Synchronisation de phase - Boucle à remodulation souple

The phase estimation is a really important step in digital communication systems. Without a good synchronization, using error correction codes and turbo-codes is suboptimum. This paper describes a new synchronizing algorithm which can update the phase of each received symbol. The estimated phase is calculated with a Soft Decision Feedback Loop. This loop uses the Log-Likelihood Ratio (LLR) provided by the turbo-decoder’s soft output. A forward-backward loop improves phase estimation. This algorithm can be applied on every QAM’s constellations and good performance is achieved till near Shannon’s limit SNRs.