WO2019105107A1

WO2019105107A1 - Visible light communication system based on sdr technology

Info

Publication number: WO2019105107A1
Application number: PCT/CN2018/106250
Authority: WO
Inventors: 蒋伟楷
Original assignee: 广州市浩洋电子股份有限公司
Priority date: 2017-11-28
Filing date: 2018-09-18
Publication date: 2019-06-06
Also published as: CN207543109U

Abstract

Disclosed is a visible light communication system based on SDR technology. The visible light communication system comprises a signal modulation device, a visible light signal emission device, a visible light signal receiving device and a signal demodulation device, wherein the signal modulation device is used for performing coding and modulation on an input original signal to modulate same into a modulated signal which can be recognized by the visible light signal emission device, and transmitting the modulated signal to the visible light signal emission device; the visible light signal emission device is used for receiving the modulated signal, and converting the modulated signal into a visible light signal and then transmitting same to the visible light signal receiving device; the visible light signal receiving device is used for receiving the visible light signal, and converting the visible light signal into a modulated signal and then transmitting same to the signal demodulation device; and the signal demodulation device is used for performing demodulation and decoding on the modulated signal to restore the original signal, thus realizing visible light communication. Compared with the prior art, the present utility model has the beneficial effects of being simple and easy to implement, having good stability, and being universal and easy to maintain.

Description

A visible light communication system based on SDR technology

Technical field

The utility model relates to the technical field of visible light communication, and more particularly to a visible light communication system based on SDR technology.

Background technique

SDR (Software Definition Radio), short for "software defined radio". SDR is a radio broadcast communication technology that is based on software-defined wireless communication rather than hardwired. In other words, band, air interface protocols and functions can be upgraded through software downloads and updates without having to completely replace the hardware.

Offset Quadrature Phase Shift Keying (OQPSK) is a modern modulation technique that is an improved QPSK with spectral characteristics of constant envelope modulation and with very high spectral efficiency and power utilization. Widely used in high-speed wireless data transmission systems.

Visible Light Communications (VLC) is a new type of high-speed wireless communication technology developed in technologies such as Light Emitting Diode (LED). It uses LED as a light source to transmit information by emitting visible light signals that are not noticeable to the naked eye and high-speed light and dark. At the receiving end, photoelectric conversion is performed by photodiodes (PD), and then electrical signals are received, reproduced, and demodulated. Realize the delivery of information.

Currently popular wireless communication such as WiFi, Bluetooth, and 2.4G wireless technology are working in the ISM 2.4GHz public frequency band, and the frequency band is crowded. In the face of today's tight wireless spectrum resources, many frequency bands have been occupied, the use of visible light communication can effectively solve the problem of wireless spectrum resources. The visible light band used by VLC is still a blank spectrum and can be used without authorization. Therefore, VLC technology grabs the blank spectrum and utilizes resources effectively. It also has no electromagnetic interference, no spectrum authentication, green environmental protection, high security, good confidentiality, etc. Many advantages have been paid more and more attention in recent years.

technical problem

In order to overcome the existing technical defects, the present invention provides a visible light communication system based on SDR technology, which is simple, easy to implement, has good stability, is generally easy to maintain, and realizes modulation or demodulation signals through software and digitization.

Technical solution

A visible light communication system based on SDR technology, comprising a modulation signal device, a visible light signal transmitting device, a visible light signal receiving device and a demodulation signal device, wherein the modulated signal device is used for encoding and modulating an input original signal, and modulating into a visible light signal a modulation signal capable of being recognized by the transmitting device, and transmitting the modulated signal to the visible light signal transmitting device; the visible light signal transmitting device is configured to receive the modulated signal, and convert the modulated signal into a visible light signal and then transmit the signal to the visible light signal receiving device; The signal receiving device is configured to receive the visible light signal, and convert the visible light signal into a modulated signal and then transmit the signal to the demodulated signal device. The demodulated signal device is configured to demodulate and decode the modulated signal, restore the original signal, and implement visible light communication.

SDR technology utilizes software-defined radio technologies based on software-defined wireless communications rather than hardwired. SDR technology is very flexible and open. It can form various modulation waveforms and communication protocols. It can also be applied to various radio communication between the new system and the old system, thus greatly extending the service life of the radio. The life cycle of software radio also saves costs. The SDR technology is applied to the visible light communication system. The first is to simplify the operation procedure of visible light communication and improve the stability of visible light communication. The second is to facilitate the maintenance and use of the whole system and save costs. The third is to improve the technical effect and practicality. More sexual.

Further, the modulation signal device comprises a host computer, a single chip microcomputer, a programmable logic device, a DAC digital-to-analog converter, a wireless transceiver and a mixer, wherein the upper computer is used for data encapsulation and transmission of the input original signal. For the single-chip microcomputer, the single-chip microcomputer outputs parallel data information and controls the programmable logic device, and encodes and modulates the input original signal to be modulated into a digital baseband signal; the DAC digital-to-analog converter is used to convert the modulated digital baseband signal into an analog baseband signal. The wireless transceiver is configured to receive an analog baseband signal, and convert the analog baseband signal into a modulated signal, and down-convert the mixer to the visible light signal transmitting device.

The upper computer combines the single-chip microcomputer to control the programmable logic device, and encodes and modulates the original signal of the input modulation signal device, and the modulated signal is converted into an analog signal by the DAC digital-to-analog converter, and converted into a modulated signal by the wireless transceiver, in order to improve the visible light. The error transmission rate and output power are then down-converted by the mixer, and the output signal is sent to the visible light emitting device.

Further, the programmable logic device is a CPLD complex programmable logic device using an OQPSK modulation algorithm, and the input signal is coded and modulated and then transmitted to the visible light signal transmitting device.

The OQPSK modulation algorithm, also called offset quadrature phase shift keying, is a modern modulation technique with very high spectral efficiency and power utilization. The OQPSK modulation algorithm is applied to visible light communication systems, making it easier to debug complex functions. To achieve visible light communication. Further, the OQPSK algorithm used in the present application adopts the IEE802.15.4 protocol as a communication standard, and the IEE802.15.4 protocol is a communication standard based on the OQPSK modulation and demodulation method, which has a communication distance, a cost, and a power consumption. The obvious advantages are very suitable for short-distance communication systems such as home networks. The structure is obviously different from the traditional communication methods, and the automation program is high and practical.

Further, the visible light signal transmitting device comprises a low-pass filter, an electric amplifier, a biaser and an LED lamp which are sequentially connected, and the low-pass filter is configured to receive the modulated signal modulated by the modulated signal device, and filter the channel. Noise and other disturbances and taking out low frequency components, the electrical amplifier is used to amplify the electrical signal, the bias is used to combine the DC signal into a signal to reach the threshold voltage of the LED lamp, and the LED lamp is used for visible light emission And transmitting the visible light signal to the visible light signal receiving device.

Further, the visible light signal receiving device includes a photodetector, an electric amplifier and a low pass filter which are sequentially connected, and the photodetector is configured to convert the received visible light signal into an electrical signal to realize photoelectric conversion, and the electric amplifier is used for The amplified electrical signal and the low pass filter are used to extract low frequency components and to filter out channel noise and other interference, and to transmit the signals to the demodulation signal device.

Further, the visible light signal receiving device further includes a lens and a filter disposed before the photodetector, and the signal passing through the visible light signal receiving device is sequentially transmitted through the lens and the filter to be transmitted to the photodetector, and the lens is used for Concentration increases the signal strength, and the filter is used to increase the sensitivity of the photodetector to the signal.

Further, the demodulation signal device includes a mixer, a wireless transceiver, an ADC analog-to-digital converter, a programmable logic device, a single chip microcomputer and a host computer, which are sequentially connected, and the mixer is used to transmit the visible light signal receiving device. The modulated signal is up-converted and transmitted to a wireless transceiver, and the wireless transceiver is configured to convert the modulated signal into an analog baseband signal, and the ADC analog-to-digital converter is used to convert the analog baseband signal into a digitized baseband signal, and the running host computer Combined with the single-chip microcomputer to control the programmable logic device, the received signal is demodulated and decoded, and finally the original signal is recovered to realize visible light communication.

The process of demodulating the decoded signal by the demodulated signal device is equivalent to the process of modulating the encoded signal by the modulating signal device. The electrical signal transmitted by the visible light signal transmitting device to the demodulated signal device is first up-converted by the mixer to convert the electrical signal into a wireless signal. The modulated signal that can be processed by the transceiver is converted into an analog baseband signal by the wireless transceiver, and then the digitized baseband signal is obtained by the ADC analog-to-digital converter, and the programmable logic device is controlled by the running upper computer combined with the single-chip microcomputer to receive the signal. Demodulation and decoding are performed, and finally the original signal is recovered to realize visible light communication.

Further, the programmable logic device is a CPLD complex programmable logic device using an OQPSK modulation algorithm, and the obtained digital baseband signal is demodulated and decoded to be restored to an original signal.

Beneficial effect

Compared with the prior art, the present invention provides a visible light communication system based on SDR technology with the following beneficial effects:

(1) The utility model realizes visible light communication in a digitalized and softwareized manner, and is generally not affected by the environment, and has little influence on individual performance differences. After the circuit design is completed, it can be copied in a large amount without circuit debugging, and has high stability. General easy to maintain and practical advantages.

(2) The modulation and coding signal process and the demodulation and decoding signal process of the modulation signal device and the demodulation signal device of the present invention are realized by software and digitalization, and the digital modulation and demodulation algorithm is more easily realized by computer simulation design. Function, more adjustable.

DRAWINGS

Figure 1 is a schematic view showing the structure of the present invention.

2 is a schematic view showing the structure of a modulation signal device of the present invention.

3 is a schematic view showing the structure of a visible light signal emitting device of the present invention.

4 is a schematic view showing the structure of a visible light signal receiving device of the present invention.

Figure 5 is a schematic view showing the structure of the demodulation signal device of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

As shown in FIG. 1, a visible light communication system based on SDR technology includes a modulation signal device, a visible light signal transmitting device, a visible light signal receiving device, and a demodulation signal device, and the modulation signal device is configured to encode an input original signal. Modulating, modulating into a modulated signal that can be recognized by the visible light signal transmitting device, and transmitting the modulated signal to the visible light signal transmitting device; the visible light signal transmitting device is configured to receive the modulated signal, and convert the modulated signal into a visible light signal and then transmit the signal to the visible light signal a receiving device; the visible light signal receiving device is configured to receive a visible light signal, and convert the visible light signal into a modulated signal and then transmit the signal to the demodulated signal device; the demodulated signal device is configured to demodulate and decode the modulated signal to restore the original signal To achieve visible light communication.

As shown in FIG. 2, the modulation signal device includes a host computer, a single chip microcomputer, a CPLD complex programmable logic device, a DAC digital-to-analog converter, a wireless transceiver, and a mixer, and the upper computer is configured to input an original signal. The data is encapsulated and transmitted to the single chip microcomputer, and the single chip outputs the parallel data information and controls the programmable logic device, and encodes and modulates the input original signal to be modulated into a digital baseband signal; the DAC digital-to-analog converter is used to modulate the digitized baseband signal Converted into an analog baseband signal, the wireless transceiver is configured to receive an analog baseband signal, and convert the analog baseband signal into a modulated signal and then downconverted by a mixer to the visible light signal transmitting device. Among them, the CPLD complex programmable logic device encodes and modulates the input signal by using the OQPSK modulation algorithm, and then transmits it to the visible light signal transmitting device.

The data signal input to the visible light communication system through the PC is sequentially transmitted to the visible light signal transmitting device through the upper computer, the single chip microcomputer, the CPLD complex programmable logic device, the DAC digital-to-analog converter, the wireless transceiver and the mixer.

As shown in FIG. 3, the visible light signal transmitting device includes a low-pass filter, an electric amplifier, a biaser, and an LED lamp, which are sequentially connected, and the low-pass filter is configured to receive a modulated signal modulated by the modulated signal device. Filtering out channel noise and other disturbances and extracting low frequency components, the electrical amplifier is used to amplify the electrical signal, and the biasing device is used to combine the DC signal into a signal to reach the threshold voltage of the LED lamp, and the LED lamp is used for The visible light emission is performed, and the visible light signal is transmitted to the visible light signal receiving device.

The modulated signal device modulates the encoded signal and sequentially passes through a low pass filter, an electric amplifier, a bias, and an LED lamp in the visible light signal transmitting device, and then transmits the light to the visible light signal receiving device through the optical channel.

As shown in FIG. 4, the visible light signal receiving device includes a lens, a filter, a photodetector, an electric amplifier and a low-pass filter which are sequentially connected, the lens is used for collecting light to increase signal intensity, and the filter is used for To improve the sensitivity of the photodetector to the signal, the photodetector is used to convert the received visible light signal into an electrical signal for photoelectric conversion, the electrical amplifier is used to amplify the electrical signal and the low pass filter is used to extract low frequency components and filter channel noise. And other interference, and transmit the signal to the demodulation signal device.

The visible light signal emitted by the visible light signal transmitting device is sequentially transmitted to the demodulation signal device through a filter, a filter, a photodetector, an electric amplifier, and a low pass filter in the visible light signal receiving device.

As shown in FIG. 5, the demodulation signal device includes a mixer, a wireless transceiver, an ADC analog-to-digital converter, a CPLD complex programmable logic device, a single chip microcomputer and a host computer, which are sequentially connected, and the mixer is used for transmitting visible light. The modulated signal transmitted by the signal receiving device is up-converted and transmitted to a wireless transceiver, wherein the wireless transceiver is configured to convert the modulated signal into an analog baseband signal, and the ADC analog-to-digital converter is configured to convert the analog baseband signal into a digital baseband signal. The upper computer combines with the single-chip microcomputer to control the CPLD complex programmable logic device, demodulates and decodes the signal, restores the original signal, and realizes visible light communication. The CPLD complex programmable logic device in the demodulation signal device uses the OQPSK modulation algorithm to demodulate and decode the obtained digital baseband signal and restore the original signal.

The demodulation signal device receives the signal transmitted by the visible light signal receiving device, and sequentially converts the electrical signal into a digital baseband signal through a mixer, a wireless transceiver and an ADC analog-to-digital converter, and finally is programmed by the upper computer combined with the single-chip microcomputer to control the CPLD. The logic device demodulates and decodes the digitized baseband signal, restores the original signal, and realizes visible light communication.

Claims

A visible light communication system based on SDR technology, comprising: a modulation signal device, a visible light signal transmitting device, a visible light signal receiving device and a demodulation signal device, wherein the modulation signal device is configured to encode and modulate an input original signal, Modulating a modulated signal that can be recognized by the visible light signal transmitting device, and transmitting the modulated signal to the visible light signal transmitting device; the visible light signal transmitting device is configured to receive the modulated signal, and convert the modulated signal into a visible light signal and then transmit the signal to the visible light signal receiving device The visible light signal receiving device is configured to receive the visible light signal, and convert the visible light signal into a modulated signal and then transmit the signal to the demodulated signal device; the demodulated signal device is configured to demodulate and decode the modulated signal, restore the original signal, and implement Visible light communication.

2 . The visible light communication system based on SDR technology according to claim 1 , wherein the modulation signal device comprises a host computer, a single chip microcomputer, a programmable logic device, a DAC digital-to-analog converter, a wireless transceiver, and a hybrid device. The upper computer is used for data encapsulation of the input original signal, and then transmitted to the single chip microcomputer, the single chip outputs parallel data information and controls the programmable logic device, and encodes and modulates the input original signal to be modulated into a digital baseband signal; The DAC digital-to-analog converter is configured to convert the modulated digital baseband signal into an analog baseband signal, and the wireless transceiver is configured to receive an analog baseband signal, and modulate the analog baseband signal into a modulated signal, and then transmit the frequency by a mixer. A visible light signal emitting device.

3 . The visible light communication system based on SDR technology according to claim 2 , wherein the programmable logic device is a CPLD complex programmable logic device using an OQPSK modulation algorithm, and the input signal is coded and modulated. Then transmitted to the visible light signal transmitting device.

4 . The visible light communication system based on SDR technology according to claim 1 , wherein the visible light signal transmitting device comprises a low-pass filter, an electric amplifier, a biaser and an LED lamp connected in sequence, a low pass filter for receiving a modulated signal modulated by the modulated signal device, filtering out channel noise and other interference and extracting low frequency components, the electrical amplifier for amplifying the electrical signal, the biasing device for combining with the direct current signal Signaling to reach a threshold voltage of the LED lamp for transmitting visible light and transmitting the visible light signal to the visible light signal receiving device.

The visible light communication system based on SDR technology according to claim 1, wherein the visible light signal receiving device comprises a photodetector, an electric amplifier and a low pass filter which are sequentially connected, and the photodetector is used. Converting the received visible light signal into an electrical signal for photoelectric conversion, the electrical amplifier is used to amplify the electrical signal and the low pass filter for taking out low frequency components and filtering out channel noise and other interference, and transmitting the signal to the demodulation signal device .

6 . The visible light communication system based on SDR technology according to claim 5 , wherein the visible light signal receiving device further comprises a lens and a filter disposed before the photodetector, and the visible light signal receiving device The signal is transmitted through the lens and filter in turn to a photodetector that is used to concentrate to increase signal strength, the filter being used to increase the sensitivity of the photodetector to the signal.

7 . The visible light communication system based on SDR technology according to claim 1 , wherein the demodulation signal device comprises a mixer connected in sequence, a wireless transceiver, an ADC analog to digital converter, and programmable logic. a device, a single chip microcomputer and a host computer, wherein the mixer is configured to up-convert the modulated signal transmitted by the visible light signal receiving device to the wireless transceiver, and the wireless transceiver is configured to convert the modulated signal into an analog baseband signal, the ADC mode The digital converter is used to convert the analog baseband signal into a digital baseband signal, and the programmable host device is controlled by the running upper computer to control the programmable logic device, and the received signal is demodulated and decoded, and finally the original signal is recovered to realize visible light communication.

8 . The visible light communication system based on SDR technology according to claim 7 , wherein the programmable logic device is a CPLD complex programmable logic device using an OQPSK modulation algorithm, and the obtained digital baseband signal is solved. The tone is restored to the original signal after decoding.