TRANSCEIVER REDUNDANCY IN AN ELECTRONIC TOLL COLLECTION SYSTEM
First Claim
1. An electronic toll collection system for conducting toll transactions with vehicle-mounted transponders travelling in a multi-lane roadway, the electronic toll collection system comprising:
- one or more antennas for engaging in RF communications with transponders, each antenna defining a capture zone in a portion of at least one lane of the multi-lane roadway;
two or more RF transceivers, each RF transceiver having an RF port;
a switching network connected to the antennas and to the RF ports of the transceivers, the switching network selectively connecting at least one of said transceivers to at least one of said antennas;
a controller for controlling the switching network and the transceivers; and
failure detection circuitry connected to the RF ports of the transceivers for detecting whether any of the transceivers output an RF signal having a power level below a threshold level, the failure detection circuitry providing a result signal to the controller,whereby the controller is configured to control the switching network to connect the antennas to the transceivers in accordance with a scanning pattern, and wherein the controller is configured to cause the switching network exclude one of the transceivers if the result signal from the failure detection circuitry indicates a failure in said one of the transceivers.
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Accused Products
Abstract
An electronic toll collection system wherein the reader includes a switching network and a plurality of transceivers operating under the control of a controller. The reader further includes failure detection circuitry for determining whether any of the transceivers have failed based upon the RF outputs of the transceivers. If the controller determines that a transceiver has failed, then it alters the switching pattern such that the switching network excludes the failed transceiver from being connected to the antennas. The reader thereby provides for adaptive RF channel assignment, as the particular transceiver used to excite a particular antenna may be dynamically altered, and the provision of at least two transceivers in the reader ensures transceiver redundancy.
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Citations
15 Claims
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1. An electronic toll collection system for conducting toll transactions with vehicle-mounted transponders travelling in a multi-lane roadway, the electronic toll collection system comprising:
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one or more antennas for engaging in RF communications with transponders, each antenna defining a capture zone in a portion of at least one lane of the multi-lane roadway; two or more RF transceivers, each RF transceiver having an RF port; a switching network connected to the antennas and to the RF ports of the transceivers, the switching network selectively connecting at least one of said transceivers to at least one of said antennas; a controller for controlling the switching network and the transceivers; and failure detection circuitry connected to the RF ports of the transceivers for detecting whether any of the transceivers output an RF signal having a power level below a threshold level, the failure detection circuitry providing a result signal to the controller, whereby the controller is configured to control the switching network to connect the antennas to the transceivers in accordance with a scanning pattern, and wherein the controller is configured to cause the switching network exclude one of the transceivers if the result signal from the failure detection circuitry indicates a failure in said one of the transceivers. - View Dependent Claims (2, 3, 4, 5)
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6. A method for adaptively switching transceiver usage in an electronic toll collection system used to conduct toll transactions with vehicle-mounted transponders travelling in a multi-lane roadway, the system including one or more antennas for engaging in RF communications with transponders, two or more RF transceivers wherein each RF transceiver has an RF port, and a switching network connected to the antennas and to the RF ports of the transceivers, the switching network selectively connecting at least one of the transceivers to at least one of the antennas under control of a controller, and wherein the system further includes failure detection circuitry connected to the RF ports for detecting whether any of the transceivers output an RF signal having a power level below a threshold level, the failure detection circuitry providing an output signal to the controller, the method comprising steps of:
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designating a set of active transceivers, wherein the set of active transceivers includes at least one of said transceivers; conducting RF communications through one of the antennas using said set of active transceivers; determining that the RF signal from one of said active transceivers falls below a threshold power level; and excluding said one of said active transceivers from the set of active transceivers. - View Dependent Claims (7, 8, 9, 10, 11)
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12. An electronic toll collection system for conducting toll transactions with vehicle-mounted transponders travelling in a multi-lane roadway, the electronic toll collection system comprising:
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one or more antennas for engaging in RF communications with transponders; two or more RF transceivers, each RF transceiver having an RF port; controller means for controlling the transceivers to implement a scanning pattern switching means connected to the antennas and to the RF ports of the transceivers, the switching means selectively connecting at least one of said transceivers to at least one of said antennas under control of the controller means; and failure detection means connected to the RF ports of the transceivers for detecting whether any of the transceivers output an RF signal having a power level below a threshold level, the failure detection means providing a result signal to the controller means, wherein the controller means further includes means for causing the switching means to connect the antennas to the transceivers in accordance with a scanning pattern, and wherein the controller means includes means for causing the switching network exclude one of the transceivers if the result signal from the failure detection means indicates a failure in said one of the transceivers. - View Dependent Claims (13, 14, 15)
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Specification