We describe and analyze Minimum Path Difference (MPD), a metric to improve threshold-based Selection Decode-and-Forward (SDF) protocols in cooperative wireless networks with channel coding. By observing the decoding process, MPD provides a more frequent channel quality estimation than CRC or SNR and, thus, allows SDF to forward only the parts of a message that are likely to be correct. In this paper, we describe MPD’s efficient integration into Viterbi decoders and SDF protocols, analyze its accuracy and threshold selection, and study its end-to-end Bit Error Rate in practical cooperative WLANs where ideal block fading and ideal channel codes cannot be assumed. Our studies validate that, unlike all prior methods, in these practical scenarios, MPD significantly improves SDF’s performance and experiences only a marginal performance penalty if suboptimal, constant thresholds are selected.
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