Two-wavelength adaptive thresholding for uplink from smartphone’s low-luminance WDM/SDM screen to camera

Kawade, Alisa; Chujo, Wataru; Kobayashi, Kentaro

doi:10.1587/comex.2022xbl0074

Cited by 5 publications

(6 citation statements)

References 5 publications

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“…where 𝑤 represents the coupling coefficient from the outer The optimal threshold for the central cell, 𝑃 is determined with the outer 8-cell pattern in every 3×3 cells [17], [18].…”

Section: Principle Of Spatial 4ppm Correlationmentioning

confidence: 99%

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Threshold-Free Symbol Decision Based on Spatial 4PPM Correlation for Uplink Screen Camera Communication Using Low-Luminance SDM Screen

Kawade,

Chujo,

Kobayashi

2024

IEEE Photonics J.

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In uplink screen camera communication from a smartphone screen to an indoor telephoto camera at a distance of 3.5 meters, low-luminance space division multiplexing screen is used to increase bitrate and enhance physical layer security (PLS) at wide angles. Since the low-luminance pixels on the screen are affected by ambient light, it is difficult to determine each cell symbol correctly using pre-trained pixel value threshold. To make symbol decisions without threshold learning, symbol decisions based on correlation of spatial 4 pulse position modulation (4PPM) pattern are demonstrated with numerical models and experiments. To increase bitrate further, thresholdfree symbol decision methods combining 4PPM and inverted 4PPM cells are demonstrated. In addition, to enhance PLS at wide angles while maintaining error-free transmission in the front direction, threshold-free symbol decision methods are analyzed and experimentally verified at wide angles.

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“…where 𝑤 represents the coupling coefficient from the outer The optimal threshold for the central cell, 𝑃 is determined with the outer 8-cell pattern in every 3×3 cells [17], [18].…”

Section: Principle Of Spatial 4ppm Correlationmentioning

confidence: 99%

“…To overcome the spatial ISI, adaptive thresholding, which considers the surrounding 8-cell OOK pattern, was demonstrated [17], [18]. The adaptive thresholding sets the optimal threshold for a central cell with each outer 8-cell pattern in 3×3 cells.…”

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confidence: 99%

Threshold-Free Symbol Decision Based on Spatial 4PPM Correlation for Uplink Screen Camera Communication Using Low-Luminance SDM Screen

Kawade,

Chujo,

Kobayashi

2024

IEEE Photonics J.

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“…An indoor uplink SCC with a relatively long distance [12], [13] realizes full-duplex communication with downlink OCC, personal authentication such as smartphone payment, and interference-free communication in hospitals, factories, etc. Figure 1 shows schematic diagram of an uplink from a smartphone screen to a video camera indoor at a distance of 3.5 meters.…”

Section: System Model For Indoor Uplink Sccmentioning

confidence: 99%

“…Since the high-luminance cells and the black cells are equal in size, the screen pixel value of the high-luminance cell needs to decrease. To achieve low-luminance space division multiplexing, this type of cell arrangement was used [12], [13].…”

Section: Principle Of High-luminance Cell-size Reduction Arrangementmentioning

confidence: 99%

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Space Division Multiplexing Using High-Luminance Cell-Size Reduction Arrangement for Low-Luminance Smartphone Screen to Camera Uplink Communication

Kawade

Chujo

Kobayashi

2023

IEICE Trans. Fundamentals

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To simultaneously enhance data rate and physical layer security (PLS) for low-luminance smartphone screen to camera uplink communication, space division multiplexing using high-luminance cellsize reduction arrangement is numerically analyzed and experimentally verified. The uplink consists of a low-luminance smartphone screen and an indoor telephoto camera at a long distance of 3.5 meters. The highluminance cell-size reduction arrangement avoids the influence of spatial inter-symbol interference (ISI) and ambient light to obtain a stable lowluminance screen. To reduce the screen luminance without decreasing the screen pixel value, the arrangement reduces only the high-luminance cell area while keeping the cell spacing. In this study, two technical issues related to high-luminance cell-size reduction arrangement are solved. First, a numerical analysis and experimental results show that the high-luminance cell-size reduction arrangement is more effective in reducing the spatial ISI at low luminance than the conventional low-luminance cell arrangement. Second, in view point of PLS enhancement at wide angles, symbol error rate should be low in front of the screen and high at wide angles. A numerical analysis and experimental results show that the high-luminance cell-size reduction arrangement is more suitable for enhancing PLS at wide angles than the conventional low-luminance cell arrangement.

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Low-Luminance Space Division Multiplexing With Spatial 4-PPM Correlation for Smartphone Screen to Camera Uplink Communication

Kawade

Chujo

Kobayashi

2023

2023 IEEE 20th Consumer Communications &Amp; Networking Conference (CCNC)

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Two-wavelength adaptive thresholding for uplink from smartphone’s low-luminance WDM/SDM screen to camera

Cited by 5 publications

References 5 publications

Threshold-Free Symbol Decision Based on Spatial 4PPM Correlation for Uplink Screen Camera Communication Using Low-Luminance SDM Screen

Threshold-Free Symbol Decision Based on Spatial 4PPM Correlation for Uplink Screen Camera Communication Using Low-Luminance SDM Screen

Space Division Multiplexing Using High-Luminance Cell-Size Reduction Arrangement for Low-Luminance Smartphone Screen to Camera Uplink Communication

Low-Luminance Space Division Multiplexing With Spatial 4-PPM Correlation for Smartphone Screen to Camera Uplink Communication

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