Permission-based TDMA chaotic communication systems

• US 8,848,909 B2
• Filed: 07/22/2009
• Issued: 09/30/2014
• 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.
• Primary Examiner(s): Hirl, Joseph P.
• Assistant Examiner(s): NGUY, CHI D
• Application Number:
  US12/507,512
• Publication Number:
  US 20110019817A1
• Time in Patent Office: 1,896 Days
• Field of Search: 380/263, 380/31, 380/38
• US Class Current: 380/200
• 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:

performing discrete-time modulation processes using at least two protected data signals including protected data to form at least two first modulated signals;

performing a numerical sequence generation process to generate first chaotic spreading codes;

combining the first modulated signals with respective ones of said 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;

wherein different values for a polynomial equation parameter for said numerical sequence generation process are used during a first pre-defined duration and a second pre-defined duration to generate at least one of said first chaotic spreading codes, said first and second pre-defined durations equal to a duration of a TDM frame or a timeslot; and

wherein different parameters for at least one of said discrete-time modulation processes are used during said first-defined duration and said second pre-defined duration to generate at least one of said first modulated signals.

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

3. The method according to claim 1, wherein each of the 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.

4. The method according to claim 3, wherein the second modulated signal is formed using an amplitude-and-time-discrete modulation process.

5. 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.

6. 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 said TDM frame.

7. 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 said TDM frame.

8. 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 said TDM frame.

9. 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 said 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.

10. 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 said TDM frame.

11. 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:

performing discrete-time modulation processes using at least two protected data signals including protected data to form at least two first modulated signals;

performing a numerical sequence generation process to generate first chaotic spreading codes;

combining the first modulated signals with respective ones of said 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;

wherein different values for a sequence location parameter for said numerical sequence generation process are used during a first pre-defined duration and a second pre-defined duration to generate at least one of said first chaotic spreading codes, said first and second pre-defined durations equal to a duration of a TDM frame or a timeslot;

wherein different parameters for at least one of said discrete-time modulation processes are used during said first-defined duration and said second pre-defined duration to generate at least one of said first modulated signals; and

wherein different values for at least one of a polynomial equation parameter and an N-tuple of moduli parameter are used for said numerical sequence generation process during said first pre-defined duration and said second pre-defined duration to generate at least one of said first chaotic spreading codes.

12. 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:

performing discrete-time modulation processes using at least two protected data signals including protected data to form at least two first modulated signals;

performing a numerical sequence generation process to generate first chaotic spreading codes;

combining the first modulated signals with respective ones of said 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;

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

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

time division multiplexing the composite protected data communication signal with said 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;

wherein different values for a sequence location parameter for said numerical sequence generation process are used during a first pre-defined duration and a second pre-defined duration to generate at least one of said first chaotic spreading codes, said first and second pre-defined durations equal to a duration of a TDM frame or a timeslot;

wherein different parameters for at least one of said discrete-time modulation processes are used during said first-defined duration and said second pre-defined duration to generate at least one of said first modulated signals; and

wherein an 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.

13. 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 perform discrete-time modulation processes using at least two protected data signals including protected data to form at least two first modulated signals;

a first sequence generator configured to perform a numerical sequence generation process to generate first chaotic spreading codes;

a first combiner configured to combine the first modulated signals with respective ones of said 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;

wherein different values for a polynomial equation parameter for said numerical sequence generation process are used by said first generator during a first pre-defined duration and a second pre-defined duration to generate at least one of said first chaotic spreading codes, said first and second pre-defined duration equal to a duration of a TDM frame or a timeslot; and

wherein different parameters for at least one of said discrete-time modulation processes are used during said first-defined duration and said second pre-defined duration to generate at least one of said first modulated signals.

14. The communication system according to claim 13, further comprising at least one generator configured to generate each of said first chaotic spreading codes using a plurality of polynomial equations and modulo operations.

15. The communication system according to claim 13, 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.

16. The communication system according to claim 15, wherein the second modulated signal is formed using an amplitude-and-time-discrete modulation process.

17. The communication system according to claim 13, 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 said TDM frame.

18. The communication system according to claim 13, 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 said TDM frame.

19. The communication system according to claim 13, wherein the second communication device having at least one key to recover only the global data transmitted during two or more timeslots of said TDM frame.

20. The communication system according to claim 13, wherein at least a portion of the composite protected data communication signal is transmitted in a first timeslot of said 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.

21. The communication system according to claim 13, 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 said TDM frame.

22. 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 perform discrete-time modulation processes using at least two protected data signals including protected data to form at least two first modulated signals;

a first sequence generator configured to perform a numerical sequence generation process to generate first chaotic spreading codes;

a first combiner configured to combine the first modulated signals with respective ones of said 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;

wherein different values for a sequence location parameter for said numerical sequence generation process are used by said first generator during a first pre-defined duration and a second pre-defined duration to generate at least one of said first chaotic spreading codes, said first and second pre-defined duration equal to a duration of a TDM frame or a timeslot;

wherein different parameters for at least one of said discrete-time modulation processes are used during said first-defined duration and said second pre-defined duration to generate at least one of said first modulated signals; and

wherein different values for at least one of a polynomial equation parameter and an N-tuple of moduli parameter are used for said numerical sequence generation process during said first pre-defined duration and said second pre-defined duration to generate at least one of said first chaotic spreading codes.