Enhanced cross-network handoff for mobile IP service mobility

• US 8,145,210 B2
• Filed: 12/29/2006
• Issued: 03/27/2012
• Est. Priority Date: 12/29/2006
• Status: Active Grant

• Current Assignee: United States Cellular Corporation (Telephone & Data Systems, Inc.)
• Original Assignee: United States Cellular Corporation (Telephone & Data Systems, Inc.)
• Inventors: Thalanany, Sebastian, Irizarry, Michael, Saxena, Narothum
• Primary Examiner(s): Corsaro, Nick
• Assistant Examiner(s): Ngo, Chuong A
• Application Number:
  US11/618,534
• Publication Number:
  US 20080159232A1
• Time in Patent Office: 1,915 Days
• Field of Search: 370/331, 370/332, 370/395.21, 370/395.3, 370/238, 455/422, 455/432.1, 455/433, 455/435.1, 455/442, 455/452.1, 455/452.2, 455/445
• US Class Current: 455/432.1
• CPC Class Codes: H04W 36/0016 Hand-off preparation specially adapted for end-to-end data sessions
• CPC Class Codes: H04W 36/0019 adapted for mobile IP [MIP]
• CPC Class Codes: H04W 36/144 over a different radio air interface technology
• CPC Class Codes: H04W 48/18 Selecting a network or a communication service
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]

Abstract

A system and method are described whereby an enhanced handoff scheme provides for monitoring of mobile device conditions and network conditions associated with a current access network attachment, as well as with a plurality of access networks on a preferred access network list, to proactively initiate a handoff operation, thereby preserving the QoS constraints necessary for seamless delivery of IP multimedia services. In an embodiment, each of the plurality of access networks is connected to an IMS core network, whereby a policy function receives quality of service constraints associated with the launched application from the mobile device and orders a list of preferred access networks accordingly. Preferably, the policy function selects an appropriate access gateway associated with a target access network based at least in part on the mobile device conditions reported by the mobile device and the access network conditions monitored by the policy function.

Claims

1. A method for maintaining an IP network session according to quality of service constraints for an application running on a mobile user device, the method comprising:

receiving a list of preferred access networks for the mobile user device, the list comprising a plurality of access networks authorized for the mobile user device;

receiving the quality of service constraints from the mobile user device;

establishing the IP network session via a first access network based on the quality of service constraints, wherein the first access network is one of the plurality of networks;

monitoring mobile user device conditions for the first access network and at least some of the plurality of networks on the list of preferred access networks to determine whether the first access network is able to maintain the IP network session with the mobile user device in accordance with the quality of service constraints for the application; and

transferring, when the first access network is not able to maintain the IP network session with the mobile user device in accordance with the quality of service constraints, the IP network session to a second access network, the second access network being selected based at least in part on the mobile user device conditions, the mobile user device conditions including at least one of the group consisting of;

a mobility direction indicator configured to indicate an access network technology type corresponding to the second access network, and

a battery consumption indicator configured to indicate a battery life status of the mobile user device to be taken into account with the access network technology type of the second access network for selecting the second access network among the plurality of access networks in the preferred access network list.

2. The method of claim 1 further comprising ordering the list of preferred access networks based on the quality of service constraints.

3. The method of claim 1 further comprising:

monitoring access network conditions for the first access network and at least some of the plurality of networks on the preferred access network list;

selecting the second access network among the plurality of access networks in the preferred access network list for transferring the IP network session based on the access network conditions; and

wherein the access network conditions comprise one or more network condition triggers for each of the plurality of access networks, the network condition triggers associated with the quality of service constraints for the application.

4. The method of claim 3 wherein the network condition triggers include a plurality of thresholds comprising a bandwidth threshold, a latency threshold, a packet loss threshold, and a capacity threshold.

5. The method of claim 1 wherein the mobile user device conditions include a received signal quality indicator.

6. The method of claim 5 further comprising ordering the at least some of the plurality of networks from the list of preferred access networks according to the received signal quality indicator.

7. The method of claim 5 wherein the received signal quality indicator comprises at least one of a received signal strength indicator, a bit error rate indicator, and a signal-to-noise ratio indicator.

8. The method of claim 1 wherein the mobile user device is capable of accessing a cellular network and a Wi-Fi network.

9. The method of claim 1 further comprising controlling the IP network session via an IP Multimedia Subsystem (IMS) core network, wherein each of the plurality of access networks is connected to the IMS core network.

10. A system for maintaining an IP network session according to quality of service constraints for an application running on a mobile user device, the system comprising:

a policy function server having a list of preferred access networks for the mobile user device, the list comprising a plurality of access networks authorized for the mobile user device;

the mobile user device capable of initiating the IP network session for the application on a first access network according to the quality of service constraints, wherein the mobile user device monitors mobile user device conditions associated with the first access network and at least some of the plurality of networks on the list of preferred access networks; and

wherein the policy function server is adapted to transfer the IP network session for the mobile user device to a second access network when the first access network is not able to maintain the IP network session with the mobile user device in accordance with the quality of service constraints, the second access network being selected based at least in part on the mobile user device conditions, the mobile user device conditions including at least one of the group consisting of;

a mobility direction indicator configured to indicate an access network technology type corresponding to the second access network, and

a battery consumption indicator configured to indicate a battery life status of the mobile user device to be taken into account with the access network technology type of the second access network for selecting the second access network among the plurality of access networks in the preferred access network list.

11. The system of claim 10 wherein the policy function server orders the list of preferred access networks based on the quality of service constraints.

12. The system of claim 10 wherein the policy function server monitors access network conditions for the first access network and at least some of the plurality of networks on the preferred access network list and selects the second access network among the plurality of access networks in the preferred access network list for transferring the IP network session based on the access network conditions, the access network conditions comprising one or more network condition triggers for each of the plurality of access networks, the network condition triggers associated with the quality of service constraints for the application.

13. The system of claim 12 wherein the network condition triggers include a plurality of thresholds comprising a bandwidth threshold, a latency threshold, a packet loss threshold, and a capacity threshold.

14. The system of claim 10 wherein the mobile user device conditions include a received signal quality indicator.

15. The system of claim 14 wherein the mobile user device orders the at least some of the plurality of networks on the list of preferred access networks according to the received signal quality indicator.

16. The system of claim 14 wherein the received signal quality indicator comprises at least one of a received signal strength indicator, a bit error rate indicator, and a signal-to-noise ratio indicator.

17. The system of claim 10 wherein the mobile user device is capable of accessing a cellular network and a Wi-Fi network.

18. The system of claim 10 further comprising an IP Multimedia Subsystem (IMS) core network for controlling the IP network session, wherein each of the plurality of access networks is connected to the IMS core network.

19. A mobile user device for running an application by initiating an IP network session on a first access network according to quality of service constraints for the application, wherein the mobile user device monitors at least one handoff parameter associated with the first access network and one or more additional access networks and sends the at least one handoff parameter to a policy function server when the first access network is not able to maintain the IP network session with the mobile user device in accordance with the quality of service constraints for the application;

and

wherein, in response to receiving the at least one handoff parameter, the policy function server transfers the IP network session with the mobile user device to a second access network, the second access network being selected based at least in part on the at least one handoff parameter, the at least one handoff parameter including at least one of the group consisting of;

a mobility direction indicator configured to indicate an access network technology type corresponding to the second access network, and

a battery consumption indicator configured to indicate a battery life status of the mobile user device to be taken into account with the access network technology type of the second access network for selecting the second access network.

20. The mobile user device of claim 19 wherein the policy function server includes a list of preferred access networks for the mobile user device, the list ordered based on the quality of service constraints.

21. The mobile user device of claim 20 wherein the policy function selects the second access network based on the at least one handoff parameter and the list of preferred access networks ordered based on the quality of service constraints.

22. The mobile user device of claim 19 wherein the at least one handoff parameter further comprises an ordered list of the one or more additional access networks based on a received signal quality monitored by the mobile user device.

23. The mobile user device of claim 22 wherein the received signal quality comprises at least one of a received signal strength indicator, a bit error rate indicator, and a signal-to-noise ratio indicator.

24. The mobile user device of claim 19 wherein the mobile user device is capable of accessing a cellular network and a Wi-Fi network.