Selection of network access entity in a communication system

• US 20040208144A1
• Filed: 05/06/2004
• Published: 10/21/2004
• Est. Priority Date: 03/23/2004
• Status: Active Grant

• Current Assignee: WSOU Investments, LLC (WSOU Holdings, LLC)
• Original Assignee: Nokia Corporation
• Inventors: Vinayakray-Jani, Preetida
• Granted Patent: US 7,362,731 B2
• Time in Patent Office: Days
• US Class Current: 370/331
• CPC Class Codes: H04W 48/18 Selecting a network or a communication service

Abstract

A mechanism for selecting a serving network access entity for a mobile node in a communication system including network access entities broadcasting periodic advertisement messages. The method utilizes a waiting period measured from a first reference moment. When no advertisement message is received within the waiting period from the network access entity being currently the serving network access entity for the mobile node, the node issues a router solicitation message and initiates a measurement of a solicitation period from a second reference moment. The mobile node further monitors whether a response to the router solicitation message is received from the network access entity within the solicitation period, and based on the monitoring step decides whether it remains connected to the said network access entity.

Claims

1. A method for selecting a serving network access entity for a mobile node in a communication system comprising network access entities broadcasting periodic advertisement messages, the method comprising the steps of:

receiving a first advertisement message from a first network access entity currently acting as a serving network access entity for the mobile node;

starting measurement of a waiting period at a first reference moment;

issuing a solicitation message when no new advertisement message is received from the first network access entity during the waiting period;

in response to the issuing step, initiating measurement of a solicitation period at a second reference moment;

monitoring whether a response to the solicitation message is received from the first network access entity during the solicitation period; and

selecting a serving network access entity for the mobile node based on the monitoring step.

2. The method according to claim 1, wherein the starting step includes starting the measurement of the waiting period if a first advertisement message is received from the first network access entity.

3. The method according to claim 1, further comprising a step of preserving the first network access entity as the serving network access entity if a new advertisement message is received from the first network access entity during the waiting period.

4. The method according to claim 1, wherein the initiating step includes initiating the measurement of the solicitation period during the issuing step.

5. The method according to claim 3, wherein the selecting step includes preserving the first network access entity as the serving network access entity if the response is received from the first network access entity during the solicitation period.

6. The method according to claim 5, further comprising a step of receiving a second advertisement message from a second network access entity.

7. The method according to claim 6, further comprising a step of selecting the second network access entity as the serving network access entity if the mobile node fails to receive a response from the first network access entity during the solicitation period.

8. The method according to claim 1, further comprising a step of controlling a length of the waiting period.

9. The method according to claim 1, further comprising a step of controlling a length of the solicitation period.

10. The method according to claim 8, wherein the controlling step is performed in dependence on an application communicating through the serving network access entity, the application residing in the mobile node.

11. The method according to claim 8, wherein the waiting period is controllable between zero and an upper limit which is no more than a fixed value that substantially corresponds to a period between two consecutive advertisement messages broadcast by the serving network access entity.

12. The method according to claim 1, wherein the solicitation period is substantially shorter than the waiting period.

13. The method according to claim 1, wherein the mobile node is assigned a network address enabling traffic to be routed through the serving network access entity to the mobile node, the method further comprising a step of updating the network address in response to the selecting step.

14. The method according to claim 1, further comprising a step of transferring the mobile node to a hold state by stopping the measurement of the waiting period.

15. The method according to claim 14, further comprising a step of transferring the mobile node from the hold state to a measurement state by allowing the measurement of the waiting period to continue.

16. A mobile node for a communication system comprising network access entities broadcasting periodic advertisement messages, the mobile node comprising:

reception means for receiving advertisement messages from network access entities;

first timer means, responsive to the reception means, for measuring a waiting period starting from a first reference moment;

triggering means, responsive to the first timer means, for triggering an issuance of a solicitation message when the mobile node fails to receive an advertisement message from a first network access entity during the waiting period, the first network access entity acting as a serving network access entity that provides connectivity for the mobile node;

second timer means, responsive to the triggering means, for measuring a solicitation period starting from a second reference moment;

monitoring means for monitoring if a response is received from the first network access entity during the solicitation period; and

selection means, responsive to the monitoring means, for selecting a serving network access entity for the mobile node.

17. The mobile node according to claim 16, wherein the first timer means measures from the first reference moment, and wherein the first reference moment substantially corresponds to a moment of reception of an advertisement message from the first network access entity.

18. The mobile node according to claim 16, wherein the second timer means measures from the second reference moment, and wherein the second reference moment substantially corresponds to a moment of the issuance of the solicitation message.

19. The mobile node according to claim 16, wherein the selection means is configured to preserve the first network access entity as the serving network access entity if an advertisement message is received from the first network access entity during the waiting period.

20. The mobile node according to claim 19, wherein the selection means is further configured to preserve the first network access entity as the serving network access entity if the response is received from the first network access entity during the solicitation period.

21. The mobile node according to claim 20, wherein the selection means is further configured to select a second network access entity as the serving network access entity if the mobile node fails to receive a response from the first network access entity during the solicitation period, the second network access entity comprising a network access entity from which the mobile node is currently receiving advertisement messages.

22. The mobile node according to claim 16, wherein the mobile node further comprises first controlling means for controlling a length of the waiting period.

23. The mobile node according to claim 16, wherein the mobile node further comprises second controlling means for controlling a length of the solicitation period.

24. The mobile node according to claim 22, wherein the first controlling means is configured to control the length of the waiting period in dependence on an application communicating through the serving network access entity, the application residing in the mobile node.

25. The mobile node according to claim 24, wherein the mobile node comprises a data repository for storing application-specific information indicating the length of the waiting period.

26. The mobile node according to claim 25, wherein the data repository is in a module removable from the mobile node.

27. A computer usable medium having computer readable program code embodied therein to enable a mobile node to select a serving network access entity in a communication system comprising network access entities broadcasting periodic advertisement messages, the computer readable program code comprising:

a first computer readable program code portion for causing the mobile node to start measurement of a waiting period from a first reference moment with respect to an advertisement message received from a first network access entity acting as a serving network access entity for the mobile node;

a second computer readable program code portion for causing the mobile node to issue a solicitation message when no new advertisement message is received from the first network access entity within the waiting period;

a third computer readable program code portion for causing the mobile node to initiate measurement of a solicitation period from a second reference moment;

a fourth computer readable program code portion for causing the mobile node to monitor whether a response to the solicitation message is received from the first network access entity during the solicitation period; and

a fifth computer readable program code portion for causing the mobile node to select a serving network access entity for the mobile node based on the monitoring performed.

28. The computer usable medium according to claim 27, wherein the first, second, third, fourth, and fifth computer readable program code portions are stored in a memory card insertable into the mobile node.

29. The computer usable medium according to claim 27, wherein the first, second, third, fourth, and fifth computer readable program code portions are stored in the mobile node.

30. A mobile node configured to be used in a communication system comprising network access entities broadcasting periodic advertisement messages, the mobile node comprising:

a receiver configured to receive advertisement messages from network access entities;

a first timer, responsive to the receiver, configured to measure a waiting period starting from a first reference moment;

a first controller, responsive to the first timer, configured to trigger an issuance of a solicitation message if the mobile node fails to receive an advertisement message from a first network access entity during the waiting period, the first network access entity being configured to act as a serving network access entity that provides connectivity for the mobile node;

a second timer, responsive to the first controller, configured to measure a solicitation period starting from a second reference moment;

a second controller configured to monitor if a response is received from the first network access entity during the solicitation period; and

a third controller, responsive to the second controller, configured to select a serving network access entity for the mobile node.