Method for determining organization parameters in a wireless communication system

• US 6,496,700 B1
• Filed: 04/04/1996
• Issued: 12/17/2002
• Est. Priority Date: 04/04/1996
• Status: Expired due to Fees

• Current Assignee: AT&T Mobility II LLC (AT&T, Inc.)
• Original Assignee: AT&T Wireless Services Incorporated (AT&T, Inc.)
• Inventors: Dunn, Michael Jeffrey, Chawla, Kapil K., Valenzuela, Reinaldo A.
• Primary Examiner(s): Kincaid, Lester G.
• Application Number:
  US08/628,214
• Time in Patent Office: 2,448 Days
• Field of Search: 455/422, 455/443, 455/446, 455/447, 455/450, 455/517, 455/522, 455/524, 455/62, 455/63, 455/67.1, 455/456, 455/69
• US Class Current: 455/435.2
• CPC Class Codes: H04B 17/318 Received signal strength
• CPC Class Codes: H04B 17/391 Modelling the propagation channel
• CPC Class Codes: H04W 16/18 Network planning tools
• CPC Class Codes: H04W 24/02 Arrangements for optimising operational condition
• CPC Class Codes: H04W 52/223 predicting future states of the transmission
• CPC Class Codes: H04W 52/242 taking into account path loss

Abstract

A level of automated adjustment of system organization parameters in a wireless communication system is provided by determining the parameter settings using a characterization of signal propagation of the system'"'"'s coverage area. This characterization is based on measurements of path loss-related characteristics by the system'"'"'s base stations and wireless terminals operating throughout the coverage area. An exemplary path loss-related characteristic is path loss as determined by measuring received signal strength (RSS) at wireless terminals based on signals transmitted at known powers by a plurality of the system'"'"'s base stations. It is possible for the wireless terminals to take measurements while operating in the coverage area, whether idle or during communication with the system, and for such terminals to be associated with the system'"'"'s subscribers. A resulting characterization of signal propagation in the coverage area based on the measured path loss-related characteristic can then be used to determine a variety of parameter settings including base station transmission power settings, wireless terminal access parameters, neighbor lists, sets of base stations that can reuse channels and base station transmission power settings when base stations are added to or removed from the system.

Claims

1. A method comprising:

intermittently measuring a path-loss related characteristic between a base station of a wireless communication system and one or more wireless terminals at a plurality of geographic locations within a service area of the wireless communication system thereby obtaining a measured path-loss characteristic, wherein the measuring is performed in substantial absense of correlation to an absolute geographic location regarding where the path-loss characteristic measurements were taken;

storing the measured path-loss characteristic in a form relating the measured path-loss characteristic between the base station and the geographic locations of the wireless terminals thereby forming a stored measured path-loss characteristic, wherein the number of the stored measured path-loss characteristics relating the path-loss measurements and geographic locations within the service area of the base station is substantially greater than one;

determining at least one continuous system organization parameter of the wireless communication system based on the stored measured path-loss characteristics; and

altering the at least one continuous system organization parameter based on the stored measured path-loss characteristics.

2. The method of claim 1 wherein the path-loss characteristic is based on measurements taken over a period of time of normal operation of the wireless communication system.

3. The method of claim 1 wherein the measuring includes measuring respective signal strengths received by the one or more wireless terminals from signals transmitted by the base station.

4. The method of claim 1 wherein the path-loss characteristic is a measurement of signal propagation.

5. The method of claim 1 wherein said system comprises a plurality of said base stations.

6. The method of claim 5 wherein the at least one continuous system organization parameter includes a transmission power setting for the base station.

7. The method of claim 6 wherein the transmission power setting is determined upon a deactivation of one of the two or more base stations.

8. The method of claim 6 wherein the transmission power setting is determined upon adding an additional base station to the wireless communication system.

9. The method of claim 5 wherein the two or more base stations provide service to respective service areas and wherein the at least one continuous system organization parameter is determined by an overlap of the service areas.

10. The method of claim 1 further comprising:

for at least one base station, determining an isolation value for the at least one base station based on up-link interference caused by at least one interfering wireless terminal in a coverage area not serviced by the at least one base station based on the measured path-loss characteristics from the at least one interfering wireless terminal; and

determining the at least one continuous system organization parameter based on the isolation value.

11. The method of claim 10 wherein the isolation value for the at least one base station is further based on the measured path-loss characteristics corresponding to at least one wireless terminal in a coverage area serviced by the at least one base station.

12. The method of claim 10 wherein the isolation value is based on the measured path-loss characteristics for a plurality of interfering wireless terminals in locations of a particular coverage area serviced by another base station.

13. The method of claim 10 wherein the at least one continuous system organization parameter includes identifying channels usable by the respective base stations.

14. The method of claim 10 wherein the at least one continuous system organization parameter includes a determination of a first neighbor base station which is operable to receive communication hand-offs from a second neighbor base station.

15. The method of claim 10 wherein the isolation value is based on at least one up-link carrier-to-interference ratio value.

16. The method of claim 1 further comprising, for at least one base station, determining a first isolation value for a coverage area of the base station based on down-link interference caused by another base station in the wireless communication system based on the measured path loss-related characteristic.

17. The method of claim 16 wherein the at least one continuous system organization parameter is related identifying channels usable by the respective base stations.

18. The method of claim 16 wherein the at least one continuous system organization parameter is determined by a first neighbor base station being operable to receive communication hands-off from a second base station.

19. The method of claim 16 wherein the first isolation value is based on at least one down-link carrier-to-interference ratio value.

20. The method of claim 16 further comprising determining a second isolation value for the base station based on up-link interference caused by at least one interfering wireless terminal in a coverage area serviced by another base station based on the measured path loss related characteristic between the interfering wireless terminal, wherein the at least one continuous system organization parameter is determined based on the first and second isolation values.

21. The method of claim 20 wherein the first isolation value for the base station is further based on measurements corresponding to at least one wireless terminal in a coverage area serviced by the base station.

22. The method of claim 20 wherein the first isolation value is based on at least one up-link carrier-to-interference ratio value.

23. The method of claim 22, further comprising the steps of:

(a) measuring received signal strengths of packets transmitted from/received at a mobile wireless terminal to/from the base stations, the packets being received sufficiently nearly simultaneously so that a mobile wireless terminal'"'"'s location is essentially unchanged between the packets, and storing in correlation with each other the received signal strengths of the packets or characterizations of the path-losses at which the packets are received thereby forming stored measured signal strength data or stored path-loss characterizations;

(b) repeating step (a) with the mobile terminal at a plurality of locations in an aggregate service area of the base stations thereby accumulating a table relating path-loss or signal strength of the base stations to the plurality of locations, the plurality of locations being much greater than the number of base stations;

(c) determining at least one continuous system organization parameter by analyzing the stored path-loss characterizations or stored measured signal strength data;

(d) operating the wireless communication system in accord with the determined system organization parameter.

24. The method of claim 5, further comprising the steps of:

(a) receiving a packet from a mobile wireless terminal at a plurality of the base stations, packet transmission and reception of at least one base station occurring as part of normal operation of the wireless communication system, and storing a characteristic of the path-loss at which the packet is received at the base stations receiving the packet thereby forming stored path-loss data, the plurality of stored path loss data for the packet being stored in correlation with each other;

(b) repeating step (a) for a plurality of packets during regular operation of the wireless communication system;

(c) analyzing the stored path-loss data to determine at least one continuous system organization parameter;

(d) operating the wireless communication system in accord with the determined at least one continuous system organization parameter.

25. The method of claim 5, further comprising the steps of:

(a) measuring received signal strengths of packets transmitted from/received at a mobile wireless terminal to/from the base stations, the packets being received sufficiently nearly simultaneously so that a mobile wireless terminal'"'"'s location is essentially unchanged between the packets, and storing in correlation with each other the received signal strengths of the packets or characterizations of the path-losses at which the packets are received, thereby forming stored measured signal strength data or stored path-loss characterizations;

(b) repeating step (a) with the mobile wireless terminal at a plurality of locations in the aggregate service area of the base stations, thereby accumulating a table relating path-loss or signal strength of the base stations to the plurality of locations, the plurality of locations being much greater than the number of base stations;

(c) determining at least one continuous system organization parameter by analyzing the stored path-loss characterizations or stored measured signal strength data;

(d) operating the wireless communication system in accord with the determined at least one continuous system organization parameter.

26. A method for adjusting at least one continuous system organization parameter for a wireless communication system having at least one base station arranged to serve at least one wireless terminal in a particular geographic area, the method comprising:

measuring intermittently a path-loss related characteristic between a plurality of locations for wireless terminals and the at least one base station thereby obtaining a measured path-loss characteristics, wherein measuring is performed in substantial absence of correlation to absolute geographic information regarding where the measurements were taken;

establishing a characterization of signal propagation for signals generated within the geographic area based on the measured path-loss characteristics

determining the continuous system organization parameter based on the measured path-loss characteristics; and

altering the continuous system organization parameter based on the measured path-loss characteristics.

27. The method of claim 26 wherein the path-loss characteristic is based on measurements taken over a period of time of normal operation of the wireless communication system.

28. The method of claim 26 wherein measuring includes respective signal strengths received by the wireless terminals from signals transmitted by the at least one base station.

29. The method of claim 26 wherein the path-loss characteristic is a measurement of signal propagation.

30. The method of claim 26 wherein the wireless communication system comprises a plurality of base stations.

31. The method of claim 30 wherein the continuous system organization parameter is transmission power setting for at least one of the base stations.

32. The method of claim 31 wherein the transmission power setting is determined upon a deactivation of one of the base stations.

33. The method of claim 31 wherein the transmission power setting is determined upon adding an additional base station to the system.

34. The method of claim 30 wherein the plurality of base stations provide service to respective service areas of the geographic area and wherein the at least one continuous system organization parameter is determined by an overlap of service areas.

35. The method of claim 30 further comprising:

for at least one base station, determining an isolation value for the at least one base station based on up-link interference caused by at least one interfering wireless terminal in a coverage area not serviced by the at least one base station based on the measured path-loss characteristics from the at least one interfering wireless terminal; and

determining the at least one continuous system organization parameter based on the isolation value.

36. The method of claim 35 wherein the isolation value for the at least one base station is further based on the measured path-loss characteristics corresponding to at least one wireless terminal in a coverage area serviced by the at least one base station.

37. The method of claim 35 wherein the isolation value is based on the measured path-loss characteristics between the base station and a plurality of interfering wireless terminals located in a particular coverage area serviced by another base station.

38. The method of claim 35 wherein the at least one continuous system organization parameter includes identifying channels usable by the respective base stations.

39. The method of claim 35 wherein the at least one continuous system organization parameter includes a determination of a first neighbor base station operable to receive communication hand-offs from a second neighbor base station.

40. The method of claim 35 wherein the isolation value is based on at least one up-link carrier-to-interference ratio value.

41. The method of claim 30 further comprising:

for at least one base station, determining a first isolation value for a coverage area of the base station based on down-link interference caused by another base station in the wireless communication system based on the measured path-loss characteristics between at least one wireless terminal in the coverage area and the base station as well as between the at least one wireless terminal and the other base station; and

determining the at least one continuous system organization parameter based on the first isolation value.

42. The method of claim 41 wherein said parameter is related to identifying channels usable by the respective base stations.

43. The method of claim 41 wherein the at least one continuous system parameter is determined by at least one neighbor base station being operable to receive communication hand-offs from a different neighbor base station.

44. The method of claim 41 wherein the first isolation value is based on at least one down-link carrier-to-interference ratio value.

45. The method of claim 41 further comprising determining a second isolation value for the base station based on up-link interference caused by at least one interfering wireless terminal in a coverage area serviced by another base station based on the measured path loss related characteristic between the interfering wireless terminal and the base station, wherein the at least one continuous system parameter is determined based on the first and second isolation values.

46. The method of claim 45 wherein the isolation value is based on at least one up-link carrier-to-interference ratio value.

47. The method of claim 45 wherein the first isolation value for the base station is further based on measurements corresponding to at least one wireless terminal in a coverage area serviced by the base station.

48. The method of claim 26, the wireless communication system having a plurality of base stations, the method further comprising the steps of:

(a) receiving a packet from a mobile wireless terminal at a plurality of the base stations, packet transmission and reception of at least one base station occurring as part of normal operation of the wireless communication system, and storing a characteristic of the path loss at which the packet is received at the base stations receiving the packet thereby forming stored path-loss data, the plurality of path loss data for the packet being stored in correlation with each other;

(b) repeating step (a) for a plurality of packets during regular operation of the wireless communication system;

(c) analyzing the stored path loss data to determine at least on continuous system organization parameter;

(d) operating the wireless communication system in accord with the determined at least one continuous system organization parameter.

49. A method comprising the steps of:

(a) receiving a same packet from a mobile wireless terminal at a plurality of base stations of a wireless communication system, and storing a characteristic of the path-loss at which the packet is received at the base stations receiving the packet, the plurality of path-loss data for the packet being stored in correlation with each other thereby forming stored path-loss packet data;

(b) repeating step (a) for a plurality of packets during operation of the wireless system;

(c) analyzing intermittently the stored path loss packet data to alter a continuous system organization parameter, the analyzing being performed in substantial absence of correlation to absolute geographic information regarding where the measurements were taken;

(d) operating the wireless communication system in accord with the altered continuous system organization parameter.

50. The method of claim 49, wherein the number of stored path-loss packet data is much greater than the number of base stations in the wireless communication system.

51. A method comprising the steps of:

(a) measuring received signal strengths or path-loss characteristics of packets transmitted from or received at a mobile wireless terminal to or from a plurality of base stations of a wireless communication system thereby obtaining a measured signal strength or a measured path-loss characteristic, the packets being received sufficiently nearly simultaneously so that a mobile terminal'"'"'s location is essentially unchanged between the packets, and storing in correlation with each other the received signal strengths of the packets or characterizations of the path-losses at which the packets are received thereby forming stored signal strength data or path-loss characterization data, wherein measuring is performed in substantial absence of correlation to absolute geographic information regarding where the measurements were taken;

(b) repeating step (a) with the mobile terminal at a plurality of locations in an aggregate service area of the base stations, and creating a table relating path loss or signal strength of the base stations to the plurality of locations, the plurality of locations being much greater than the number of base stations;

(c) determining at least one continuous system organization parameter by analyzing the stored path loss or signal strength data;

(d) altering the at least one continuous system organization parameter by analyzing intermittently the stored path loss data or signal strength data; and

(e) operating the wireless communication system in accord with the determined continuous system organization parameter.

52. The method of claim 51 wherein the continuous system organization parameter is transmission power setting for at least one of the base stations.

53. The method of claim 51 wherein the base stations provide service to respective service areas wherein the continuous system organization parameter is determination by an overlap of service areas.

54. The method of claim 51 further comprising:

for at least one base station, determining an isolation value for the at least one base station based on up-link interference caused by at least one interfering wireless terminal in a coverage area not serviced by the at least one base station based on the measured signal strength from the interfering wireless terminal; and

determining the at least one continuous system organization parameter based on the isolation value.

55. The method of claim 54 wherein the isolation value for the base station is further based on measurements corresponding to at least one wireless terminal in a coverage area serviced by the base station.

56. The method of claim 54 wherein the isolation value is based on respective measurements between the base station and a plurality of interfering wireless terminals located in a particular coverage area serviced by another base station.

57. The method of claim 54 wherein the system organization parameter includes identify channels usable by the respective base stations.

58. The method of claim 54 wherein the system organization parameter is determined by at least one neighbor base station operable to receive communication hands-offs from a particular base station.

59. The method of claim 54 wherein the isolation value is based on at least one up-link carrier-to-interference ratio value.

60. The method of claim 51 further comprising:

for at least one base station, determining a first isolation value for a coverage area of one of the plurality of base stations based on down-link interference caused by another of the plurality of base station in the system based on the measured signal strength between at least one wireless terminal in the coverage area and the base station as well as between the wireless terminal and the other base station; and

determining the at least one continuous system organization parameter based on the first isolation value.

61. The method of claim 60 wherein the at least one continuous system parameter is related to identifying channels that are useable by the respective base stations.

62. The method of claim 60 wherein the at least one continuous system parameter is determined by a first neighbor base station being operable to receive communication hand-offs from a second base station.

63. The method of claim 60 wherein the first isolation value is based on at least one down-link carrier-to-interference ratio value.

64. The method of claim 60 further comprising determining a second isolation value for the base station based on up-link interference caused by at least one interfering wireless terminal in a coverage area serviced by another base station based on the measured path-loss characteristic between the interfering wireless terminal and the base station, wherein the at least one continuous system parameter is determined based on the first and second isolation values.

65. The method of claim 64 wherein the isolation value is based on at least one up-link carrier-to-interference ratio value.

66. The method of claim 60 wherein the isolation value for the base station is further based on measurements corresponding to at least one wireless terminal in a coverage area serviced by the base station.

67. The method of claim 51, wherein the packets are transmitted and received as part of normal operation of the wireless system.