PERMISSION-BASED TDMA CHAOTIC COMMUNICATION SYSTEMS

• US 20110019817A1
• Filed: 07/22/2009
• Published: 01/27/2011
• Est. Priority Date: 07/22/2009
• Status: Active Grant

• Current Assignee: Harris Corporation (L3Harris Technologies, Inc.)
• Original Assignee: Harris Corporation (L3Harris Technologies, Inc.)
• Inventors: Michaels, Alan J., Chester, David B.
• Granted Patent: US 8,848,909 B2
• Time in Patent Office: Days
• US Class Current: 380/38
• CPC Class Codes: H04K 1/02 by adding a second signal to make the desired signal unintelligible
• CPC Class Codes: H04K 1/025 using an analogue chaotic signal

Abstract

Systems (100) and methods for selectively controlling access to data streams communicated from a first communication device (FCD) using a timeslotted shared frequency spectrum and shared spreading codes. Protected data signals (130₁, . . . , 130_S) are modulated to form first modulated signals (132₁, . . . , 132_S). The first modulated signals are combined with first chaotic spreading codes to form digital chaotic signals. The digital chaotic signals are additively combined to form a protected data communication signal (PDCS). The PDCS (136) and a global data communication signal (GDCS) are time division multiplexed to form an output communication signal (OCS). The OCS (140) is transmitted from FCD (102) to a second communication device (SCD) over a communications channel. The SCD (106, 108, 110) is configured to recover (a) only global data from the OCS, or (b) global data and at least some protected data from the OCS.

Claims

1. A method for selectively controlling access to multiple data streams which are communicated from a first communication device using a timeslotted shared frequency spectrum and shared spreading codes, comprising the steps of:

modulating at least two protected data signals including protected data to form at least two first modulated signals;

combining the first modulated signals with first chaotic spreading codes to form digital chaotic signals having spread spectrum formats;

additively combining the digital chaotic signals to form a composite protected data communication signal;

time division multiplexing the composite protected data communication signal with a global data communication signal including global data to form an output communication signal; and

transmitting said output communication signal from the first communication device over a communications channel.

2. The method according to claim 1, further comprising generating the first chaotic spreading codes using different values for at least one generation parameter of a chaotic sequence.

3. The method according to claim 2, wherein the generation parameter is selected from the group comprising a sequence location parameter, a polynomial equation parameter and an N-tuple of moduli parameter.

4. The method according to claim 1, further comprising generating the first chaotic spreading codes by dynamically varying a value for a generation parameter of a chaotic sequence according to a chosen TDM frame.

5. The method according to claim 1, further comprising generating the first chaotic spreading codes by dynamically varying a value for a generation parameter of a chaotic sequence according to a timeslot duration.

6. The method according to claim 1, further comprising selecting each of said chaotic spreading codes to be a chaotic spreading sequence generated using a plurality of polynomial equations and modulo operations.

7. The method according to claim 1, wherein the first modulated signals are formed using a plurality of discrete-time modulation processes.

8. The method according to claim 7, wherein each of the plurality of discrete-time modulation processes is selected from the group comprising an M-ary phase shift keying modulation process, a quadrature amplitude modulation process and an amplitude shift keying modulation process.

9. The method according to claim 1, further comprising the steps of:

modulating a global data signal to form a second modulated signal; and

combining the second modulated signal with a second chaotic spreading code to form the global data communication signal having a spread spectrum format.

10. The method according to claim 8, wherein the second modulated signal is formed using an amplitude-and-time-discrete modulation process.

11. The method according to claim 9, wherein the amplitude-and-time-discrete modulation process is selected from the group comprising an M-ary phase shift keying modulation process, a quadrature amplitude modulation process and an amplitude shift keying modulation process.

12. The method according to claim 1, wherein the output communication signal is transmitted from the first communication device to a second communication device having at least one key to recover all of the protected data and the global data transmitted during two or more timeslots of a TDM frame.

13. The method according to claim 1, wherein the output communication signal is transmitted from the first communication device to a second communication device having at least one key to recover the global data and a portion of the protected data transmitted during two or more timeslots of a TDM frame.

14. The method according to claim 1, wherein the output communication signal is transmitted from the first communication device to a second communication device having at least one key to recover only the global data transmitted during two or more timeslots of a TDM frame.

15. The method according to claim 1, wherein at least a portion of the composite protected data communication signal is transmitted in a first timeslot of a TDM frame and at least a portion of the global data communication signal is transmitted in a second timeslot different from the first timeslot of the TDM frame.

16. The method according to claim 1, wherein at least a portion of the composite protected data communication signal and at least a portion of the global data communication signal are transmitted in the same timeslot of a TDM frame.

24. The communication system according to claim 1, further comprising:

a second modulator configured to modulate a global data signal to form a second modulated signal; and

a third combiner configured to combine the second modulated signal with a second chaotic spreading code to form the global data communication signal having a spread spectrum format.

25. The communication system according to claim 24, wherein the second modulated signal is formed using an amplitude-and-time-discrete modulation process.

17. A communication system configured for selectively controlling access to multiple data streams which are communicated using a timeslotted shared frequency spectrum and shared spreading codes, comprising:

a first modulator configured to modulate at least two protected data signals including protected data to form at least two first modulated signals;

a first combiner configured to combine the first modulated signals with first chaotic spreading codes to form digital chaotic signals having spread spectrum formats;

a second combiner configured to additively combine the digital chaotic signals to form a composite protected data communication signal;

a multiplexer configured to time division multiplex the composite protected data communication signal with a global data communication signal including global data to form an output communication signal; and

a transceiver configured to transmit said output communication signal from a first communication device to a second communication device over a communications channel.

18. The communication system according to claim 17, further comprising at least one sequence generator configured to generate the first chaotic spreading codes using different values for at least one generation parameter of a chaotic sequence.

19. The communication system according to claim 18, wherein the generation parameter is selected from the group comprising a sequence location parameter, a polynomial equation parameter and an N-tuple of moduli parameter.

20. The communication system according to claim 17, further comprising at least one generator configured to generate the first chaotic spreading codes by dynamically varying a value for a generation parameter of a chaotic sequence according to a chosen TDM frame.

21. The communication system according to claim 17, further comprising at least one generator configured to generate the first chaotic spreading codes by dynamically varying a value for a generation parameter of a chaotic sequence according to a timeslot duration.

22. The communication system according to claim 17, further comprising at least one generator configured to generate each of said chaotic spreading codes using a plurality of polynomial equations and modulo operations.

23. The communication system according to claim 17, wherein the first modulated signals are formed using a plurality of discrete-time modulation processes.

26. The communication system according to claim 17, wherein the second communication device has at least one key to recover all of the protected data and the global data transmitted during two or more timeslots of a TDM frame.

27. The communication system according to claim 17, wherein the second communication device has at least one key to recover the global data and a portion of the protected data transmitted during two or more timeslots of a TDM frame.

28. The communication system according to claim 17, wherein the second communication device having at least one key to recover only the global data transmitted during two or more timeslots of a TDM frame.

29. The communication system according to claim 17, wherein at least a portion of the composite protected data communication signal is transmitted in a first timeslot of a TDM frame and at least a portion of the global data communication signal is transmitted in a second timeslot different from the first timeslot of the TDM frame.

30. The communication system according to claim 17, wherein at least a portion of the composite protected data communication signal and at least a portion of the global data communication signal are transmitted in the same timeslot of a TDM frame.