A vehicle networking system based on optical communication sensing integration and implementation method

Abstract

The vehicle networking system based on optical intersensory integration adopted by the present invention to solve its technical problems is composed of a transmitter and a receiver. The transmitter is composed of an information encoding module, a balanced encoding module, a modulation module and an LED transmitter; the receiver is composed of a photoelectric receiver, a front AC coupling conditioning circuit, an analog-to-digital converter, and a digital signal processing unit. The information encoding module encodes information; the balanced encoding module makes data transmission flicker-free; the modulation module converts the data symbol to be sent into a modulation signal; the LED transmitter receives the modulation signal and generates modulated light; the photoelectric receiver converts the optical signal into an electrical signal; the front AC coupling conditioning circuit couples the electrical signal output by the photoelectric receiver, and processes the signal to drive the analog-to-digital converter; the analog-to-digital converter converts the analog signal into a digital signal; the digital signal processing unit is used to process the digital signal output by the analog-to-digital converter, and realize environmental perception and data communication at the same time.

Description

Technical Field

[0001] The present invention belongs to the field of vehicle networking, optical communication technology, and intelligent connected vehicles, and in particular relates to a vehicle networking communication coding and decoding algorithm based on a combination of rateless coding and network coding. The system uses the vehicle head / tail lights to build an integrated interaceptive channel to achieve information exchange and status perception of adjacent vehicles. Background Art

[0002] With the increasing number of vehicles, the safe, stable and efficient operation of vehicles has become a pressing issue in the road transportation system. Therefore, many countries and institutions are actively supporting the development of Intelligent Transportation Systems (ITS) to improve road safety and increase traffic capacity. Platooning is an application of ITS systems that can enable vehicles to travel closely and coordinately while maintaining a certain distance through a platoon of vehicles. By measuring the distance to the vehicle in front in real time and exchanging information with neighboring vehicles through vehicle-to-vehicle communication, the platoon can detect potential dangerous situations early and avoid collisions. At present, most vehicle-to-vehicle communication network systems usually rely on radio communication technologies, such as dedicated short-range communication (DSRC) and cellular vehicle-to-everything (C-V2X). However, in the case of dense vehicles, radio communications interfere with each other seriously and cannot meet the strict Quality-of-Service-QoS requirements in vehicle-to-vehicle communication.

[0003] Therefore, a new wireless communication technology is urgently needed to meet the needs of vehicle-to-vehicle communication. In recent years, optical wireless communication ( OWC ) using infrared light (IR), visible light (VL) or ultraviolet light (UV) as communication media has received widespread attention. Its application in the field of Internet of Vehicles has many advantages, such as the reuse of car headlights and taillights as optical communication transmitters to reduce system deployment costs, and the strong directionality of optical wireless communication suitable for dense networking, which has attracted a lot of research. A large number of experimental results have also shown that in high-density scenarios, optical wireless communication has better performance and higher reliability than traditional radio communication. However, the existing Internet of Vehicles based on optical wireless communication is only used to realize vehicle-to-vehicle communication functions, ignoring the vehicle's demand for perception functions, and is far from meeting the requirements of vehicle formation operation in real scenarios.

[0004] Therefore, the present invention aims to utilize the integrated optical wireless communication and sensing technology and the optical transceiver equipment such as the headlights / taillights on the vehicle to build an integrated communication and perception channel between neighboring vehicles, so as to achieve efficient communication and real-time environmental perception between vehicle formations. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide an integrated light-based wireless communication perception technology, which utilizes the lights on vehicles to build communication perception channels between adjacent vehicles, thereby achieving low-latency and highly reliable information exchange and status perception between adjacent vehicles.

[0006] The vehicle networking system based on optical tele-sensing integration adopted by the present invention to solve its technical problems consists of two parts: a transmitter and a receiver. The transmitter is mainly composed of an information encoding module, a DC balanced encoding module, a modulation module and an LED transmitter; the receiver is mainly composed of a photoelectric receiver, a front AC coupling conditioning circuit, an analog-to-digital converter, and a digital signal processing unit. The information encoding module is used to encode the transmitted information and generate data packets to be sent to combat possible data packet loss during the transmission process. Generally, a coding method combining rateless coding and network coding is adopted; the balanced coding module is used to encode the data packets to be sent to ensure that no flicker is generated during data transmission; the modulation module performs data symbol mapping on the encoded data packets and converts the data symbols to be sent into modulation signals; the LED transmitter receives the modulation signal and generates modulated light to realize the conversion of digital signals and optical signals and information transmission. The photoelectric receiver is used to receive optical signals in free space and convert them into electrical signals, which are generally photodiodes or phototransistors and their arrays; the front AC coupling conditioning circuit is used to couple the electrical signals output by the photoelectric receiver, and amplify, filter and other conditioning on the signals to drive the subsequent analog-to-digital converter; the analog-to-digital converter converts the analog signal into a digital signal; the digital signal processing unit is used to process the digital signal output by the analog-to-digital converter, and process the signal to extract information such as the signal strength and phase for sensing the environmental status of the vehicle and communication demodulation and decoding, restore the transmitted information, and realize environmental perception and data communication at the same time.

[0007] Furthermore, the headlights and taillights of the vehicle lights are light-weighted and have the function of transmitting and receiving optical signals, thereby enabling full-duplex communication and status perception;

[0008] Furthermore, the headlight and taillight of the vehicle lamp use light of different frequencies as the synaesthesia medium, the headlight uses white light, and the taillight uses infrared light or red light;

[0009] Furthermore, the information coding module adopts a combination of rateless coding and network coding, preferably a combination of Raptor coding and network coding;

[0010] Furthermore, LT encoding is adopted, through XOR encoding, that is, the original data is split into the original data and the XOR data pair;

[0011] Furthermore, the photoelectric receiver is a single or multiple photosensors and arrays thereof;

[0012] Furthermore, the front AC coupling conditioning circuit adopts AC coupling to connect the photoelectric receiver and the amplification or filtering circuit;

[0013] Furthermore, the analog-to-digital conversion module is preferably an analog-to-digital converter built into the microprocessor, or a high-speed analog-to-digital converter;

[0014] Furthermore, the digital signal processing unit is a microcontroller (MCU) or a digital signal processor (DSP) or a field programmable array (FPGA) or an application-specific digital signal processing chip (ASIC);

[0015] Furthermore, the transmitting end and the receiving end may be independent or may be coordinated in multiple ways.

[0016] The present invention solves the technical problem by using a vehicle networking system based on optical communication sensing integration and an implementation method, which comprises the following steps:

[0017] A. The information to be sent first passes through the information encoding module, and the original data is divided into data packets with identifiable codes; the data packets are then balanced encoded, and the data inside the data packets are decomposed into several data tuples according to the modulation order to be adopted. Each data tuple is encoded in an XOR encoding manner, and the original data tuple is encoded into a pairing form of the original data tuple and its XOR code;

[0018] B. The modulation module performs data symbol mapping on the encoded data and generates a corresponding modulation signal, which directly drives the transmitter to emit modulated light;

[0019] C. The photoelectric receiver in the receiving end receives the optical signal in the free space and outputs the electrical signal. The subsequent front-end AC coupling conditioning circuit amplifies and filters the signal. The analog-to-digital conversion module converts the analog electrical signal into a digital signal that can be recognized by the digital signal processing unit.

[0020] D. The digital signal processing unit first performs digital filtering on the digital signal to remove noise and extract information such as signal strength and phase. The digital signal processing unit obtains the state of the current communication channel by processing the signal strength or phase information, thereby inferring the distance to the adjacent vehicles, whether there is any queue cut-in and other vehicle operating environment states, and issues an alarm or other prompts according to the pre-set threshold;

[0021] E. The digital signal processing unit processes the extracted signal strength, phase and other information in combination with the timing relationship to demodulate the received digital signal sequence to obtain a data symbol stream, and uses the balanced coding characteristics to verify the data symbol stream; the verified data symbols are further converted into binary data to obtain the original data packet; after receiving enough data packets, the transmitted information is restored according to the decoding method corresponding to the forward coding.

[0022] The beneficial effects of the present invention are to provide a low-cost integrated telepathy solution for future Internet of Vehicles and intelligent networked vehicles with strong practicality, high data transmission rate and high reliability, specifically: (1) By combining rateless coding with network coding, the data relay and forwarding efficiency when a vehicle formation is cut in line can be effectively improved, the communication capacity of the entire vehicle-to-vehicle network system can be improved, and the transmission delay can be reduced; (2) The headlights and taillights use light of different frequencies as telepathy media to eliminate mutual interference and enhance the reliability of communication; (3) Due to the use of DC balanced coding and decoding, the impact of data communication on the lighting function can be suppressed, and the characteristics of DC balanced coding can be used to realize the verification of received data, which can reduce the bit error rate and improve the reliability of communication; (4) Due to the full use of the principle of optical telepathy integration, communication and perception are integrated, the deployment of hardware facilities is reduced, and costs are saved. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a structural block diagram of an embodiment of the present invention;

[0024] Figure 2 A coding schematic diagram according to an embodiment of the present invention;

[0025] Figure 3 A schematic diagram of a data packet transmission process according to an embodiment of the present invention;

[0026] Figure 4 This is a schematic diagram of a state perception algorithm involved in the present invention. DETAILED DESCRIPTION

[0027] The present invention is further described below in conjunction with the accompanying drawings. It should be noted that the description of these embodiments is only used to further illustrate the present invention and does not constitute a limitation of the present invention.

[0028] like Figures 1 to 4As shown, the vehicle network intersensory integration system based on optical communication of the present invention includes two parts: a transmitter 1 and a receiver 2. The transmitter includes an information encoding module 10, a balanced encoding module 11, a modulation module 12 and an LED transmitter 13; the receiver 2 includes a photoelectric receiver 20, a front AC coupling conditioning circuit 21, an analog-to-digital converter 22, and a digital signal processing unit 23; the information encoding module 10 is used to encode the information to be transmitted; the balanced encoding module 11 ensures that no flicker is generated during data transmission; the modulation module 12 performs data symbol mapping on the encoded data packet and converts the data symbol to be transmitted into a modulation signal; the LED transmitter 13 receives the modulation signal to generate modulated light, realizing the conversion of digital signals and optical signals and information transmission. The receiving end 2 receives the optical signal in the free space by using the photodiode through the photoelectric receiver 20 and converts the optical signal into an electrical signal; the front AC coupling conditioning circuit 21 adopts AC coupling to couple the electrical signal output by the photoelectric receiver 20, and amplifies, filters and other conditioning on the signal to drive the subsequent analog-to-digital converter 22; the digital signal processing unit 23 is used to process the digital signal output by the analog-to-digital converter, and processes the signal to extract the signal strength, phase and other information for sensing the environmental state of the vehicle and communication demodulation and decoding, restore the transmitted information, and realize environmental perception 231 and data communication 232 at the same time; Figure 2 The coding method that can be used in the embodiment of the present invention is demonstrated, including four parts: rateless coding 100, LT coding 101, network coding 102 and Manchester coding 103. The information coding module 10 is used to encode the information to be sent and generate a data packet 104 to be sent to combat possible data packet loss during transmission. Generally, a rateless coding method 100 such as Raptor coding can be used. LT coding 101 encodes the data packet to be sent by means of XOR coding, splitting the original data into the original data and its XOR data pair; network coding 102 can realize the information forwarding of adjacent vehicles when a vehicle cuts in line; Manchester coding 103 provides clock synchronization to enhance the anti-interference ability of the signal; Figure 3The data packet transmission process in the embodiment of the present invention is shown. The information encoding module 11 of the transmitting end 1 of the present invention transmits data packet slices. Redundant data packets 1041 are generated during the transmission of data packets 1040. After receiving data packets 1040 and 1041, the receiving end integrates the information. When the cache 1042 is greater than the threshold, the transmitting end transmits ACK data packet 1043 for feedback. When packet loss occurs and the cache 1042 is less than the threshold, the transmitting end 1 will not receive the ACK data packet 1043 feedback. If the feedback times out, the redundant data packet 1041 will continue to be sent. This process assumes that IP1-2 is lost 10400 and IP2-3 is lost 10410, and the amount of data in the cache 1042 is greater than the threshold, then the receiving end 2 will perform decoding. At the receiving end 2, if all data symbols meet the verification rules, data demodulation and decoding are completed to output a complete data packet, stop this data detection, and complete data communication. It can be seen from the above steps that the present invention adopts balanced coding 11 during encoding to ensure the stability of the output power of the transmitting end 1 and prevent the light from flickering due to data transmission; and when demodulating and decoding at the receiving end 2, the characteristics of the balanced code (i.e., the pairing of the original data symbol and the XOR symbol) are used again to improve the accuracy of the data packet, thereby improving the reliability of data transmission.

[0029] The principle adopted by the state detection algorithm of the present invention is as follows:

[0030] Light sensing principle: In non-line-of-sight optical wireless links, we usually assume that the radiation intensity of the LED follows the Lambertian radiation pattern. The received optical power can be described as:

[0031] , (1)

[0032] Where Pr and Pt represent the receiver power and transmitter power respectively. H(d) represents the channel DC increment related to the distance d between the transmitter and the receiver. Gr represents the receiver increment, which can be calibrated once. The expression of H(d) is as follows:

[0033] , (2)

[0034] Where A is the physical area of ​​the detector in the PD, g(Φ) is the gain of the optical concentrator, and is constant if the incident angle is within the field of view of the detector. θ and Φ are the incident and irradiation angles, respectively. m is the Lambertian radiation index of the LED and is (half-power angle of LED). According to the physical meaning of the parameters, A, g(Φ) and m are constants in the same set of hardware. Therefore, we can simplify equation (2) to the following equation when using the same hardware:

[0035] , (3)

[0036] Where C is a constant determined by hardware and can be tested experimentally. Finally, we use equation (3) as the basic model for sensing distance. This model accurately describes the relationship between distance and received signal strength indicator. Therefore, the receiver can use the received energy to calculate the distance by fitting the function. By simply monitoring the intensity changes of the light signal received from the head / tail light array, a fast risk detection algorithm is designed to achieve early detection and collision avoidance of potential risk situations.

[0037] Specifically, if Figure 4 As shown, the proposed algorithm uses the change of optical signal 3 to detect three key states in extreme cases by using only symmetric channels. A) Emergency braking 300: optical link distance shortened 30; B) Turning 320: bidirectional link broken 32; C) Queue cutting 310: unidirectional link broken 31. Algorithm description: The safety distance is equal to the distance generated by the reaction time plus the braking distance. The reaction distance and braking distance data are provided by the manufacturer. 1) When the left distance or the right distance is less than the safety distance, the vehicle brakes urgently; 2) When the detected left and right distance difference is close to infinity, the convoy is cut in; 3) When the left and right distances are less than the safety distance, the vehicle turns.

[0038] The present invention adopts full-duplex communication, and through the multi-channel advantage of the head / tail light array and the PD array, two-way communication between adjacent vehicles can be achieved, and the state change of the adjacent vehicles can be quickly detected.

[0039] Finally, it should be noted that: Obviously, the above embodiments are only examples for clearly explaining the present invention, and are not intended to limit the implementation methods. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from this are still within the scope of protection of the present invention.

Claims

1. A vehicle networking system based on optical communication integration, characterized in that: It comprises a transmitting end (1) and a receiving end (2); the transmitting end (1) comprises an information encoding module (10), a balanced encoding module (11), a modulation module (12) and an LED transmitting end (13); The receiving end (2) comprises a photoelectric receiver (20), a front AC coupling conditioning circuit (21), an analog-to-digital converter (22), and a digital signal processing unit (23); The transmitting end (1) is used to encode and transmit information. The information to be transmitted is encoded by an information encoding module (10). The encoding method includes four parts: rateless encoding (100), LT encoding (101), network encoding (102) and Manchester encoding (103). Among them, a coding method combining rateless encoding (100) and network encoding (102) is used to generate a data packet to be transmitted to combat data packet loss that may exist during the transmission process. The LT encoding (101) adopts an exclusive OR encoding method, that is, the original data is split into the original data and the data pair after exclusive OR. The network coding (102) can realize the information forwarding of adjacent vehicles when a vehicle cuts in line. The Manchester encoding (103) provides clock synchronization to enhance the anti-interference ability of the signal. The balanced encoding module (11) is used to encode the data packet to be sent to ensure that no flicker is generated during data transmission; The modulation module (12) performs data symbol mapping on the encoded data packet and converts the data symbol to be sent into a modulation signal; The LED transmitting end (13) receives the modulated signal and generates modulated light, thereby realizing the conversion of digital signals and optical signals and information transmission; The receiving end (2) is used to receive modulated light with information in free space, and uses a photodiode to receive the optical signal in free space through a photoelectric receiver (20) and convert the optical signal into an electrical signal; The front AC coupling conditioning circuit (21) uses AC coupling to couple the electrical signal output by the photoelectric receiver (20), and amplifies, filters and conditions the signal to drive the subsequent analog-to-digital converter (22); The digital signal processing unit (23) is used to process the digital signal output by the analog-to-digital converter (22), and to process the signal, extract the signal strength and phase information for sensing the environmental state of the vehicle and communication demodulation and decoding, restore the transmitted information, and simultaneously realize environmental perception and data communication.

2. The vehicle networking system based on optical communication integration according to claim 1 is characterized by: The headlights and taillights of the vehicle have been transformed into lightweight ones and have the function of sending and receiving optical signals, enabling full-duplex communication and status perception.

3. The vehicle networking system based on optical communication integration according to claim 1 is characterized by: The headlights and taillights of a car use light of different frequencies as synaesthesia media, the headlights use white light and the taillights use infrared light or red light.

4. The vehicle networking system based on optical communication integration according to claim 1 is characterized by: In the information coding module (10), a combination of Raptor coding (100) and network coding (102) is adopted.

5. The vehicle networking system based on optical communication integration according to claim 1 is characterized by: The front AC coupling conditioning circuit (21) adopts an AC coupling method to connect the photoelectric receiver and the amplification or filtering circuit.

6. The vehicle networking system based on optical communication integration according to claim 1 is characterized by: The digital signal processing unit is a microcontroller (MCU) or a digital signal processor (DSP) or a field programmable array (FPGA) or an application-specific digital signal processing chip (ASIC).

7. The vehicle networking system based on optical communication integration according to claim 1 is characterized by: The digital signal processing unit (23) designs a state monitoring algorithm using the light sensing principle.

8. The vehicle networking system based on optical communication integration according to claim 1 is characterized by: The transmitting end (1) can be a single transmitting end or multiple transmitting ends can be coordinated.

9. A method for implementing a vehicle networking system based on optical communication sensing integration, applied to the vehicle networking system according to any one of claims 1 to 8, characterized in that: The following steps are involved: A. The information to be sent first passes through the information encoding module (10), and the original data is divided into data packets with identifiable codes; the data packets are then balanced encoded, and the data inside the data packets are decomposed into a number of data tuples according to the modulation order to be adopted, and each data tuple is encoded in an XOR encoding manner, and the original data tuple is encoded into a pairing form of the original data tuple and its XOR code; The encoding method of the information encoding module (10) includes four parts: rateless encoding 100, LT encoding 101, network encoding 102 and Manchester encoding 103; Encoding the information to be sent by combining rateless coding (100) with network coding (102) and generating data packets to be sent to combat possible data packet loss during transmission; LT encoding (101) encodes the data packet to be sent by means of XOR encoding, and splits the original data into the original data and the XOR data pair; Through network coding (102), information forwarding between adjacent vehicles can be achieved when a vehicle cuts in line; Manchester encoding (103) provides clock synchronization and enhances the signal's anti-interference capability; B. The modulation module (12) performs data symbol mapping on the encoded data and generates a corresponding modulation signal to directly drive the LED (13) to emit modulated light; C. The photoelectric receiver (20) at the receiving end receives the optical signal in the free space and outputs an electrical signal, the subsequent front-end AC coupling conditioning circuit (21) amplifies and filters the signal, and the analog-to-digital conversion module (22) converts the analog electrical signal into a digital signal that can be recognized by the digital signal processing unit (23); D. The digital signal processing unit (23) first performs digital filtering on the digital signal to filter out noise and extract the strength and phase of the signal. On the one hand, the digital signal processing unit (23) obtains the state of the current communication channel by processing the signal strength or phase information, thereby inferring the distance of the adjacent vehicle and the operating environment state of the vehicle being cut in line, and issues an alarm according to a preset threshold value; E. The digital signal processing unit (23) demodulates the received digital signal sequence by processing the extracted signal strength, phase and timing relationship to obtain a data symbol stream, and verifies the data symbol stream using the balanced coding characteristic; the verified data symbols are further converted into binary data to obtain the original data packet; after receiving enough data packets, the transmitted information is restored according to the decoding method corresponding to the forward coding.

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