Protocol conversion method and system for converting power line carrier to visible light communication

Abstract

The invention provides a protocol conversion method and system for converting power line carrier to visible light communication, and relates to the technical field of power line carrier communication and visible light communication. The protocol conversion method comprises the following steps: sampling a power line carrier signal, filtering out a high-frequency carrier, and carrying out fidelity reduction amplification on the high-frequency carrier signal to obtain a first high-frequency filtering signal; demodulating the first high-frequency filtering signal into a digital signal, encoding the digital signal, packaging the code into a frame, and writing an LED driving instruction into a packaged data frame; and controlling and driving an LED instruction to transmit the data frame in a space in a high-frequency flickering visible light signal form, and receiving the visible light signal based on a communication terminal. According to the protocol conversion method provided by the invention, the high-cost application disadvantage of visible light communication wiring is made up, and the application development problem of limited power line carrier communication frequency bands is solved.

Description

Technical Field

[0001] The present invention relates to power line carrier communication technology and visible light communication technology, and in particular to a power line carrier to visible light communication protocol conversion method and system. Background Art

[0002] Power Line Communication (PLC) is an advanced technology that uses existing power lines for data transmission. This technology loads digital information onto the power line through high-frequency signals, and receives and decodes the signal at the receiving end to restore the original digital information. PLC technology has been widely used in power meter reading, intelligent building management, remote monitoring and other fields due to its advantages such as economy, convenience, long transmission distance and stable signal. However, despite the many advantages of PLC technology, the carrier current will radiate electromagnetic waves into space when it is transmitted on the power line, which may interfere with broadcasting, flight, navigation and other navigation services in this frequency band. Therefore, governments of various countries have imposed restrictions on the transmission power, which has limited the further development of PLC technology to a certain extent.

[0003] On the other hand, as an emerging communication method, Visible Light Communication (VLC) technology uses light in the visible light band as an information carrier to directly transmit optical signals in the air. VLC technology does not require wired channels such as optical fibers. The receiving end receives changes in the intensity of optical signals through photodiodes (PDs) and converts the optical signals back into electrical signals. VLC technology has the advantages of high transmission rate, high confidentiality, no electromagnetic interference, and rich spectrum resources. It performs well in high-speed data transmission. However, the widespread application of VLC technology also faces some challenges. Due to the need to lay special visible light communication equipment, which brings about higher costs, VLC technology is currently difficult to use alone on a large scale.

[0004] In view of the advantages and limitations of PLC technology and VLC technology, combining the two has become a feasible solution. PLC technology uses existing power lines as information transmission carriers, eliminating the need to lay additional lines, which can well make up for the cost shortcomings of VLC technology. VLC technology, with its high-speed data transmission characteristics, can improve the performance of the entire communication system. Therefore, a solution is urgently needed to combine visible light communication technology with power line carrier communication technology. Summary of the invention

[0005] The purpose of the present invention is to provide a protocol conversion method and system for power line carrier to visible light communication. Through the protocol conversion of power line carrier communication and visible light communication, the technical advantages of the two are coupled, the high cost application disadvantage of visible light communication wiring is compensated, and the application development problem of limited frequency band of power line carrier communication is solved.

[0006] The present invention provides a method for converting a power line carrier to visible light communication protocol using the following technical solutions:

[0007] Accessing the power line communication system based on the power line interface to sample the power line carrier signal, filtering out the high-frequency carrier based on the filter circuit, and performing fidelity restoration and amplification on the high-frequency carrier signal based on the amplifier circuit to obtain a first high-frequency filtered signal;

[0008] Demodulating the first high-frequency filtered signal into a digital signal based on an analog-to-digital signal converter, encoding the digital signal based on an MCU, encapsulating the code into a frame, performing error control and flow control operations, and writing a driving LED instruction into the encapsulated data frame;

[0009] Based on the MCU control driving LED instruction, the data frame is transmitted in the space in the form of a high-frequency flashing visible light signal, and the visible light signal is received based on the communication terminal.

[0010] Optionally, the power line interface is a twisted pair or cable interface for accessing high-frequency carrier signals; the main components of the filtering circuit are miniature coupling capacitors for filtering out the required high-frequency carrier signals from the power line carrier; the amplification circuit adopts a multi-stage common base amplifier circuit for restoring and amplifying the analog signal processed by the power line carrier conversion module.

[0011] Optionally, the analog-to-digital signal converter adopts a high-speed 12-bit ADC chip, supports differential input, and is used to convert the power line carrier analog signal into a digital signal; the MCU adopts STM32, which is used to encode the converted digital signal, encapsulate it into a frame, and program it into a driving LED instruction.

[0012] Optionally, in the process of encoding the digital signal based on the MCU, the encoding method adopts 4B / 5B encoding, and the array stream of the digital signal is converted into a 5-bit code in groups of 4 bits.

[0013] Optionally, the process of encapsulating the code into frames, error control, and flow control operations includes: encapsulating the code based on the zero-bit filling method to obtain a visible light signal frame, and using Hamming code to perform error detection and correction on the visible light signal frame, and selecting a retransmission protocol to perform data transmission flow control; the visible light signal frame includes a frame header, frame data, and a frame tail, the frame header includes a frame start identification field, an address identification field, and a function field, the frame data includes a data field and a check error correction code field, and the frame tail includes a frame end identification field.

[0014] Optionally, the frame start identification field of the frame header consists of 6 bits, which is specified as 111110, that is, five consecutive high-level signals followed by a low-level signal indicate the start of the frame; the address identification field of the frame header consists of 8 bits, which is the address identification of the communication terminal to be transmitted by the carrier data; the function field of the frame header is composed of 16 residual codes encoded in 4B / 5B, and the corresponding function operation code is specified according to the terminal communication requirements to realize the function of data downloading at the terminal, and the function operation code includes a register read operation code and a register write operation code.

[0015] Optionally, the data field of the frame data is a variable-length byte with a length not exceeding 126 bytes, which is the encoded high and low level digital signal data; the check and error correction code field of the frame data is determined by the Hamming code encoding rule, and n zeros are added after the data according to the data order n, and the new data is divided modulo 2 to take the remainder, which is the check and error correction code. The check and error correction codes are arranged bit by bit in the second n-th position to facilitate check and error correction according to the Hamming code rule.

[0016] Optionally, the frame end identification field at the end of the frame consists of 6 bits, which is specified as 000001, that is, five consecutive low-level signals followed by a high-level signal indicate the end of the frame.

[0017] Optionally, if the data field of the frame data contains the frame start identification field of the frame header or the frame end identification field of the frame tail, the content of the data field of the frame data is escaped to avoid incorrect recognition or truncation of the frame.

[0018] In a second aspect of the present invention, a power line carrier to visible light communication protocol conversion system is provided, comprising a power line carrier conversion module, a communication protocol conversion processing module, and a high-power LED drive control module, wherein:

[0019] Power line carrier conversion module: configured to access the power line communication system based on the power line interface to sample the power line carrier signal, filter out the high-frequency carrier based on the filter circuit, and restore and amplify the high-frequency carrier signal based on the amplifier circuit to obtain a first high-frequency filtered signal;

[0020] A communication protocol conversion processing module: configured to demodulate the first high-frequency filtered signal into a digital signal based on an analog-to-digital signal converter, encode the digital signal based on an MCU, encapsulate the code into a frame, perform error control and flow control operations, and write the LED driving instruction into the encapsulated data frame;

[0021] High-power LED drive control module: configured to transmit the data frame in the form of a high-frequency flashing visible light signal in space based on the MCU control driving LED instruction, and receive the visible light signal based on the communication terminal.

[0022] The present invention provides a power line carrier to visible light communication protocol conversion method and system, the beneficial effects are:

[0023] 1. The present invention couples the technical advantages of power line carrier communication and visible light communication through protocol conversion, making up for the high cost application disadvantage of visible light communication wiring and solving the application development problem of limited frequency band of power line carrier communication;

[0024] 2. The present invention realizes rapid conversion and collaboration between power line carrier communication and visible light communication, combines the advantages of power line carrier without repeated wiring and visible light energy without electromagnetic pollution, interference and fast transmission rate, and realizes green communication and high-speed communication at a lower cost;

[0025] 3. The present invention makes the data transmission process have a certain robustness through the design of the protocol data frame, further exerting the high security of visible light communication. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a flowchart of the protocol conversion method;

[0027] Figure 2 Schematic diagram of visible light signal frame format;

[0028] Figure 3 An example diagram of a scenario for implementing the protocol conversion method;

[0029] Figure 4 Schematic diagram of a scene communication protocol conversion device. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Unless otherwise defined, the technical terms or scientific terms used herein should be understood by people with general skills in the field to which the present invention belongs. "Including" and similar words used in this article mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects.

[0031] The embodiment of the present invention provides a protocol conversion method for power line carrier to visible light communication, see Figure 1 ,include:

[0032] S1, accessing the power line communication system based on the power line interface to sample the power line carrier signal, filtering out the high-frequency carrier based on the filtering circuit, and performing fidelity restoration and amplification on the high-frequency carrier signal based on the amplification circuit to obtain a first high-frequency filtered signal;

[0033] S2, demodulating the first high-frequency filtered signal into a digital signal based on an analog-to-digital signal converter, encoding the digital signal based on an MCU, encapsulating the code into a frame, performing error control and flow control operations, and writing the LED driving instruction into the encapsulated data frame;

[0034] S3, based on the MCU control driving LED instruction, the data frame is transmitted in the space in the form of a high-frequency flashing visible light signal, and the visible light signal is received based on the communication terminal.

[0035] In some embodiments, the process of executing step S1 includes:

[0036] S1.1, high frequency carrier filter reception;

[0037] S1.2, signal restoration and amplification.

[0038] Specifically, when executing step S1.1, high-frequency carrier filtering and receiving, the power line communication system is accessed based on the power line interface to receive signals, the power line carrier signal is sampled, and the high-frequency carrier is filtered out through the filtering circuit.

[0039] Furthermore, the power line interface is a twisted pair or cable interface for accessing a high-frequency carrier signal; the main components of the filter circuit are micro-coupling capacitors for filtering out the required high-frequency carrier signal from the power line carrier.

[0040] Specifically, when executing step S1.2, signal restoration and amplification, the high-frequency carrier signal is restored and amplified based on the amplifier circuit to obtain a first high-frequency filtered signal, and then the first high-frequency filtered signal is transmitted to the analog-to-digital signal converter.

[0041] Furthermore, the amplifier circuit adopts a multi-stage common base amplifier circuit for restoring and amplifying the analog signal processed by the power line carrier conversion module.

[0042] In some embodiments, the process of executing step S2 includes:

[0043] S2.1. Demodulating the first high-frequency filtered signal into a digital signal based on an analog-to-digital signal converter;

[0044] S2.2, encoding digital signals based on MCU;

[0045] S2.3, encapsulating the code;

[0046] S2.4, write the LED driving instruction into the encapsulated data frame.

[0047] Specifically, when executing S2.1, the first high-frequency filtered signal is demodulated into a digital signal based on an analog-to-digital signal converter, and the analog-to-digital signal converter adopts a high-speed 12-bit ADC chip, supports differential input, and is used to convert the power line carrier analog signal into a digital signal.

[0048] Specifically, in executing step S2.2, when encoding the digital signal based on the MCU, the encoding method adopts 4B / 5B encoding, and the array stream of the digital signal is converted into 5-bit code in groups of 4 bits. The MCU adopts STM32 to encode the converted digital signal, encapsulate it into a frame for processing, and compile it into driving LED instructions.

[0049] Specifically, when executing step S2.3, encapsulating the code, see Figure 2 , encapsulating the code based on a zero-bit filling method to obtain a visible light signal frame, using a Hamming code to perform error detection and correction on the visible light signal frame, and selecting a retransmission protocol to perform flow control of data transmission.

[0050] Furthermore, the visible light signal frame includes a frame header, frame data, and a frame trailer. The frame header includes a frame start identification field, an address identification field, and a function field. The frame data includes a data field and a checksum error correction code field. The frame trailer includes a frame end identification field.

[0051] Furthermore, the frame start identification field of the frame header is composed of 6 bits, which is specified as 111110, that is, five consecutive high-level signals followed by a low-level signal indicate the start of the frame; the address identification field of the frame header is composed of 8 bits, which is the address identification of the communication terminal to be transmitted by the carrier data; the function field of the frame header is composed of 16 residual codes encoded in 4B / 5B, and the corresponding function operation code is specified according to the terminal communication requirements to realize the function of data downloading at the terminal, and the function operation code includes register reading and register writing.

[0052] Furthermore, the data field of the frame data is a variable-length byte with a length not exceeding 126 bytes, which is the encoded high and low level digital signal data; the check and error correction code field of the frame data is determined by the Hamming code encoding rule, and n zeros are added after the data according to the data order n, and the new data is divided modulo 2 to obtain the remainder, which is the check and error correction code. The check and error correction code is arranged bit by bit in the 1st, 2nd, 4th, 8th... and other 2nd nth positions, which is convenient for checking and correcting errors according to the Hamming code rule.

[0053] Furthermore, the frame end identification field at the end of the frame consists of 6 bits, which is specified as 000001, that is, five consecutive low-level signals followed by a high-level signal indicate the end of the frame.

[0054] In fact, if the data field of the frame data contains the frame start identification field of the frame header or the frame end identification field of the frame tail, the content of the data field of the frame data is escaped to avoid incorrect recognition or truncation of the frame.

[0055] Specifically, when executing step S2.4 and writing the LED driving instruction into the encapsulated data frame, the MCU will control the LED driving instruction and output a high-frequency flashing visible light signal frame as a downlink data transmission form to transmit the data to the communication terminal.

[0056] In some embodiments, the process of executing step S3 includes: modulating the data frame to the high-power LED transmitter based on the MCU control driving LED instruction, transmitting it in space in the form of a high-frequency flashing visible light signal through the LED, and receiving the visible light signal based on the communication terminal.

[0057] The embodiment of the present invention further provides a power line carrier to visible light communication protocol conversion system, including a power line carrier conversion module, a communication protocol conversion processing module, and a high-power LED drive control module, wherein:

[0058] Power line carrier conversion module: configured to access the power line communication system based on the power line interface to sample the power line carrier signal, filter out the high-frequency carrier based on the filter circuit, and restore and amplify the high-frequency carrier signal based on the amplifier circuit to obtain a first high-frequency filtered signal;

[0059] A communication protocol conversion processing module: configured to demodulate the first high-frequency filtered signal into a digital signal based on an analog-to-digital signal converter, encode the digital signal based on an MCU, encapsulate the code into a frame, perform error control and flow control operations, and write the LED driving instruction into the encapsulated data frame;

[0060] High-power LED drive control module: configured to transmit the data frame in the form of a high-frequency flashing visible light signal in space based on the MCU control driving LED instruction, and receive the visible light signal based on the communication terminal.

[0061] Figure 3 One of the specific implementation scenarios listed for the present invention that can be used includes but is not limited to the downlink signal transmission process of smart street lights through power line carrier communication and visible light communication. When communication terminal 1 or communication terminal 2 contacts the server through uplink communication; the following example shows that communication terminal 1 contacts the server, such as requesting to download data. The server modulates the address identifier, download operation function identifier, data field requested to be transmitted, and other signals of the communication terminal 1 into a high-frequency carrier, and then loads them into the power line to perform power line carrier communication transmission through underground cables. When the communication conversion device receives the high-frequency carrier signal, see Figure 4 The signal is sampled through the power line interface 1.1, and the high-frequency signal is filtered out through the filter circuit 1.2. Then, it is amplified by the amplifier circuit 1.3 at multiple levels of fidelity, and demodulated into a digital signal by the ADC chip 2.1. The MCU 2.2 encodes the digital signal in 4B / 5B, and then Figure 2 The frame format shown encapsulates the signal into a data frame. During the framing process, the check error correction code is encoded into the data field according to the Hamming code rule. After the framing operation is completed, the MCU controls the LED to transmit the data frame as a high-frequency flashing visible light signal, and the optical signal frame 1 can be transmitted to the communication terminal 1 to complete the communication requirements.

[0062] Although the embodiments of the present invention are described in detail above, it is obvious to those skilled in the art that various modifications and variations can be made to these embodiments. However, it should be understood that such modifications and variations are within the scope and spirit of the present invention as described in the claims. Moreover, the present invention described herein may have other embodiments and may be implemented or realized in a variety of ways.

Claims

1. A protocol conversion method for power line carrier to visible light communication, characterized in that: The following steps are involved: Accessing the power line communication system based on the power line interface to sample the power line carrier signal, filtering out the high-frequency carrier based on the filter circuit, and performing fidelity restoration and amplification on the high-frequency carrier signal based on the amplifier circuit to obtain a first high-frequency filtered signal; Demodulating the first high-frequency filtered signal into a digital signal based on an analog-to-digital signal converter, encoding the digital signal based on an MCU, encapsulating the code into a frame, performing error control and flow control operations, and writing a driving LED instruction into the encapsulated data frame; Based on the MCU control driving LED instruction, the data frame is transmitted in the space in the form of a high-frequency flashing visible light signal, and the visible light signal is received based on the communication terminal.

2. The method for converting a power line carrier to visible light communication protocol according to claim 1, characterized in that: The power line interface is a twisted pair or cable interface for accessing high-frequency carrier signals; the main components of the filtering circuit are micro-coupling capacitors for filtering out the required high-frequency carrier signals from the power line carrier; the amplifier circuit adopts a multi-stage common base amplifier circuit for restoring and amplifying the analog signal processed by the power line carrier conversion module.

3. The method for converting a power line carrier to visible light communication protocol according to claim 1, characterized in that: The analog-to-digital signal converter adopts a high-speed 12-bit ADC chip, supports differential input, and is used to convert the power line carrier analog signal into a digital signal; the MCU adopts STM32, which is used to encode the converted digital signal, encapsulate it into a frame, and compile it into a driving LED instruction.

4. The method for converting a power line carrier to visible light communication protocol according to claim 1, characterized in that: In the process of encoding digital signals based on MCU, 4B / 5B encoding is used to convert the array stream of digital signals into 5-bit codes in groups of 4 bits.

5. The method for converting a power line carrier to visible light communication protocol according to claim 1, characterized in that: The process of encapsulating the code into frames, performing error control, and performing flow control operations includes: Encapsulating the code based on a zero-bit filling method to obtain a visible light signal frame, performing error detection and correction on the visible light signal frame using a Hamming code, and selecting a retransmission protocol to perform flow control of data transmission; The visible light signal frame includes a frame header, frame data, and a frame tail. The frame header includes a frame start identification field, an address identification field, and a function field. The frame data includes a data field and a check error correction code field. The frame tail includes a frame end identification field.

6. The method for converting a power line carrier to visible light communication protocol according to claim 5, characterized in that: The frame start identification field of the frame header consists of 6 bits, which is specified as 111110, that is, five consecutive high-level signals followed by a low-level signal indicate the start of the frame; The address identification field of the frame header consists of 8 bits, which is the address identification of the communication terminal to which the data is to be transmitted; The function field of the frame header is played by 16 remaining codes encoded by 4B / 5B. The corresponding function operation code is specified according to the terminal communication requirements to realize the function of data download at the terminal. The function operation code includes register read operation code and register write operation code.

7. The method for converting a power line carrier to visible light communication protocol according to claim 5, characterized in that: The data field of the frame data is a variable length byte, the length does not exceed 126 bytes, and is the encoded high and low level digital signal data; The check and error correction code field of the frame data is determined by the Hamming code encoding rule. According to the data order n, n zeros are added after the data, and the new data is divided modulo 2 to take the remainder. The remainder is the check and error correction code. The check and error correction code is arranged bit by bit in the second n-th position to facilitate the check and error correction according to the Hamming code rule.

8. The method for converting a power line carrier to visible light communication protocol according to claim 5, characterized in that: The frame end identification field at the end of the frame consists of 6 bits, which is specified as 000001, that is, five consecutive low-level signals followed by a high-level signal indicate the end of the frame.

9. The method for converting a power line carrier to visible light communication protocol according to claim 5, characterized in that: If the data field of the frame data contains the frame start identification field of the frame header or the frame end identification field of the frame tail, the content of the data field of the frame data is escaped to avoid incorrect recognition or truncation of the frame.

10. A protocol conversion system for power line carrier to visible light communication, characterized in that: It includes a power line carrier conversion module, a communication protocol conversion processing module, and a high-power LED drive control module, among which: Power line carrier conversion module: configured to access the power line communication system based on the power line interface to sample the power line carrier signal, filter out the high-frequency carrier based on the filter circuit, and restore and amplify the high-frequency carrier signal based on the amplifier circuit to obtain a first high-frequency filtered signal; A communication protocol conversion processing module: configured to demodulate the first high-frequency filtered signal into a digital signal based on an analog-to-digital signal converter, encode the digital signal based on an MCU, encapsulate the code into a frame, perform error control and flow control operations, and write the LED driving instruction into the encapsulated data frame; High-power LED drive control module: configured to transmit the data frame in the form of a high-frequency flashing visible light signal in space based on the MCU control driving LED instruction, and receive the visible light signal based on the communication terminal.

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