Method of evaluation of the effect of channel reassignment and/or parameter changes on interference throughout a cellular system

• US 20020022480A1
• Filed: 06/15/2001
• Published: 02/21/2002
• Est. Priority Date: 07/02/1997
• Status: Active Grant

• Current Assignee: Allen Telecom LLC (CommScope Holding Company, Inc.)
• Original Assignee: Scoreboard Inc. (CommScope Holding Company, Inc.)
• Inventors: Jensen, Eric
• Granted Patent: US 6,496,698 B2
• Time in Patent Office: Days
• US Class Current: 455/423
• CPC Class Codes: H04W 16/18 Network planning tools

Abstract

A computer implemented process compares signals communicated between a known position and a plurality of base stations in a cellular telephone system to determine the level of interference with a signal on a channel expected to serve the known position, and determines a value indicating a probability of interference with a signal on a channel expected to serve the known position.

Claims

1. A computer implemented process comprising the steps of:

comparing signals communicated between a known position and a plurality of base stations in a cellular telephone system to determine the level of interference with a signal on a channel expected to serve the known position, and

determining a value indicating a probability of interference at the known position.

2. A computer implemented process as claimed in claim 1 in which the step of determining a value indicating a probability of interference at the known position includes the steps of:

combining for each signal being received at the known position a probability of receipt of such signal and a weighting indicating the severity of interference to be expected from such signal at the known position to determine an effect for such signal, and

combining the effects for all signals being received at the known position to determine the value indicating a probability of interference at the known position.

3. A computer implemented process as claimed in claim 2 in which the step of combining the effects for all signals being received at the known position includes the effect of only a strongest interfering signal during any interval.

4. A computer implemented process as claimed in claim 1 comprising the additional step of averaging values indicating a probability of interference at known positions within a communication area served by one of the base stations to determine a value indicating a probability of interference within the communication area served by the base station.

5. A computer implemented process as claimed in claim 3 comprising the additional step of averaging values indicating a probability of interference at known positions within a communication area served by one of the base stations to determine a value indicating a probability of interference within the communication area served by the base station.

6. A computer implemented process as claimed in claim 4 comprising the additional step of averaging values indicating a probability of interference within the communication areas served by the plurality of base stations to determine a value indicating a probability of interference within the communication area served by the cellular telephone system.

7. A computer implemented process as claimed in claim 5 comprising the additional step of averaging values indicating a probability of interference within the communication areas served by the plurality of base stations to determine a value indicating a probability of interference within the communication area served by the cellular telephone system.

8. A computer implemented process as claimed in claim 1 in which the signals are determined from actual field tests.

9. A computer implemented process as claimed in claim 8 in which the signals are determined from actual field tests of cellular systems establishing channels on a basis different than the basis of the cellular telephone system.

10. A computer implemented process comprising the steps of:

combining values indicating strength of signals communicated between each of a plurality of closely adjacent known positions and a plurality of base stations in a cellular telephone system to determine average strengths of signals communicated between an average known position and the plurality of base stations,

comparing the average strength of signals communicated between an average known position and a plurality of base stations in a cellular telephone system to determine the level of interference with a signal on a channel expected to serve the average known position, and

determining a value indicating a probability of interference at the average known position.

11. A computer implemented process as claimed in claim 10 including the further steps of:

selecting a projected change to implement which affects strength of a signal between the known position and the plurality of base stations, and

determining the improvement in the value indicating a probability of interference at the average known position by implementing the projected change.

12. A computer implemented process as claimed in claim 11 including the further steps of:

selecting additional projected changes to implement which affect strength of a signal between the known position and the plurality of base stations, and

determining the improvement in the value indicating a probability of interference at the average known position by implementing the projected change until the improvement is less than a predetermined value.

13. A computer implemented process as claimed in claim 10 in which the values indicating strength of signals are values determined from actual field tests.

14. A computer implemented process as claimed in claim 13 in which the values indicating strength of signals are values determined from actual field tests of cellular systems establishing channels on a basis different than the basis of the cellular telephone system.

15. A computer implemented process comprising the steps of:

collecting 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 defining an entire mobile communications system,

comparing actual strengths of all signals serving a point from each of the plurality of cells with all other signals received by a mobile unit at each point of the system to detect signals other than desired signals which rise to established levels of interference for the particular system,

determining a value which measures a level of interference at each point in the system,

utilizing the values to determine values which measure the level of interference for each cell and the system,

determining whether any value which measures the level of interference for each cell is sufficient to warrant reducing interference in the cell, and

selecting corrections in cell characteristics which reduce signal strength of interfering signals until interference has been reduced below a predetermined interference level throughout the system.