Apparatus and method for geostatistical analysis of wireless signal propagation

• US 6,711,404 B1
• Filed: 07/21/2000
• Issued: 03/23/2004
• Est. Priority Date: 07/21/2000
• Status: Expired due to Fees

• Current Assignee: Allen Telecom LLC (CommScope Holding Company, Inc.)
• Original Assignee: Scoreboard Inc. (CommScope Holding Company, Inc.)
• Inventors: Arpee, John, Touati, Mustafa, Gutowski, Stan
• Primary Examiner(s): Tran, Sinh
• Assistant Examiner(s): Nguyen, Huy D
• Application Number:
  US09/620,850
• Time in Patent Office: 1,341 Days
• Field of Search: 455/423, 455/446, 455/67.1, 455/456, 455/447, 455/67.16
• US Class Current: 455/423
• CPC Class Codes: H04W 16/18 Network planning tools

Abstract

A method utilizing statistical interpolation techniques to analyze and simulate the spatial variability and continuity of radio frequency data collected from a wireless cellular system. The method is used for cellular system planning and management. After installation and setup of cellular base stations, further analysis and refinement of RF data is implemented to determine signal coverage of the tower, location of RF holes in system, reuse of frequencies, and overlapping RF signals between two or more towers causing interference. The method analyzes raw RF power data that is collected by drive testing a sample of roads in a cellular system. A geostatistical model of the RF propagation at a cellular system is determined through kriging. The RF path loss trend estimation is extracted from each the raw data and modeled to describe data variability across the entire cellular system ares. An estimated path loss signal map is then prepared for any area of interest within a cellular system.

Claims

1. A method for assessing RF propagation in a wireless communication system comprising the steps of:

collecting measured RF path loss data within said wireless communication system corresponding to known geographic locations within said wireless communication system;

interpolating said measured RF path loss data;

establishing a data set of interpolated path loss signal strength levels from said collected measured RF path loss data; and

casting a final RF propagation data set including said measured data for said known geographic locations and selected data points from said interpolated data set for geographic locations having no corresponding measured data; and

wherein the weights of dispersed neighboring data values are equilibrated to elustered neighboring data values for interpolating said measured RF path loss data interpolation.

2. A method for assessing RF propagation in a wireless communication system according to claim 1, further comprising:

interpolating a plurality of data sources utilizing the variance of said data sources to weight the significance of said data.

3. A method for assessing RF propagation in a wireless communication system comprising the steps of:

collecting wireless signal data comprised of a plurality of data elements for one or more wireless base stations;

associating the data elements of said wireless signal data with geographic locations corresponding to a location at which each said data element was gathered;

associating said data elements with a source;

applying an interpolation model to said wireless signal data base on a spatial continuity analysis; and

using said interpolation model to manage a wireless network;

wherein said step of associating said data elements with a source includes identifying a digital identification code within said wireless signal data.

4. A method for assessing RF propagation in a wireless communication system according to claim 3, wherein;

said step of identifying a digital indentification code includes utilizing a rapid color code decoder to increase the probability of obtaining information under adverse conditions.

5. A method for assessing RF propagation in a wireless communication system according to claim 3, wherein said applying an interpolation model includes applying a linear weighted-averaging method depending upon a model of spatial correlation.

6. A method for assessing RF propagation in a wireless communication system according to claim 3, further comprising the steps of:

defining a spatial trend in said gathered wireless signal data;

defending said wireless signal data by filtering said spatial trend from said wireless signal data thereby creating defended wireless signal data; and

utilizing said detrended wireless signal data in the step of said applying a geostatistical an interpolation model to said wireless signal data.

7. A method for assessing RF propagation in a wireless communication system according to claim 3, wherein:

said step of applying an interpolation model includes;

creating a model consisting of a plurality of bins overlaying at least part of said wireless communication system;

creating a second residual data set by removing a spatial trend from said wireless signal data at each said bin;

interpolating said second residual data set using geostatistical techniques thereby creating and interpolated residual data set;

adding said spatial trend data to said interpolated second residual data set; and

reporting wireless signal path loss estimations at said bius.

8. A method for assessing RF propagation in a wireless communication system according to claim 7, wherein:

said step of interpolating said second residual data set using geostatistical techniques includes kriging, cokriging, kriging with external drift, or colocation cokriging to calculate path losses of said wireless signal data.

9. A method for assessing RF propagation in a wireless communication system according to claim 8, wherein said geostatistical techniques include:

searching a neighborhood of values of said wireless signal data near a bin;

computation of computing a kriging matrix;

finding the weights of linear combinations of said neighboring values of said wireless signal data and weights of said neighboring values of said wireless signal data;

calculating the a variance of an estimation of the path loss; and

computing the an estimated residual data point at a bin location.

10. A method for assessing RF propagation in a wireless communication system, comprising the steps of:

creating a model consisting of a plurality of bins overlaying at least part of a wireless system;

collecting wireless signal data from one or more wireless base stations thereby creating collected wireless signal data;

creating residuals by removing a spatial trend from said data at said bins;

modeling said residuals with an interpolation technique based on spatial continuity analysis thereby creating modeled residuals;

adding said spatial trend to modeled residuals; and

reporting modeled path loss data at said bins.

11. The method of claim 10, wherein said step of creating residuals by removing a spatial trend from said wireless signal data includes:

recognizing a spatial trend in said gathered collected wireless data;

detrending said wireless signal data by filtering said spatial trend from said wireless signal data thereby creating detrended data; and

utilizing said detrended data in said step of modeling said residuals with an interpolation technique to said wireless signal data.

12. A method for assessing RF propagation in a wireless communication system according to claim 10, wherein:

said step of modeling said residuals with an interpolation technique based on spatial continuity analysis includes modeling with geostatistical interpolation techniques.

13. A method for assessing RF propagation in a wireless communication system according to claim 12, wherein:

said step of modeling said residuals with an interpolation technique includes at least one of the group comprised of kriging, cokriging, kriging with external drift, and colocation cokriging to calculate path losses of said wireless signal data.

14. A method for assessing RF propagation in a wireless communication system, comprising the steps of:

collecting data sets of measured path loss signal strength levels gathered from within said wireless communication system from known geographic locations within said wireless communication system; and

analyzing said data sets using multivariate statistical techniques;

deriving independent parameter sets from said multivariate statistical analysis of said data set for input into a plurality of propagation models of said data sets, each said model corresponding to one of said multivariate statistical analysis.

15. A method for assessing RF propagation in a wireless communication system according to claim 14, wherein:

said multivariate statistical analysis includes multivariate geostatistical analysis techniques.

16. An apparatus for assessing RF propagation in a wireless communication system comprising:

wireless receiving equipment for gathering wireless signal data comprised of a plurality of data elements from one or more wireless base stations thereby creating gathered wireless signal data;

geographic location equipment connected to said wireless receiving equipment for associating the data elements of said wireless signal data with geographic locations corresponding to the a location at which each said data element was gathered;

signal strength measuring equipment for determining the signal strength of each element of said gathered data thereby creating measured data;

digital decoding equipment for indentifying a digital indentification code within said gathered data; and

a processor for establishing a data set of interpolated path loss signal strength levels form said collected gathered wireless signal data; and

creating a final RF propagation data set including said measured data for known geographic location and selected data points from said data set of interpolated path loss signal strength levels for geographic locations having no corresponding measured data; and

wherein the weight of dispersed neighboring data values are equilibrated to elustered neighboring data values for establishing a data set of interpolated path loss signal strength levels.

17. An apparatus for assessing RF propagation in a wireless communication system according to claim 16,

wherein said processor interpolates a plurality of data sources utilizing the a variance of said data sources to weight the significance of said data.