Viterbi Decoding Implementation Suitable for Both Soft Decision and Hard Decision Approaches

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In digital communication systems, we conducted in-depth research on 8PSK (8-Phase Shift Keying) and TCM (Trellis Coded Modulation) schemes. The implementation includes complete MATLAB source code that employs the Viterbi decoding algorithm - a dynamic programming approach that finds the most likely sequence of states in a trellis diagram. The decoder implementation is particularly versatile as it supports both soft decision decoding (using Euclidean distance metrics with quantized analog values) and hard decision decoding (using Hamming distance with binary decisions). This dual compatibility allows for performance optimization based on channel conditions, where soft decision typically provides approximately 2 dB gain over hard decision. The MATLAB code includes functions for trellis structure generation, branch metric calculation, path metric updating, and traceback operations for both decoding methods.