Method, information processing device and system
According to one embodiment, a method includes receiving a first wireless signal transmitted from a first wireless device, receiving a second wireless signal transmitted from a second wireless device, and estimating a range of a propagation loss index corresponding to a space between the first wireless device and an information processing device based on a strength of the first wireless signal at the time of reception, a strength of the second wireless signal at the time of reception, and a distance between the first wireless device and the second wireless device. The propagation loss index is used to convert the strength of the first wireless signal into the distance between the first wireless device and the information processing device.
1 . A method executed by an information processing device to obtain a distance between the information processing device and a first wireless device which is installed in a known location and with which the first wireless device can wirelessly communicate, the method comprising:
receiving a first wireless signal transmitted from the first wireless device;
receiving a second wireless signal transmitted from at least one second wireless device installed in a known location different from the first wireless device; and
estimating a range of a propagation loss index corresponding to a space between the first wireless device and the information processing device based on a strength of the first wireless signal at the time of reception, a strength of the second wireless signal at the time of reception, and a distance between the first wireless device and the second wireless device, wherein the propagation loss index is used to convert the strength of the first wireless signal at the time of reception into the distance between the first wireless device and the information processing device.
2 . The method of claim 1 , wherein the range of the propagation loss index is estimated based on the following formulas (1) and (2);
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2
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1
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D
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2
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2
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where
d1x represents the distance between the first wireless device and the information processing device,
d2x represents a distance between the second wireless device and the information processing device, and
D12 represents the distance between the first wireless device and the second wireless device.
3 . The method of claim 1 , further comprising converting the strength of the first wireless signal at the time of reception into a range of the distance between the first wireless device and the information processing device by using the range of the propagation loss index.
4 . The method of claim 3 , further comprising:
calculating a median value of the range of the propagation loss index as the propagation loss index; and
converting the strength of the first wireless signal at the time of reception into the distance between the first wireless device and the information processing device by using the propagation loss index.
5 . The method of claim 3 , further comprising specifying a location of the information processing device by using the range of the distance between the first wireless device and the information processing device.
6 . The method of claim 1 , wherein:
the range of the propagation loss index is estimated when the strength of the first wireless signal at the time of reception and the strength of the second wireless signal at the time of reception are greater than or equal to a threshold set in advance, and
the range of the propagation loss index is not estimated when the strength of the first wireless signal at the time of reception and the strength of the second wireless signal at the time of reception are less than the threshold.
7 . An information processing device which can wirelessly communicate with a first wireless device installed in a known location, the information processing device comprising:
a memory;
a receiver which receives a first wireless signal transmitted from the first wireless device, and a second wireless signal transmitted from at least one second wireless device installed in a known location different from the first wireless device;
a hardware processor which, under control of a program stored in the memory, is configured to execute processes comprising:
a measurement process which measures a strength of the first wireless signal at the time of reception and a strength of the second wireless signal at the time of reception; and
an estimation process which estimates a range of a propagation loss index corresponding to a space between the first wireless device and the information processing device based on the strength of the first wireless signal at the time of reception, the strength of the second wireless signal at the time of reception, and a distance between the first wireless device and the second wireless device,
wherein the propagation loss index is used to convert the strength of the first wireless signal at the time of reception into a distance between the first wireless device and the information processing device.
8 . The information processing device of claim 7 , wherein the range of the propagation loss index is estimated based on the following formulas (3) and (4):
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1
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d
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1
2
(
4
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where
d1x represents the distance between the first wireless device and the information processing device,
d2x represents a distance between the second wireless device and the information processing device, and
D12 represents the distance between the first wireless device and the second wireless device.
9 . The information processing device of claim 7 , wherein the processes further comprise a conversion process which converts the strength of the first wireless signal at the time of reception into a range of the distance between the first wireless device and the information processing device by using the range of the propagation loss index.
10 . The information processing device of claim 9 , wherein:
the estimation process calculates a median value of the range of the propagation loss index as the propagation loss index, and
the conversion process converts the strength of the first wireless signal at the time of reception into the distance between the first wireless device and the information processing device by using the propagation loss index.
11 . The information processing device of claim 9 , wherein the processes further comprise a specification process which specifies a location of the information processing device by using the range of the distance between the first wireless device and the information processing device.
12 . The information processing device of claim 7 , wherein:
the estimation process starts estimation of the range of the propagation loss index when the strength of the first wireless signal at the time of reception and the strength of the second wireless signal at the time of reception are greater than or equal to a threshold set in advance, and
the estimation process terminates the estimation of the range of the propagation loss index when the strength of the first wireless signal at the time of reception and the strength of the second wireless signal at the time of reception are less than the threshold.
13 . A system comprising:
the information processing device of claim 11 ;
the first wireless device;
the at least one second wireless device; and
a control device which can wirelessly communicate with the information processing device,
wherein
the first wireless device and the second wireless device are mounted in or extrinsically attached to electronic devices or installed in locations different from the electronic devices, and
the control device transmits a control signal for controlling operation of an electronic device provided near the information processing device based on the specified location of the information processing device.