- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Generalized Likelihood Block Detection for SPAD-based Underwater VLC System
摘要： In the underwater visible light communication (VLC) system, the single photon avalanche diode (SPAD) can expand communication distance. However, the output signals from practical SPADs under dead time limit are not Poisson distributed. In this paper, the generalized likelihood block detection (GLBD) receiver is developed for practical SPAD-based underwater VLC system with on-off keying (OOK) modulation. The proposed receiver can detect the data sequence without any prior knowledge of the channel and the background radiation. Correspondingly, a fast search algorithm for GLBD receiver is also proposed. In addition, a block coding scheme is utilized to solve the error floor problem. Simulation results show that the bit error rate (BER) performance of the proposed receiver is closer to the BER low bound compared to the existing receiver. Moreover, the fast search algorithm reduces the computational complexity without any performance loss.
关键词： Underwater visible light communication,photon counting,blind detection
更新于2025-09-23 15:22:29
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Sherman-Morrison Formula Aided Adaptive Channel Estimation for Underwater Visible Light Communication With Fractionally-sampled OFDM
摘要： In this paper, we investigate the channel estimation (CE) problem in an underwater visible light communication (UVLC) system invoking fractionally-sampled optical orthogonal frequency division multiplexing (FS-OOFDM). In practical UVLC scenarios, the communication links inevitably suffer from many stochastic channel effects including multi-path dispersion, scattering, turbulence, etc., and/or from the mobility of the transceiver, therefore resulting in a time-varying, location-dependent non-stationary propagation environment. Naturally, compared with the indoor visible light communication (VLC) scenario with a typical assumption being the time-flat channel models, it becomes a notable challenge for designing a low-complexity adaptive CE in the much more complicated UVLC scenarios. To solve this problem, we derive a class of Bayesian CE algorithms referred to as the Sherman-Morrison formula (SMF) based CE (SMF-CE), by exploiting the property of rank-one structure of the second-order channel statistics in the delay domain. Furthermore, an adaptive version of SMF-CE (ASMF-CE) can be obtained through updating the imperfect a priori knowledge of the channel and the noise’s statistics. Simulation results demonstrate the superior performances of the proposed algorithms in comparison to existing methods, while maintaining a reduced computational complexity in comparison to the conventional linear minimum mean square error (LMMSE) scheme.
关键词： Sherman-Morrison formula (SMF),Channel estimation (CE),underwater visible light communication (UVLC),fractional sampling (FS),optical orthogonal frequency division multiplexing (OOFDM)
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE 30th Annual International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC) - Istanbul, Turkey (2019.9.8-2019.9.11)] 2019 IEEE 30th Annual International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC) - Transmit Laser Selection for Underwater Visible Light Communication Systems
摘要： Visible light communication (VLC) has the potential to serve as a high-speed underwater wireless connectivity solution to support real-time image and video transmission. Underwater propagation medium imposes additional challenges on the design of VLC systems which were originally proposed for indoor applications. Temperature and salinity fluctuations result in fluctuations of the refractive index of seawater and eventually introduce turbulence-induced fading. In this paper, to mitigate the effects of fading, we propose transmit laser selection for a diver-to-diver underwater VLC link where the transmitter has multiple laser sources and the receiver has one photodetector. The source with the highest received instantaneous signal-to-noise ratio is selected for transmission while the remaining sources remain idle. We derive a closed-form expression for asymptotical bit error rate over log-normal distributed underwater turbulence channels and derive the achievable diversity order. We further present simulation results to confirm our derivations and diversity gain analysis.
关键词： bit error rate performance,underwater optical turbulence,transmit laser selection,diversity order,Underwater visible light communication
更新于2025-09-16 10:30:52
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[IEEE 2019 IEEE International Conference on Signal Processing, Communications and Computing (ICSPCC) - Dalian, China (2019.9.20-2019.9.22)] 2019 IEEE International Conference on Signal Processing, Communications and Computing (ICSPCC) - Enabling technologies for high-speed LED based underwater visible light communications
摘要： Underwater optical wireless communication (UWOC) is an interesting area need to be explored. In recent years, underwater visible light communication (UVLC) is expected to act as an alternative candidate in next-generation underwater wireless optical communications for the Internet of Underwater Things. The challenge is that the absorption, scattering, diffraction effect and turbulence of water medium, which can bring large attenuation and nonlinearity penalty. Therefore, it needs to apply lots of advanced modulation formats which including orthogonal frequency division multiplexing (OFDM), discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-S OFDM) and carrier-less amplitude and phase modulation (CAP) in UVLC signal system. What’s more, advanced digital processing algorithm such as pre/post equalization, nonlinear compensation and other algorithms based on artificial intelligence are needed. In this paper, we introduce three advanced modulation formats including DFT-S OFDM, OFDM and CAP employing probabilistic shaping for high-speed LED based underwater visible light communication.
关键词： underwater visible light communication,probabilistic shaping,advanced modulation formats
更新于2025-09-16 10:30:52