Overhead reduction in frequency hopping system for intermittent transmission
First Claim
1. A telemetry system comprising:
- a plurality of transmitters each of which, when operative, transmits independently of any other of said plurality of transmitters and independently of any equipment for receiving from any of said plurality of transmitters and at transmission frequency and time between transmissions controlled according to a time-frequency pattern that is different for each of said plurality of transmitters, and includes selectively, in transmissions, portions of information payload according to said time-frequency pattern; and
a receiver for;
(a) holding, simultaneously for each plurality of transmissions, data indicative of an expected time and an expected frequency of at least one future transmission, and (b) identifying said portions of information payload based on said time-frequency pattern.
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Abstract
A radio transmission telemetry system includes several transmitters intermittently transmitting short messages indicative associated sensors status and a receiver for collecting data from the sensors. The transmitters transmit short messages separated by long time intervals independently of any receiver capable of receiving from any of the transmitters. Each transmitter changes time and frequency of transmissions according to a time-frequency pattern that is different for each transmitter. The receiver holds information about the expected time and the expected frequency of the future transmissions for each transmitter. The receiver identifies each source of transmissions based on its unique variations of the transmission time and frequency, thus eliminating the necessity to include the transmitter ID code in each transmitted message. The sensor status and other supervisory information such as battery status are partitioned and included in the transmitted messages in portions according to the state of the PN-generator for producing the time-frequency pattern.
37 Citations
15 Claims
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1. A telemetry system comprising:
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a plurality of transmitters each of which, when operative, transmits independently of any other of said plurality of transmitters and independently of any equipment for receiving from any of said plurality of transmitters and at transmission frequency and time between transmissions controlled according to a time-frequency pattern that is different for each of said plurality of transmitters, and includes selectively, in transmissions, portions of information payload according to said time-frequency pattern; and
a receiver for;
(a) holding, simultaneously for each plurality of transmissions, data indicative of an expected time and an expected frequency of at least one future transmission, and (b) identifying said portions of information payload based on said time-frequency pattern. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A receiver comprising:
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logic for holding, simultaneously for each plurality of transmissions, data indicative of an expected time and an expected frequency of at least one future transmission, wherein each said plurality of transmissions is transmitted by different one of a plurality of transmitters, and wherein each of said plurality of transmitters, when operative, transmits independently of any other of said plurality of transmitters and independently of any equipment for receiving from any of said plurality of transmitters, and wherein, transmission frequency and time between transmissions are controlled according to a time-frequency pattern that is different for each of said plurality of transmitters; and
logic for identifying portions of information payload bits included in transmissions based on said time-frequency pattern. - View Dependent Claims (9, 10)
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11. A plurality of telemetry transmitters, each of which comprises:
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a circuit for transmitting intermittently, at various transmission frequencies, independently of any other of said plurality of transmitters, and independently of any apparatus for receiving from any of said plurality of transmitters, and logic for controlling transmission frequency and time between transmissions according to a frequency-time pattern that is different for each of said plurality of transmitters, wherein, in operation, each of a plurality of transmissions comprises a portion of information payload, wherein said portion is selected based on said frequency-time pattern. - View Dependent Claims (12, 13, 14, 15)
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Specification