Performance Analysis of the LDPC‐Coded Hybrid L QAM‐MPPM for UWOC Systems

Tools

Jiang, Hongyan and Hu, Wanyi and Liao, Xin and He, Ning and Popoola, Wasiu and Omar, Ahmad Fairuz and Rajbhandari, Sujan (2026) Performance Analysis of the LDPC‐Coded Hybrid L QAM‐MPPM for UWOC Systems. IET Optoelectronics, 20 (1). e70025. ISSN 1751-8768 (https://doi.org/10.1049/ote2.70025)

[thumbnail of IET Optoelectronics - 2026 - Jiang - Performance Analysis of the LDPC‐Coded Hybrid LQAM‐MPPM for UWOC Systems]
Preview
 Text. Filename: IET_Optoelectronics_-_2026_-_Jiang_-_Performance_Analysis_of_the_LDPC_Coded_Hybrid_LQAM_MPPM_for_UWOC_Systems.pdf
Final Published Version
License: Creative Commons Attribution-NonCommercial 4.0 logo
Download (3MB)| Preview

Abstract

This paper proposes a hybrid optical modulation scheme that integrates spectrally efficient quadrature amplitude modulation (QAM) and power‐efficient multipulse pulse position modulation (MPPM) for underwater wireless optical communication (UWOC) to achieve high spectral and energy efficiencies and combines it with LDPC codes to mitigate the adverse effects imposed by the underwater turbulence channel. Considering the effect of both direct‐current (DC) bias level and modulation index on signal‐to‐noise ratio (SNR), for the first time, an approximate closed‐form bit error rate (BER) expression for the hybrid L‐QAM‐MPPM UWOC system over turbulence channels is derived and verified using Monte Carlo (MC) simulations. Subsequently, comparisons among the hybrid L‐QAM‐MPPM, conventional MPPM and QAM systems with comparable spectral efficiency for exponentiated Weibull (EW)‐modelled turbulence channel indicate that hybrid modulation offers resilience to turbulence, although the BER in the additive white Gaussian noise (AWGN)‐only channel is higher. Finally, the effectiveness of LDPC codes in improving the performance of hybrid modulations is discussed, with coded 128‐QAM‐(12, 2) MPPM offering ∼6.5 and 5.8 dB code gains at a BER of 10 − 4 ${10}^{-4}$ in strong and moderate turbulence, respectively. These results demonstrate the promise of hybrid modulation with LDPC as a robust and efficient modulation scheme for UWOC systems.

ORCID iDs

Jiang, Hongyan, Hu, Wanyi, Liao, Xin, He, Ning, Popoola, Wasiu, Omar, Ahmad Fairuz and Rajbhandari, Sujan ORCID logoORCID: https://orcid.org/0000-0001-8742-118X;
  • Item type:Article
    ID code:95129
    Dates:
    Date
    Event
    1 January 2026
    Published
    30 December 2025
    Published Online
    18 December 2025
    Accepted
    28 June 2025
    Submitted
    Subjects:Science > Physics
    Department:Faculty of Science > Physics > Institute of Photonics
    Depositing user: Pure Administrator
    Date deposited:05 Jan 2026 15:36
    Last modified:22 Jan 2026 09:43
    URI:https://strathprints.strath.ac.uk/id/eprint/95129
CORE (COnnecting REpositories)