Method and apparatus for wireless communication system organization

• US 5,878,328 A
• Filed: 12/21/1995
• Issued: 03/02/1999
• Est. Priority Date: 12/21/1995
• Status: Expired due to Term

• Current Assignee: AT&T Mobility II LLC (AT&T, Inc.)
• Original Assignee: AT&T Wireless Services Incorporated (AT&T, Inc.)
• Inventors: Raffel, Michael Allen, Chawla, Kapil K., Valenzuela, Reinaldo A., Kibria, Masud, Dunn, Michael Jeffrey
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): Armstrong, Darnell R.
• Application Number:
  US08/575,974
• Time in Patent Office: 1,167 Days
• Field of Search: 455/69.1, 455/67.1, 455/33.1, 455/67.4, 455/63.2, 455/408, 455/423, 455/456, 455/436, 455/446, 455/447, 455/450, 379/27, 379/29, 379/34, 379/1
• US Class Current: 455/67.11
• CPC Class Codes: H04W 16/18 Network planning tools
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements

Abstract

A level of system self-organization in a wireless communication system is provided using a combined design, planning and verification process to determine system organization parameters. The process determines the parameters based on a measured path loss-related characteristic, such as path loss or bit error rate, between base stations and a plurality of regions in a coverage area. For each region, the characteristic is measured to each base station irrespective of the proximity between the region and the base stations. The measured characteristics enable the prediction of signal strength received at the regions of signals transmitted by the base stations independent of the region location. Accordingly, the characteristics can be measured without information correlating the absolute geographic locations of the regions. The resulting unique characterization of the path loss-related information can be used to determine a variety of system organization parameters, such as the number and transmission power of base stations, neighbor lists, sets of base stations that can reuse channels and the identity of base stations, if any, that can be omitted from the system.

Claims

1. A method for determining at least one system organization parameter in a wireless communication system having a plurality of base stations arranged to serve at least one mobile unit in a particular geographic area, the method comprising:

measuring a path loss-related characteristic from a plurality of regions in said geographic area to each base station, said step of measuring being performed in substantial absence of correlation to absolute geographic information regarding where the measurements were taken;

based on said measurements, establishing a characterization of signal propagation for at least one of said regions for signals generated within said geographic area; and

determining the system organization parameter based on said characterization.

2. The method of claim 1 wherein the step of determining said parameter is a verification that an existing parameter setting substantially achieves a desired performance.

3. The method of claim 1 wherein said parameter is transmission power settings for the base stations to provide service to a substantial portion of said geographic area.

4. The method of claim 1 wherein each base station provides service to a respective service area of said geographic area and wherein said parameter is a determination of an overlap of service areas.

5. The method of claim 1 wherein said parameter is a determination of whether a base station can be removed from the communication system without substantial loss in coverage of said geographic area.

6. The method of claim 1 further comprising:

for at least one base station, identifying which of said regions are to be serviced by said base station based on said measurements;

determining an isolation value for said base station based on up-link interference that would be caused by at least one interfering mobile unit in a region of the coverage area not serviced by said base station based on said measurements from the interfering mobile unit region and said identified regions; and

determining said system organization parameter based on said isolation value.

7. The method of claim 6 wherein the system organization parameter is related to identifying channels useable by the respective base stations.

8. The method of claim 6 wherein the system organization parameter is a determination of neighbor base stations which is operable to receive communication hand-offs from a particular base station.

9. The method of claim 6 wherein the isolation value is based on at least one up-link carrier-to-interference ratio value.

10. The method of claim 1 further comprising:

for at least one base station, identifying which of said regions are to be serviced by said base station based on said measurements;

determining a first isolation value for at least one region of said identified regions based on down-link interference that would be caused by another base station in said system based on said measurements from said other base station to said region of said identified regions; and

determining said system organization parameter based on said first isolation value.

11. The method of claim 10 wherein said parameter is related to identifying channels useable by the respective base stations.

12. The method of claim 10 wherein said parameter is a determination of neighbor base stations which is operable to receive communication hand-offs from a particular base station.

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

14. The method of claim 10 further comprising:

determining a second isolation value for said base station based on up-link interference that would be caused by at least one interfering mobile unit in a region serviced by said other base station based on said measurements from the interfering mobile unit region and said identified regions to said based station, wherein said parameter is determined based on said first and second isolation values.

15. The method of claim 1 wherein said step of establishing a characterization of signal propagation establishes the characterization that correlates said measurements for substantially contiguous regions in said geographic area;

identifying base stations that provide service to regions within close proximity to regions in coverage holes;

determining if an increase in transmission power of the identified base stations would provide service to at least a portion of said regions in coverage holes; and

determining a system organization parameter of transmission power for said identified base stations based on said transmission power determination.

16. The method of claim 1 wherein the step of measuring the path loss-related characteristic comprises:

transmitting a test signal with a known signal power using a mobile test unit from said regions;

detecting signal strength of the received test signal at each base station; and

determining path loss values from the detected signal strength and said known signal power.

17. A method for determining at least one system organization parameter in a wireless communication system having a plurality of base stations arranged to serve at least one mobile unit in a particular geographic area, the method comprising:

measuring a path loss-related characteristic from a plurality of regions in said geographic area to each base station wherein the step of measuring the path loss-related characteristic includes,

transmitting a test signal with a known signal power using a mobile test unit from each of said regions,

detecting signal strength of the received test signal from each region at each base station, and

determining path loss values from the detected signal strength and said known signal power based on said measurements, establishing a characterization of signal propagation for at least one of said regions for signals generated within said geographic area; and

determining the system organization parameter based on said characterization.

18. The method of claim 17 wherein the mobile test unit is moved to different regions and each of the base stations synchronously detects said signal strength from the mobile test unit at said different regions.

19. A method of communicating between (A) at least one mobile unit and (B) a wireless communication system having a plurality of base stations that service a geographic area, the method comprising:

establishing communication over at least one channel between the mobile unit and a base station of said system using at least one system organization parameter, wherein the parameter is determined according to a method comprising;

measuring a path loss-related characteristic from a plurality of regions in said geographic area to each base station, wherein the step of measuring said path loss-related characteristic is performed in substantial absence of correlation to absolute geographic information regarding where the measurements were taken;

based on said measurements, establishing a characterization of signal propagation for at least one of said regions for signals generated within said geographic area; and

determining said system organization parameter based on said characterization.

20. The method of claim 19 wherein said step of establishing a characterization of signal propagation establishes the characterization that correlates said measurements for substantially contiguous regions in said geographic area;

identifying base stations that provide service to regions within close proximity to regions in coverage holes;

determining if an increase in transmission power of the identified base stations would provide service to at least a portion of said regions in coverage holes; and

determining a system organization parameter of transmission power for said identified base stations based on said transmission power determination.

21. The method of claim 19 wherein the step of measuring the path loss-related characteristic comprises:

transmitting a test signal at a known signal power using a mobile test unit from said regions;

detecting signal strength of the received test signal at each base station; and

determining path loss values from the detected signal strength and said known signal power.

22. The method of claim 21 wherein the mobile test unit is moved to different regions and each of the base stations synchronously detects said signal strength from the mobile test unit at said different regions.

23. The method of claim 19 wherein the step of determining said parameter is a verification that an existing system organization parameter setting substantially achieves a desired performance.

24. The method of claim 19 wherein said parameter is transmission power required by the base stations to provide coverage to a substantial portion of said geographic area.

25. The method of claim 19 wherein each base station provides service to a respective service area of said geographic area and wherein said parameter is a determination of an overlap of service areas.

26. The method of claim 19 further comprising:

for at least one base station, identifying which of said regions are to be serviced by said base station based on said measurements;

determining an isolation value for said base station based on up-link interference that would be caused by at least one interfering mobile unit in a region of the coverage area not serviced by said base station based on said measurements from the interfering mobile unit region and said identified regions; and

determining said system organization parameter based on said isolation value.

27. The method of claim 26 wherein said parameter is related to identifying channels useable by the base stations.

28. The method of claim 26 wherein said parameter is a determination of at least one neighbor base station which is operable to receive communication hand-offs from a particular base station.

29. The method of claim 26 wherein the isolation value is based on at least one up-link carrier-to-interference ratio value.

30. The method of claim 19 further comprising:

for at least one base station, identifying which of said regions are to be serviced by said base station based on said measurements;

determining a first isolation value for at least one region of said identified regions based on down-link interference that would be caused by another base station in said system based on said measurements from said other base station to said region of said identified regions; and

determining said system organization parameter based on said first isolation value.

31. The method of claim 30 wherein said parameter is related to identifying channels useable by the base stations.

32. The method of claim 30 wherein said parameter is a determination of at least one neighbor base station which is operable to receive communication hand-offs from a particular base station.

33. The method of claim 30 wherein the first isolation value is based on at least one down-link carrier-to-interference ratio value.

34. A method of communicating between (A) at least one mobile unit and (B) a wireless communication system having a plurality of base stations that service a geographic area, the method comprising:

establishing a communication channel between the mobile unit and one of said base stations, the particular channel being selected based on a channel allocation rule determined according to a method comprising;

measuring a path loss-related characteristic from a plurality of regions in said geographic area to said base station and at least one other base station, wherein the step of measuring said path loss-related characteristic is performed in substantial absence of correlation to absolute geographic information regarding where the measurements were taken,

identifying those regions that are to be serviced by said base station and at least one other base station based on said measurements for those regions;

determining an isolation value indicative of a carrier-to-interference ratio for a particular channel for said base station, wherein said isolation value determination is based on said measurements from the identified regions; and

creating the channel allocation rule based on said isolation value.

35. The method of claim 34 further comprising:

for at least one base station, identifying which of said regions are to be serviced by said base station based on said measurements;

determining an isolation value for said base station based on up-link interference that would be caused by at least one interfering mobile unit in a region of the coverage area not serviced by said base station based on said measurements from the interfering mobile unit region and said identified regions; and

determining said system organization parameter based on said isolation value.

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

37. The method of claim 34 further comprising:

for at least one base station, identifying which of said regions are to be serviced by said base station based on said measurements;

determining a first isolation value for at least one region of said identified regions based on down-link interference that would be caused by another base station in said system based on said measurements from said other base station to said region of said identified regions; and

determining said system organization parameter based on said first isolation value.

38. The method of claim 37 wherein the first isolation value is based on at least one down-link carrier-to-interference ratio value.

39. The method of claim 37 further comprising:

determining a second isolation value for said base station based on up-link interference that would be caused by at least one interfering mobile unit in a region serviced by said other base station based on said measurements from the interfering mobile unit region and said identified regions to said based station, wherein said parameter is determined based on said first and second isolation values.

40. A method for establishing initial system organization in a wireless communication system having a plurality of base stations arranged to serve at least one mobile unit in particular geographic area, the method comprising:

locating a first plurality of base stations at positions throughout the geographic area;

for each of a plurality of regions in the geographic area measuring a path loss related characteristic from that region to each of said first plurality of base stations;

compiling the measurements in a memory;

analyzing the compiled measurements to define at least three start up parameters selected from the group of start up parameters including the number of base stations to be designated;

the location of designated system base stations;

the transmission power settings of designated base stations;

base-station hand-off protocols;

designated base station channel assignments;

isolation values and channel re-use designations.