Method to minimize compatibility error in hierarchical modulation using variable phase

• US 20050113040A1
• Filed: 10/27/2004
• Published: 05/26/2005
• Est. Priority Date: 11/26/2003
• Status: Abandoned Application

• Current Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Original Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Inventors: Dibiaso, Eric A., Walker, Glenn A., Hiatt, Michael L. Jr.
• Application Number:
  US10/974,279
• Publication Number:
  US 20050113040A1
• Time in Patent Office: Days
• US Class Current: 455/102
• CPC Class Codes: H04B 7/18513 Transmission in a satellite or space-based system
• CPC Class Codes: H04L 27/183 Multiresolution systems
• CPC Class Codes: H04L 27/3488 Multiresolution systems

Abstract

The present invention provides a method, receiver and transmitter for use in a SDAR system. The method involves generating a first modulated signal based on first input data. Additional modulation is superimposed on the first modulated signal based on additional input data, being spread across a plurality of symbols in the first modulated signal in a predetermined pattern to generate a modified signal which is then transmitted. The modified signal is decoded by performing a first demodulation of the first modulated signal then additional demodulation is performed to obtain additional input data. The superimposing step uses a plurality of offset sequence values to add the additional modulation to the first modulated signal. The offset sequence may appear as a pseudo-random distribution of offset sequence values, and may include at least one zero offset value. Alternatively, the additional modulated signal may be a fromed as a direct sequence spread spectrum modulation and the offset sequence appearing as a pseudo-noise distribution. A Hadamard matrix sequence may be used as the direct sequence code.

Claims

1. A method for transmitting at least two levels of data in a hierarchical transmission system comprising the steps of:

generating a first modulated signal based on first input data;

superimposing at least a second modulation on the first modulated signal based on at least a second input data, the second modulation being spread across a plurality of symbols in the first modulated signal in a predetermined pattern to create a modified signal;

transmitting the modified signal;

decoding the modified signal by performing a first demodulation of the first modulated signal then a second demodulation to obtain the first input data and the second input data.

2. The method of claim 1 wherein the superimposing step uses a plurality of offset sequence values as the predetermined pattern to spread the at least second modulation across the first modulated signal.

3. The method of claim 2 wherein the plurality of offset sequence values includes a pseudo-random distribution of offset sequence values.

4. The method of claim 2 wherein the plurality of offset sequence values includes at least one zero offset value.

5. The method of claim 2 wherein the at least a second modulated signal involves direct sequence spread spectrum modulation and the predetermined pattern is a pseudo-noise distribution.

6. The method of claim 5 wherein the predetermined pattern includes a Hadamard matrix sequence.

7. A receiver for receiving at least two levels of data in a hierarchical transmission system comprising:

an antenna for receiving RF signals;

a demodulator coupled to said antenna for downconverting received RF signals;

a first detector coupled to said demodulator, said first detector having a first output and capable of providing digital information based on a first level of data on said first output; and

at least a second detector coupled to said demodulator, said at least a second detector having at least a second output and capable of providing digital information based on at least a second level of data on said at least a second output, said at least a second detector being adapted to detect the at least a second level of data as a predetermined pattern spread over the first level of data.

8. The receiver of claim 7 wherein said at least a second detector uses a plurality of predetermined offset sequence values as the predetermined pattern to detect the at least a second level of data.

9. The receiver of claim 8 wherein the plurality of offset sequence values includes a pseudo-random distribution of offset sequence values.

10. The receiver of claim 8 wherein the plurality of offset sequence values includes at least one zero offset value.

11. The receiver of claim 8 wherein said at least a second detector is capable of detecting a direct sequence spread spectrum modulation with the predetermined pattern including a pseudo-noise distribution.

12. The receiver of claim 111 wherein said at least a second detector includes a predetermined pattern comprising a Hadamard matrix sequence.

13. A transmitter for transmitting at least two levels of data in a hierarchical transmission system comprising:

an encoder adapted to receive a first and at least a second input data, said encoder capable of providing digital information based on a first level of data on an output stream, said encoder capable of providing digital information based on at least a second level of data on said output stream, said encoder being adapted to superimpose the at least a second level of data as a predetermined pattern spread over the first level of data;

a modulator coupled to said encoder for upconverting said output stream; and

an antenna coupled to said modulator for transmitting RF signals based on the upconverted output stream.

14. The transmitter of claim 13 wherein said encoder uses a plurality of predetermined offset sequence values as the predetermined pattern to superimpose the at least a second level of data over the first level of data.

15. The transmitter of claim 14 wherein the plurality of offset sequence values includes a pseudo-random distribution of offset sequence values.

16. The transmitter of claim 14 wherein the plurality of offset sequence values includes at least one zero offset value.

17. The transmitter of claim 14 wherein said modulator is capable of modulating said output stream as a direct sequence spread spectrum modulation and said predetermined pattern includes a pseudo-noise distribution.

18. The transmitter of claim 17 wherein said predetermined pattern comprises a Hadamard matrix sequence.