Cellular telephone interference prediction and frequency reuse planning

• US 5,926,762 A
• Filed: 05/17/1996
• Issued: 07/20/1999
• Est. Priority Date: 05/17/1996
• Status: Expired due to Term

• Current Assignee: Allen Telecom LLC (CommScope Holding Company, Inc.)
• Original Assignee: Internet Mobility Corporation
• Inventors: Miller, Eric A., Arpee, John E., Jensen, Eric H.
• Primary Examiner(s): Urban, Edward F.
• Application Number:
  US08/648,998
• Time in Patent Office: 1,159 Days
• Field of Search: 455/33.1, 455/33.4, 455/39.1, 455/63, 455/62, 455/67.7, 455/134, 455/135, 455/67.1, 455/67.3, 455/446, 455/447, 455/450, 455/524, 455/525, 379/59
• US Class Current: 455/447
• CPC Class Codes: H04W 16/12 Fixed resource partitioning
• CPC Class Codes: H04W 16/18 Network planning tools

Abstract

A computer implemented process which includes furnishing data indicating the actual strengths of all signals to be transmitted by a plurality of cells each positioned at an individual physical position in a mobile communications system and to be received by a mobile unit at a plurality of points of an entire mobile communications system, relating data indicating the actual strengths of all signals to the physical positions from which the signals are to be transmitted, identifying cells transmitting signals likely to serve each point of the plurality of points, and comparing planned frequencies to be used at any position serving a point with planned frequencies to be used at other positions to identify cells transmitting signals which might interfere with signals transmitted by cells serving a point.

Claims

1. A computer implemented process for assigning channels to cells in a reuse pattern comprising the steps of:

furnishing data indicating the strengths of signals in the absence of other signals on the same channel transmitted from a plurality of transmitters each positioned at an individual physical site in a mobile communications system and received at a plurality of points over an entire mobile communications system,

relating the signals received to the physical sites from which transmitted, identifying sites transmitting signals likely to serve each of the plurality of points,

comparing planned reuse channels to be used at any site serving a point with planned reuse channels at other sites to identify sites transmitting signals which might interfere with signals transmitted by sites serving a point, and

furnishing an interference plot, based on comparing planned reuse channels, of generated signals from cells which actually interfere with signals from different cells over the entire mobile communications system.

2. A computer implemented process as claimed in claim 1 in which the step of comparing planned reuse channels to be used at any site serving a point with planned reuse channels at other sites to identify sites transmitting signals which might interfere with signals transmitted by sites serving a point comprises:

comparing the strengths of signals of the same planned reuse channel received at a point to determine whether the strength of a possibly interfering signal is sufficient compared to a strength of a signal serving the point to interfere with the signal serving the point.

3. A computer implemented process as claimed in claim 1 in which the step of comparing planned reuse channels to be used at any site serving a point with planned reuse channels at other sites to identify sites transmitting signals which might interfere with signals transmitted by sites serving a point comprises:

comparing the strengths of signals of adjacent frequencies received at a point to determine whether a strength of a possibly interfering signal is sufficient compared to a strength of a signal serving the point to interfere with the signal serving the point.

4. A computer implemented process as claimed in claim 1 in which the step of comparing planned reuse channels to be used at any site serving a point with planned reuse channels at other sites to identify sites transmitting signals which might interfere with signals transmitted by sites serving a point comprises:

comparing the strengths of signals of the same reuse channels received at a point to determine whether the strength of a possibly interfering signal is sufficient compared to a strength of a signal serving the point to interfere with the signal serving the point, and

comparing the strengths of signals of adjacent reuse channels received at a point to determine whether a strength of a possibly interfering signal is sufficient compared to a strength of a signal serving the point to interfere with the signal serving the point.

5. A computer implemented process as claimed in claim 1 in which the step of identifying sites transmitting signals likely to serve each of the plurality of points comprises selecting from among signals strong enough to serve a point based on criteria in addition to signal strength to determine a site serving a point in a mobile communications system.

6. A computer implemented process as claimed in claim 5 in which the step of selecting from among signals strong enough to serve a point based on criteria in addition to signal strength to determine a site serving a point in a mobile communications system comprises using network configuration and control information as criteria.

7. A computer implemented process comprising the steps of:

furnishing data indicating the actual strengths of all signals on reuse channels planned to be implemented to be transmitted between a plurality of cells each positioned at an individual physical position in a mobile communications system and a mobile unit at a plurality of points of an entire mobile communications system in the absence of other signals on the same channel,

relating data indicating the actual strengths of all signals to the physical positions from which the signals are to be transmitted,

identifying cells transmitting signals able to serve each point of the plurality of points,

comparing planned channels to be used at any position serving a point with planned channels to be used at other positions to identify cells transmitting signals which might interfere with signals transmitted by cells serving a point, and

determining whether planned channels to be used at any position serving a point interfere with planned channels to be used at other positions over the entire mobile communications system.

8. A computer implemented process as claimed in claim 7 in which the step of determining whether planned channels to be used at any position serving a point interfere with planned channels to be used at other positions over the entire mobile communications system comprises the steps of:

comparing the data indicating the actual strengths of all signals received at each point from different cells on channels which might interfere with signals transmitted by cells serving a point,

determining whether interference exists for signals on the same channels of a first strength compared to signals from a cell serving a point, and

determining whether interference exists for adjacent signals on the same channels of a second strength compared to signals from a cell serving a point.

9. A computer implemented process as claimed in claim 8 in which the step of furnishing data indicating the actual strengths of all signals to be transmitted between a plurality of cells each positioned at an individual physical position in a mobile communications system and a mobile unit at a plurality of points of an entire mobile communications system comprises:

combining data from different tests, and

normalizing data accumulated in different tests indicating the actual strengths of all signals received at each point.

10. A computer implemented process as claimed in claim 8 in which the step of furnishing data indicating the actual strengths of all signals to be transmitted between a plurality of cells each positioned at an individual physical position in a mobile communications system and a mobile unit at a plurality of points of an entire mobile communications system comprises:

adjusting the levels of signal strength measuring uplink data to match signal strengths of downlink data.

11. A computer implemented process as claimed in claim 7 in which the step of furnishing data indicating the actual strengths of all signals on reuse channels planned to be implemented to be transmitted between a plurality of cells each positioned at an individual physical position in a mobile communications system and a mobile unit at a plurality of points of an entire mobile communications system comprises:

transmitting signals on individual channels from each position at which a cell might be placed in an area,

receiving the signals transmitted on individual channels from each position at which a cell might be placed in an area at a single mobile unit using a scanning receiver, and

recording strength values for the signals received at the mobile unit with data indicating the position of the mobile unit.

12. A computer implemented process as claimed in claim 7 in which the step of furnishing data indicating the actual strengths of all signals to be transmitted between a plurality of cells each positioned at an individual physical position in a mobile communications system and a mobile unit at a plurality of points of an entire mobile communications system comprises:

transmitting signals over the entire area on one frequency from a single mobile unit,

receiving the signals transmitted from the mobile unit at each position at which a cell might be placed in the area, and

recording strength values for the signals received from the mobile unit and data indicating the position of the mobile unit.

13. A computer implemented process as claimed in claim 12 in which the step of recording strength values for the signals received from the mobile unit and data indicating the position of the mobile unit records data indicating the position of the mobile unit at the mobile unit.

14. A computer implemented process as claimed in claim 12 in which the step of recording strength values for the signals received from the mobile unit and data indicating the position of the mobile unit records data indicating the position of the mobile unit at each cell.

15. A computer implemented process as claimed in claim 12 in which the data indicating the position of the mobile unit comprises a time at which data is transmitted.

16. A computer implemented process as claimed in claim 12 in which the data indicating the position of the mobile unit comprises a physical position of the mobile unit.

17. A computer implemented process as claimed in claim 7 comprising the further step of changing cell configuration parameters to be used at any position serving a point if interference exists until interference has been eliminated.