Interleaver for turbo codes as a function of the puncturing pattern

A non-transitory computer-readable medium comprising a computer program stored thereon and comprising instructions for implementing a method of encoding when this the instructions are executed by a processor of a turbo-encoder, the method comprising:

• encoding an input digital message bearing K information symbols using the turbo-encoder, the turbo-encoder forming a turbocode and comprising an interleaver and first and second encoders for encoding according to at least one elementary code and delivering said information symbols and redundancy symbols,
• wherein, with a puncturing of the symbols delivered by the turbo-encoder being done according to at least one periodic puncturing pattern of a length N, defining the puncturing period, said interleaver distributes the information symbols of said input message into Q layers of the interleaved input message in complying with an interleaving function defined from said at least one puncturing pattern, according to the relationship:
• π(i)=Pi+S(i mod Q)mod K=Pi+(Tl+AlQ)mod K
• with:
• i=0, . . . , K−1 being the position of an information symbol in said interleaved input message, in the interleaved order and π(i) the position of said information symbol in said input message, in the natural order;
• P an integer value co-prime with the length K of said input message, called an interleaver period;
• S(i mod Q)=S(l)=Tl+AlQ are the parameters of adjustment of the interleaving function, with l=0, . . . , Q−1 the layer number;
• Q a degree of disorder inserted into the interleaver, corresponding to the number of layers, such that Q=qN, with q≥1 being an integer and Q being a divider of K;
• Tl a value of inter-layer adjustment defined from said at least one puncturing pattern;
• and Al a value of intra-layer adjustment.

A turbo-encoder device comprising:

• a processor;
• and
• a non-transitory computer-readable medium comprising instructions stored thereon, which when executed by the processor configure the turbo-encoder device to:
• encode an input digital message bearing K information symbols using an interleaver and first and second encoders for encoding according to at least one elementary code, and delivering said information symbols and redundancy symbols,
• wherein a puncturing of the symbols delivered by said turbo-encoder being done according to at least one periodic puncturing pattern of a length N, defining the puncturing period, said interleaver distributes the information symbols of said input message in Q layers of the interleaved input message in complying with an interleaving function defined from said at least one puncturing pattern, according to the relationship:
• π(i)=Pi+S(i mod Q)mod K=Pi+S(l)mod K=Pi+(Tl+AlQ)mod K
• with:
• i=0, . . . , K−1 being the position of an information symbol in said interleaved input message, in the interleaved order and π(i) the position of said information symbol in said input message, in the natural order;
• P an integer value co-prime with the length K of said input message, called an interleaver period;
• S(i mod Q)=S(l)=Tl+AlQ the parameters of adjustment of the interleaving function, with l=0, . . . , Q−1 the layer number;
• Q a degree of disorder inserted into the interleaver, corresponding to the number of layers, such that Q=qN, with q≥1 being an integer and Q being a divider of K;
• Tl is a value of inter-layer adjustment defined from said at least one puncturing pattern;
• and
• Al a value of intra-layer adjustment.