In-phase and quadrature frequency-shift keying for low-power optical wireless communications

• Published in: Physical communication Vol. 66; p. 102441
• Main Authors: Azim, Ali Waqar, Le Guennec, Yannis, Ros, Laurent
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-10-2024; Elsevier
• Subjects: Coherent detection; Energy efficiency; Engineering Sciences; Frequency-shift keying; Intensity modulation and direct-detection; Modulation and coding; Non-coherent detection; Signal and Image processing; Spectral efficiency; Spectral efficiency; Non-coherent detection; Intensity modulation and direct-detection; Energy efficiency; Frequency-shift keying; Coherent detection; Modulation and coding; intensity modulation and direct-detection; spectral efficiency; energy efficiency
• ISSN: 1874-4907; 1876-3219
• DOI: 10.1016/j.phycom.2024.102441

This article proposes using in-phase and quadrature frequency-shift keying (IQFSK) modulation for low-power optical wireless communications (OWC). IQFSK independently leverages both cosine and sine basis functions to enhance the system’s spectral efficiency (SE). It uses only the odd harmonic frequencies for these basis functions, allowing the clipping of negative amplitude excursions without losing information, making the waveform compatible with OWC The work presents optimal maximum likelihood and low-complexity sub-optimal detection mechanisms for IQFSK. The proposed scheme is analyzed analytically and with numerical simulations. The simulation and analytical results indicate that the proposed scheme is more energy-efficient, can attain a better energy and SE trade-off by exploiting the frame structure of the waveform, and has a lower minimum squared Euclidean distance relative to other state-of-the-art FSK-based counterparts, thus establishing it as one of the most efficient FSK approaches for low-power OWCs.