Method for calibrating an on-board unit and a test device, a method for wireless toll collection
First Claim
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1. A method, comprising:
- receiving a first signal transmitted by a first road-side unit and detecting a strength of the first signal with a first on-board unit disposed at a preset position;
calculating, by the first on-board unit, a calculated strength of the first signal according to the detected strength of the first signal;
storing the calculated strength of the first signal in a memory accessible by the first on-board unit;
receiving a second signal transmitted by a test device and detecting a strength of the second signal with the first on-board unit;
calculating, by the first on-board unit, a calculated strength of the second signal according to the detected strength of the second signal; and
adjusting at least one of a transmission strength of the second signal and a channel between the first on-board unit and the test device until the calculated strength of the second signal is equal to the stored strength of the first signal;
wherein calculating a calculated strength of the first signal according to the detected strength of the first signal comprising;
calculating the calculated strength of the first signal following an equation below;
Pin=(20 log(RSSI)+x−
y)−
Gagc where Pin is the calculated strength of the first signal, RSSI is the detected strength of the first signal, Gagc is a gain achieved by an automatic gain controller in the first on-board unit, x is a dBV-to-dBm conversion factor and y is a gain of an analog-to-digital conversion.
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Abstract
A method comprises: disposing an on-board unit at a preset relative position with respect to a road-side unit; transmitting a signal by the road-side unit; receiving the signal by the on-board unit and detecting a strength of the received signal; calculating, by the on-board unit, a calculated strength of the received signal according to the detected strength of the received signal; storing the calculated strength of the received signal in a memory accessible by the on-board unit; using the stored calculated strength of the received signal to determine if payment of a toll should be made.
7 Citations
9 Claims
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1. A method, comprising:
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receiving a first signal transmitted by a first road-side unit and detecting a strength of the first signal with a first on-board unit disposed at a preset position; calculating, by the first on-board unit, a calculated strength of the first signal according to the detected strength of the first signal; storing the calculated strength of the first signal in a memory accessible by the first on-board unit; receiving a second signal transmitted by a test device and detecting a strength of the second signal with the first on-board unit; calculating, by the first on-board unit, a calculated strength of the second signal according to the detected strength of the second signal; and adjusting at least one of a transmission strength of the second signal and a channel between the first on-board unit and the test device until the calculated strength of the second signal is equal to the stored strength of the first signal; wherein calculating a calculated strength of the first signal according to the detected strength of the first signal comprising; calculating the calculated strength of the first signal following an equation below;
Pin=(20 log(RSSI)+x−
y)−
Gagcwhere Pin is the calculated strength of the first signal, RSSI is the detected strength of the first signal, Gagc is a gain achieved by an automatic gain controller in the first on-board unit, x is a dBV-to-dBm conversion factor and y is a gain of an analog-to-digital conversion. - View Dependent Claims (2, 3, 4, 5)
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6. A method for electronic toll collection, comprising:
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receiving a signal from a road-side unit and detecting a strength of the signal by an on-board unit; calculating, by the on-board unit, a calculated strength of the signal according to the detected strength of the signal; comparing the calculated strength of the signal with a reference strength; transmitting, by the on-board unit, an indication signal indicating payment of a toll to the road-side unit if the calculated strength of the signal is stronger than or equal to the reference strength; wherein calculating the calculated strength of the signal following an equation below;
Pin=(20 log(RSSI)+x−
y)−
Gagcwhere Pin is the calculated strength of the first signal, RSSI is the detected strength of the first signal, Gagc is a gain achieved by an automatic gain controller in the first on-board unit, x is a dBV-to-dBm conversion factor and y is a gain of an analog-to-digital conversion.
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7. An on-board unit in an electronic toll collection system, comprising:
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a primary module configured to receive a signal transmitted by a road-side unit; a processor configured to detect a strength of the signal and calculate a calculated strength of the signal according to the detected strength of the signal; wherein the processor is further configured to compare the calculated strength of the signal with a reference strength; and the primary module is further configured to transmit an indication signal indicating payment of a toll to the road-side unit if the calculated strength of the signal is stronger than or equal to the retrieved strength; wherein the processor is configured to calculate the calculated strength of the received signal following an equation below;
Pin=(20 log(RSSI)+x−
y)−
Gagc. - View Dependent Claims (8)
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9. An on-board unit in an electronic toll collection system, comprising:
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a wake-up circuit; a primary module; a processor and a memory; wherein the wake-up circuit is configured to activate the processor upon receipt of a wake-up signal from a road-side unit, wherein the processor is configured to wake the primary module upon activation; the primary module includes; a match circuit configured to receive a signal from a road-side unit; a low noise amplifier configured to amplify an amplitude of the signal to generate an amplified signal; an automatic gain controller configured to receive the amplified signal and adjust an amplitude of the amplified signal so as to generate a gain-controlled signal; an analog-to-digital converter configured to receive and convert the gain-controlled signal to a digital signal; the memory is configured to store a reference strength; the processor is configured to detect a strength of the digital signal, and calculate a calculated strength of the digital signal following an equation below;
Pin=(20 log(RSSI)+x−
y)−
Gagcwhere Pin is the calculated strength of the digital signal, RSSI is the detected strength of the digital signal, Gagc is a gain achieved by an automatic gain controller x is a dBV-to-dBm conversion factor and y is a gain of an analog-to-digital conversion the processor is further configured to compare the calculated strength of the digital signal with the reference strength and, if the calculated strength of the digital signal is stronger than or equal to the reference strength, instruct the primary module to transmit an indication signal indicating payment of a toll to the road-side unit.
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Specification