# Shaped On-Off Keying Using Polar Codes

## TL;DR

This paper introduces a polar code-based joint distribution matching and error correction scheme for power-efficient on-off keying, achieving near-optimal signaling and significant performance gains over uniform transmission.

## Contribution

It proposes a novel polar coding scheme that jointly performs distribution matching and error correction for OOK, surpassing previous methods that used separate or time-sharing approaches.

## Key findings

- Achieves 1.8 dB gain over uniform transmission at 0.25 bits/channel use
- Uses a blocklength of 65,536 bits for numerical simulations
- Enables asymptotically optimal signaling with polar codes

## Abstract

The probabilistic shaping scheme from Honda and Yamamoto (2013) for polar codes is used to enable power-efficient signaling for on-off keying (OOK). As OOK has a non-symmetric optimal input distribution, shaping approaches that are based on the concatenation of a distribution matcher followed by systematic encoding do not result in optimal signaling. Instead, these approaches represent a time sharing scheme where only a fraction of the codeword symbols is shaped. The proposed scheme uses a polar code for joint distribution matching and forward error correction which enables asymptotically optimal signaling. Numerical simulations show a gain of 1.8 dB compared to uniform transmission at a spectral efficiency of 0.25 bits/channel use for a blocklength of 65,536 bits.