Method and system for non-persistent communication

Patent metadata

Field	Value
Publication number	US-2016336977-A1
Application number	US-201615155490-A
Country	US
Kind code	A1
Filing date	May 16, 2016
Priority date	May 5, 2014
Publication date	Nov 17, 2016
Grant date	—

Abstract

A method for carrying data on a live host signal, comprising the steps of: varying timing in a host signal in response to data to be encoded, wherein variations in timing are smaller than a sampling period for detection and capture of the digital signal receiving the live host signal; sensing pulse timing variations in the received live host signal by comparison to a reference signal; and determining information in the sensed timing variations.

First claim

1 .- 8 . (canceled)

9 . A method for encoding data in a carrier signal comprising:
encoding a data signal in timing jitter of the carrier signal having timing jitter of a given level; and transmitting the encoded carrier signal.

10 . The method of claim 9 wherein encoding the data signal in the timing jitter of the carrier signal comprises varying the timing in the carrier signal in response to the data signal to be encoded, wherein variations in the timing are smaller than a sampling period for detection and capture of the encoded carrier signal.

11 . The method of claim 10 wherein the carrier signal is a regenerated version of an existing signal; and the regenerated version has at least one frequency component with lower phase noise than the existing signal from which it was created; and wherein the carrier signal was regenerated by using a frequency reference from a high stability oscillator that has a level of stability that is greater than the level of stability of the existing signal.

12 . The method of claim 9 wherein the data signal is configured to be recovered from the timing jitter of the encoded carrier signal by sensing variations in the timing of the encoded carrier signal by comparison of the modulated carrier signal to a first reference signal that has a level of stability that is greater than the level of stability of the encoded carrier signal.

13 . The method of claim 9 , wherein the data signal represents covert data, the carrier signal is a digital signal and the timing jitter comprises variations in pulse timing.

14 . The method of claim 13 , wherein the pulse timing variations comprise variations of one of a leading edge of digital pulses, a trailing edge of digital pulses or pulse width of digital pulses.

15 . The method of claim 13 , wherein the digital pulses comprise marks and spaces and wherein the pulse timing variations comprise variations in time position of the marks and spaces.

16 . The method of claim 9 , wherein the carrier signal is a periodic waveform or a non-periodic waveform, and the timing variations are performed by modulating the phase of at least one frequency of the carrier signal.

17 . The method of claim 9 wherein the carrier signal is a periodic waveform or a non-periodic waveform, and the timing variations comprise variations of one of a particular bit represented by a waveform or of a plurality of bits represented by the waveform.

18 . The method of claim 17 wherein the plurality of bits are consecutive or non-consecutive.

19 . A transmitter for surreptitious communication of data comprising:
a carrier signal source and a data signal source; a high stability oscillator configured as a frequency reference to generate the carrier signal from the carrier signal source with at least one frequency that has a level of stability that is greater than the level of stability of a receiver to which the communication is intended to be surreptitious; and a modulator coupled to the high stability oscillator and to the data signal source to modulate the carrier signal with the data signal.

20 . The transmitter of claims 19 wherein the data signal is encoded onto the carrier either by modulating the high stability oscillator, wherein the high stability oscillator generates a frequency reference for carrier signal generation, or by modulating the carrier signal after the carrier signal is generated by an unmodulated high stability oscillator.

21 . The transmitter of claim 19 wherein the carrier signal is a frequency tone that has a level of stability that is greater than the level of stability of the receiver to which the communication is intended to be surreptitious.

22 . The transmitter of claim 19 wherein the carrier signal is a periodic or non-periodic waveform that has a level of stability that is greater than the level of stability of the receiver to which the communication is intended to be surreptitious.

23 . The transmitter of claim 19 wherein the data signal is configured to be decoded from the timing jitter of the encoded carrier signal by sensing variations in the timing of the encoded carrier signal by comparison of the modulated carrier signal to a first reference signal that has a level of stability that is greater than the level of stability of the encoded carrier signal.

24 . The transmitter of claim 19 wherein variations in the timing are smaller than a sampling period for detection and capture of the encoded carrier signal.

25 . The transmitter of claim 19 wherein the encoder is configured to encode the carrier signal by modulating the phase of at least one of a plurality of frequencies of the carrier signal.

26 . A receiver comprising:
a carrier signal receiver configured to receive an encoded carrier signal, the carrier signal being encoded with a data signal in the timing jitter of the carrier; a high stability oscillator configured to generate a first reference signal that has a level of stability that is greater than the level of stability of the received encoded carrier signal; and a demodulator coupled to the high stability oscillator and to the carrier receiver to demodulate the encoded carrier signal with the first reference signal to produce a demodulated data signal.

27 . The receiver of claim 26 wherein the first reference signal comprises the carrier signal without the encoded data signal in the timing jitter of the carrier signal, and wherein the data signal is recovered by comparison of the encoded carrier signal to the un-encoded carrier signal.

28 . The receiver of claim 27 wherein recovery of the data signal comprises detecting timing variations in the encoded carrier signal.

29 . The receiver of claim 26 wherein the first reference signal is a frequency tone that has a level of stability that is greater than the level of stability of the encoded carrier signal.

30 . The receiver of claim 26 wherein the first reference signal is a regeneration of the un-encoded carrier signal that has a level of stability that is greater than the level of stability of the encoded carrier signal.

31 . The receiver of claim 26 wherein the data signal is decoded from the timing jitter of the encoded carrier signal by sensing variations in the timing of the encoded carrier signal by comparison to the first reference signal that has a level of stability that is greater than the level of stability of encoded carrier signal.

32 . The receiver of claim 26 wherein variations in the timing are smaller than a sampling period for detection and capture of the encoded carrier signal.

Assignees

• Raytheon Co

Inventors

• Kowalevicz Andrew
• Borton Thomas
• Reese Michael C
• Graceffo Gary M

Classifications

• H04L7/042

  Detectors therefor, e.g. correlators, state machines (digital correlators in general G06F17/15) · CPC title

• H04L25/4902 Primary

  Pulse width modulation; Pulse position modulation · CPC title

• H04B1/0475 Primary

  with means for limiting noise, interference or distortion (H04B1/0483 takes precedence) · CPC title

• G06F1/12

  Synchronisation of different clock signals {provided by a plurality of clock generators} · CPC title

• H04L7/065

  and superimposed by modulation · CPC title