Systems and methods for determining signal coverage

• US 6,959,189 B2
• Filed: 08/15/2001
• Issued: 10/25/2005
• Est. Priority Date: 08/15/2000
• Status: Expired due to Term

• Current Assignee: LCC International Incorporated (Tech Mahindra Network Services International, Inc.)
• Original Assignee: LCC International Incorporated (Tech Mahindra Network Services International, Inc.)
• Inventors: Cotanis, Nicolae G.
• Primary Examiner(s): D AGOSTA, STEPHEN M
• Application Number:
  US09/929,034
• Publication Number:
  US 20020042268A1
• Time in Patent Office: 1,532 Days
• Field of Search: 455 9- 10, 455 631- 65, 455 6711- 6714, 455/114, 4551151-1154, 455/404.2, 455/421, 455/423, 455/425, 455440-441, 4554561-457, 455501-506, 455/436, 370241-253, 370/310.2, 370/317, 370/332
• US Class Current: 455/436
• CPC Class Codes: G01C 21/34 Route searching; Route guidance
• CPC Class Codes: G01S 11/02 using radio waves G01S19/00 takes precedence
• CPC Class Codes: G01S 5/02521 using a radio-map
• CPC Class Codes: H04B 17/26 using historical data, averaging values or statistics
• CPC Class Codes: H04B 17/27 for locating or positioning the transmitter
• CPC Class Codes: H04B 17/318 Received signal strength
• CPC Class Codes: H04W 52/225 Calculation of statistics, e.g. average, variance

Abstract

Methods and systems are provided for processing signal strength information from a radio frequency transmitter and for determining signal coverage for a wireless device. In one embodiment, the method includes receiving signal strength information indicating a power for the radio frequency transmitter at one or more first locations; receiving location information representing a geographic location for one or more second locations; dividing the received signal strength information into one or more subsets of signal strength information; determining, for each of the one or more subsets, a local mean such that the local mean represents an average for one of the one or more subsets; and estimating a location for the local mean based on the received location information.

Claims

1. A method for processing signal strength information from a radio frequency transmitter comprising the steps of:

receiving signal strength information indicating a power for the radio frequency transmitter at one or more first locations;

receiving location information representing a geographic location for one or more second locations;

dividing the received signal strength information into one or more subsets of signal strength information, such that the one or more subsets are determined based on a speed of a receiver of the received signal strength information and a corresponding distance associated with the speed;

determining, for each of the one or more subsets, a local mean, such that the local mean represents an average for one of the one or more subsets;

estimating a location for the local mean based on the received location information;

determining at least one distance between the estimated location and another estimated location based on the speed of the receiver and the signal strength information.

2. The method of claim 1, further comprising the step of:

interpolating the local mean when the at least one distance exceeds a predetermined distance.

3. The method of claim 1, wherein said step of determining further comprises the step of:

determining a plurality of local means such that each local mean corresponds to one of the one or more subsets.

4. The method of claim 3, wherein said step of determining further comprises the step of:

averaging one or more of the plurality of local means to provide a window average.

5. The method of claim 4, wherein said step of averaging further comprises the step of:

determining a difference value based on one of the plurality of local means and the window average.

6. The method of claim 5, wherein said step of averaging further comprises the step of:

determining a plurality of difference values.

7. The method of claim 6, further comprising the step of:

calculating a standard deviation based on the plurality of difference values.

8. The method of claim 7, further comprising the step of:

determining a signal coverage at a location for a wireless device based on the following equation;

$\mathrm{Cp}<br><br>\left(r\right)=\frac{1}{2}-\mathrm{erf}<br><br>\frac{w_t-\mathrm{LM}<br><br>\left(r\right)}{{\mathrm{\sigma <br><br>}}_{\mathrm{LM}}}$

wherein r represents the location, σ

_LM represents the standard deviation, LM(r) represents the local mean corresponding to the location, w_t represents a service threshold for the wireless device, and erf is a normal distribution error function.

9. The method of claim 8, wherein said step of determining the signal coverage further comprises the step of:

defining the location as at least one of the one or more first locations.

10. The method of claim 1, further comprising the step of:

defining the one or more first locations as locations that differ from the one or more second locations.

11. A method for processing signal strength information from a radio frequency transmitter comprising the steps of:

receiving signal strength information indicating a power for the radio frequency transmitter at one or more first locations, wherein the signal strength information includes a set of signal strength data based on a signal trace;

receiving location information representing a geographic location for one or more second locations, wherein the received location information for one or more second locations includes one or more of the following;

a latitude, a longitude, or at least one of a plurality of first time stamps from a receiver of global positioning system information;

attaching at least one of a plurality of second time stamps to the set of signal strength data;

smoothing the plurality of second time stamps based on the plurality of first time stamps;

dividing the received signal strength information into one or more subsets of signal strength information, such that the one or more subsets are determined based on a speed of a receiver of the received signal strength information;

determining, for each of the one or more subsets, a local mean such that the local mean represents an average for one of the one or more subsets;

estimating a location for the local mean based on the received location information.

12. The method of claim 11, wherein said smoothing further comprises the step of:

smoothing the plurality of second time stamps based on a slope for the plurality of first time stamps.