Data source hand-off in a broadcast-based data dissemination environment

• US 6,463,265 B1
• Filed: 06/05/2001
• Issued: 10/08/2002
• Est. Priority Date: 06/05/2001
• Status: Expired due to Term

• Current Assignee: D-Link Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Cohen, Norman H., Yeh, Danny L., Wong, Luke, Purakayastha, Apratim
• Primary Examiner(s): Maung, Nay
• Assistant Examiner(s): GELIN, JEAN ALLAND
• Application Number:
  US09/874,095
• Time in Patent Office: 490 Days
• Field of Search: 455/152.1, 455/158.1, 455/186.1, 455/45, 455/134, 455/161.1, 455/161.2, 455/161.3, 455/150.1, 455/185.1, 455/188.1, 455/188.2, 455/194.2, 455/434, 455/436, 455/439
• US Class Current: 455/186.1
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 36/322 by location data
• CPC Class Codes: H04W 4/08 User group management

Abstract

A method, system, and apparatus for handing-off data receivers in a broadcast-based data dissemination environment. Data receiver hand-off is carried out between data sources in different data cells broadcasting information of the same category. Furthermore, data cell ranges are based on geographic regions rather than signal strength coverage. Generally, the hand-off process involves acquiring the current receiver location of the data receiver and comparing the receiver location with a current data cell range. If the current receiver location is outside the current data cell range, a hand-off controller searches for a new data source encompassing the current receiver location coordinates and having an associated data topic matching the current topic. Once a new data source is found, the hand-off controller subscribes the data receiver to the new data source.

Claims

1. A method for delivering data streams categorized by topic to at least one data receiver in a broadcast-based data dissemination environment, the method comprising:

defining a first data cell having a first data cell range, the first data cell created by at least one first base station having a first base station signal range, wherein the first data cell range is different than the first base station signal range;

defining a second data cell having a second data cell range, the second data cell created by at least one second base station having a second base station signal range, wherein the second data cell range is different than the second base station signal range;

subscribing the data receiver to a first data source when the data receiver is located at a first receiver position within the first data cell range, the first data source broadcasting a first data stream across a first data channel, the first data stream being categorized by a topic subject;

detecting when the data receiver is located at a second receiver position, the second receiver position being outside the first data cell range and within the second data cell range; and

subscribing the data receiver to a second data source when the data receiver is located at the second receiver position, the second data source broadcasting a second data stream across a second data channel, the second data stream having the same topic subject as the first data stream.

2. The method of claim 1, wherein detecting when the data receiver is located at the second receiver position further comprises acquiring location coordinates of the data receiver.

3. The method of claim 1, wherein detecting when the data receiver is located at the second receiver position further comprises comparing the second receiver position with the first data cell range.

4. The method of claim 3, wherein detecting when the data receiver is located at the second receiver position further comprises comparing the second receiver position with the second data cell range.

5. The method of claim 1, wherein subscribing the data receiver to the second data source further comprises opening the second data channel.

6. The method of claim 5, wherein subscribing the data receiver to the second data source further comprises coupling the data receiver with the second data stream.

7. The method of claim 1, wherein subscribing the data receiver to the second data source further comprises synchronizing the second data stream with the first data stream.

8. The method of claim 1, further comprising:

defining a data sub-cell range based on a geographic region; and

selectively filtering the second data stream when the data receiver is located within the data sub-cell range.

9. The method of claim 1, further comprising:

determining a probability distribution based on a position sample rate of the data receiver; and

preemptively opening the second data channel based on the probability distribution.

10. The method of claim 1, further comprising:

determining a probability distribution based on the data receiver velocity; and

preemptively opening the second data channel based on the probability distribution.

11. The method of claim 1, further comprising setting the second receiver position to a constant value.

12. The method of claim 1, further comprising adding a position offset to the first receiver position and the second receiver position.

13. A computer-readable medium having computer-executable instructions for performing the operations recited in claim 1.

14. A broadcast-based data dissemination system comprising:

a first data source having an associated first data cell range, an associated first signal broadcast range and an associated first data topic, the first data cell range being different than the first signal broadcast range, the first data source configured to broadcast a first data stream across a first data channel;

a data receiver having a current receiver position and subscribing to the first data source;

a second data source having an associated second data cell range, an associated second signal broadcast range and an associated second data topic matching the first data topic, the second data cell range being different than the second signal broadcast range, the second data source configured to broadcast a second data stream across a second data channel; and

a hand-off controller configured to subscribe the data receiver to the second data source if the current receiver position changes from the first data cell range to the second data cell range.

15. The broadcast-based data dissemination system of claim 14, further comprising a data channel proxy controller having a first input coupled to the first data stream, a second input coupled to the second data stream, and an output switchably coupled between the first input and the second input, the output being further coupled to the data receiver, the data channel proxy controller being configured to switch the output from the first input to the second input if the current receiver position changes from the first data cell range to the second data cell range.

16. The broadcast-based data dissemination system of claim 14, further comprising a speculative data channel controller configured to preemptively open the second data channel based on a probability distribution of a position sample rate of the data receiver.

17. The broadcast-based data dissemination system of claim 14, further comprising a speculative data channel controller configured to preemptively open the second data channel based on a probability distribution of the data receiver velocity.

18. The broadcast-based data dissemination system of claim 14, further comprising a data filter configured to selectively filter the second data stream when the data receiver is located within a data sub-cell range, the data sub-cell range being based on a third geographic region.

19. In a computer-readable medium having stored thereon a data structure for use in a hand-off process between data sources within a broadcast-based data dissemination environment, the data structure comprising:

a primary data source identifier field identifying at least one data source within the broadcast-based data dissemination environment, the data source including at least one base station having a signal broadcast range;

a data cell range field coupled to the primary data source identifier field, the data cell range field describing a geographical range of a data cell controlled by the data source, wherein the data cell range is different than the signal broadcast range; and

a communication link field coupled to the primary data source identifier field, the communication link field describing at least one data channel for receiving data streams from the data source.

20. The data structure of claim 19, further comprising a topics field, the topics field identifying data sources broadcasting data categorized by a common topic.

21. The data structure of claim 19, further comprising:

a data receiver identifier field identifying data receivers within the broadcast-based data dissemination environment;

a location information field coupled to the data receiver identifier field, the location information field describing geographical locations of the data receivers; and

a secondary data source identifier field coupled to the location information field, the secondary data source identifier field identifying data sources subscribed to by the data receivers.

22. A method for handing-off a data receiver to a data source in a broadcast-based data dissemination environment, the data receiver having a current receiver location and receiving a current data stream from a current data source, the current data source having a current topic and a current data cell range, the current data cell range being defined by a geographic region, the method comprising:

acquiring the current receiver location of the data receiver;

comparing the current receiver location with the current data cell range; and

if the current receiver location is outside the current data cell range;

searching for a new data source having an associated new data cell range encompassing the current receiver location and an associated data topic matching the current topic, the new data source including at least one base station having a signal broadcast range that is different than the new data cell range, wherein the new data source broadcasts a new data stream across a new data channel; and

subscribing the data receiver to the new data source.

23. The method of claim 22, wherein subscribing the data receiver to the new data source further comprises opening the new data channel.

24. The method of claim 22, wherein searching for a new data source further comprises comparing the current receiver location with the new data cell range.

25. The method of claim 22, wherein subscribing the data receiver to the new data source further comprises coupling the data receiver with the new data stream.

26. The method of claim 22, wherein subscribing the data receiver to the new data source further comprises synchronizing the new data stream with the current data stream.

27. The method of claim 22, further comprising:

determining a probability distribution based on a position sample rate of the data receiver; and

preemptively opening the new data channel based on the probability distribution.

28. The method of claim 22, further comprising:

determining a probability distribution based on the data receiver velocity; and

preemptively opening the new data channel based on the probability distribution.

29. The method of claim 22, further comprising adding a position offset to the current receiver location.

30. A computer-readable medium having computer-executable instructions for performing the operations recited in claim 22.

31. A data receiver configured to present a data stream from a data source in a broadcast-based data dissemination environment to a user, the data receiver comprising:

a position sensor configured to sense a current geographical location of the data receiver;

a broadcast receiver configured to receive a current data stream from a current data source, the current data source having a current topic and a current data cell range, the current data cell range being defined by a current geographic region;

a data source table identifying data sources, data cell ranges, and data channels within the broadcast-based data dissemination environment; and

a hand-off controller configured to subscribe the data receiver to a new data source listed in the data source table if the current geographical location of the data receiver is outside the current data cell range, the new data source having an associated new data cell range encompassing the current geographical location of the data receiver and an associated data topic matching the current topic, the new data source including at least one base station having a signal broadcast range different than the new data cell range.

32. The data receiver of claim 31, further comprising a topics table identifying data sources within the broadcast-based data dissemination environment broadcasting data streams with a common topic.

33. The data receiver of claim 31, further comprising a speculative data channel controller configured to preemptively open the second data channel based on a position sample rate of the data receiver.

34. The data receiver of claim 31, further comprising an output device configured to communicate the current data stream to the user.

35. The data receiver of claim 34, further comprising a data channel proxy controller configured to couple the new data stream to the output device if the current geographical location of the data receiver is outside the current data cell range and within the new data cell range.

36. The data receiver of claim 31, further comprising a data filter configured to selectively filter the current data stream when the current geographical location of the data receiver is within a data sub-cell range, the data sub-cell range being based on a sub-cell geographic region.