A visible light communication device based on power line carrier circuit and communication method thereof

Abstract

The present invention discloses a visible light communication device based on a power line carrier circuit and a communication method thereof. The device includes: an Ethernet interface circuit, a power line carrier circuit, a switching switch, a signal attenuation circuit, a light source driving circuit, a light source, an avalanche photodiode, a photoelectric conversion circuit, a linear amplifier circuit, and a power detection circuit. The switching switch can switch the signal transmission mode from visible light communication to power line communication when the optical communication quality is poor, thereby improving the stability of the communication system. The power line carrier circuit modulates the signal in various ways, including OFDM, QPSK, BPSK, and ROBO. Compared with traditional visible light communication systems using OOK modulation, the communication rate and stability are significantly improved. The power detection circuit, the signal attenuation circuit, and the light source driving circuit cooperate to effectively control the power of the transmitted signal, enabling the signal to be transmitted without distortion. In addition, the power line can be replaced with a wire, twisted pair, etc., further improving the anti-interference capability and mobility.

Description

Technical Field

[0001] The present invention relates to the technical field of visible light communication, and in particular to a visible light communication device based on a power line carrier circuit. Background Art

[0002] Visible light communication (VLC) technology has garnered widespread attention in recent years. Based on novel light-emitting diodes (LEDs), VLC utilizes visible light as a communication carrier. It boasts advantages such as high density, a rich spectrum, zero electromagnetic radiation, and high confidentiality. Its environmentally friendly design addresses shortcomings inherent in traditional wireless communications while offering the added advantage of both illumination and communication.

[0003] While visible light communication technology offers significant advantages, it also has significant shortcomings that severely limit its widespread adoption. Typical visible light communication systems require AC signals to control the brightness of LEDs, and wiring to conduct power is also required. Consequently, communication costs are often high and efficiency is low.

[0004] Therefore, in order to further increase the stability of the system and reduce the communication cost, the traditional visible light communication technology is improved and a new communication device is proposed, which has very important practical significance for the large-scale application of visible light communication technology. Summary of the Invention

[0005] The purpose of the present invention is to overcome the shortcomings of the existing technology and propose a visible light communication device based on a power line carrier circuit, comprising: an Ethernet interface circuit, a power line carrier circuit, a switch, a signal attenuation circuit, a light source driving circuit, a light source, an avalanche photodiode, a photoelectric conversion circuit, a linear amplifier circuit and a power detection circuit;

[0006] The Ethernet interface processing circuit is connected to the power line carrier circuit, which modulates and demodulates the input signal; the power line carrier circuit is connected to the switching switch, which is respectively connected to the signal attenuation circuit. The switching switch is also connected to the power line. The switching switch can select the signal output by the power line carrier circuit to pass through the power line communication or enter the signal attenuation circuit for optical communication; the signal attenuation circuit linearly attenuates the input signal to a certain extent, and the attenuated signal is input to the light source driving circuit. The light source driving circuit provides the bias voltage required to drive the light source and loads the attenuated signal to both ends of the light source, and the light source emits the optical signal; the avalanche photodiode receives the optical signal and transmits it to the photoelectric conversion circuit. The photoelectric conversion circuit is respectively connected to the amplification circuit and the power detection circuit. The amplification circuit is connected to the switching switch, and the power detection circuit detects the power of the output signal of the photoelectric conversion circuit.

[0007] Preferably, the power line carrier circuit includes a power line carrier communication chip.

[0008] Preferably, the signal modulation modes that can be performed by the power line carrier circuit include: OFDM, QPSK, BPSK or ROBO.

[0009] Preferably, the power detection circuit includes a plurality of light-emitting diodes of different colors, and the light-emitting diodes emit light according to the detected power.

[0010] Preferably, the bias voltage of the light source driving circuit can be adjusted according to the power detected by the power detection circuit at the receiving end.

[0011] Preferably, the attenuation of the signal attenuation circuit can be adjusted according to the power detected by the power detection circuit at the receiving end.

[0012] Preferably, the light source may be laser, Mini-LED or Micro-LED.

[0013] Preferably, the power line can be replaced by a twisted pair or a conductive wire.

[0014] To overcome the deficiencies of the prior art, the present invention further proposes a communication method for a visible light communication device based on the above-mentioned power line carrier circuit, the steps of which are as follows:

[0015] Step 1: Determine the optical communication conditions. If there are no obstacles, proceed to step 2. If there are obstacles, proceed to step 3.

[0016] Step 2: The switch is connected to the signal attenuation circuit, and the Ethernet signal is input to the Ethernet interface processing circuit of the transmitting end. After processing, the signal passes through the power line carrier circuit and the switch, enters the signal attenuation circuit and the light source driving circuit for processing, and is finally sent as an optical signal; the avalanche photodiode at the receiving end receives the optical signal, transmits the signal to the photoelectric conversion circuit and the linear amplification circuit, and after processing, enters the Ethernet interface processing circuit, and is finally converted into an Ethernet signal for transmission; at the same time, the power detection circuit detects the power of the signal output by the photoelectric conversion circuit, and adjusts the attenuation value of the signal attenuation circuit and the bias voltage value of the light source driving circuit at the transmitting end according to the signal power;

[0017] In step 3, the switch is connected to the power line. The Ethernet signal at the transmitting end is input into the Ethernet interface processing circuit. After processing, the signal enters the power line carrier circuit and the switch, and is sent through the power line in the form of an electrical signal. The power line at the receiving end receives the electrical signal. The signal passes through the switch and the power line carrier circuit, enters the Ethernet interface processing circuit, and is converted into an Ethernet signal for transmission.

[0018] The present invention has the following beneficial effects:

[0019] (1) The present invention has the function of performing two communication modes: duplex visible light communication and wired communication (including but not limited to power line carrier communication). By switching the switch, it can switch to wired communication when the optical communication quality is poor, thereby improving the stability of the communication system;

[0020] (2) When performing visible light wireless communication, since the power line carrier circuit can modulate Ethernet signals using modulation methods including but not limited to OFDM, QPSK, BPSK, and ROBO, its communication rate, stability, and other performance are significantly improved compared to traditional visible light communication systems using OOK modulation. At the same time, the cooperation of the power detection circuit, signal attenuation circuit, and light source driving circuit can attenuate the signal to varying degrees and adjust the bias voltage, effectively controlling the power of the transmitted signal and enabling the signal to be transmitted without distortion, thereby achieving high-speed and stable communication effects of the system.

[0021] (3) When conducting wired communication, since the power line carrier circuit integrates a power line carrier communication chip, it has the general advantages of power line communication. In addition, the replacement options for power lines include but are not limited to flexible, low-loss, and low-interference wires, twisted pairs, and other signal transmission media. Compared with power line communication systems that use fixed, high-loss, and complex channel environment power lines as transmission media, the anti-interference ability and mobility are significantly improved.

[0022] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is an architectural diagram of an embodiment of the present invention;

[0024] Figure 2 This is a schematic diagram of an embodiment of the present invention when it is working. DETAILED DESCRIPTION

[0025] See also Figure 1 As shown, it is an architecture diagram of an embodiment of the present invention, including: an Ethernet interface processing circuit 1, a power line carrier circuit 2, a switching switch 3, a signal attenuation circuit 4, a light source driving circuit 5, a light source 6, an avalanche photodiode 7, a photoelectric conversion circuit 8, a power detection circuit 9, and a linear amplification circuit 10.

[0026] Among them, the functions of the Ethernet interface processing circuit 1 are: (1) extracting the Ethernet physical layer signal and outputting a differential signal; (2) receiving the differential signal and converting the differential signal into an Ethernet signal; the functions of the power line carrier circuit 2 are: (1) modulating the differential signal output by the Ethernet interface circuit 1 and outputting a modulated signal; (2) receiving a modulated signal, demodulating the modulated signal and outputting a differential signal; the switching switch 3 is used to control the free switching between visible light communication and wired communication. When there is no obstacle blocking the light, the switch 3 is connected to the signal attenuation circuit 4 to perform visible light communication; when the light signal encounters an obstacle blocking the light and causing the communication to be interrupted, the switch 3 is used to perform wired communication; the signal attenuation circuit 4 is used to linearly attenuate the modulated signal output by the power line carrier circuit 2, and output a small modulated signal attenuated at a certain ratio; the functions of the light source driving circuit 5 include: (1) providing a bias voltage to drive the light source 6 to emit light; (2) loading the small modulated signal output by the signal attenuation circuit 4 to both ends of the light source 6; the light source 6 completes the emission of the light signal, and the selection of the light source 6 includes but is not limited to laser, Mini-LED or Micro- Any light source such as LED; the avalanche photodiode 7 receives the light signal from the transmitting end and outputs a small current signal; the photoelectric conversion circuit 8 performs I / V conversion and amplification processing on the small photocurrent output by the avalanche photodiode 7, and outputs a voltage signal; the power detection circuit 9 performs power detection on the signal output by the photoelectric conversion circuit 8, and adjusts the attenuation value of the transmitting end signal attenuation circuit 4 and the bias voltage value provided by the light source driving circuit 5 according to the detection result, so as to ensure that the power of the transmitting end signal is within an appropriate range; the linear amplifier circuit 10 is used to linearly amplify the electrical signal output by the photoelectric conversion circuit 8, and output an amplified voltage signal.

[0027] See also Figure 2, which is a schematic diagram of an embodiment of the present invention in operation. The solid arrows in the figure indicate the signal transmission direction for optical communication, and the dashed arrows indicate the signal transmission direction for power lines. The transmitting end shown in the figure is the transmitting end of the downlink, and the receiving end is the receiving end of the downlink. The transmitting end receives signals from Ethernet port 11 and sends the signals to user terminal 12.

[0028] The embodiment of the present invention selects optical communication or power line communication according to the conditions of optical communication; when the optical communication channel is unobstructed, visible light communication is performed, and the working process is as follows:

[0029] S1: Ethernet port 11 outputs Ethernet signal;

[0030] S2: The Ethernet signal is input to the Ethernet interface processing circuit 1, and the Ethernet interface processing circuit 1 extracts the Ethernet signal and outputs a differential signal;

[0031] S3: The differential signal output by the Ethernet interface processing circuit 1 is input to the power line carrier circuit 2. The power line carrier circuit 2 performs BPSK modulation and other processing on the differential signal and outputs a BPSK modulated signal.

[0032] S4: The BPSK signal output by the power line carrier circuit 2 is input to the switch 3. In the visible light communication state, the switch 3 is connected to the signal attenuation circuit 4. The attenuation circuit 4 attenuates the BPSK signal from the power line carrier circuit 2 to a certain extent and outputs an attenuated BPSK signal.

[0033] S5: The signal attenuation circuit 4 outputs the attenuated BPSK signal and inputs it to the light source driving circuit 5. The light source driving circuit 5 couples the attenuated BPSK signal with the light source driving voltage provided by itself and loads the coupled signal to both ends of the light source 6.

[0034] S6: Light source 6 converts the electrical signal into an optical signal and transmits the optical signal;

[0035] S7: After the optical signal propagates through free space, it reaches the receiving end. The avalanche photodiode 7 at the receiving end receives the optical signal and performs photoelectric conversion to output a photocurrent signal.

[0036] S8: The photocurrent signal output by the avalanche photodiode 7 is input to the photoelectric conversion circuit 8, which performs I / V conversion and amplification on the photocurrent signal and outputs a voltage signal;

[0037] S9: The voltage signal output by the photoelectric conversion circuit 8 is input to the power detection circuit 9 and the linear amplifier circuit 10. The power detection circuit 9 detects the power of the input signal. It is equipped with three light-emitting diodes of different colors. Based on the light emission of the three light-emitting diodes, the power of the input signal can be determined. The attenuation value of the transmitting-end signal attenuation circuit 4 and the light source bias voltage of the light source driver circuit 5 are adjusted accordingly.

[0038] S10: The voltage signal output by the photoelectric conversion circuit 8 is input to the linear amplifier circuit 10, which further amplifies the signal and outputs an amplified voltage signal;

[0039] S11: The linear amplifier circuit 10 outputs an amplified voltage signal which is input to the power line carrier circuit 2. The power line carrier circuit 2 performs demodulation and other processing on the voltage signal and outputs a differential signal.

[0040] S12: The differential signal output by the power line carrier circuit 2 is input to the Ethernet interface circuit 1, which converts the differential signal into an Ethernet signal that can be directly used by the user terminal 12, and finally completes the downlink visible light communication.

[0041] The communication process of the uplink is similar to that of the downlink.

[0042] When the optical signal encounters an obstacle during propagation, causing communication interruption, the communication mode can be switched from visible light communication to wired communication by switching switch 3. The working process is as follows:

[0043] S1: Ethernet port 11 outputs Ethernet signal;

[0044] S2: The Ethernet signal is input to the Ethernet interface processing circuit 1, and the Ethernet interface processing circuit 1 extracts the Ethernet signal and outputs a differential signal;

[0045] S3: The differential signal output by the Ethernet interface circuit 1 is input to the power line carrier circuit 2, and the power line carrier circuit 2 performs BPSK modulation and other processing on the differential signal and outputs a BPSK modulated signal;

[0046] S4: The BPSK signal output by the power line carrier circuit 2 is input to the switch 3, which is connected to a wired transmission medium and loads the BPSK modulated signal onto the wired transmission medium for transmission. The wired transmission medium includes but is not limited to a twisted pair, a conductor, and a power line.

[0047] S5: The receiving end switches switch 3 to receive the BPSK signal transmitted from a medium such as a twisted pair, a conductor, or a power line;

[0048] S6: Switch 3 to input the received BPSK modulated signal to the power line carrier circuit 2;

[0049] S7: The power line carrier circuit 2 performs demodulation and other processing on the BPSK signal and outputs a differential signal;

[0050] S8: The differential signal output by the power line carrier circuit 2 enters the Ethernet interface processing circuit 1, and the Ethernet interface processing circuit 1 converts the input differential signal into an Ethernet signal that can be used by the user terminal 12, thereby completing the downlink communication.

[0051] The power line uplink communication process is similar to the downlink.

[0052] As can be seen, the present invention proposes a visible light communication device based on a power line carrier circuit, which has the function of performing both duplex visible light communication and wired communication (including but not limited to power line carrier communication). By switching a switch, it can switch to wired communication when the optical communication quality is poor, thereby improving the stability of the communication system. Because the power line carrier circuit can modulate Ethernet signals using modulation methods including but not limited to OFDM, QPSK, BPSK, and ROBO, its communication rate, stability, and other performance are significantly improved compared to traditional visible light communication systems using OOK modulation. At the same time, the cooperation of the power detection circuit, the signal attenuation circuit, and the light source driving circuit can attenuate the signal to varying degrees and adjust the bias voltage, effectively controlling the power of the transmitted signal and achieving distortion-free transmission of the signal, thereby achieving high-speed and stable communication effects of the system. When performing wired communication, since the power line carrier circuit integrates a power line carrier communication chip, it has the general advantages of power line communication. In addition, alternative options for the power line include but are not limited to flexible, low-loss, and low-interference wires, twisted pairs, and other signal transmission media, further improving anti-interference capabilities and mobility.

[0053] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A visible light communication device based on a power line carrier circuit, characterized in that: include: Ethernet interface circuit, power line carrier circuit, switch, signal attenuation circuit, light source driving circuit, light source, avalanche photodiode, photoelectric conversion circuit, linear amplifier circuit and power detection circuit; The Ethernet interface processing circuit is connected to the power line carrier circuit, and the power line carrier circuit modulates and demodulates the input signal; the power line carrier circuit is connected to the switching switch, and the switching switch is respectively connected to the signal attenuation circuit. The switching switch is also connected to the power line, and the switching switch can be used to select the signal output by the power line carrier circuit to pass through the power line communication or enter the signal attenuation circuit for optical communication; the signal attenuation circuit linearly attenuates the input signal to a certain extent, and the attenuated signal is input to the light source driving circuit. The light source driving circuit provides the bias voltage required to drive the light source and loads the attenuated signal to both ends of the light source, and the light source emits the optical signal; The avalanche photodiode receives the optical signal and transmits it to the photoelectric conversion circuit, the photoelectric conversion circuit is connected to the amplifier circuit and the power detection circuit respectively, the amplifier circuit is connected to the switch, and the power detection circuit detects the power of the output signal of the photoelectric conversion circuit; The switch is used to control the free switching between visible light communication and wired communication. Specifically, when there is no obstacle blocking the light, the switch is connected to the signal attenuation circuit to perform visible light communication. When the optical signal encounters an obstacle blocking the light and causing communication interruption, wired communication is performed through the switch. The attenuation of the signal attenuation circuit is adjusted according to the power detected by the power detection circuit at the receiving end; The bias voltage of the light source driving circuit is adjusted according to the power detected by the power detection circuit at the receiving end.

2. The visible light communication device based on the power line carrier circuit according to claim 1, characterized in that: The power line carrier circuit includes a power line carrier communication chip.

3. The visible light communication device based on the power line carrier circuit according to claim 1, characterized in that: The signal modulation modes that can be performed by the power line carrier circuit include: OFDM, QPSK, BPSK or ROBO.

4. The visible light communication device based on the power line carrier circuit according to claim 1, characterized in that: The power detection circuit includes a plurality of light emitting diodes of different colors, and the light emitting diodes emit light according to the detected power level.

5. The visible light communication device based on the power line carrier circuit according to claim 1, characterized in that: The light source may be laser, Mini-LED or Micro-LED.

6. The visible light communication device based on the power line carrier circuit according to claim 1, characterized in that: The power lines may be replaced by twisted pairs or wires.

7. A communication method for a visible light communication device based on a power line carrier circuit, comprising the following steps: Step 1: Determine the optical communication conditions. If there are no obstacles blocking the communication channel, proceed to step 2. If there are obstacles blocking the communication channel, proceed to step 3. Step 2: The switch is connected to the signal attenuation circuit, and the Ethernet signal is input to the Ethernet interface processing circuit of the transmitting end. After processing, the signal passes through the power line carrier circuit and the switch, enters the signal attenuation circuit and the light source driving circuit for processing, and is finally sent as an optical signal; the avalanche photodiode at the receiving end receives the optical signal, transmits the signal to the photoelectric conversion circuit and the linear amplification circuit, and after processing, enters the Ethernet interface processing circuit, and is finally converted into an Ethernet signal for transmission; at the same time, the power detection circuit detects the power of the signal output by the photoelectric conversion circuit, and adjusts the attenuation value of the signal attenuation circuit and the bias voltage value of the light source driving circuit at the transmitting end according to the signal power; Step 3: The switch is connected to the power line. The Ethernet signal from the transmitter is input into the Ethernet interface processing circuit. After processing, the signal enters the power line carrier circuit and the switch, and is sent through the power line in the form of an electrical signal. The power line at the receiving end receives the electrical signal, which passes through the switch and the power line carrier circuit, enters the Ethernet interface processing circuit, and is converted into an Ethernet signal for transmission.

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