High Throughput Probabilistic Shaping with Product Distribution Matching

TL;DR

This paper introduces Product Distribution Matching (PDM), a low-complexity, high-throughput method for probabilistic shaping that improves power efficiency in multi-carrier systems by sharing distribution matchers across sub-carriers.

Contribution

The paper proposes PDM, a novel parallel architecture for distribution matching that enables efficient probabilistic amplitude shaping in multi-carrier systems, reducing complexity and increasing power efficiency.

Findings

PDM achieves power efficiency comparable to single DMs for 64-ASK.

PDM enables PAS in multi-carrier systems like DSL and OFDM.

PDM improves power efficiency by up to 0.93 dB over uniform signaling.

Abstract

Product distribution matching (PDM) is proposed to generate target distributions over large alphabets by combining the output of several parallel distribution matchers (DMs) with smaller output alphabets. The parallel architecture of PDM enables low-complexity and high-throughput implementation. PDM is used as a shaping device for probabilistic amplitude shaping (PAS). For 64-ASK and a spectral efficiency of 4.5 bits per channel use (bpcu), PDM is as power efficient as a single full-fledged DM. It is shown how PDM enables PAS for parallel channels present in multi-carrier systems like digital subscriber line (DSL) and orthogonal frequency-division multiplexing (OFDM). The key feature is that PDM shares the DMs for lower bit-levels among different sub-carriers, which improves the power efficiency significantly. A representative parallel channel example shows that PAS with PDM is 0.93 dB more power efficient than conventional uniform signaling and PDM is 0.35 dB more power efficient than individual per channel DMs.