Enhanced Visible Light Communication Modulator With Dual-Feedback Control

Arulandu, Kumar; Linnartz, Jean-Paul M. G.; Deng, Xiong

doi:10.1109/jestpe.2019.2962999

Cited by 9 publications

(5 citation statements)

References 24 publications

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“…In the visible spectrum, the widespread use of LED-based lighting is offering opportunities for their use for simultaneous lighting and communications. Indeed, this requires ensuring comfortable and non-distracting illumination experience for the users [97]- [100]. The use cases includes supporting illumination in indoor and outdoor scenarios, as well as signalling (e.g., traffic signals and vehicles head and tail lights).…”

Section: Owc System a Transmittersmentioning

confidence: 99%

Optical Wireless Communications: Illuminating the Path for Cooper's Law

Eltokhey,

Bashir,

Younus

et al. 2024

Preprint

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Section: Owc System a Transmittersmentioning

confidence: 99%

Optical Wireless Communications: Illuminating the Path for Cooper's Law

Eltokhey,

Bashir,

Younus

et al. 2024

Preprint

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“…It consists of a miniaturized (thus short wired) series-transistor modulator topology with AC feedback control of the emitter current and DC biasing control, designed using the principles described in detail in Ref. [64]. This ensures current driving.…”

Section: Model Parameter Characterizationmentioning

confidence: 99%

“…That is, the modulator forces a well-defined current into the LED, rather than placing a voltage across the LED. So the modulator can be seen as one with a very high output impedance, which is inherent to an AC current source [64,65]. A structure with a feedback sense resistor can further help to guarantee this and mitigate the distortion caused by a nonlinear current-voltage (I-V) curve of the LED [64], offering a better fit with ABC models based on electron flows (thus, currents).…”

Section: Model Parameter Characterizationmentioning

confidence: 99%

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Characterization of dynamic distortion in LED light output for optical wireless communications

et al. 2021

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“…where σ 2 mod is the variance of LED AC current i led (t) and where η is the modulation LED power amplifier efficiency, used in a Bias-T setting [34]. An extensive study [34] into the power efficiency of a series transistor modulator revealed a total power consumption of P tot ≈ (V 0 + 2R LED I LED )I LED where factor 2 is due to an extra voltage headroom R LED {max I LED (t)} required to operate the modulating series transistor [34]. More generically, a versatile power constraint is the weighted sum of moments of the probability of the signal…”

Section: Owc Power Constraintsmentioning

confidence: 99%

Optimization and Comparison of M-PAM and Optical OFDM Modulation for Optical Wireless Communication

Mardanikorani

Deng

Linnartz

2020

IEEE Open J. Commun. Soc.

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Illumination LEDs, but also infrared LEDs have limited bandwidth. To achieve high throughput, one needs to modulate the LED significantly above its 3 dB bandwidth. Orthogonal Frequency Division Multiplexing (OFDM) is a popular modulation technique to cope with the frequency selectivity of the LED channel. In this paper, we challenge whether its large Peak-to-Average-Power Ratio (PAPR) and resulting large DC bias are justified. We compare systems using the same power and derive how PAM and OFDM variants reach their optimum throughput at different bandwidths and differently shaped spectral densities, thus at very different Signal to Noise Ratio (SNR) profiles but nonetheless the same transmit power. When corrected for the path loss and normalized to the noise power in the 3 dB bandwidth of the LED, we call this the Normalized Power Budget (NPB). OFDM can exploit the low-pass LED response using a waterfilling approach. This is attractive if the NPB exceeds 60 dB. OFDM will then have to spread its signal over more than ten times the LED bandwidth and requires a DC bias of more than 4 times the rms modulation depth. Second-order distortion and LED droop may then become a limitation, if not compensated. At lower power (NPB between 30 and 60 dB), DCO-OFDM outperforms PAM, provided that it significantly reduces its bias and only if it uses an appropriate adaptive bit and power loading. Without adaptive bit loading, thus using a frequency-constant modulation order, for instance made feasible by a pre-emphasis, OFDM always shows lower performance than PAM; about 2.5 dB at a NPB around 60 dB. Below 30 dB of NPB, even waterfilling cannot outweigh the need for a larger bias in OFDM, and PAM should be preferred. We argue that a mobile system that has to operate seamlessly in wide coverage and short-range high-throughput regimes, needs to adapt not only its bandwidth and its bit-loading profile, but also its DCO-OFDM modulation depth, and preferably falls back from OFDM to PAM.

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Enhanced Visible Light Communication Modulator With Dual-Feedback Control

Cited by 9 publications

References 24 publications

Optical Wireless Communications: Illuminating the Path for Cooper's Law

Optical Wireless Communications: Illuminating the Path for Cooper's Law

Characterization of dynamic distortion in LED light output for optical wireless communications

Optimization and Comparison of M-PAM and Optical OFDM Modulation for Optical Wireless Communication

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