Asynchronous communication system for remote monitoring of objects or an environment
First Claim
1. A method comprising:
- allocating a unique set of spreading codes to each of a plurality of transponders from among a plurality of spreading codes based on transponder identification information uniquely associated with each of the plurality of transponders;
receiving, with at least one of the plurality of transponders, an interrogation signal;
generating one of the spreading codes based on the associated transponder identification information and based on monitored data information; and
transmitting a transponder signal that includes the generated spreading code and that has a transmit frequency determined by the interrogation signal.
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Accused Products
Abstract
A system provides for remote monitoring using asynchronous code division multiple access (CDMA) communication techniques between a base station and one or more transponders. Each transponder is attached or otherwise associated with an object or an environment to be monitored. Upon receipt of an interrogation signal, a transponder generates and transmits a coded transponder signal containing the monitored data. The coded transponder signal is generated using a spreading code. Each transponder is associated with a unique, mutually exclusive set of spreading codes. Each spreading code is based on a unique transponder address and the monitored data to be sent. A detector asynchronously monitors received signals for any of the available spreading codes. Once the detector detects a particular spreading code, the base station can identify the source transponder and extract the monitored data.
29 Citations
18 Claims
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1. A method comprising:
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allocating a unique set of spreading codes to each of a plurality of transponders from among a plurality of spreading codes based on transponder identification information uniquely associated with each of the plurality of transponders; receiving, with at least one of the plurality of transponders, an interrogation signal; generating one of the spreading codes based on the associated transponder identification information and based on monitored data information; and transmitting a transponder signal that includes the generated spreading code and that has a transmit frequency determined by the interrogation signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method comprising:
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allocating a unique set of spreading codes to each of a plurality of transponders from among a plurality of spreading codes based on transponder identification information uniquely associated with each of the plurality of transponders; and asynchronously examining received signals to detect presence of one or more of the plurality of spreading codes generated by one or more of the transponders based on the transponder identification information uniquely associated with the one or more transponders and on monitored data information associated with the one or more transponders. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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Specification