Methods and systems for controlling handoffs in a wireless communication system

• US 20050026618A1
• Filed: 07/29/2003
• Published: 02/03/2005
• Est. Priority Date: 07/29/2003
• Status: Active Grant

• Current Assignee: WSOU Investments, LLC (WSOU Holdings, LLC)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Lawrence, Victor B., Gehlot, Narayan L.
• Granted Patent: US 7,197,310 B2
• Time in Patent Office: Days
• US Class Current: 455/440
• CPC Class Codes: H04W 36/32 by location or mobility data, e.g. speed data
• CPC Class Codes: H04W 36/322 by location data

Abstract

Techniques for controlling handoffs in a wireless communication system include receiving a location vector from a mobile unit, and determining whether to perform a handoff of the mobile unit based on the received vector. The vector may also include time information related to the time at which the vector was transmitted. The vector may be obtained from a GPS satellite signal or one or more terrestrial stations.

Claims

1. A method for controlling handoffs in a wireless communication system, comprising the steps of:

receiving a location vector associated with a mobile unit; and

determining whether to perform a handoff of the mobile unit based on the received vector.

2. The method of claim 1, further comprising the steps of:

transmitting the location vector to the mobile unit, wherein the vector includes location and time coordinates; and

receiving a response from the mobile unit based on the transmitted vector.

3. The method of claim 1, wherein the location vector comprises Global Positioning System (GPS) data.

4. The method of claim 1 wherein the location vector comprises terrestrial data.

5. The method of claim 2, wherein the determining step further comprises the step of determining whether to perform the handoff based on the received response.

6. The method of claim 1, wherein the determining step further comprises the step of calculating a magnitude of the received vector, wherein the magnitude corresponds to a coverage area of a base station.

7. The method of claim 6, wherein the determining step further comprises the steps of:

receiving one or more magnitudes corresponding to coverage areas of one or more other base stations;

comparing the calculated magnitude to the received magnitudes; and

determining that the handoff is necessary when one of the received magnitudes is less than the calculated magnitude.

8. The method of claim 1, further comprising the steps of:

receiving a plurality of received vectors associated with the mobile unit;

calculating a magnitude of each of the plurality of received vectors;

combining the calculated magnitudes into a combined magnitude; and

determining whether the handoff is necessary based on the combined magnitude.

9. The method of claim 8, wherein the determining step further comprises the step of:

receiving one or more magnitudes from one or more other base stations;

comparing the combined magnitude to the received magnitudes; and

determining that a handoff is necessary when one of the received magnitudes is less than the combined magnitude.

10. The method of claim 1, further comprising the steps of:

receiving a plurality of vectors associated with the mobile unit;

detecting multipath propagation when at least two of the plurality of received vectors include identical location and time coordinates; and

performing the handoff when multipath propagation is detected.

11. The method of claim 1, wherein the determining step further comprises the steps of:

obtaining service quality data based on the received vector, wherein the service quality data includes at least one of an environmental and geographical condition related to a coverage area of a base station; and

determining whether to perform the handoff based on the service quality data.

12. The method of claim 11, wherein the obtaining step further comprises the steps of:

extracting at least one of a location and time coordinate from the received vector; and

retrieving the service quality data from a database based on the extracted information.

13. The method of claim 12, wherein the retrieving step further comprises the step of:

retrieving a geographical condition from the database based on location coordinates extracted from the received vector, the retrieved geographical condition including at least one of;

topographical data, structural data, and known reflection path.

14. The method of claim 12, wherein the retrieving step further comprises the step of:

retrieving an environmental condition from the database based on time information extracted from the received vector, the environmental condition selected from the group consisting of at least;

rain, wind, temperature and humidity.

15. The method of claim 1, further comprising the steps of:

receiving a plurality of received vectors associated with the mobile unit;

estimating future location coordinates for the mobile unit based on the plurality of received vectors; and

retrieving a geographical condition from a database based on the estimated future location coordinates.

16. The method of claim 1, wherein the received vector further comprises time information.

17. The method as in claim 1 further comprising the step of generating the vector at the mobile unit.

18. The method as in claim 1 further comprising the step of generating the vector at a base station.

19. The method as in claim 1 further comprising generating the vector at a GPS satellite.

20. A device for controlling handoffs in a wireless communication system, comprising:

means for receiving a location vector associated with a mobile unit; and

means for determining whether to perform a handoff of the mobile unit based on the received vector.

21. The device of claim 20, further comprising:

means for transmitting the location vector to the mobile unit, wherein the vector includes location and time coordinates; and

means for receiving a response from the mobile unit based on the transmitted vector.

22. The device of claim 20, wherein the location vector comprises Global Positioning System (GPS) data.

23. The device of claim 20 wherein the location vector comprises terrestrial data.

24. The device of claim 21, further comprising means for determining whether to perform the handoff based on the received response.

25. The device of claim 20, further comprising means for calculating a magnitude of the received vector, wherein the magnitude corresponds to a coverage area of a base station.

26. The device of claim 25, wherein the means for calculating further comprises:

means for receiving one or more magnitudes corresponding to coverage areas of one or more other base stations;

means for comparing the calculated magnitude to the received magnitudes; and

means for determining that the handoff is necessary when one of the received magnitudes is less than the calculated magnitude.

27. The device of claim 20, further comprising:

means for receiving a plurality of received vectors associated with the mobile unit;

means for calculating a magnitude of each of the plurality of received vectors;

means for combining the calculated magnitudes into a combined magnitude; and

means for determining whether the handoff is necessary based on the combined magnitude.

28. The device of claim 27, further comprising:

means for receiving one or more magnitudes from one or more other base stations;

means for comparing the combined magnitude to the received magnitudes; and

means for determining that a handoff is necessary when one of the received magnitudes is less than the combined magnitude.

29. The device of claim 20, further comprising:

means for receiving a plurality of vectors associated with the mobile unit;

means for detecting multipath propagation when at least two of the plurality of received vectors include identical location and time coordinates; and

means for performing the handoff when multipath propagation is detected.

30. The device of claim 20, further comprising means for obtaining service quality data based on the received vector, wherein the service quality data includes at least one of an environmental and geographical condition related to a coverage area of a base station, and means for determining whether to perform the handoff based on the service quality data.

31. The device of claim 30, further comprising means for extracting at least one of a location and time coordinate from the received vector and means for retrieving the service quality data from a database based on the extracted information.

32. The device of claim 31, wherein the means for retrieving further comprises means for retrieving a geographical condition from the database based on location coordinates extracted from the received vector, the retrieved geographical condition including at least one of:

topographical data, structural data, and known reflection path.

33. The device of claim 31, wherein the means for retrieving further comprises means for retrieving an environmental condition from the database based on time information extracted from the received vector, the environmental condition selected from the group consisting of at least:

rain, wind, temperature and humidity.

34. The device of claim 20, further comprising:

means for receiving a plurality of received vectors associated with the mobile unit;

means for estimating future location coordinates for the mobile unit based on the plurality of received vectors; and

means for retrieving a geographical condition from a database based on the estimated future location co-ordinates.

35. The device of claim 20, wherein the received vector further comprises time information.

36. The device as in claim 20 further comprising means for generating the vector at the mobile unit.

37. The device as in claim 20 further comprising means for generating the vector at a base station.

38. The method as in claim 20 further comprising means for generating the vector at a GPS satellite.