heterogeneous network communications system and a device are provided herein. The method includes: an information server receives a location update request message from a multimode terminal; the information server searches the pre-stored location area mapping information for the location area information of the second interface; and the information server sends the location update request message of the second interface to a second Paging Coordinator (PC) corresponding to the second interface, where the request message carries the found location area information of the second interface so that the second PC can update existing location area information of the second interface. The system includes an information server, a first PC and a second PC.

Abstract: A method of paging for a wireless device with multiple radio interfaces corresponding to multiple access networks. The method provides a first interface from the multiple radio interfaces to listen to paging for the multiple radio interfaces; turns the rest of the multiple radio interfaces into deep-sleep mode; and maintains attachment for each of the deep-sleep interfaces to a corresponding serving base station or access point.