Granted Patent B2

US 7,599,441 · App. 11/471,187 · Granted Oct 6, 2009

Abstract

Claims (117)

1. A communication system comprising:

a convolutional encoder;

an interleaver operatively connected to said convolutional encoder;

a quadrature amplitude modulation (QAM) mapper operatively connected to said interleaver;

a channel component operatively connected to said QAM mapper;

a QAM demapper operatively connected to said channel component;

a de-interleaver operatively connected to said QAM demapper, wherein said de-interleaver is adapted to decode a soft decision metric computation comprising a log-likelihood ratio (LLR) soft decision metric of a binary bit stream of a signal, and wherein said LLR corresponding to said binary bit stream of a signal equals

1

4

⁢

(

m

0

⁡

(

c

l

)

-

m

1

⁡

(

c

l

)

)

,

wherein c l represents transmitted code of said binary bit stream, wherein m 0 represents a minimum Euclidean distance from a received soft decision symbol to hard decision symbols in a subset of constellation points with an i th bit equal to zero, and wherein m 1 represents a minimum Euclidean distance from said received soft decision symbol to said hard decision symbols in said subset of constellation points with said i th bit equal to one; and

a Viterbi decoder operatively connected to said de-interleaver.

2. The system of claim 1 , wherein said interleaver comprises:

a bit-wise interleaver; and

a symbol-wise interleaver operatively connected to said bit-wise interleaver.

3. The system of claim 1 , wherein said de-interleaver comprises:

a bit-wise de-interleaver; and

a symbol-wise de-interleaver operatively connected to said bit-wise de-interleaver.

4. The system of claim 1 , wherein said de-interleaver is adapted to decode a soft decision metric for any of a quadrature phase-shift (QPSK), 16QAM, and 64QAM modulation.

5. The system of claim 1 , wherein said convolutional encoder adds redundancy to said binary bit stream of a signal.

6. The system of claim 1 , wherein said Viterbi decoder is adapted to decode a de-interleaved binary bit stream transmitted from said de-interleaver.

7. The system of claim 1 , wherein each of said convolutional encoder and said Viterbi decoder comprise Forward Error Control (FEC) coding modules.

8. A method comprising:

providing a data stream;

rearranging a sequence of the data stream into a digital bit sequence using bit-wise and symbol-wise interleaving;

mapping said digital bit sequence according to a predetermined modulation scheme;

introducing a channel factor to a modulated digital bit sequence;

demapping said modulated digital bit sequence;

de-interleaving the demapped digital bit sequence using bit-wise and symbol-wise de-interleaving;

decoding a soft decision metric computation comprising a log-likelihood ratio (LLR) soft decision metric of a binary bit stream of a signal, wherein said LLR corresponding to said binary bit stream of a signal equals

1

4

⁢

(

m

0

⁡

(

c

l

)

-

m

1

⁡

(

c

l

)

)

,

wherein c l represents transmitted code of said binary bit stream, wherein m 0 represents a minimum Euclidean distance from a received soft decision symbol to hard decision symbols in a subset of constellation points with an i th bit equal to zero, and wherein m 1 represents a minimum Euclidean distance from said received soft decision symbol to said hard decision symbols in said subset of constellation points with said i th bit equal to one; and

decoding the de-interleaved digital bit sequence using a Viterbi decoder.

9. The method of claim 8 , further comprising decoding a soft decision metric for any of a quadrature phase-shift (QPSK), 16QAM, and 64QAM modulation.

10. The method of claim 8 , further comprising adding redundancy to said data stream.

11. The method of claim 8 , further comprising executing said method using a computer.

12. A communication system comprising:

a convolutional encoder;

an interleaver operatively connected to said convolutional encoder;

a quadrature amplitude modulation (QAM) mapper operatively connected to said interleaver;

a channel component operatively connected to said QAM mapper;

a QAM demapper operatively connected to said channel component;

a de-interleaver operatively connected to said QAM demapper, wherein said de-interleaver is adapted to decode a soft decision metric computation comprising a log-likelihood ratio (LLR) soft decision metric of a binary bit stream of a signal, and wherein said soft decision metric of a k th symbol of a received noisy QAM symbol, y k , said LLR corresponding to an i th bit in a k th symbol of a received noisy QAM symbol, y k , equals

1

4

⁢

(

m

0

⁡

(

y

k

,

i

)

-

m

1

⁡

(

y

k

,

i

)

)

,

wherein m 0 represents a minimum Euclidean distance from a received soft decision symbol to hard decision symbols in a subset of constellation points with an i th bit equal to zero, and wherein m 1 represents a minimum Euclidean distance from said received soft decision symbol to said hard decision symbols in said subset of constellation points with said i th bit equal to one; and

a Viterbi decoder operatively connected to said de-interleaver.

13. The system of claim 12 , wherein said interleaver comprises:

a bit-wise interleaver; and

a symbol-wise interleaver operatively connected to said bit-wise interleaver.

14. The system of claim 12 , wherein said de-interleaver comprises:

a bit-wise de-interleaver; and

a symbol-wise de-interleaver operatively connected to said bit-wise de-interleaver.

15. The system of claim 12 , wherein said de-interleaver is adapted to decode a soft decision metric for any of a quadrature phase-shift (QPSK), 16QAM, and 64QAM modulation.

16. The system of claim 12 , wherein said convolutional encoder adds redundancy to said binary bit stream of a signal.

17. The system of claim 12 , wherein said Viterbi decoder is adapted to decode a de-interleaved binary bit stream transmitted from said de-interleaver.

Assignments (31)