Interplay of Probabilistic Shaping and the Blind Phase Search Algorithm

Abstract

Probabilistic shaping (PS) is a promising technique to approach the Shannon limit using typical constellation geometries. However, the impact of PS on the chain of signal processing algorithms of a coherent receiver still needs further investigation. In this work we study the interplay of PS and phase recovery using the blind phase search (BPS) algorithm, which is widely used in optical communications systems. We first investigate a supervised phase search (SPS) algorithm as a theoretical upper bound on the BPS performance, assuming perfect decisions. It is shown that PS influences the SPS algorithm, but its impact can be alleviated by moderate noise rejection window sizes. On the other hand, BPS is affected by PS even for long windows because of correlated erroneous decisions in the phase recovery scheme. The simulation results also show that the capacity-maximizing shaping is near to the BPS worst-case situation for square-QAM constellations, causing potential implementation penalties.

Accepted for publication in the next available issue of the IEEE/OSA Journal of Lightwave Technology (https://ieeexplore.ieee.org/document/8457202/)

References in corpus (2)

• LDPC Coded Modulation with Probabilistic Shaping for Optical Fiber Systems
• Experimental Comparison of Probabilistic Shaping Methods for Unrepeated Fiber Transmission

Cited by in corpus (6)

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• End-to-end Learning of a Constellation Shape Robust to Channel Condition Uncertainties
• On the Nonlinear Shaping Gain with Probabilistic Shaping and Carrier Phase Recovery
• Modified QPSK Partition Algorithm Based on MAP Estimation for Probabilistically-Shaped 16-QAM