Pre-registration, storing of pre-registration session information and session transfer in a wireless communication system

• US 20090207805A1
• Filed: 02/14/2008
• Published: 08/20/2009
• Est. Priority Date: 02/14/2008
• Status: Active Grant

• Current Assignee: Alcatel-Lucent SA (Nokia Corporation)
• Original Assignee: Alcatel-Lucent SA (Nokia Corporation)
• Inventors: Zou, Jialin
• Granted Patent: US 8,842,632 B2
• Time in Patent Office: Days
• US Class Current: 370/331
• CPC Class Codes: H04W 60/04 using triggered events
• CPC Class Codes: H04W 76/00 Connection management

Abstract

Example embodiments are directed to a system and methods of pre-registration, storing of pre-registered session information and session transfer, which may occur when an access terminal is in close proximity to a border area between a first radio access technology (RAT) area and a second RAT area. A method includes obtaining pre-registration session information if an access terminal enters a pre-registration zone, starting a pre-registration session information timer associated with the obtained pre-registration session information, and storing the obtained pre-registration session information until the associated pre-registration information timer expires. Further, both an access terminal and an access network include one or more memories configured to store more than one group of pre-registration session information and more than one timer. Each of the timers are associated with a corresponding set of pre-registration session information.

Claims

1. A wireless communication method, the method comprising:

obtaining pre-registration session information if an access terminal in a first coverage area moves into a portion of the first coverage area defined as a pre-registration zone for a second coverage area, the second coverage area bordering the first coverage area;

starting a pre-registration session information timer associated with the obtained pre-registration session information; and

storing the obtained pre-registration session information until the associated pre-registration information timer expires.

2. The method of claim 1, further comprising:

deleting pre-registration session information if the pre-registration information timer associated with the obtained pre-registration information expires.

3. The method of claim 1, further comprising:

receiving a border indicator from an access network indicating the access terminal has entered the pre-registration zone; and

determining if previously stored pre-registration session information is available in the access terminal, wherein

the obtaining step reuses the previously stored pre-registration session information to communicate with the access network if the previous pre-registration session information is available, and pre-registers with the access network to negotiate the pre-registration session information if the previously stored pre-registration session information is not available.

4. The method of claim 1, further comprising:

sending a session transfer request to an access network indicating the access terminal is moving into the pre-registration zone of a second subnet of the second coverage area when there is only the pre-registered session information with a first subnet of the access network;

converting the obtained pre-registration session information associated with the first subnet to pre-registration session information associated with the second subnet; and

starting a new pre-registration information timer associated with the pre-registration session information associated with the second subnet.

5. The method of claim 1, further comprising:

transmitting a keep alive signal to an access network if the access terminal stays in the pre-registration zone for a predetermined time duration;

re-starting the pre-registration session information timer each time a keep alive signal is transmitted to the access network.

6. The method of claim 1, further comprising:

receiving a request from the access terminal requesting pre-registration session information for the second coverage area; and

determining if the request is a session transfer request, wherein

the obtaining step

converts previously-stored pre-registration session information associated with a first subnet to pre-registration session information associated with a second subnet and starts a new timer associated with the pre-registration information associated with the second subnet if the request is a session transfer request, and

pre-registers the access terminal to negotiate the pre-registration session information if the request is not a session transfer request.

7. The method of claim 1, further comprising:

receiving a keep alive signal from the access terminal;

re-starting the pre-registration session information timer each time a keep alive signal is received from the access terminal.

8. The method of claim 1, wherein at least a portion of signaling and messaging exchanges between an access network of the second coverage area and the access terminal are tunneled through the RAT of the first coverage area.

9. An access terminal comprising:

a transceiver configured to communicate with a first access network of a first coverage area having a first technology type and a second access network of a second coverage area having a second technology type;

a controller configured to control operations of the access terminal; and

a memory configured to store a plurality of pre-registration session information and a plurality of timers, each of the plurality of timers being associated with a corresponding one of the plurality of pre-registration session information stored in the memory, each of the pre-registration session information includes information for communicating with the second access network prior to a possible handoff from the first access network to the second access network.

10. The access terminal of claim 9, wherein the controller obtains pre-registration session information if the receiver receives broadcast information including a border indicator, starts the timer associated with the obtained pre-registration session information, and instructs the memory to store the obtained pre-registration session information until the timer expires.

11. The access terminal of claim 9, wherein the controller converts previously-stored pre-registration session information associated with a first subnet of the second coverage area to pre-registration session information of a second subnet of the second coverage area in response to the receiver receiving a different subnet indicator indicating the access terminal is moving from a first subnet into a second subnet, and starts a timer associated with the pre-registration session information associated with the converted pre-registration session information.

12. The access terminal of claim 9, wherein the controller deletes pre-registration session information if the corresponding timer expires.

13. The access terminal of claim 9, wherein the controller

instructs the transceiver to transmit a keep alive signal to the second access network if the access terminal stays in a pre-registration zone for the second coverage area for a time duration, the pre-registration zone for the second coverage area being a portion of the first coverage area bordering a border of the first coverage area and the second coverage area, and

re-starts the timer associated with pre-registration session information currently being used by the access terminal to communicate with the second access network.

14. The access terminal of claim 9, wherein the memory stores a predefined number of the plurality of pre-registered session information, and if the number is exceeded, an oldest of the plurality of pre-registration session information and corresponding timer is replaced with a newly transferred or negotiated plurality of pre-registration session information and newly started timer corresponding to the newly transferred or negotiated plurality of pre-registration information.

15. The access terminal of claim 9, wherein at least a portion of signaling and messaging exchanges between the second access network of the second coverage area and the transceiver of the access terminal are tunneled through a radio access technology of the first coverage area.

16. An access network comprising:

a transceiver configured to communication with at least one access terminal;

a controller configured to control operation of the access network; and

at least one memory configured to store a plurality of pre-registration session information associated with an access terminal and a plurality of timers, each of the plurality of timers being associated with a corresponding one of the plurality of pre-registration session information stored in the at least one memory, each of the plurality of pre-registration session information includes information for communicating with the access terminal prior to a possible handoff of the access terminal to the access network.

17. The access network of claim 16, wherein

the transceiver receives a request from the access terminal, and

the controller obtains pre-registration session information for the access terminal, and starts a timer associated with the obtained pre-registration session information.

18. The access network of claim 17, wherein the controller

determines if the request is a session transfer request, and

obtains the pre-registration session information by converting and transferring previous pre-registration session information residing at a first subnet to a second subnet and starts a new timer associated with the converted and transferred pre-registration information associated with the second subnet if the request is determined to be a session transfer request, and pre-registering the access terminal to negotiate the pre-registration session information if the request is determined not to be a session transfer request.

19. The access network of claim 16, wherein the controller instructs the at least one memory to delete pre-registration session information if the corresponding timer expires.

20. The access network of claim 16, wherein the controller restarts the timer associated with the obtained pre-registration information currently being used to communicate with the access terminal in response to the transceiver receiving a keep alive signal from the access terminal.