# US 2019/0356385 A1 · S2-psk optical wireless communication method and apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0356385 A1 - Document ID: US20190356385A1 - Status: Published application - Kind: A1 - Application number: 16/069,822 - Filed: 2016-11-28 - Published: 2019-11-21 - Earliest claimed: 2016-01-12 - Assignees: Kookmin University Industry Academy Cooperation Foundation - Applicants: Kookmin University Industry Academy Cooperation Foundation - Inventors: Yeong Min JANG; Van Trang NGUYEN; Chang Hyun HONG - Web page: https://patentgrep.com/patent/US20190356385A1 ## CPC - H04B 10/116: Visible light communication - H04B 10/5561: {Digital phase modulation} - H04B 10/676: {for all-optical demodulation of the input optical signal} - H04L 27/10: Frequency-modulated carrier systems, i.e. using frequency-shift keying (H04L27/32 takes precedence) - H04L 27/18: Phase-modulated carrier systems, i.e. using phase-shift keying (H04L27/32 takes precedence) - H04N 7/22: Adaptations for optical transmission - H04B: TRANSMISSION - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract An optical wireless communication apparatus includes: a modulator for generating a reference signal including periodically repeating binary zeros and ones, receiving an input of a first binary data signal, and outputting a second binary data signal, wherein the second binary data signal has the same frequency as the reference signal, and has the same phase as the reference signal when the first binary data signal comprises binary zeros and has an opposite phase to the reference signal when the first binary data signal comprises binary ones, or has the same phase as the reference signal when the first binary data signal comprises binary ones and has an opposite phase to the reference signal when the first binary data signal comprises binary zeros, and a transmitter for turning a first light source on or off according to the reference signal, and turning a second light source on or off according to the second binary data signal. ## Claims ### Claim 1 An optical wireless communication apparatus comprising: a modulator; and a transmitter, wherein the modulator generates a reference signal periodically repeating binary value 0s and 1s, receives an input of a first binary data signal, and outputs a second binary data signal, wherein the second binary data signal has a frequency the same as that of the reference signal, and a phase the same as that of the reference signal when the first binary data signal is a binary value 0 and a phase opposite to that of the reference signal when the first binary data signal is a binary value 1, or a phase the same as that of the reference signal when the first binary data signal is a binary value 1 and a phase opposite to that of the reference signal when the first binary data signal is a binary value 0; and the transmitter turns on and off a first light source according to the reference signal and turns on and off a second light source according to the second binary data signal. ### Claim 2 (depends on 1) The apparatus according to claim 1, wherein the second binary data signal has a phase the same as that of the reference signal when the first binary data signal is a binary value 0 and a phase opposite to that of the reference signal when the first binary data signal is a binary value 1. ### Claim 3 (depends on 1) The apparatus according to claim 1, further comprising a line encoder for receiving an input of a third binary data signal, encoding the third binary data signal at a code rate of ½, and outputting the first binary data signal, wherein the line encoder outputs a binary value (0, 0) or (1, 1) when the input signal is a binary value 0 and a binary value (0, 1) or (1, 0) when the input signal is a binary value 1, or a binary value (0, 1) or (1, 0) when the input signal is a binary value 0 and a binary value (0, 0) or (1, 1) when the input signal is a binary value 1. ### Claim 4 (depends on 3) The apparatus according to claim 3, wherein the line encoder outputs a binary value (0, 0) when the input signal is a binary value 0 and a binary value (0, 1) when the input signal is a binary value 1. ### Claim 5 (depends on 1) The apparatus according to claim 1, wherein the modulator receives an input of a third binary data signal and outputs a fourth binary data signal, wherein the fourth binary data signal has a frequency the same as that of the reference signal, and a phase the same as that of the reference signal when the third binary data signal is a binary value 0 and a phase opposite to that of the reference signal when the third binary data signal is a binary value 1, or a phase the same as that of the reference signal when the third binary data signal is a binary value 1 and a phase opposite to that of the reference signal when the third binary data signal is a binary value 0; and the transmitter turns on and off a third light source according to the fourth binary data signal. ### Claim 6 An optical wireless communication apparatus comprising: a receiver; and a demodulator, wherein the receiver receives consecutively photographed images from an image sensor; and the demodulator outputs a first binary data signal of a binary value 0 when an ON/OFF phase of a first light source on the images is the same as an ON/OFF phase of a second light source on the images and a binary value 1 when the ON/OFF phase of the first light source is opposite to the ON/OFF phase of the second light source, or a binary value 1 when the ON/OFF phase of the first light source is the same as the ON/OFF phase of the second light source and a binary value 0 when the ON/OFF phase of the first light source is opposite to the ON/OFF phase of the second light source, on the basis of the images. ### Claim 7 (depends on 6) The apparatus according to claim 6, wherein the demodulator outputs the first binary data signal of a binary value 0 when the ON/OFF phase of the first light source on the images is the same as the ON/OFF phase of the second light source on the images and a binary value 1 when the ON/OFF phase of the first light source is opposite to the ON/OFF phase of the second light source. ### Claim 8 (depends on 6) The apparatus according to claim 6, further comprising a light source detector for detecting positions of the first light source and the second light source from the images, wherein the demodulator outputs the first binary data signal on the basis of the detected positions of the first light source and the second light source. ### Claim 9 (depends on 8) The apparatus according to claim 8, wherein the light source detector includes an artificial neural network for detecting the positions of the first light source and the second light source, wherein the artificial neural network includes a first neuron layer and a second neuron layer, and each of the first neuron layer and the second neuron layer includes a convolution layer and an RoI pooling layer, and the light source detector reads previous positions of the first light source and the second light source, builds a learning data set for the artificial neural network on the basis of the previous positions, obtains an output of the artificial neural network using the learning data set as an input, obtains, if an error in the output does not satisfy a targeted error, an output of the artificial neural network using the learning data set as an input after updating weighting factors of the artificial neural network by backpropagation, and outputs, if the error in the output satisfies the targeted error, the positions of the first light source and the second light source. ### Claim 10 (depends on 6) The apparatus according to claim 6, wherein the demodulator includes an artificial neural network for calculating an XOR value or an NXOR value of the ON/OFF states of the first light source and the second light source considering noise, wherein the artificial neural network includes a first hidden layer having five neurons and a second hidden layer having three neurons, all the neurons of the artificial neural network are completely connected, and an activation function of the first and second hidden layers is a tan-sigmoid function, and the demodulator reads ON/OFF states of the first light source and the second light source, builds a learning data set for the artificial neural network on the basis of the ON/OFF states, obtains an output of the artificial neural network using the learning data set as an input, obtains, if an error in the output does not satisfy a targeted error, an output of the artificial neural network using the learning data set as an input after updating weighting factors of the artificial neural network by backpropagation, and outputs, if the error in the output satisfies the targeted error, the XOR value or the NXOR value of the ON/OFF states of the first light source and the second light source. ### Claim 11 (depends on 6) The apparatus according to claim 6, further comprising a line decoder for receiving an input of a first binary data signal, decoding the first binary data signal at a code rate of ½, and outputting a second binary data signal, wherein the line decoder outputs a binary value 0 when the input signal is a binary value (0, 0) or (1, 1) and a binary value 1 when the input signal is a binary value (0, 1) or (1, 0), or a binary value 1 when the input signal is a binary value (0, 0) or (1, 1) and a binary value 0 when the input signal is a binary value (0, 1) or (1, 0). ### Claim 12 (depends on 11) The apparatus according to claim 11, wherein the line decoder outputs a binary value 0 when the input signal is a binary value (0, 0) or (1, 1) and a binary value 1 when the input signal is a binary value (0, 1) or (1, 0). ### Claim 13 (depends on 11) The apparatus according to claim 11, wherein the receiver receives images photographed in a rolling shutter method from the image sensor. ### Claim 14 (depends on 8) The apparatus according to claim 8, wherein the light source detector detects a position of a third light source from each of the images, and the demodulator outputs a second binary data signal of a binary value 0 when the ON/OFF phase of the first light source is the same as an ON/OFF phase of the third light source and a binary value 1 when the ON/OFF phase of the first light source is opposite to the ON/OFF phase of the third light source, or a binary value 1 when the ON/OFF phase of the first light source is the same as the ON/OFF phase of the third light source and a binary value 0 when the ON/OFF phase of the first light source is opposite to the ON/OFF phase of the third light source, on the basis of positions of the first light source and the third light source. ### Claim at position 15 15-16. (canceled) ### Claim 17 An optical wireless communication method comprising: generating, by a modulator, a reference signal periodically repeating binary value 0s and 1s; receiving, by the modulator, an input of a first binary data signal; outputting, by the modulator, a second binary data signal having a frequency the same as that of the reference signal, and a phase the same as that of the reference signal when the first binary data signal is a binary value 0 and a phase opposite to that of the reference signal when the first binary data signal is a binary value 1, or a phase the same as that of the reference signal when the first binary data signal is a binary value 1 and a phase opposite to that of the reference signal when the first binary data signal is a binary value 0; and turning on and off, by a transmitter, a first light source according to the reference signal, and turning on and off a second light source according to the second binary data signal. ### Claim 18 (depends on 17) The method according to claim 17, further comprising: receiving an input of a third binary data signal, encoding the third binary data signal at a code rate of ½, and outputting the first binary data signal, by a line encoder, wherein the line encoder outputs a binary value (0, 0) or (1, 1) when the input signal is a binary value 0 and a binary value (0, 1) or (1, 0) when the input signal is a binary value 1, or a binary value (0, 1) or (1, 0) when the input signal is a binary value 0 and a binary value (0, 0) or (1, 1) when the input signal is a binary value 1. ### Claim 19 An optical wireless communication method comprising: receiving, by a receiver, consecutively photographed images from an image sensor; and outputting, by a demodulator, a first binary data signal of a binary value 0 when an ON/OFF phase of a first light source of the images is the same as an ON/OFF phase of a second light source of the images and a binary value 1 when the ON/OFF phase of the first light source is opposite to the ON/OFF phase of the second light source, or a binary value 1 when the ON/OFF phase of the first light source is the same as the ON/OFF phase of the second light source and a binary value 0 when the ON/OFF phase of the first light source is opposite to the ON/OFF phase of the second light source, on the basis of the images. ### Claim 20 (depends on 19) The method according to claim 19, further comprising: detecting, by a light source detector, positions of the first light source and the second light source from the images, wherein outputting a first binary data signal is performed on the basis of the detected positions of the first light source and the second light source. ### Claim 21 (depends on 20) The method according to claim 20, wherein the light source detector includes an artificial neural network for detecting the positions of the first light source and the second light source, wherein the artificial neural network includes a first neuron layer and a second neuron layer, and each of the first neuron layer and the second neuron layer includes a convolution layer and an RoI pooling layer, and detecting, by the light source detector, the positions of the first light source and the second light source includes: reading previous positions of the first light source and the second light source; building a learning data set for the artificial neural network on the basis of the previous positions; obtaining an output of the artificial neural network using the learning data set as an input; obtaining, if an error in the output does not satisfy a targeted error, an output of the artificial neural network using the learning data set as an input after updating weighting factors of the artificial neural network by backpropagation; and outputting, if the error in the output satisfies the targeted error, the positions of the first light source and the second light source. ### Claim 22 (depends on 19) The method according to claim 19, wherein the demodulator includes an artificial neural network for calculating an XOR value or an NXOR value of the ON/OFF states of the first light source and the second light source considering noise, wherein the artificial neural network includes a first hidden layer having five neurons and a second hidden layer having three neurons, all the neurons of the artificial neural network are completely connected, and an activation function of the first and second hidden layers is a tan-sigmoid function, and outputting, by the demodulator, a first binary data signal includes: reading ON/OFF states of the first light source and the second light source; building a learning data set for the artificial neural network on the basis of the ON/OFF states; obtaining an output of the artificial neural network using the learning data set as an input; obtaining, if an error in the output does not satisfy a targeted error, an output of the artificial neural network using the learning data set as an input after updating weighting factors of the artificial neural network by backpropagation; and outputting, if the error in the output satisfies the targeted error, the XOR value or the NXOR value of the ON/OFF states of the first light source and the second light source. ### Claim 23 (depends on 19) The method according to claim 19, further comprising receiving an input of a first binary data signal, decoding the first binary data signal at a code rate of ½, and outputting the second binary data signal, by a line decoder, wherein the line decoder outputs a binary value 0 when the input signal is a binary value (0, 0) or (1, 1) and a binary value 1 when the input signal is a binary value (0, 1) or (1, 0), or a binary value 1 when the input signal is a binary value (0, 0) or (1, 1) and a binary value 0 when the input signal is a binary value (0, 1) or (1, 0). ### Claim 24 (depends on 17) A computer-readable recording medium recording a program for executing the method according to claim 17. ### Claim 25 (depends on 19) A computer-readable recording medium recording a program for executing the method according to claim 19.