Transmitting Extra Bits by Rotating Signal Constellations

TL;DR

This paper introduces a novel LDPC coding scheme that transmits extra bits by rotating signal constellations, enabling additional information transfer without extra power or bandwidth, and uses statistical learning for decoding.

Contribution

The paper presents a new method to embed extra bits via constellation rotation in LDPC schemes, enhancing data capacity without additional resource costs.

Findings

Up to four extra bits transmitted with negligible reliability impact.

Rotation angle estimated using statistical learning of LDPC syndrome.

Scheme applicable to standard LDPC codes of length 2304.

Abstract

In this letter, we propose a novel LDPC coding scheme to transmit extra bits aided by rotated signal constellations without any additional cost in transmission power or bandwidth. In the proposed scheme, the LDPC coded data are modulated by a rotated two-dimensional signal constellation, in which the rotation angle is specified by the given extra bits. At the receiver, the rotation angle is estimated with the aid of the statistical learning of the syndrome of the LDPC code. After recovering the rotation angle, the coded payload data can be decoded by the LDPC decoder. The simulation results show that, for an LDPC code of length 2304, up to four extra bits can be transmitted with negligible influence on the reliability of the LDPC coded data.