Multilevel encoder

• US 5,970,098 A
• Filed: 10/02/1997
• Issued: 10/19/1999
• Est. Priority Date: 05/02/1997
• Status: Expired due to Term

• Current Assignee: Ikanos Communications Incorporated (Qualcomm, Inc.)
• Original Assignee: Globespan Technologies, Inc.
• Inventors: Herzberg, Hanan
• Primary Examiner(s): Chin, Stephen
• Assistant Examiner(s): DEPPE, BETSY LEE
• Application Number:
  US08/944,941
• Time in Patent Office: 747 Days
• Field of Search: 375/264, 375/262, 375/261, 375/286, 375/295, 375/298, 332/103, 341/56, 714/755, 714/758, 714/786, 714/790, 714/792, 714/794, 714/795, 714/809, 714/810
• US Class Current: 375/264
• CPC Class Codes: H04L 1/0041 Arrangements at the transmitter end
• CPC Class Codes: H04L 1/005 Iterative decoding, including iteration between signal detection and decoding operation
• CPC Class Codes: H04L 1/006 Trellis-coded modulation
• CPC Class Codes: H04L 1/0066 Parallel concatenated codes
• CPC Class Codes: H04L 1/0069 Puncturing patterns
• CPC Class Codes: H04L 27/3433 using an underlying square constellation

Abstract

A improved multilevel encoder and associated method is described. The encoder includes a device (e.g., serial to parallel converter) for presenting a plurality of information bits in parallel format. A symbol selector having a plurality of inputs and an output, the symbol selector being configured to output a symbol that is defined by a signal constellation, whereby the symbol is defined by a magnitude and phase that are uniquely associated with a state of the plurality of inputs. A first encoder has an input and an output, the input of the first encoder being associated with at least one of the outputs of the device and the output being associated with at least one of the inputs of the symbol selector, the first encoder configured by a code defining a four-way set partition of the signal constellation. A second encoder has an input and an output, the input of the second encoder being associated with at least one of the outputs of the device and the output being associated with at least one of the inputs of the symbol selector, the second encoder configured by a code defining a two-way set partition of the signal constellation.

Claims

1. An encoder for providing a multilevel encoded signal comprising:

a device for presenting a plurality of information bits in parallel format;

a symbol selector having a plurality of inputs and an output, the symbol selector being configured to output a symbol that is defined by a signal constellation, whereby the symbol is defined by a magnitude and phase that are uniquely associated with a state of the plurality of inputs;

a first encoder having an input and an output, the input of the first encoder being associated with at least one of the outputs of the device and the output being associated with at least one of the inputs of the symbol selector, the first encoder being defined by a code, wherein the first encoder is configured to generate an output that defines a four-way set partition of the signal constellation; and

a second encoder having an input and an output, the input of the second encoder being associated with at least one of the outputs of the device and the output being associated with at least one of the inputs of the symbol selector, the second encoder being defined by a code, wherein the second encoder is configured to generate an output that defines a two-way set partition of the signal constellation.

2. The encoder as defined in claim 1, wherein the device is a serial to parallel converter configured to receive information bits at an input in a serial format and deliver the information bits to the output in a parallel format.

3. The encoder as defined in claim 1, further including an output of the device being electrically connected with an input of the symbol selector.

4. The encoder as defined in claim 1, wherein the signal constellation is a 64 point CAP constellation.

5. The encoder as defined in claim 1, wherein the first encoder is a rate-half encoder.

6. The encoder as defined in claim 1, wherein the second encoder is a rate-half encoder.

7. The encoder as defined in claim 1, further including a puncture block disposed between the output of the second encoder and the symbol selector, the puncture block being configured to puncture the output of the second encoder.

8. The encoder as defined in claim 7, wherein the effective rate of the second encoder as modified by the puncture block is 13/14 rate.

9. The encoder as defined in claim 7, wherein the puncture block is defined by the following matrix:

##STR1##10.

10. The encoder as defined in claim 1, further including a puncture block disposed between the output of the first encoder and the symbol selector, the block configured to puncture the output of the first encoder.

11. The encoder as defined in claim 1, wherein the first encoder defines a parallel concatenated code.

12. A method for encoding signals for transmission across a communication channel comprising the steps of:

providing a plurality of information bits in parallel format for communication to a symbol selector;

directing a first group of the bits to a first encoder, the first encoder having a first output that is directed to the symbol selector;

directing a second group of the bits to a second encoder, the second encoder having a second output that is directed to the symbol selector;

using the first output to define a four-way set partition of a signal constellation; and

using the second output to define a two-way set partition of the signal constellation.

13. The method as defined in claim 12, further including the step of directing a third group of the bits directly to the symbol selector.

14. The method as defined in claim 12, wherein the signal constellation is a 64 point CAP constellation.

15. The method as defined in claim 12, wherein the first encoder is a rate-half encoder.

16. The method as defined in claim 12, wherein the second encoder is a rate-half encoder.

17. The method as defined in claim 12, further including the step of puncturing the output of the second encoder before delivering that output to the symbol selector.

18. The method as defined in claim 17, wherein the effective rate of the second encoder as modified by the puncture block is 13/14 rate.

19. The method as defined in claim 17, wherein the step of puncturing is defined by the following matrix:

##STR2##20.

20. The method as defined in claim 12, further including the step of puncturing the output of the first encoder before delivering that output to the symbol selector.

21. The method as defined in claim 12, wherein the first encoder defines a parallel concatenated code.