Alamouti-type coding for visible light communication based on direct detection using image sensor

Spatially-modulated space-time coding in visible light communications using 2×2 LED array

“…Given D.j / D d .j / kl Á , according to entries "0" and "1" of the matrix, we have intensity modulated waveforms represented by u 0 .t / and u 1 .t/: where T is the symbol duration and A is the constant intensity of LED light source at the transmitter for symbol "1." In our ST coding [7], one waveform is expressed in terms of the other by…”

“…In such long range situation where the number of pixels to capture the LED array is one, we showed in [7] that the use of ST coding allows to successfully extract symbols (bits) transmitted by two different LEDs. ST coding greatly extends the error-free transmission distance, and yet the information rate remains constant, even if the receiver approaches the LED array of the transmitter where the image sensor has the image of the LED array with more number of pixels in its image plane.…”

Image Sensors Meet LEDs

“…Two bits s 1 and s 2 in {s} ∈ {b, c, d} are fed to the individual STC encoder, it generates s 1 = (s 1 , s 2 ) and s 2 = (s 2 , s * 1 ). Note that although s * 1 indicates the complex conjugate of s 1 in the complex system, in the unipolar system we treat it as the opposite binary state [42]: i.e., s * 1 = s 1 . The purpose of STC encoding is to expand the communication range limited by the pixel resolution of imaging system.…”

V2X communications with an image sensor

“…We researched VLC using image sensors for automotive applications (i.e., ISC), mainly targeting V2X communications [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] . In this paper, a selection of our research on ISC is introduced including our most significant findings (e.g., the basics of ISC, a vehicle motion model for ISC, and range estimation positioning).…”

“…As shown in Fig. 1, data transmitted from LED traffic lights, signage, pavement markers, headlights, and tail lights can be received using the image sensor [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] . An LED traffic light transmits safety information to cars.…”