Hopping pattern generation method in frequency hopping system for intermittent transmission
First Claim
1. A method of transmitting telemetry, said method comprising in each of a plurality of transmitters:
- producing a first sequence based on a first group of selecting bits, and producing a second sequence based on a second group of selecting bits, wherein said second sequence is shifted relative to said first sequence according to a third group of selecting bits, and transmitting intermittently transmissions independently of any apparatus capable of receiving any of said transmissions and independently of any other of said plurality of transmitters, wherein transmission frequency and transmission time interval are varied based on said first sequence and said second sequence.
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Abstract
A radio transmission system including many radio transmitters using frequency hopping carriers to intermittently transmit very short messages indicative of status of stimuli associated with the transmitters. The transmitters transmit transmissions independently of a receiver receiving the transmissions and independent of each other. In operation, radio transmitters transmit messages at varying frequencies at time intervals that can be varied as well. The frequency and time intervals are varied according to patterns that can be determined individually for each transmitter. A receiver holds data indicative of the future transmission frequency and time for each transmitter and updates the data based on the time and the content of the received messages. In addition, a simple method is provided to generate a very large number of orthogonal frequency-time hopping sequences that are individual for each transmitter and based on the transmitter ID.
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Citations
15 Claims
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1. A method of transmitting telemetry, said method comprising in each of a plurality of transmitters:
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producing a first sequence based on a first group of selecting bits, and producing a second sequence based on a second group of selecting bits, wherein said second sequence is shifted relative to said first sequence according to a third group of selecting bits, and transmitting intermittently transmissions independently of any apparatus capable of receiving any of said transmissions and independently of any other of said plurality of transmitters, wherein transmission frequency and transmission time interval are varied based on said first sequence and said second sequence. - View Dependent Claims (2, 3, 4, 5)
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6. A plurality of telemetry transmitters each of which comprises:
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a circuit for transmitting intermittently transmissions independently of any apparatus for receiving any of said transmissions and independently of any other of said plurality of transmitters, and logic for varying, for said transmissions, transmission frequency channel and transmission time interval according to a frequency-time hopping pattern based on;
(a) a first sequence selected according to a first group of selecting bits and (b) a second sequence selected according to a second group of selecting bits, wherein said second sequence is shifted relative to said first sequence according to a third group of selecting bits.- View Dependent Claims (7, 8, 9, 10)
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11. A system comprising:
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a plurality of transmitters, each of which is for transmitting intermittently transmissions, at varied time interval and at varied transmission frequency, independently of any receiver capable of receiving any of said transmissions and independently of any other of said plurality of transmitters, and a receiver for holding, simultaneously for each of said plurality of transmitters, data indicative of an expected time and an expected frequency of at least one future transmission, wherein for each of said plurality of transmitters, said data is based on a frequency-time hopping pattern based on;
(a) a first sequence selected according to a first group of selecting bits and (b) a second sequence selected according to a second group of selecting bits, wherein said second sequence is shifted relative to said first sequence according to a third group of selecting bits.- View Dependent Claims (12, 13, 14, 15)
said receiver comprises a frequency selective circuit, and wherein in operation, for each of said plurality of transmitters, said receiver changes frequency of said frequency selective circuit to said expected transmission frequency at such time relative to said expected time to receive and demodulate said at least one future transmission. -
13. The system of claim 11 wherein each of said plurality of transmitters comprises an identification and at least one of said first, second, and third group of selecting bits is based on said identification.
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14. The system of claim 11 wherein each of a plurality of said transmissions comprises at least a portion of data indicative of at least one of said first, second, and third group of selecting bits.
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15. The system of claim 11 wherein said frequency-time hopping pattern is different for each of said plurality of transmitters.
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Specification