Bit signal structure for differentially encoded broadcasts

• US 9,294,321 B2
• Filed: 05/14/2010
• Issued: 03/22/2016
• Est. Priority Date: 05/14/2010
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Gutt, Gregory M.
• Primary Examiner(s): Liu, Shuwang
• Assistant Examiner(s): TAYONG, HELENE E
• Application Number:
  US12/780,365
• Publication Number:
  US 20150288415A1
• Time in Patent Office: 2,139 Days
• Field of Search: 375/259, 375/140, 375/145, 375/149, 375/150, 375/308, 375/146, 370/535
• US Class Current: 1/1
• CPC Class Codes: G01S 19/02 Details of the space or ground control segments
• CPC Class Codes: H04L 27/2331 wherein the received signal is demodulated using one or more delayed versions of itself

Abstract

In one embodiment, a communication device comprises a differential encoder to receive data for transmission and encode the data for transmission using a set of codes that, when processed by the differential encoder, place the differential encoder in a known state and generate uncorrelated output sequences.

Claims

1. A method comprising:

receiving, at a differential encoder, data for transmission while the differential encoder is in a first logical state; and

encoding a portion of the data using a transmission code to generate an encoded signal, wherein the transmission code is selected from a set of code words, and wherein the transmission code is selected so that the differential encoder enters a second logical state that is different than the first logical state after encoding the portion of the data; and

encoding a second portion of the data using a second transmission code to generate a second encoded signal, wherein the second transmission code is selected from the set of code words, and wherein the second transmission code is selected so that the differential encoder enters a third logical state that is different than the second logical state after encoding the second portion of the data.

2. The method of claim 1, wherein the transmission code is further selected so that the encoded signal includes a global positioning system (GPS) signal.

3. The method of claim 1, further comprising:

modulating the encoded signal to generate a modulated signal;

amplifying the modulated signal to generate an amplified signal; and

transmitting the amplified signal.

4. The method of claim 3, wherein transmitting the amplified signal includes transmitting a message burst, wherein the message burst includes the amplified signal and a second amplified signal corresponding to the second encoded signal, wherein the encoded signal includes a first Gray code, and wherein the second encoded signal includes a second Gray code.

5. The method of claim 1, further comprising:

modulating the second encoded signal to generate a second modulated signal;

amplifying the second modulated signal to generate a second amplified signal; and

transmitting the second amplified signal.

6. The method of claim 1, wherein the encoded signal comprises a global positioning system (GPS) signal, a Gray code signal, or a combination thereof.

7. The method of claim 1, wherein the set of code words comprises a first plurality of code words based on a super bit encoding scheme.

8. The method of claim 7, wherein the first plurality of code words includes a first code word based on the super bit encoding scheme, the first code word including a multi-bit sequence appended to a string of pseudo-random bits.

9. The method of claim 1, wherein a signal to noise ratio of the encoded signal is sufficiently high to enable a user device located within a building to acquire timing information.

10. The method of claim 1, wherein the differential encoder is located within a communication system that is used as a positioning system.

11. The method of claim 1, wherein the set of code words includes a first code word including a first 10 bit string of pseudo-random bits representing a logical zero, wherein the set of code words includes a second code word including a second 10 bit string of pseudo-random bits representing a logical one, and wherein the transmission code is selected from the first code word and the second code word.

12. The method of claim 1, wherein the differential encoder utilizes Quadrature Phase Shift Key (QPSK) modulation schemes.

13. The method of claim 1, wherein the differential encoder utilizes Binary Phase Shift Key (BPSK) modulation schemes.

14. The method of claim 1, wherein the differential encoder is within a mobile communication system.

15. The method of claim 1, wherein the differential encoder is within a stationary communication system.

16. A communication device comprising:

a differential encoder configured to;

receive data for transmission while the differential encoder is in a first logical state;

encode a portion of the data using a transmission code to generate an encoded signal, wherein the transmission code is selected from a set of code words, and wherein the transmission code is selected so that the differential encoder enters a second logical state that is different than the first logical state after encoding the portion of the data;

encode a second portion of the data using a second transmission code to generate a second encoded signal, wherein the second transmission code is selected from the set of code words, and wherein the second transmission code is selected so that the differential encoder enters a third logical state that is different than the second logical state after encoding the second portion of the data; and

a transmitter configured to transmit the encoded signal and the second encoded signal generated by the differential encoder.

17. The communication device of claim 16, wherein the transmission code is further selected so that the encoded signal includes a global positioning system (GPS) signal.

18. The communication device of claim 16, further comprising:

a modulator to modulate the encoded signal to generate a modulated signal; and

an amplifier to amplify the modulated signal to generate an amplified signal, wherein the transmitter is configured to transmit the amplified signal.

19. The communication device of claim 16, wherein the transmitter is configured to transmit a message burst, and wherein the message burst includes the encoded signal and the second encoded signal.

20. The communication device of claim 16, wherein the encoded signal includes a first Gray code, and wherein the second encoded signal includes a second Gray code.

21. The communication device of claim 16, wherein the encoded signal comprises a global positioning system (GPS) signal, a Gray code signal, or a combination thereof.

22. The communication device of claim 16, wherein the set of code words comprises a first plurality of code words based on a super bit encoding scheme.

23. The communication device of claim 22, wherein the first plurality of code words includes a first code word based on the super bit encoding scheme, the first code word including a multi-bit sequence appended to a string of pseudo-random bits.

24. The communication device of claim 16, wherein the set of code words includes a first code word including a first 10 bit string of pseudo-random bits representing a logical zero, wherein the set of code words includes a second code word including a second 10 bit string of pseudo-random bits representing a logical one, and wherein the transmission code is selected from the first code word and the second code word.

25. A method comprising:

receiving, at a differential encoder in a first logical state, data for transmission;

encoding a portion of the data using a transmission code to generate an encoded signal,

wherein the transmission code is selected from a set of code words, and wherein the transmission code is selected so that the differential encoder reenters the first logical state after encoding the portion of the data, and wherein transmitting the encoded signal includes transmitting a message burst; and

encoding a second portion of the data using a second transmission code to generate a second encoded signal, wherein the second transmission code is selected from the set of code words, and wherein the second transmission code is selected so that the differential encoder reenters the first state after encoding the second portion of the data.

26. The method of claim 25, wherein the transmission code is further selected so that the encoded signal includes a global positioning system (GPS) signal.

27. The method of claim 25, wherein the set of code words includes a first code word including a first 10 bit string of pseudo-random bits representing a logical zero, wherein the set of code words includes a second code word including a second 10 bit string of pseudo-random bits representing a logical one, and wherein the transmission code is selected from the first code word and the second code word.

28. The method of claim 25, further comprising:

modulating the encoded signal to generate a modulated signal;

amplifying the modulated signal to generate an amplified signal; and

transmitting the amplified signal.

29. The method of claim 25, further comprising transmitting the message burst to a mobile device.

30. The method of claim 29, wherein the mobile device is configured to use the encoded signal to determine a position of the mobile device.

31. The method of claim 25, wherein the set of code words comprises a first plurality of code words based on a super bit encoding scheme.

32. The method of claim 25, wherein the encoded signal includes a first Gray code, and wherein the second encoded signal includes a second Gray code.

33. The method of claim 25, wherein the differential encoder is located within a communication system that is used as a positioning system.

34. The method of claim 25, wherein the encoded signal comprises at least one of a global positioning system (GPS) signal, a Gray code signal, or a combination thereof.

35. The method of claim 25, wherein the differential encoder encodes the portion of the data using a Quadrature Phase Shift Key (QPSK) modulation scheme.

36. The method of claim 25, wherein the differential encoder encodes the portion of the data using a Binary Phase Shift Key (BPSK) modulation scheme.

37. A communication device comprising:

a differential encoder, the differential encoder configured to;

receive data for transmission while the differential encoder is in a first logical state; and

encode a portion of the data using a transmission code to generate an encoded signal, wherein the transmission code is selected from a set of code words, and wherein the transmission code is selected so that the differential encoder reenters the first logical state after encoding the portion of the data;

encode a second portion of the data using a second transmission code to generate a second encoded signal, wherein the second transmission code is selected from the set of code words, and wherein the second transmission code is selected so that the differential encoder reenters the first state after encoding the second portion of the data; and

a transmitter configured to transmit the encoded signal and the second encoded signal generated by the differential encoder.

38. The communication device of claim 37, wherein the transmission code is further selected so that the encoded signal includes a global positioning system (GPS) signal.

39. The communication device of claim 37, wherein the set of code words includes a first code word including a first 10 bit string of pseudo-random bits representing a logical zero, wherein the set of code words includes a second code word including a second 10 bit string of pseudo-random bits representing a logical one, and wherein the transmission code is selected from the first code word and the second code word.

40. The communication device of claim 37, further comprising:

a modulator to modulate the encoded signal to generate a modulated signal; and

an amplifier to amplify the modulated signal to generate an amplified signal, wherein the transmitter is configured to transmit the amplified signal.

41. The communication device of claim 37, wherein the transmitter is configured to transmit a message burst, and wherein the message burst includes the encoded signal and the second encoded signal.

42. The communication device of claim 37, wherein the encoded signal comprises a global positioning system (GPS) signal, a Gray code signal, or a combination thereof.

43. The communication device of claim 37, wherein the encoded signal includes a first Gray code and wherein the second encoded signal includes a second Gray code.

44. The communication device of claim 37, wherein the differential encoder is within a mobile communication system.

45. The communication device of claim 37, wherein the differential encoder is within a stationary communication system.