SYSTEMS/METHODS OF SEQUENTIAL MODULATION OF A SINGLE CARRIER FREQUENCY BY A PLURALITY OF ELEMENTS OF A WAVEFORM

• US 20110206086A1
• Filed: 05/05/2011
• Published: 08/25/2011
• Est. Priority Date: 06/22/2005
• Status: Active Grant

• Current Assignee: Odyssey Wireless, Inc.
• Original Assignee: Odyssey Wireless, Inc.
• Inventors: Karabinis, Peter D.
• Granted Patent: US 8,199,837 B2
• Time in Patent Office: Days
• US Class Current: 375/131
• CPC Class Codes: H04B 1/69 Spread spectrum techniques
• CPC Class Codes: H04K 1/00 Secret communication
• CPC Class Codes: H04L 27/001 using chaotic signals for secret or secure communication H04L9/001

Abstract

Systems and/or methods are disclosed for generating a waveform that comprises a plurality of elements by using a Fourier transform and/or an inverse Fourier transform. The waveform that comprises the plurality of elements may be transmitted by transmitting, sequentially in time, the plurality of elements. In some embodiments, the Fourier transform and/or inverse Fourier transform comprises a Fast Fourier Transform and/or Inverse Fast Fourier Transform and the waveform that comprises the plurality of elements may be transmitted by using, sequentially in time, the plurality of elements to modulate a single carrier frequency.

Claims

1. A communications method comprising:

forming a desired spectrum shape for a waveform;

generating the waveform responsive to the desired spectrum shape; and

transmitting the waveform by using a plurality of elements thereof sequentially one after another to modulate a single carrier frequency;

wherein generating the waveform responsive to the desired spectrum shape comprises generating a discrete time-domain waveform U(nT);

wherein n denotes a discrete time index of U(nT);

wherein n=1, 2, . . . , N; and

NT≦

τ

;

wherein τ

denotes a time span of the discrete time-domain waveform U(nT); and

wherein transmitting the waveform by using a plurality of elements thereof sequentially one after another to modulate a single carrier frequency comprises using substantially all of the elements of U(nT) sequentially to modulate the single carrier frequency by using U(T), followed by using U(2T), . . . , followed by using U(NT).

2. The communications method according to claim 1, wherein said forming a desired spectrum shape for a waveform is performed at a transmitter.

3. The communications method according to claim 1, wherein said forming a desired spectrum shape for a waveform is performed at a distance from a transmitter and is then relayed to the transmitter.

4. The communications method according to claim 1, wherein said forming a desired spectrum shape for a waveform further comprises:

using a first plurality of frequencies over a first time interval; and

using a second plurality of frequencies over a second time interval;

wherein the first plurality of frequencies differs from the second plurality of frequencies in at least one frequency.

5. The communications method according to claim 1, wherein said forming a desired spectrum shape for a waveform further comprises:

forming the desired spectrum shape to include a first frequency interval comprising a first spectral level that is non-zero and to also include a second frequency interval comprising a second spectral level that is substantially zero.

6. The communications method according to claim 5, wherein said forming a desired spectrum shape for a waveform further comprises:

forming the desired spectrum shape to also include a third frequency interval comprising a third spectral level that is non-zero;

wherein the second frequency interval that comprises the second spectral level that is substantially zero is situated between the first and third frequency intervals.

7. A communications method comprising:

forming a desired spectrum shape for a waveform;

generating the waveform responsive to the desired spectrum shape; and

transmitting the waveform by using a plurality of elements thereof sequentially one after another to modulate a single carrier frequency;

wherein forming a desired spectrum shape for a waveform comprises;

selecting a frequency interval over which the waveform is to exist;

allowing at least one frequency that is included in the selected frequency interval to provide a frequency content to the waveform; and

excluding at least one frequency that is included in the selected frequency interval from providing a frequency content to the waveform.

8. The communications method according to claim 7, wherein said forming a desired spectrum shape for a waveform is performed at a transmitter.

9. The communications method according to claim 7, wherein said forming a desired spectrum shape for a waveform is performed at a distance from a transmitter and is then relayed to the transmitter.

10. The communications method according to claim 7, wherein said forming a desired spectrum shape for a waveform further comprises:

using a first plurality of frequencies over a first time interval; and

using a second plurality of frequencies over a second time interval;

wherein the first plurality of frequencies differs from the second plurality of frequencies in at least one frequency.

11. The communications method according to claim 7, wherein said forming a desired spectrum shape for a waveform further comprises:

forming the desired spectrum shape to include a first frequency interval comprising a first spectral level that is non-zero and to also include a second frequency interval comprising a second spectral level that is substantially zero.

12. The communications method according to claim 11, wherein said forming a desired spectrum shape for a waveform further comprises:

forming the desired spectrum shape to also include a third frequency interval comprising a third spectral level that is non-zero;

wherein the second frequency interval that comprises the second spectral level that is substantially zero is situated between the first and third frequency intervals.

13. A communications system comprising:

a processor that is configured to form a desired spectrum shape for a waveform and to generate the waveform responsive to the desired spectrum shape; and

a transmitter that is configured to transmit the waveform by using a plurality of elements thereof sequentially one after another to modulate a single carrier frequency;

wherein the waveform comprises a discrete time-domain waveform U(nT);

wherein n denotes a discrete time index of U(nT);

wherein n=1, 2, . . . , N; and

NT≦

τ

;

wherein τ

denotes a time span of the discrete time-domain waveform U(nT); and

wherein the transmitter is further configured to use substantially all of the elements of U(nT) sequentially to modulate the single carrier frequency by using U(T), followed by using U(2T), . . . , followed by using U(NT).

14. The communications system according to claim 13, wherein the processor is configured to form the desired spectrum shape to include:

a first plurality of frequencies over a first time interval; and

a second plurality of frequencies over a second time interval;

wherein the first plurality of frequencies differs from the second plurality of frequencies in at least one frequency.

15. The communications system according to claim 13, wherein the processor is configured to form the desired spectrum shape to include:

a first frequency interval comprising a first spectral level that is non-zero and a second frequency interval comprising a second spectral level that is substantially zero.

16. The communications system according to claim 15, wherein the processor is configured to form the desired spectrum shape to further include:

a third frequency interval comprising a third spectral level that is non-zero;

wherein the second frequency interval that comprises the second spectral level that is substantially zero is situated between the first and third frequency intervals.

17. A communications system comprising:

a processor that is configured to form a desired spectrum shape for a waveform and to generate the waveform responsive to the desired spectrum shape;

and a transmitter that is configured to transmit the waveform by using a plurality of elements thereof sequentially one after another to modulate a single carrier frequency;

wherein the processor is configured to form the desired spectrum shape for the waveform to include;

at least one frequency that provides a frequency content to the waveform; and

at least one frequency that is excluded from providing a frequency content to the waveform.

18. The communications system according to claim 17, wherein the processor is further configured to form the desired spectrum shape to include:

a first plurality of frequencies over a first time interval; and

a second plurality of frequencies over a second time interval;

wherein the first plurality of frequencies differs from the second plurality of frequencies in at least one frequency.

19. The communications system according to claim 17, wherein the processor is further configured to form the desired spectrum shape to include:

a first frequency interval comprising a first spectral level that is non-zero and to also include a second frequency interval comprising a second spectral level that is substantially zero.

20. The communications system according to claim 19, wherein the processor is further configured to form the desired spectrum shape to further include:

a third frequency interval comprising a third spectral level that is non-zero;

wherein the second frequency interval that comprises the second spectral level that is substantially zero is situated between the first and third frequency intervals.

21. A communications method comprising:

selecting a frequency interval over which a waveform U(nT) is to exist;

wherein n denotes a discrete time index and wherein n=1, 2, . . . , N;

allowing at least one frequency that is included in the selected frequency interval to provide a frequency content to the waveform U(nT);

excluding at least one frequency that is included in the selected frequency interval from providing a frequency content to the waveform U(nT);

forming the waveform U(nT) comprising a plurality of elements U(T), U(2T), . . . , U(NT), corresponding to respective integer values 1, 2, . . . , N of the discrete time index n; and

transmitting the waveform U(nT) by using the plurality of elements U(T), U(2T), . . . , U(NT) sequentially one after another to modulate a single carrier frequency by first using U(T) to modulate the single carrier frequency, followed by using U(2T) to modulate the single carrier frequency, . . . , followed by using U(NT) to modulate the single carrier frequency.

22. The communications method according to claim 21, wherein said forming the waveform U(nT) comprises:

generating a first waveform using a first plurality of frequencies over a first time interval; and

generating a second waveform using a second plurality of frequencies over a second time interval;

wherein the second plurality of frequencies differs from the first plurality of frequencies in at least one frequency.

23. The communications method according to claim 21, wherein said forming the waveform U(nT) comprises:

generating a waveform comprising a first spectral shape that is non-zero over a first plurality of frequencies that is included in said selected frequency interval and a second spectral shape that is substantially zero over a second plurality of frequencies that is also included in said selected frequency interval.

24. The communications method according to claim 21, wherein said selecting a frequency interval over which a waveform U(nT) is to exist comprises:

identifying frequencies to be used to communicate; and

reducing a measure of interference by preferentially using the identified frequencies while refraining from using other frequencies.

25. The communications method according to claim 21, wherein said selecting a frequency interval over which a waveform U(nT) is to exist comprises:

selecting a frequency interval that is between 1525 MHz and 1660.5 MHz and excluding a GPS frequency interval that is included therein.

26. The communications method according to claim 21, wherein said forming the waveform U(nT) comprises:

using a Fourier transform and an inverse Fourier transform.

27. A communications system comprising:

a processor that is configured to select a frequency interval over which a waveform U(nT) is to exist, wherein n denotes a discrete time index and wherein n=1, 2, . . . , N;

to allow at least one frequency that is included in the selected frequency interval to provide a frequency content to the waveform U(nT);

to exclude at least one frequency that is included in the selected frequency interval from providing a frequency content to the waveform U(nT) and to form the waveform U(nT) comprising a plurality of elements U(T), U(2T), . . . , U(NT), corresponding to respective integer values 1, 2, . . . , N of the discrete time index n; and

a transmitter that is configured to transmit the waveform U(nT) by using the plurality of elements U(T), U(2T), . . . , U(NT) sequentially one after another to modulate a single carrier frequency by first using U(T) to modulate the single carrier frequency, followed by using U(2T) to modulate the single carrier frequency, . . . , followed by using U(NT) to modulate the single carrier frequency.

28. The communications system according to claim 27, wherein the processor is further configured to:

generate a first waveform using a first plurality of frequencies over a first time interval; and

generate a second waveform using a second plurality of frequencies over a second time interval;

wherein the second plurality of frequencies differs from the first plurality of frequencies in at least one frequency.

29. The communications system according to claim 27, wherein the processor is further configured to:

generate a waveform comprising a first spectral shape that is non-zero over a first plurality of frequencies that is included in said selected frequency interval and a second spectral shape that is substantially zero over a second plurality of frequencies that is also included in said selected frequency interval.

30. The communications system according to claim 27, wherein the processor is further configured to:

identify frequencies to be used to communicate such as to reduce a measure of interference and to preferentially use the identified frequencies and refrain from using other frequencies.

31. The communications system according to claim 27, wherein the processor is further configured to:

select a frequency interval that is between 1525 MHz and 1660.5 MHz and exclude a GPS frequency interval that is included therein.

32. The communications system according to claim 27, wherein the transmitter comprises a wireless transmitter.

33. The communications system according to claim 27, wherein the processor is further configured to form the waveform U(nT) comprising the plurality of elements U(T), U(2T), . . . , U(NT) by using a Fourier transform and an inverse Fourier transform.