Method of building a locating service for a wireless network environment

• US 20060063535A1
• Filed: 11/24/2004
• Published: 03/23/2006
• Est. Priority Date: 09/21/2004
• Status: Active Grant

• Current Assignee: Institute For Information Industry
• Original Assignee: Institute For Information Industry
• Inventors: Liu, Chien-Tsung, Hung, Ting-Yueh
• Granted Patent: US 7,203,504 B2
• Time in Patent Office: Days
• US Class Current: 455/456.100
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 4/00 Services specially adapted for wireless communication networks; Facilities therefor
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

A method of building a locating service for a wireless network environment includes: an environment input step, a detection point calculation step, a measuring step and an assumed non-detected position point step to find measured position points and to measure a four-directional signal strength of the measured position point. By assuming signal strengths of non-detected position points, an entire positioning system can be established. A measuring process includes a portable device signal measuring step, a position point calculation step, and a signal feed back step to send the corresponding position information to the portable device to provide information to a user.

Claims

1. A method of building a locating service in a location-based system for a wireless network environment comprising:

an environment input step for dividing an environment into a plurality of position points and setting a position point as an obstacle according to environment information;

a detection point calculation step for obtaining a plurality of suggested detection points according to a detection algorithm;

a measuring step for measuring the suggested detection points and at least one positioning signal strength from the suggested detection points to establish a relational list between the at least one positioning signal strength and the suggested detection points;

an assumed non-detected position points step for assuming and adding to the relational list at least one positioning signal strength from a plurality of non-detected position points according to an assumption calculation;

a portable device signal measuring step for measuring at least one positioning signal strength from a portable device at a current location;

a position point calculation step for comparing the at least one positioning signal strength from the portable device with the positioning signal strengths in the relational list and obtaining corresponding position information according to a positioning algorithm; and

a signal feed back step for sending the corresponding position information to the portable device to inform a user.

2. The method of building a locating service in a location-based system for a wireless network environment as claimed in claim 1, wherein the detection algorithm comprises:

a detection point ratio input step for inputting a detection point ratio into the location-based system;

a detection point selection step for setting a plurality of selected detection points;

a detection point suggestion step for obstacles for selecting a plurality of position points around a plurality of obstacles and setting the plurality of position points as a plurality of suggested detection points;

a detection point suggestion step for a first area for selecting a plurality of non-obstacles and non-detection point position points and setting the position points as a plurality selected detection points when a first area around every position point has no obstacles, selected detection points or suggested detection points;

a detection point suggestion step for a second area for selecting a plurality of non-obstacles and non-detection point position points and setting the position points as a plurality selected detection points when a second area around every position point has no obstacles, selected detection points or suggested detection points; and

a random detection point suggestion step for selecting a plurality of non-obstacles and non-detection point position points and setting the position points as a plurality of selected detection points so that a ratio between a total number of the suggested detection points and the selected detection points and a number of the position points in the location-based system is larger than the input detection point ratio.

3. The method of building a locating service in a location-based system for a wireless network environment as claimed in claim 1, wherein the assumption calculation is performed according to the formula

$P$

( d ) = P ⁡

( d 0 ) - 10 ⁢

n ⁢

 

⁢

log ⁡

( ⅆ

ⅆ

0 ) - nW ×

WAF

to obtain the at least one positioning signal strength P(d), wherein, d is a distance between the positioning points and a acess point, d₀ is a distance between a signal obtained point and the acess point, WAF is an obstacle fading factor, n is a signal fading factor, nW is the number of the obstacles between the positioning points and the acess points, and P(d₀) is a signal strength of the signal obtained points.

4. The method of building a locating service in a location-based system for a wireless network environment as claimed in claim 3, wherein when nW exceeds a predetermined obstacle number threshold value C, the at least one positioning signal strength is determined by

$P$

( d ) = P ⁡

( d 0 ) - 10 ⁢

n ⁢

 

⁢

log ⁡

( ⅆ

ⅆ

0 ) - C ×

WAF .

5. The method of building a locating service in a location-based system for a wireless network environment as claimed in claim 3, wherein the signal obtained point is located along a link between the positioning point and the acess point.

6. The method of building a locating service in a location-based system for a wireless network environment as claimed in claim 3, wherein the signal obtained point is the acess point, and d₀=1.

7. The method of building a locating service in a location-based system for a wireless network environment as claimed in claim 1, wherein a positioning modification step is further performed after the detection point calculation step, and is used for modifying the corresponding positioning information via a modification model.

8. The method of building a locating service in a location-based system for a wireless network environment as claimed in claim 1, wherein a service integration step is further performed after the detection point calculation step, and is used for activating a back-end application service according to the corresponding positioning information.

9. The method of building a locating service in a location-based system for a wireless network environment as claimed in claim 1, wherein the positioning algorithm is a Viterbi algorithm.

10. The method of building a locating service in a location-based system for a wireless network environment as claimed in claim 1, wherein the at least one positioning signal strength in the measuring step is a positioning signal strength from front, back, left and right directions.