Soft decoding without soft demapping with ORBGRAND

TL;DR

This paper demonstrates that ORBGRAND, a universal soft detection decoder, can be adapted to operate directly on symbol-level soft information, eliminating the need for soft demapping and reducing complexity without sacrificing error correction performance.

Contribution

The authors adapt ORBGRAND to work with symbol-level soft information, removing the need for soft demapping in higher order modulation schemes.

Findings

Reduces decoding complexity compared to traditional soft demapping methods.

Maintains error correction performance equivalent to optimal demappers.

Simplifies receiver design for spectral efficiency systems.

Abstract

For spectral efficiency, higher order modulation symbols confer information on more than one bit. As soft detection forward error correction decoders assume the availability of information at binary granularity, however, soft demappers are required to compute per-bit reliabilities from complex-valued signals. Here we show that the recently introduced universal soft detection decoder ORBGRAND can be adapted to work with symbol-level soft information, obviating the need for energy expensive soft demapping. We establish that doing so reduces complexity while retaining the error correction performance achieved with the optimal demapper.