Passive wireless system
First Claim
Patent Images
1. A passive wireless system for monitoring a protected area comprising:
- a plurality of passive sensors deployed throughout the protected area, each of the plurality of passive sensors operable to detect a respective security event at a location of the passive sensor within the protected area;
a reader that receives signals from the plurality of passive sensors;
a plurality of exciters disposed at respective known locations throughout the protected area, each of the plurality of exciters transmitting a radio frequency pulse at a variable time interval that powers at least one passive sensor of the plurality of passive sensors; and
a controller that separately controls each of the plurality of exciters to transmit the radio frequency pulse at the variable time interval and that detects responses through the reader from sensors located near and that are powered by the radio frequency pulse of the transmitting exciter, wherein each of the plurality of exciters has a different variable transmission interval such that there is no signal interference among the plurality of exciters and wherein by varying the time interval and controlling each of the exciters separately, the controller identifies the location of the at least one passive sensor which transmitted a signal in response to the transmitted radio frequency pulse based upon the known location of the transmitting exciter wherein the controller selects the variable time interval of at least some of the plurality of passive sensors depending on a status of said passive wireless security system, said status being disarmed, armed-stay and armed-away.
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Abstract
A passive wireless system for monitoring a protected area. The passive wireless system comprises at least one passive sensor for sensing an event, a reader for receiving signals from the at least one passive sensor, a plurality of exciters disposed within the protected area for transmitting a radio frequency pulse at a variable time interval to the at least one passive sensor, and a controller for controlling each of the plurality of exciters to transmit the radio frequency pulse at the variable time interval. The radio frequency pulse powers the passive sensors.
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Citations
12 Claims
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1. A passive wireless system for monitoring a protected area comprising:
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a plurality of passive sensors deployed throughout the protected area, each of the plurality of passive sensors operable to detect a respective security event at a location of the passive sensor within the protected area; a reader that receives signals from the plurality of passive sensors; a plurality of exciters disposed at respective known locations throughout the protected area, each of the plurality of exciters transmitting a radio frequency pulse at a variable time interval that powers at least one passive sensor of the plurality of passive sensors; and a controller that separately controls each of the plurality of exciters to transmit the radio frequency pulse at the variable time interval and that detects responses through the reader from sensors located near and that are powered by the radio frequency pulse of the transmitting exciter, wherein each of the plurality of exciters has a different variable transmission interval such that there is no signal interference among the plurality of exciters and wherein by varying the time interval and controlling each of the exciters separately, the controller identifies the location of the at least one passive sensor which transmitted a signal in response to the transmitted radio frequency pulse based upon the known location of the transmitting exciter wherein the controller selects the variable time interval of at least some of the plurality of passive sensors depending on a status of said passive wireless security system, said status being disarmed, armed-stay and armed-away. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A wireless communication method between a plurality of passive sensors and a wireless reader within a protected area comprising the steps of:
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deploying the plurality of passive sensors throughout the protected area; integrating a plurality of wireless exciters into the protected area at different respective known locations; assigning a respective transmission time for each of a plurality of wireless exciters wherein each of the plurality of wireless exciters has a different variable transmission interval such that there is no signal interference among the plurality of exciters; transmitting control signal including the assigned transmission time to each of the plurality of wireless exciters; and transmitting, during the assigned time, a pulse power signal from each of the plurality of exciters to the passive sensors, wherein at least some of the passive sensors located near the transmitting exciter are excited by and powered by the pulse power signal from the transmitting exciter; detecting a signal from one of the plurality of sensors in response to the power pulse signal from the transmitting exciter through the reader; and identifying the location of the passive sensor which transmitted the detected signal in response to the power pulse based upon the assigned time of the power pulse signal and known location of the transmitting exciter wherein the controller selects the variable time interval of at least some of the plurality of passive sensors depending on a status of said passive wireless security system, said status being disarmed, armed-stay and armed-away.
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Specification