Adaptive neighbor cell list

• US 5,854,981 A
• Filed: 03/01/1996
• Issued: 12/29/1998
• Est. Priority Date: 08/08/1995
• Status: Expired due to Fees

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Beliveau, Andre, Sawyer, Francois, Frodigh, Carl Magnus, Almgren, Knut Magnus, Olofsson, H.ang.kan Gunnar, Wallstedt, Kenneth Yngve
• Primary Examiner(s): Louis-Jacques, Jacques H.
• Assistant Examiner(s): ARTHUR JEANGLAUDE, GERTRUDE
• Application Number:
  US08/609,422
• Time in Patent Office: 1,033 Days
• Field of Search: 455/422, 455/436, 455/439, 455/446, 455/500, 455/517, 455/524, 455/525, 455/62, 455/67.1, 455/437, 455/438, 455/450
• US Class Current: 455/439
• CPC Class Codes: H04W 36/00835 Determination of neighbour cell lists

Abstract

A method and apparatus for adaptively reconfiguring a neighbor cell list. For a selected cell of a cellular system, data associated with the selected cell and each of a plurality of neighboring base stations is collected. The collected data includes data on events indicative of the quality of handoffs from the selected cell to each of the neighboring base stations. The collected data also includes signal level measurements made on measurement channels of the neighboring base stations. A plurality of quality values, each associated with the selected cell and one of the neighboring cells, are then determined from the collected data. A neighbor cell list is then generated for the selected cell by determining the highest quality values, and placing the handoff measurement channels of the neighboring cells associated with the highest quality values in the neighbor cell list.

Claims

1. In a mobile telecommunications system comprising a plurality of mobile stations and a fixed network comprising a first base station and a first plurality of neighboring base stations, each of said first base station and first plurality of neighboring base stations having a coverage area, a method for creating a neighbor cell list for use in determining a handoff target base station in handoff of communications with a selected mobile station from the first base station to a neighboring base station, said method comprising the steps of:

collecting data at a call control unit, the data associated with the first base station and each of the first plurality of neighboring base stations;

providing the data collected during said step of is collecting to a quality matrix generator;

determining, responsive to the data provided during said step of providing the data, at the quality matrix generator, a plurality of parameters, each of said parameters associated with the first base station and one of the plurality of neighboring base stations;

providing the plurality of parameters, determined during said step of determining, to a neighbor cell list generator; and

generating, responsive to said parameters provided to the neighbor cell list, a neighbor cell list, said neighbor cell list including a channel identifier of a channel of each of a second plurality of neighboring base stations of the first plurality of neighboring base stations.

2. The method of claim 1, wherein said step of collecting data comprises collecting data on a plurality of events, each event being associated with the first base station and one of the first plurality of neighboring base stations.

3. The method of claim 2, wherein said step of collecting data comprises collecting data on a plurality of mobile station presence verifications, each mobile station presence verification performed upon a handoff attempt from the first base station to one of the first plurality of neighboring base stations.

4. The method of claim 2, wherein said step of collecting data comprises collecting data on a plurality of handoff attempts from the first base station to one of the first plurality of neighboring base stations.

5. The method of claim 2, wherein said step of collecting data comprises collecting statistics on a plurality of lost calls, each lost call having been handed off from said first base station to one of the plurality of neighboring base stations.

6. The method of claim 2, wherein said step of collecting data further comprises measuring at at least one mobile station of a plurality of mobile stations located within the coverage area of the first base station, signal levels on a plurality of measurement channels, each channel carrying transmissions from one of the first plurality of neighboring base stations.

7. The method of claim 6, wherein the signal level measurements of said step of collecting data are performed by selectively inserting at least one of said plurality of measurement channels into at least one neighbor cell list transmitted to said at least one mobile station.

8. The method of claim 6, wherein said step of collecting data further comprises storing an indication of the location, within the coverage area of the first base station, of said at least one mobile station during each measurement of signal levels on said plurality of measurement channels.

9. The method of claim 8, wherein each of said plurality of parameters comprises at least two subvalues, both subvalues associated with the first base station and one of the base stations of the first plurality of neighboring base stations, each of said at least two subvalues associated with a separate area of the coverage area of the first base station.

10. The method of claim 2, wherein said step of collecting data comprises measuring, at the first base station, signal levels on a plurality of communications channels, each carrying transmissions from a neighboring base station.

11. The method of claim 2, wherein the selected mobile station is associated with at least one mobile station characteristic and said neighbor cell list generated in said step of generating is further generated as a function of said at least one mobile station characteristic.

12. The method of claim 11, wherein said at least one mobile station characteristic comprises a value indicative of the speed distribution of the selected mobile station.

13. The method of claim 11, wherein said at least one mobile station characteristic comprises a plurality of parameters, each parameter indicative of the frequency of usage of one of the first plurality of neighboring base stations by the selected mobile station.

14. The method of claim 2, wherein the selected mobile station is associated with at least one subscriber characteristic, said subscriber characteristic being a characteristic of the subscriber using the selected mobile station.

15. In a mobile telecommunications system comprising a plurality of mobile stations and, a fixed network comprising a first plurality of base stations, each of said first plurality of base stations having a coverage area, a method for creating a neighbor cell list for use in determining a handoff target base station in handoff of communications, between said system and a selected mobile station, from a first base station to a second base station, said method comprising the steps of:

collecting data at a call control unit, the data associated with each of a first plurality of base station pairs, each of said first plurality of base station pairs comprising a combination of two base stations of said system;

providing the data collected during said step of collecting to a quality matrix generator;

determining, responsive to the data provided to the quality matrix generator, a first plurality of parameters, each of said parameters associated with one of said first plurality of base station pairs;

providing the first plurality of parameters determined during said step of determining the first plurality of parameters to a neighbor cell list generator;

measuring, at the selected mobile station, a plurality of signal levels on a plurality of measurement channels, each measurement channel carrying transmissions from a base station of one of said first plurality of base stations;

determining, responsive to results of signal level measurements performed in said step of measuring, a second plurality of parameters, each associated with the selected mobile station and one of the base stations of said first plurality of base stations, wherein each of said second plurality of parameters is a function of said first plurality of parameters and said plurality of signal levels measured in said step of measuring;

providing the second plurality of parameters determined during said step of determining the second plurality of parameters to the neighbor cell list generator; and

generating, responsive to said second plurality of parameters, a neighbor cell list at the neighbor cell list generator, said neighbor cell list including a channel identifier of a channel of each of a second plurality of base stations of said first plurality of base stations.

16. The method of claim 15, wherein said step of collecting data comprises collecting data on a plurality of events, each event being associted with one of a first plurality of base station pairs.

17. The method of claim 16, wherein said step of collecting data comprises collecting data on a plurality of mobile station presence verifications, each mobile station presence verification performed upon a handoff attempt between base stations of one of a first plurality of base station pairs.

18. The method of claim 16, wherein said step of collecting data comprises collecting data on a plurality of handoff attempts between base stations of one of a first plurality of base station pairs.

19. The method of claim 15, wherein said step of measuring is performed by selectively inserting at least one of said plurality of measurement channels into at least one neighbor cell list transmitted to said at least one mobile station.

20. The method of claim 15, wherein the selected mobile station is associated with at least one mobile station characteristic and said neighbor cell list generator in said step of generating is further generated as a function of said at least one mobile station characteristic.

21. In a mobile telecommunications system comprising a plurality of mobile stations in a fixed network comprising a first base station and a first plurality of neighboring base stations, each of said first base station and first plurality of neighboring base stations having a coverage area and an apparatus for creating a neighbor cell list for use in determining a handoff target base station in handoff of communications with a selected mobile station from the first base station to a neighboring base station, said apparatus comprising:

a call control unit for collecting data associated with the first base station and each of the first plurality of neighboring base stations;

a quality matrix generator, coupled to said call control unit, said quality matrix generator for receiving data collected in said call control unit and generating a plurality of parameters, wherein each of said parameters is associated with the first base station and one of the plurality of neighboring base stations; and

a neighbor list generator, coupled to said quality matrix generator, said neighbor list generator for receiving said parameters generated by said quality matrix generator and generating a neighbor cell list wherein said neighbor cell list includes information on each of a second plurality of neighboring base stations of the first plurality of neighboring base stations.

22. The apparatus of claim 21, wherein said data collected by said call control unit comprises data on a plurality of events, each event being associated with the first base station and one of the first plurality of neighboring base stations.

23. The apparatus of claim 22, wherein said plurality of events comprises a plurality of mobile station presence verifications, each mobile station presence verification performed upon a handoff attempt from the first base station to one of the first plurality of neighboring base stations.

24. The apparatus of claim 22, wherein said plurality of events comprises a plurality of handoff attempts from the first base station to one of the first plurality of neighboring base stations.

25. The apparatus of claim 22, wherein said plurality of events comprises a plurality of lost call events, each lost call having been handed off from said first base station to one of the plurality of neighboring base stations.

26. The apparatus of claim 22 further comprising a candidate neighbor list generator for receiving signal level measurements made at at least one mobile station of a plurality of mobile stations located within the coverage area of the first base station, wherein said signal level measurements are made on a plurality of measurement channels, each measurement channel carrying transmissions from one of the first plurality of neighboring base stations.

27. The apparatus of claim 26, wherein said candidate neighbor list generator, further, selectively inserts at least one of said plurality of measurement channels into at least one neighbor cell list transmitted to said at least one mobile station.

28. The apparatus of claim 26, wherein said call control unit further stores an indication of the location of said at least one mobile station within the coverage area of the first base station during measurement of signal levels on each of said measurement channels.

29. The apparatus of claim 27, wherein each of said plurality of parameters comprises at least two subvalues, both subvalues associated with the first base station and one of the base stations of the first plurality of neighboring base stations, each of said at least two subvalues associated with a separate area of the coverage area of the first base station.

30. The apparatus of claim 21, wherein said quality matrix generator further comprises means for storing signal level measurements made at the first base station on a plurality of communications channels each carrying transmissions from a neighboring base station and further, wherein said quality matrix generator generates said plurality of parameters as a function of said signal level measurements.

31. The apparatus of claim 21, wherein the selected mobile station is associated with at least one mobile station characteristic and said neighbor cell list generated by said neighbor list generator is generated as a function of said at least one mobile station characteristic.

32. The apparatus of claim 31, wherein said at least one mobile station characteristic comprises a value indicative of the speed distribution of the selected mobile station.

33. The apparatus of claim 31, wherein said at least one mobile station characteristic comprises a plurality of parameters, each parameter indicative of the frequency of usage of one of the first plurality of neighboring base stations by the selected mobile station.

34. In a mobile telecommunications system comprising a plurality of mobile stations and, a fixed network comprising a first plurality of base stations, each of said first plurality of base stations having a coverage area, an apparatus for creating a neighbor cell list for use in determining a handoff target base station in handoff of communications, between said system and a selected mobile station, from a first base station to a second base station, said apparatus comprising:

a call control unit for collecting data associated with each of a first plurality of base station pairs, each of said first plurality of base station pairs comprising a combination of two base stations of said first plurality of base stations;

a quality matrix generator, coupled to said call control unit, said quality matrix generator for receiving data collected in said call control unit and determining, responsive to the data collected in said step of collecting, a first plurality of parameters, each of said first parameters associated with one of said first plurality of base station pairs; and

a neighbor list generator, coupled to said matrix generator, said neighbor list generator for receiving signal level measurements, made at the selected mobile station, on a plurality of measurement channels, each measurement channel carrying transmissions from a base station of said system, said neighbor list generator for determining, from said signal level measurements, a second plurality of parameters, each associated with the selected mobile station and one of the base stations of said first plurality of base stations, wherein each of said second plurality of parameters is a function of said first plurality of parameters and said plurality of signal level measurements, said neighbor list further generating, responsive to said second plurality of parameters, a neighbor cell list, said neighbor cell list including channel identifiers of each of a second plurality of base stations of said first plurality of base stations.

35. The apparatus of claim 34, wherein said data collected in said call control unit comprises data on a plurality of events, each event being associated with one of a first plurality of base station pairs, each comprising a combination of two base stations of said first plurality of base stations.

36. The apparatus of claim 35, wherein said plurality of events comprises a plurality of mobile station presence verifications, each mobile station presence verification performed upon a handoff attempt between base stations of one of said first plurality of base station pairs.

37. The apparatus of claim 35, wherein said plurality of events comprises a plurality of handoff attempts between base stations of one of said first plurality of base station pairs.

38. The apparatus of claim 34, wherein the selected mobile station is associated with at least one mobile station characteristic and said neighbor cell list, generated in said neighbor list generator, is generated as a function of said at least one mobile station characteristic.

39. In a mobile station-handoff method for handing off communications in a mobile telecommunications system formed of radio communication stations including at least a selected mobile station, a first base station, and a first plurality of neighboring base stations neighboring the first base station, each of said first base stations defining a coverage area, an improvement of a method for creating a neighbor cell list associated with the selected mobile station, the neighbor cell list for use in determining a handoff target base station in handoff of communications with the selected mobile station from the first base station to a neighboring base station, the handoff target base station selected out of the first plurality of neighboring base stations, said method comprising the steps of:

collecting data at a call control unit, the data associated with at least one of the radio communication stations of the mobile telecommunications system;

providing the data collected during said step of collecting to a quality matrix generator;

determining, responsive to the data provided during said step of providing the data to the quality matrix data, a plurality of parameters, including at least one parameter associated with the at least one of the radio communication stations;

providing the plurality of parameters, determined during said step of determining, to a neighbor cell list generator; and

generating, responsive to said parameters provided to the neighbor cell list generator, a neighbor cell list for the at least one radio communication station.

40. The method of claim 39 wherein the data collected during said step of collecting comprises data associated with the selected mobile station.

41. The method of claim 40 wherein the data associated with the selected mobile station comprises data associated with characteristics of the selected mobile station.

42. The method of claim 41 wherein said characteristics of the selected mobile station forming the data associated with the selected mobile station comprise inherent characteristics inherent to the selected mobile station.

43. The method of claim 41 wherein said characteristics of the selected mobile station forming the data associated with the selected mobile station comprise characteristics representative of behavior of the selected mobile stations.

44. The method of claim 41 wherein said characteristics of the selected mobile station forming the data associated with the selected mobile station comprise subscription-related characteristics of the selected mobile station.

45. The method of claim 40 wherein the data associated with the selected mobile station comprises data measured at the selected mobile station.

46. The method of claim 39 wherein the data collected during said step of collecting comprises data associated with the first base station.

47. The method of claim 39 wherein the data collected during said step of collecting comprises data associated with the first plurality of neighboring base stations.

48. The method of claim 39 wherein the neighbor cell list generated during said step of generating comprises a channel identifier of a channel of each of a second plurality of neighboring base stations of the first plurality of neighboring base stations.