Maintaining an IP connection in a mobile network

• US 8,285,200 B2
• Filed: 08/09/2010
• Issued: 10/09/2012
• Est. Priority Date: 06/21/2005
• Status: Expired due to Fees

• Current Assignee: Seven Networks LLC (SoftBank Group Corp.)
• Original Assignee: Seven Networks International Oy (SoftBank Group Corp.)
• Inventors: Everitt, Andrew, Vuornos, Lauri, Backholm, Ari, Salorinne, Seppo, Ahonen, Jukka, Daavittila, Mikko
• Primary Examiner(s): Batista, Marcos
• Application Number:
  US12/853,119
• Publication Number:
  US 20110051610A1
• Time in Patent Office: 792 Days
• Field of Search: 455/466, 455/9, 370/344
• US Class Current: 455/9
• CPC Class Codes: H04L 43/0811 by checking connectivity
• CPC Class Codes: H04L 67/14 Session management for real-time applications in data packet communications networks H04L65/1066
• CPC Class Codes: H04W 76/25 Maintenance of established connections
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]

Abstract

A method for IP [=Internet Protocol] communication between a mobile terminal and its correspondent node in a mobile radio network. The method comprises establishing (2-2) an IP connection between the mobile terminal and its correspondent node. After detecting a period of inactivity in the IP connection, (2-4) keep-alive messages are sent via the IP connection at predetermined intervals, which are varied. The method comprises monitoring (2-6) the lengths of several periods of inactivity at which the mobile radio network disconnects the IP connection. Based on the monitored lengths of periods of inactivity, a maximum interval (T_INT) between keep-alive messages is determined (2-8) such that the maximum interval meets a predetermined criterion of statistical confidence, and the interval between keep-alive messages is set (2-1) to the maximum interval (T_INT).

Claims

1. A method of maintaining a connection between a mobile terminal and a network element in a network, the method, comprising:

exchanging keep alive messages between the mobile terminal and the network element over an Internet Protocol connection;

altering a time interval between the keep alive messages exchanged between the mobile terminal and the network element;

monitoring the Internet Protocol connection to determine if disconnection of the IP connection occurs as a result of the altering of the time interval between the keep alive messages;

determining a value for the time interval, the value being determined such that the Internet Protocol connection with the network element is not disconnected and further determined based on an associated cost to send the keep-alive messages;

wherein, the cost to send the keep-alive messages includes battery life of the mobile terminal;

wherein, the time intervals are further determined based on a cumulative probability function for the disconnection of the IP connection as a function of the time interval; and

setting the time interval to be the value.

2. The method of claim 1, further comprising re-establishing the Internet Protocol connection between the mobile terminal and the network element when the Internet Protocol connection is disconnected.

3. The method of claim 1, wherein exchanging the keep alive messages comprises sending the keep alive messages from the mobile device.

4. The method of claim 1, wherein exchanging the keep alive messages comprises sending the keep alive messages from the network element.

5. The method of claim 1, wherein, the value satisfies a statistical confidence;

wherein the statistical confidence is a variance.

6. The method of claim 5, wherein the statistical confidence is based on a safety margin, and further, wherein the safety margin is based on one or more of:

an amount of time subtracted from the value of the time interval;

a percentage of the value of the time interval.

7. The method of claim 5, wherein the statistical confidence is based on a cumulative probability function for the disconnection of the Internet Protocol connection as a function of the time interval.

8. The method of claim 5, wherein altering the time interval comprises altering the time interval in both a predetermined and a variable manner.

9. The method of claim 1, further comprising storing the value for the time interval with an identifier of the network.

10. The method of claim 9, wherein the value for the time interval and the identified of the network are stored in the mobile device.

15. The network element of claim 1, wherein altering the time interval comprises altering the time interval in one or more of a predetermined and a variable manner.

11. A network element operative to maintain a connection with a mobile terminal in a mobile network, the network element, comprising:

an electronic processor programmed to execute a set of instructions;

a data storage device coupled to the processor; and

the set of instructions contained in the data storage device, wherein the set of instructions are executed by the processor, the network element maintains the connection between the mobile terminal and the network element by;

sending keep alive messages from the network element over an Internet Protocol connection, the keep alive messages being arranged with successive keep alive messages being separated by a time interval;

altering a time interval between the keep alive messages exchanged between the mobile terminal and the network element;

monitoring the Internet Protocol connection to determine if disconnection of the IP connection occurs as a result of the altering of the time interval between the keep alive messages;

determining a value for the time interval, the value being determined such that the Internet Protocol connection with the network element is not disconnected and further based on battery life of the mobile terminal and a battery consumption involved in re-establishing the IP connection;

wherein, the time intervals are further determined based on a cumulative probability function for the disconnection of the IP connection as a function of the time interval.

12. The network element of claim 11, wherein, the value satisfies a criterion of statistical confidence.

13. The network element of claim 12, wherein the criterion of statistical confidence is based on a safety margin, and further, wherein the safety margin is based on one or more of:

an amount of time subtracted from the maximum value of the time interval;

a percentage of the maximum value of the time interval;

or

a cost associated with sending the keep alive messages.

14. The network element of claim 11, wherein the criterion of statistical confidence is based on a cumulative probability function for the disconnection of the Internet Protocol connection as a function of the time interval.

16. A method of maintaining an IP connection between a mobile terminal and a network node over a network, comprising:

sending, by the mobile terminal to the network node, keep-alive messages in an absence of network traffic through the IP connection between the mobile terminal and the network node;

dynamically adjusting time intervals between the keep-alive messages sent by the mobile terminal;

further optimizing the time intervals between the keep alive messages based on a cost to send the keep-alive messages in the network and based on whether the keep-alive messages are sent with adequate frequency to maintain the IP connection;

wherein, the cost to send the keep-alive messages includes battery life of the mobile terminal;

wherein, the time intervals are further determined based on a cumulative probability function for the disconnection of the IP connection as a function of the time interval.

17. The method of claim 16, wherein, the time intervals are adjusted according to statistical characteristics of the communication history across the IP connection.

18. The method of claim 16, wherein, the cost further includes the cost to re-establish the IP connection in the event of disconnection.

19. The method of claim 16, wherein, the cost further includes a battery consumption involved in re-establishing the IP connection.

20. A method of maintaining an IP connection between a mobile terminal and a network node over a network, comprising:

sending keep-alive messages between the mobile terminal and the network node in an absence of network traffic through the IP connection between the mobile terminal and the network node;

dynamically adjusting time intervals between the keep-alive messages sent across the IP connection between the mobile terminal and the network node;

optimizing the time intervals between the keep alive messages based on battery life of the mobile terminal and further based on whether the keep-alive messages are sent with adequate frequency to maintain the IP connection;

wherein, the time intervals are further determined based on a cumulative probability function for the disconnection of the IP connection as a function of the time interval.

21. The method of claim 20, wherein, the time intervals are adjusted dynamically based on network behavior,

wherein, the network behavior includes a regularity with which the network breaks up inactive connections.

22. The method of claim 20, wherein, the keep-alive messages are sent from a server connected to the network.

23. The method of claim 20, wherein, the keep-alive messages are sent from the mobile device to the network node.