FQPSK-B viterbi receiver

• US 7,068,738 B2
• Filed: 01/16/2002
• Issued: 06/27/2006
• Est. Priority Date: 01/16/2001
• Status: Expired due to Fees

• Current Assignee: California Institute of Technology
• Original Assignee: California Institute of Technology
• Inventors: Simon, Marvin K., Lee, Dennis K., Yan, Tsun-Yee
• Primary Examiner(s): Burd, Kevin
• Assistant Examiner(s): TORRES, JUAN A
• Application Number:
  US10/051,617
• Publication Number:
  US 20020172300A1
• Time in Patent Office: 1,623 Days
• Field of Search: 375/329, 375/341
• US Class Current: 375/329
• CPC Class Codes: H04L 2025/03407 Continuous phase
• CPC Class Codes: H04L 25/03178 Arrangements involving sequence estimation techniques

Abstract

An FQPSK-B receiver uses a simplified trellis system which uses combinations of FQPSK-B waveforms to correlate against an input signal. This enables reduction of the number of correlators that are used and the number of comparisons that are made by the correlators.

Claims

1. A receiver, comprising:

a plurality of averaged waveforms, each said averaged waveform comprising an average of a plurality of FQPSK waveforms;

a plurality of correlators, to correlate an input signal with each of said averaged waveforms of said plurality to form correlations; and

a trellis decoder using said correlations to make decisions on the transmitted signals.

2. A receiver as in claim 1, wherein said plurality of averaged waveforms each represent four FQPSK waveforms.

3. A receiver as in claim 1, further comprising an input filter which filters an input signal.

4. A receiver as in claim 1, further comprising a demodulator, receiving an input signal, and producing demodulated complex signals.

5. A receiver as in claim 4, wherein said demodulated complex signals include an in-phase signal and a quadrature signal component.

6. A receiver as in claim 2, wherein there are four of said correlators to correlate said FQPSK waveforms.

7. A receiver as in claim 1, wherein each of said plurality of averaged waveforms include a plurality of basic FQPSK waveforms which have similar characteristics.

8. A receiver as in claim 7, wherein each averaged waveform comprised a combination average of four FQPSK waveforms.

9. A receiver as in claim 1, wherein said FQPSK waveform are FQPSK or FQPSK-B, waveforms.

10. A method, comprising:

obtaining a plurality of basic waveforms which represent trellis waveforms for FQPSK or FQPSK-B;

averaging groups of said plurality of waveforms to form averaged waveforms, wherein a number of said averaged waveforms is less than a number of said plurality of waveforms; and

correlating an FQPSK-B input signal against said averaged waveforms to form a group of signals to be processed by a trellis decoder.

11. A method as in claim 10, wherein said averaging groups comprises averaging tour of said PQPSK-B waveforms to form each averaged waveforms.

12. A method as in claim 10, further comprising filtering an input signal, and wherein said correlating comprises correlating against a filtered input signal.

13. A method as in claim 10, further comprising producing demodulated signals form input signals and a set of correlation from said demodulated signals.

14. A method as in claim 13, wherein said demodulated signals include an in-phase signal and a quadrature signal.

15. A method as in claim 10, wherein said correlating comprises using four of said correlators to correlated the demodulated inphase and quadrature input signal with said FQPSK-B waveforms.

16. A method as in claim 10, wherein said plurality of averaged waveforms include a plurality of waveforms which have similar characteristics.

17. A method as in claim 10, wherein each averaged waveforms comprise a combination of four FQPSK waveforms.

18. A receiver, comprising:

a filter element, receiving an input PQPSK-B signal and producing a filtered FQPSK-B signal; and

a Viterbi Algorithm receiver, producing demodulated signals based on said FQPSK-B input signals, wherein said Viterbi Algorithm receiver compares said filtered FQPSK-B signal with a plurality of averaged signals.

19. A method of receiving an FQPSK-B signal, comprising:

obtaining a plurality of basic FPQSK-B signals associated with modulation of an FQPSK-B signal;

averaging said plurality of basic FQPSK-B signals to form a plurality of averaged signals; and

comparing an input coded FQPSK-B signal with said plurality of averaged signals to carry out the modulation.

20. A method as in claim 19, wherein there are 16 of said basic FQPSK-B signals, and wherein there are four of said averaged signals.