Turbo Code Encoding and Decoding Algorithms

This program implements Turbo code encoding and decoding algorithms. The Turbo code decoding primarily includes LOG-MAP and SOVA algorithms. Turbo codes represent a highly efficient error correction coding technique widely applied in wireless and digital communication systems. By utilizing multiple encoders and iterative decoding, Turbo codes significantly enhance error correction performance. During the encoding process, input data is partitioned into multiple sub-blocks, each processed by distinct encoders. The implementation typically involves two identical recursive systematic convolutional (RSC) encoders connected through an interleaver, generating both systematic and parity bits. The decoding process employs iterative algorithms that improve decoding accuracy through feedback and information updating mechanisms. The LOG-MAP algorithm utilizes logarithmic likelihood ratio properties for decoding, implementing precise probability calculations through logarithmic domain operations to avoid numerical instability. The SOVA (Soft Output Viterbi Algorithm) performs decoding via soft output symbols, maintaining both the most likely path and alternative paths while updating soft decision information through path metric comparisons. Key implementation aspects include: - Interleaver design for decorrelating input sequences - Iterative decoding with extrinsic information exchange between component decoders - Termination criteria implementation for convergence detection - Branch metric and path metric calculations in the trellis structure These algorithms effectively enhance communication system reliability and performance through sophisticated probability processing and iterative refinement techniques. The code implementation typically includes modular structures for encoders, interleavers, and decoders with configurable iteration counts and algorithm parameters.