METHOD AND APPARATUS FOR MEASURING DISTANCE IN A WIRELESS ENVIRONMENT

• US 20090207070A1
• Filed: 02/20/2009
• Published: 08/20/2009
• Est. Priority Date: 02/20/2008
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Ha, Do-young, PARK, Jeong-Rok, Kim, Joon-Oo, Kim, Byung-Jik, Park, Sung-Kweon, Baik, Jin-Serk
• Granted Patent: US 8,330,648 B2
• Time in Patent Office: Days
• US Class Current: 342/125
• CPC Class Codes: G01S 13/76 wherein pulse-type signals are transmitted
• CPC Class Codes: G01S 7/2921 based on data belonging to one radar period

Abstract

A method and apparatus for measuring a distance in a wireless environment are provided, in which a first device transmits a distance measurement signal to a second device and receives at least one response signal for the distance measurement signal from the second device, matches the received response signal with a reference signal to detect an earliest response signal, and calculates a time taken from the transmission of the distance measurement signal to the second device and the reception of the response signal from the second device using a peak value of the matched reference signal.

Claims

1. A method for measuring a distance in a wireless environment, comprising:

transmitting a distance measurement signal to a second device and receiving at least one response signal for the distance measurement signal from the second device by a first device;

matching the received response signal with a reference signal to detect an earliest response signal by the first device; and

calculating a time taken from the transmission of the distance measurement signal to the second device and the reception of the response signal from the second device using a peak value of the matched reference signal by the first device.

2. The method of claim 1, wherein the response signal reception comprises:

determining whether the received response signal is a response for the distance measurement signal; and

eliminating noise from the received response signal by comparing the received response signal with a threshold.

3. The method of claim 2, wherein the comparison between the received response signal with the threshold comprises comparing the threshold with a width of a waveform of the response signal, classifying a signal with a waveform width less than the threshold as noise, eliminating the noise from the response signal, and detecting a signal with a waveform width larger than the threshold as an original signal.

4. The method of claim 1, wherein the matching of the received response signal is a pulse width matching that comprises detecting the earliest response signal by aligning the start of a pulse of the received response signal with the start of a pulse of the reference signal.

5. The method of claim 4, wherein a pulse width of the reference signal is computed by the following equation and the peak value of the reference signal is detected according to the pulse width of the reference signal,

reference pulse width=α

×

single pulse width

where a denotes a value proportional to Received Signal Strength Indication (RSSI) that is inversely proportional to the square of distance, ranging from 0 to 1, and single pulse width is defined as a pulse width measured at a reference RSSI.

6. An apparatus for measuring a distance in a wireless environment, comprising:

a transceiver for transmitting a distance measurement signal to a device to which a distance is to be measured and receiving a response signal for the distance measurement signal from the device;

a signal detector for detecting a peak value of an earliest response signal from the received response signal; and

a distance calculator for measuring the distance using the peak value of the earliest response signal.

7. The apparatus of claim 6, wherein the signal detector comprises:

an original signal detector for determining whether the received response signal was transmitted by the device;

a peak detector for detecting a peak value of the response signal determined as an original signal; and

a pulse width comparator for matching a pulse width of the received response signal with a pulse width of a reference signal.

8. The apparatus of claim 7, wherein the pulse width comparator compares the pulse width of the received response signal with the pulse width of the reference signal, if the pulse width of the received response signal is larger than a pulse width of a single response signal, and transmits the received response signal as the earliest response signal to the distance calculator, if the pulse width of the received response signal is less than the pulse width of the single response signal.