Method of paging a mobile terminal

1. In a wireless network which comprises a plurality of base stations that includes at least a first subnet and a second subnet of base stations and a plurality of access network gateways, a method for tracking and/or paging a mobile terminal, wherein the method comprises the steps of:

providing a mobile terminal located within the first subnet of said wireless network and wherein said mobile terminal is in an active mode and communicating with a first base station in the first subnet of base stations;

selecting a first access network gateway out of said plurality of access network gateways to be an anchor gateway for location and/or paging control associated with said mobile terminal;

providing said mobile terminal with information that allows identifying said anchor gateway;

following a period during which said mobile terminal has been in an idle mode, receiving a message at a second base station from said mobile terminal, said message being for carrying out a location update for said mobile terminal and comprising an indication that allows identifying said anchor gateway, said second base station being located in the second subnet;

informing said anchor gateway by said second base station that a request to perform said location update has been made; and

upon receiving, at said anchor gateway the request for a location update of said mobile terminal, said anchor gateway provides said second base station with information required for verifying the identity of said mobile terminal and/or for retaining the security integrity of said second base station while carrying out location update of said mobile terminal.

2. A method according to claim 1 , wherein said second base station is other than the base station with which said mobile terminal was in communication prior to its entering the idle mode.

3. A method according to claim 1 , wherein said anchor gateway comprised in said wireless network is adapted to implement authentication location registering and/or paging controlling functionalities associated with said mobile terminal.

4. A method according to claim 1 , further comprising a step of providing said mobile terminal with information to allow identification of said anchor gateway, which comprises:

providing said mobile terminal with a paging controller ID (PCID) parameter; and

providing said mobile terminal with a value associated with the PCID, indicating which access network gateway will be its corresponding anchor authenticating gateway.

5. A method according to claim 1 , further comprising a step of updating said anchor gateway about said mobile terminal's location, at times after the latter has entered an idle mode.

6. A method according to claim 1 , further comprising the a step of defining at least one virtual group comprising a plurality of base stations each associated with said access wireless network and located in a geographical vicinity from each other.

7. A method according to claim 6 , and wherein upon exiting the geographical vicinity of said virtual group of the plurality of base stations, said mobile terminal initiates a request to update its own location.

8. A method according to claim 7 , wherein a base station receiving said request, communicates with said anchor gateway to confirm the authenticity of the request thus received and to update information at said anchor gateway, which relates to the current location of the mobile terminal.