Interleaver design and pairwise codeword distance distribution enhancement for turbo autoencoder

A symmetric interleaver for a Convolutional Neural Network (CNN) or Recurrent Neural Network (RNN) encoder, comprising:

• an input interface configured to receive an input block of K elements;
• an output interface configured to output an output block of K elements;
• and
• a controller configured to:
• identify a prime relationship in which a parameter δ and K have 1 as the only common factor;
• interleave, based on the prime relationship, elements of the input block to form the output block in which an output neighborhood of elements for each element of the output block is symmetric to an input neighborhood of elements for each element of the input block;
• generate an encoded block based on the output block;
• and
• transmit a signal comprising the encoded block, wherein a value of the parameter δ is greater than a convolutional filter size, and an interleaving position of the input block is determined partially based on the parameter δ and the parameter K.