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Related Experiment Video

Updated: Feb 25, 2026

Generation and Coherent Control of Pulsed Quantum Frequency Combs

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Published on: June 8, 2018

Constellation modulation - an approach to increase spectral efficiency.

Soumya Sunder Dash, Frederic Pythoud, David Hillerkuss

|August 10, 2017

Summary

This summary is machine-generated.

Constellation modulation (CM) enhances spectral efficiency by switching between different constellations. This method offers significant gains, especially in low signal-to-noise ratio (SNR) conditions, approaching the Shannon limit.

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Published on: March 20, 2017

Area of Science:

Digital Communications
Information Theory
Signal Processing

Background:

Existing modulation schemes face limitations in spectral efficiency.
The Shannon limit defines the theoretical maximum data rate for a given bandwidth and SNR.
Novel techniques are needed to improve data transmission efficiency.

Purpose of the Study:

Introduce Constellation Modulation (CM) as a novel degree of freedom for enhancing spectral efficiency.
Investigate the performance of CM in terms of Bit-Error Ratio (BER) and Signal-to-Noise Ratio (SNR).
Explore the potential of CM to approach the Shannon limit.

Main Methods:

Encoding information using symbol selection within a constellation and by switching between different constellations.
Utilizing geometrical transformations (rotations, translations, scaling) to generate sets of constellations.
Simulating CM on top of existing modulation formats like Binary Phase Shift Keying (BPSK).

Main Results:

CM increases spectral efficiency by up to 33% at a BER of 10⁻³ and 20% at a BER of 2×10⁻² for BPSK.
CM operates within the same spectral bandwidth as the original modulation.
A 4D-CM-BPSK format achieves 0.7 bit/s/Hz at 0.2 dB SNR and a BER of 2×10⁻².

Conclusions:

Constellation modulation is a viable technique to significantly boost spectral efficiency.
CM offers advantages in low SNR environments with minimal penalties on BER or SNR.
The proposed 4D-CM-BPSK modulation is highly power-efficient and spectrally efficient.