Method for generating a signal by means of a turbo-encoder, and corresponding device and computer program

Patent metadata

Field	Value
Publication number	US-11831339-B2
Application number	US-201917416141-A
Country	US
Kind code	B2
Filing date	Dec 12, 2019
Priority date	Dec 20, 2018
Publication date	Nov 28, 2023
Grant date	Nov 28, 2023

Abstract

A method for generating a signal, including turbo-coding a set of information symbols delivering, on the one hand, the information symbols and, on the other hand, redundancy symbols. The turbo-coding implementing, to obtain the redundancy symbols: an encoding of the set of information symbols by a first encoder, an interleaving of the set of information symbols, and an encoding of the set of information symbols interleaved by a second encoder. The turbo-coding also implements a bijective transformation of the information symbols, implemented before and/or after the interleaving, the transformation modifying a value of at least two of the information symbols prior to the coding of the information symbols by the first and/or the second coder.

First claim

The invention claimed is:

1. A coding device comprising:
a turbo-encoder configured to receive an input digital message comprising a set of information symbols and configured to implement a non-binary turbo-code type error correcting code to encode the set of information symbols comprised in the input digital message, the information symbols belonging to a Galois field of cardinal q, denoted GF(q), with q>2, said turbo-encoder comprising:
a first encoder configured to code said set of information symbols and generate a first set of redundancy symbols;
an interleaver configured to interleave said set of information symbols and generate a set of interleaved information symbols;
a second encoder configured to code said set of interleaved information symbols and generate a second set of redundancy symbols; and
a processor configured to:
map the information and redundancy symbols onto modulation symbols associated with a constellation of order p, an information or redundancy symbol being mapped onto n modulation symbols, with n n≥2, the order p of the constellation being less than the cardinal q of the Galois field to which said information symbols belong;
apply a bijective transformation to said information symbols before and/or after said interleaver, said transformation modifying the value of at least two of said information symbols prior to the encoding of said information symbols by the first encoder and/or the second encoder, the bijective transformation being defined such that every input of a set of q elements of GF(q) has a unique output in the set of q elements of GF(q) by the bijective transformation and every output of the set of q elements of GF(q) has a unique antecedent in the set of q elements of GF(q), said transformation taking into account said constellation;
generate an output signal representing a code word which comprises the set of information symbols and the first and second sets of redundancy symbols; and
transmit the output signal in a communication system.

2. A non-transitory computer-readable medium comprising instructions stored therein, which when executed by a processor of a coding device, configure the coding device to:
receive an input digital message comprising a set of information symbols;
turbo-code the set of information symbols comprised in the input digital message, the information symbols belonging to a Galois field of cardinal q, denoted GF(q), with q>2, wherein the turbo-coding implements a non-binary turbo-code type error correcting code to obtain redundancy symbols and comprises:
encoding said set of information symbols by a first encoder of the coding device to generate a first set of redundancy symbols;
interleaving said set of information symbols using an interleaver of the coding device to generate a set of interleaved information symbols;
encoding said set of interleaved information symbols by a second encoder of the coding device to generate a second set of redundancy symbols;
mapping the information and redundancy symbols onto modulation symbols associated with a constellation of order p, an information or redundancy symbol being mapped onto n modulation symbols, with n≥2, the order p of the constellation being less than the cardinal q of the Galois field to which said information symbols belong;
applying a bijective transformation to said information symbols using a processor of the coding device before and/or after said interleaving, said transformation modifying a value of at least two of said information symbols prior to the coding of said information symbols by the first encoder and/or the second encoder, the bijective transformation being defined such that every input of a set of q elements of GF(q) has a unique output in the set of q elements of GF(q) by the bijective transformation and every output of the set of q elements of GF(q) has a unique antecedent in the set of q elements of GF(q), said transformation taking into account said constellation;
generating an output signal representing a code word which comprises the set of information symbols and the first and second sets of redundancy symbols; and
transmitting the output signal in a communications system.

3. A method performed by a coding device, the method comprising:
receiving an input digital message comprising a set of information symbols;
turbo-coding the set of information symbols comprised in the input digital message, the information symbols belonging to a Galois field of cardinal q, denoted GF(q), with q>2, wherein the turbo-coding implements a non-binary turbo-code type error correcting code to obtain redundancy symbols and comprises:
encoding said set of information symbols by a first encoder of the coding device to generate a first set of redundancy symbols,
interleaving said set of information symbols using an interleaver of the coding device to generate a set of interleaved information symbols;
encoding said set of interleaved information symbols by a second encoder of the coding device to generate a second set of redundancy symbols; and
applying a bijective transformation to said information symbols using a processor of the coding device before and/or after said interleaving, said transformation modifying a value of at least two of said information symbols prior to the coding of said information symbols by the first encoder and/or the second encoder, the bijective transformation being defined such that every input of a set of q elements of GF(q) has a unique output in the set of q elements of GF(q) by the bijective transformation and every output of the set of q elements of GF(q) has a unique antecedent in the set of q elements of GF(q);

generating an output signal representing a code word which comprises the set of information symbols and the first and second sets of redundancy symbols; and
transmitting the output signal in a communications system,
wherein:
said transformation generates a minimum dispersion Δ min between two information symbols S i , S j among said information symbols greater than a selection threshold, such that:
Δ min =min Δ( S i ,S j )

with:
Δ(S i ,S j )=D(S i ,S j )+D(T(S i ),T(S j ))
D(S i ,S j ) being a distance between said information symbols S i , S j before transformation,
D(T(S i ),T(S j )) being a distance between said information symbols S i , S j after transformation by the function T;

the method comprises mapping the information and redundancy symbols onto modulation symbols associated with a constellation of order p equal to the cardinal q of the Galois field to which said information symbols belong, an information or redundancy symbol being mapped onto a single modulation symbol, and said transformation takes into account said constellation; and
dispersion between two information symbols S i , S j is expressed in the form:
Δ( S i ,S j )= d euc 2 ( S i m ,S j m )+ d euc 2 ( T ( S i ) m ,T ( S j ) m )

with:
d euc 2 (S i m ,S j m )=(I s i m −I s j m ) 2 +(Q s i m −Q s j m ) 2 being the square of the Euclidean distance between the modulation symbols S i m , S j m onto which said information symbols S i , S j are mapped before transformation;
d euc 2 (T(S i ) m ,T(S j ) m )=(I T(S i ) m −I T(S j ) m ) 2 +(Q T(S i ) m −Q T(S j ) m ) 2 being the square of the Euclidean distance between the modulation symbols T(S i ) m , T(S j ) m onto which said information symbols S i , S j are mapped after transformation;
I x and Q x are the in-phase and quadrature components of a signal x in the considered constellation.

4. The method according to claim 3 , wherein the said transformation transforms a pair of information symbols intended to be mapped onto a pair of modulation symbol

Assignees

• Orange

Inventors

• Klaimi Rami
• Douillard Catherine
• Abdel Nour Charbel

Classifications

• H03M13/2771 Primary

  Internal interleaver for turbo codes (H03M13/2714 and H03M13/2725 take precedence) · CPC title

• H03M13/2714

  Turbo interleaver for 3rd generation partnership project [3GPP] universal mobile telecommunications systems [UMTS], e.g. as defined in technical specification TS 25.212 · CPC title

• H03M13/2725

  Turbo interleaver for 3rd generation partnership project 2 [3GPP2] mobile telecommunication systems, e.g. as defined in the 3GPP2 technical specifications C.S0002 · CPC title

• H03M13/1565

  Decoding beyond the bounded minimum distance [BMD] · CPC title

• H03M13/2903

  Methods and arrangements specifically for encoding, e.g. parallel encoding of a plurality of constituent codes · CPC title