Vehicle-mounted Ethernet millimeter wave full duplex wireless communication device for rail transit

Abstract

The invention belongs to the technical field of communication, and particularly relates to a rail transit-oriented vehicle-mounted Ethernet millimeter wave full duplex wireless communication device, which comprises a first device, a second device, a third device and a fourth device, the first device, the second device, the third device and the fourth device are all configured to realize full-duplex wireless transmission of Ethernet-millimeter wave-Ethernet, and the antenna polarization directions of the first device and the second device are the same, so that a first wireless link for full-duplex communication is formed; the antenna polarization directions of the third device and the fourth device are the same, and a second wireless link for full-duplex communication is formed; the polarization directions of millimeter wave signals transmitted by the first wireless link and the second wireless link are mutually orthogonal and isolated so as to realize redundant transmission or expand communication capacity. According to the invention, the marshalling and maintenance work of the train can be simplified, higher data transmission rate and lower delay are provided, and the real-time requirement of the high-speed train is met.

Description

Technical Field

[0001] The present invention relates to the field of communication technology, and in particular to an on-vehicle Ethernet millimeter wave full-duplex wireless communication device for rail transit. Background Art

[0002] With the continuous development of intelligent train driving technology, the amount of data required to be transmitted has increased significantly, including train control systems, monitoring systems, and passenger service systems. Millimeter wave technology has the characteristics of high bandwidth and low latency, which can provide high-speed data transmission capabilities for intelligent train driving and meet its needs for large data transmission.

[0003] During the operation of the train, it will inevitably be subject to various electromagnetic interferences. Millimeter wave technology has strong anti-interference capabilities due to its narrow beam and good directivity. Even in a complex electromagnetic environment, it can ensure stable communication. The intelligent driving system requires real-time response to various emergencies. The low latency characteristics of millimeter wave communication can ensure the real-time transmission of information, which is crucial for the safe operation of the train. Train intelligent driving involves the interconnection between many on-board devices and systems. Millimeter wave technology can provide high-speed wireless connections between on-board devices, which strongly supports the construction of on-board networks and the effective operation of intelligent driving functions. In addition, millimeter wave technology also has strong penetration capabilities, and can maintain the stability of communication even in severe weather conditions, which is very important for ensuring the safe operation of trains in various environments.

[0004] With the development of intelligent railways, millimeter wave technology will play a key role in automatic train driving, train safety video monitoring, train status monitoring and remote fault diagnosis. It has become the information carrier platform of the railway Internet of Things and the basis for the safety of high-speed railway operation. At present, the communication between the carriages of high-speed trains is mainly connected by wired cables. This connection method can achieve stable transmission of train control signals and the transmission rate is relatively high, but it requires a large number of cables to be laid between the carriages of the train, which will undoubtedly increase the complexity and maintenance difficulty of the system. At the same time, when the train formation changes, it is more difficult to rewire or make corresponding adjustments. Compared with wired transmission, the existing rail transit on-board wireless communication technology still has problems such as large transmission delay, lower communication rate than wired communication, and poor safety and reliability. Summary of the invention

[0005] The purpose of the present invention is to provide an on-board Ethernet millimeter wave full-duplex wireless communication device for rail transit, which solves the complex layout of wired cables between existing train carriages and realizes high-speed, low-latency, high-security, full-duplex millimeter wave communication.

[0006] To achieve the above object, the present invention adopts the following technical solution:

[0007] An on-vehicle Ethernet millimeter wave full-duplex wireless communication device for rail transit, comprising: a first device, a second device, a third device, and a fourth device;

[0008] The first device, the second device, the third device, and the fourth device are all configured to realize full-duplex wireless transmission of Ethernet-millimeter wave-Ethernet, wherein the antenna polarization directions of the first and second devices are the same (horizontal or vertical), constituting a first wireless link of full-duplex communication; the antenna polarization directions of the third and fourth devices are the same (vertical or horizontal), constituting a second wireless link of full-duplex communication; the polarization directions of the first and second devices and the third and fourth devices have two selectable states of vertical and horizontal, but cannot be in the same state at the same time, resulting in the polarization directions of the millimeter wave signals transmitted by the first wireless link and the second wireless link being orthogonal to each other and isolated from each other to realize redundant transmission or expand communication capacity.

[0009] Further, the first device, the second device, the third device and the fourth device all include: an electrical port module, a millimeter wave transmission link and a millimeter wave receiving link;

[0010] The electrical port module receives an externally input Ethernet signal or a baseband signal provided by a millimeter wave receiving link, converts the Ethernet signal into an OOK baseband signal and outputs it to the millimeter wave transmitting link, and restores the baseband signal provided by the millimeter wave receiving link into an Ethernet signal for output;

[0011] The millimeter wave transmission link includes: a first baseband low-pass filter, a millimeter wave local oscillator source, a millimeter wave up-converter, a millimeter wave VGA, a millimeter wave power amplifier, a millimeter wave duplexer and a millimeter wave antenna; the first baseband low-pass filter receives the OOK baseband signal provided by the electrical interface module and transmits it to the millimeter wave up-converter after performing band limiting processing; the millimeter wave local oscillator source is used to provide a millimeter wave sine wave signal for the millimeter up-converter; the millimeter wave up-converter modulates the millimeter wave sine wave signal according to the band-limited OOK baseband signal to obtain a millimeter wave amplitude modulation signal and transmits it to the millimeter wave VGA; after the millimeter wave VGA is cascaded with the millimeter wave power amplifier, the amplitude of the millimeter wave amplitude modulation signal is regulated, and the regulated millimeter wave amplitude modulation signal is filtered by the millimeter wave duplexer and transmitted to the millimeter wave antenna; the millimeter wave antenna radiates the filtered millimeter wave amplitude modulation signal into free space;

[0012] The millimeter wave receiving link includes: a millimeter wave antenna, a millimeter wave duplexer, a millimeter wave low noise amplifier, a directional coupler, a power control device, an envelope detector, and a second baseband low-pass filter; the millimeter wave antenna receives a millimeter wave amplitude modulated signal propagating in free space and transmits it to the millimeter wave duplexer; the millimeter wave duplexer is used to filter the received millimeter wave amplitude modulated signal and transmit the filtered millimeter wave amplitude modulated signal to the millimeter wave low noise amplifier; the millimeter wave low noise amplifier amplifies the power of the filtered millimeter wave amplitude modulated signal and transmits it to the input end of the directional coupler; the coupling end of the directional coupler is connected to the power control device, and the direct pass The end is connected to an envelope detector; the power detection device is used to detect the millimeter wave power coupled to the directional coupler in real time, and generate a voltage control signal according to the detected millimeter wave power and transmit it to the millimeter wave VGA to adjust the transmission power in real time to cope with the impact of different environments and climatic conditions on the quality of millimeter wave wireless communication; the envelope detector uses a non-coherent demodulation method to demodulate the millimeter wave amplitude modulated signal, and the obtained OOK baseband signal is transmitted to the second baseband low-pass filter for filtering. The second baseband low-pass filter transmits the filtered OOK baseband signal to the electrical port module for signal conversion, and finally restores it to an Ethernet signal.

[0013] Furthermore, the power control device includes: a millimeter wave amplifier, a power detector, an ADC, a microprocessor, a memory, and a DAC;

[0014] The input end of the millimeter wave amplifier is connected to the coupling end of the directional coupler, and is used to amplify the coupled millimeter wave amplitude modulation signal and transmit it to the power detector;

[0015] The power detector is used to convert the amplified millimeter wave amplitude modulation signal into a voltage output;

[0016] The ADC is responsible for sampling and measuring the output voltage of the power detector, and transmitting the sampled data obtained by sampling and measuring to the microprocessor;

[0017] The microprocessor reads the calibration coefficient written in advance in the memory according to the sampling data obtained by the ADC, calibrates and calculates the millimeter wave power, and finally outputs a voltage control signal to be transmitted to the DAC;

[0018] The DAC performs digital-to-analog conversion on the received voltage control signal and sends the result to the millimeter wave VGA.

[0019] Furthermore, the power detector is a power detector such as an RMS detector, a logarithmic detector, etc. operating in a millimeter wave frequency band.

[0020] Furthermore, the bandwidth of the electrical port module must be greater than the Ethernet bandwidth R b ; The cut-off frequency f of the first baseband low-pass filter and the second baseband low-pass filter LPFShould be greater than R b .

[0021] Furthermore, the millimeter wave duplexer is composed of a first waveguide filter, a second waveguide filter and a waveguide common end; the passband center frequencies of the first waveguide filter and the second waveguide filter are f1 and f2 respectively, the 3dB bandwidths are BW1 and BW2 respectively, and the frequency protection interval is Δf=|f1-f2|-(BW1+BW2) / 2, wherein f1, f2, BW1, BW2, Δf are all greater than 0, and BW1 and BW2 are both greater than R b ; The millimeter wave duplexer has three waveguide ports, namely a first port, a second port and a third port; the three waveguide ports correspond to a first waveguide filter, a second waveguide filter and a waveguide common end respectively; in the millimeter wave transmitting link, the first port is connected to the output port of the millimeter wave power amplifier, the second port is connected to the input port of the millimeter wave low noise amplifier, and the third port is connected to the waveguide port of the millimeter wave antenna; in the millimeter wave receiving link, the first port is connected to the input port of the millimeter wave low noise amplifier, the second port is connected to the output port of the millimeter wave power amplifier, and the third port is connected to the waveguide port of the millimeter wave antenna; the function of the millimeter wave duplexer is to receive and transmit signals simultaneously without interfering with each other, thereby realizing full-duplex communication.

[0022] The above-mentioned vehicle-mounted Ethernet millimeter wave full-duplex wireless communication device for rail transit, and the method for implementing Ethernet millimeter wave full-duplex wireless communication, include the steps of:

[0023] S1, power on the Nth device (N is 1, 2, 3, 4), and the electrical port module of the device starts to receive the Ethernet signal sent by the switch and converts it into the OOK baseband signal output by the RF coaxial interface;

[0024] S2, using the first baseband low-pass filter to limit the baseband OOK signal;

[0025] S3, the carrier frequency generated by the millimeter wave local oscillator source is f c_N The millimeter wave sine wave signal is transmitted to the millimeter wave up converter, and the millimeter wave up converter modulates the millimeter wave sine wave signal according to the band-limited OOK baseband signal to obtain a frequency range of [f c_N -Rb,f c_N +Rb] millimeter wave amplitude modulated signal;

[0026] S4, first cascade the millimeter wave VGA and the millimeter wave power amplifier, use the cascaded combination to amplify the power of the millimeter wave amplitude modulation signal, and then use the millimeter wave duplexer to filter and process it, and finally the millimeter wave antenna transmitting end radiates the processed millimeter wave amplitude modulation signal into the free space;

[0027] S5, using the millimeter wave antenna receiving end to receive the millimeter wave amplitude modulation signal from the free space, then using the millimeter wave duplexer to filter the millimeter wave amplitude modulation signal, and then through the millimeter wave low noise amplifier (whose gain is G LNA ) amplifies the filtered millimeter wave amplitude modulated signal, and then the directional coupler (whose coupling degree is C) transmits the amplified millimeter wave amplitude modulated signal to the envelope detector and the power control device at the same time;

[0028] S6. The power control device is equipped with a power detector and a microprocessor. The power detector is used to convert the amplified millimeter wave amplitude modulation signal into a voltage, and the output voltage Vout of the power detector is measured. The slope Slope and intercept Intercept of the power detector are known. Then the microprocessor calculates the actual received power Pr = Vout / Slope+Intercept+C-Ga-G LNA , and then according to the expected received power P SET (dBm) and allowable error M (dB) for power determination |Pr-P SET |Is it less than M: If so, perform envelope detection; if not, output a control signal to the millimeter wave VGA to continuously adjust the transmit power until the received power is within the allowable error M;

[0029] S7. Use an envelope detector to perform envelope detection on the millimeter wave signal directly passed through the directional coupler to obtain a baseband OOK signal. After passing through a second baseband low-pass filter, it is finally restored to an Ethernet signal through an electrical port module, thereby finally realizing full-duplex wireless communication of Ethernet millimeter wave signals.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. The Ethernet-millimeter wave full-duplex wireless communication solution implemented by the present invention using amplitude modulation and non-coherent demodulation technology can effectively replace the complex layout and difficult-to-arrange wired cables between existing train carriages.

[0032] 2. The signal frequencies of the millimeter wave transmission link and the millimeter wave receiving link in the wireless communication device of the present invention are different. The present invention realizes simultaneous transmission and reception of signals through a millimeter wave duplexer, that is, frequency division multiplexing technology is adopted to improve channel utilization.

[0033] In the present invention, the polarization directions of the first and second devices and the third and fourth devices have two selectable states, vertical and horizontal, but cannot be in the same state at the same time, so that the polarization directions of the millimeter wave signals transmitted by the first wireless link and the second wireless link are orthogonal to each other and isolated from each other to achieve redundant transmission or expand communication capacity, that is, polarization multiplexing technology is adopted.

[0034] 3. The present invention adopts a power control device to detect, calculate and judge the power of the received millimeter wave amplitude modulation signal in real time, and adjust the transmission power in real time, so as to cope with the influence of different environmental and climatic conditions on the quality of millimeter wave wireless communication. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without creative work. In the drawings:

[0036] Figure 1 This is an application scenario and installation diagram of the vehicle-mounted Ethernet millimeter wave full-duplex wireless communication device for rail transit according to the present invention;

[0037] Figure 2 This is a system composition block diagram of the vehicle-mounted Ethernet millimeter wave full-duplex wireless communication device for rail transit according to the present invention;

[0038] Figure 3 A system composition block diagram of the power control device of the present invention;

[0039] Figure 4 This is a design flow chart of the vehicle-mounted Ethernet millimeter wave full-duplex wireless communication solution for rail transit according to the present invention;

[0040] The specific reference numerals are as follows:

[0041] 201-electrical port module; 202-first baseband low-pass filter; 203-millimeter wave local oscillator source; 204-millimeter wave up-converter; 205-millimeter wave VGA; 206-millimeter wave power amplifier; 207-millimeter wave duplexer; 208-millimeter wave antenna; 209-millimeter wave low-noise amplifier; 210-directional coupler; 211-power control device; 212-envelope detector; 213-second baseband low-pass filter; 301-millimeter wave amplifier; 302-power detector; 303-ADC; 304-microprocessor; 305-memory; 306-ADC. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments and drawings. The schematic implementation modes and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention. The technical scheme of the present invention is described in detail below in conjunction with the drawings and specific embodiments.

[0043] Figure 1This is an application scenario and installation diagram of an on-board Ethernet millimeter wave full-duplex wireless communication device for rail transit provided by this embodiment. Figure 1 , the wireless communication device comprises:

[0044] Device 1, Device 2, Device 3, Device 4;

[0045] The first, second, third and fourth devices all use frequency division multiplexing technology, and each includes a millimeter wave transmission link and a millimeter wave reception link and is isolated from each other, so as to realize full-duplex communication;

[0046] The first, second, third, and fourth devices convert the Gigabit Ethernet signal provided by the on-board switch into a millimeter wave signal for wireless transmission, ultimately achieving full-duplex wireless transparent transmission of Ethernet-millimeter wave-Ethernet;

[0047] The antenna polarization directions of the first device and the second device are horizontal polarization, forming a first wireless link of full-duplex communication;

[0048] The antenna polarization directions of the third device and the fourth device are vertical polarization, forming a second wireless link for full-duplex communication.

[0049] Figure 2 : is a system composition block diagram of the first device, the second device, the third device, and the fourth device provided in this embodiment, each device includes: an electrical port module 201; a first baseband low-pass filter 202; a millimeter-wave local oscillator 203; a millimeter-wave up-converter 204; a millimeter-wave VGA 205; a millimeter-wave power amplifier 206; a millimeter-wave duplexer 207; a millimeter-wave antenna 208; a millimeter-wave low-noise amplifier 209; a directional coupler 210; a power control device 211; an envelope detector 212; a second baseband low-pass filter 213; wherein the input end of the first baseband low-pass filter 202 is connected to the electrical port module 201, and the output end is connected to the first input end of the millimeter-wave up-converter 204; the second input end of the millimeter-wave up-converter 204 is connected to The millimeter wave local oscillator source 203, the output end is connected to the first input end of the millimeter wave duplexer 207 through the millimeter wave VGA 205 and the millimeter wave power amplifier 206 in sequence, and the first output end of the millimeter wave duplexer 207 is connected to the transmitting end of the millimeter wave antenna 208; the receiving end of the millimeter wave antenna 208 is connected to the second input end of the millimeter wave duplexer 207, and the second output end of the millimeter wave duplexer 207 is connected to the input end of the directional coupler 210 through the millimeter wave low noise amplifier 209; the coupling end of the directional coupler 210 is connected to the input end of the power control device 211, and the through end is connected to the electrical port module 201 through the envelope detector 212 and the second low-pass filter 213 in sequence; the output end of the power controller device is connected to the millimeter wave VGA 205.

[0050] In this embodiment, the millimeter wave local oscillator source 203 is used to generate a carrier frequency fc The millimeter wave sinusoidal single tone signal is transmitted, and the local oscillator driving signal is provided for the millimeter wave up-converter at the same time; the harmonic and spurious suppression of the millimeter wave local oscillator source 203 is generally required to be better than 30dBc. The millimeter wave VGA 205 is used to controllably amplify or attenuate the amplitude of the millimeter wave amplitude modulation signal generated by the millimeter wave up-converter 204, and adjust the transmission power in real time to cope with the free space transmission loss fluctuation of the wireless link in different scenarios; the millimeter wave VGA includes four interfaces: input, output, gain control and DC power supply. The gain control interface dynamically changes its gain immediately after receiving the gain control signal sent by the power control device 211, and the DC power supply interface is connected to a DC power supply.

[0051] In the first, second, third and fourth devices, the electrical port module converts the Gigabit Ethernet signal into an OOK baseband signal outputted via coaxial cable at a rate of 1000Mbps. LPF The millimeter wave local oscillator source frequencies (N = 1, 2, 3, 4) are set to f1, f2, f1, f2 in sequence, and the harmonic and spurious suppression is 40dBc. In the first, second, third, and fourth devices, the two filter passband center frequencies of the millimeter wave duplexer are both f1 and f2, the passband bandwidth is greater than 1GHz, and they are isolated from each other.

[0052] In the first, second, third and fourth devices, the frequencies of the transmitted millimeter-wave signals correspond to [f1-1GHz, f1+1GHz], [f2-1GHz, f2+1GHz], [f1-1GHz, f1+1GHz], and [f1-1GHz, f1+1GHz], respectively, and the electric field polarization directions of the transmitted millimeter-wave signals correspond to horizontal, horizontal, vertical, and vertical, respectively; the frequencies of the received millimeter-wave signals correspond to [f2-1GHz, f2+1GHz], [f1-1GHz, f1+1GHz], [f1-1GHz, f1+1GHz], and [f1-1GHz, f1+1GHz], respectively, and the electric field polarization directions of the transmitted millimeter-wave signals correspond to horizontal, horizontal, vertical, and vertical, respectively.

[0053] In the first, second, third and fourth devices, the directional coupler is a branch waveguide coupler with a coupling degree of 10 dB.

[0054] In the first, second, third and fourth devices, the RF operating bandwidth of the envelope detector covers the frequency range of the received millimeter wave signal, and the detection video bandwidth is greater than 1 GHz.

[0055] Figure 3 is a system composition block diagram of the power control device in the first device, the second device, the third device, and the fourth device provided in the embodiment of the present disclosure, such as Figure 3As shown, the power control device includes: a millimeter wave amplifier 301, a power detector 302, an ADC 303, a microprocessor 304, a memory 305, and an ADC 306. The input end of the millimeter wave amplifier 301 is connected to a directional coupler, and the output end is connected to the first input end of the microprocessor 304 via the power detector 302 and the ADC 303 in sequence. The second input end of the microprocessor 304 is connected to the first output end of the memory 305, and the output end is connected to the millimeter wave VGA via the DAC 306. The input end of the memory 305 is connected to the second output end of the microprocessor 304. Among them, the power detector 302 is used to detect the received millimeter wave power in real time and calculate the wireless link loss, so as to adjust the transmission power in real time to cope with the influence of different environmental and climatic conditions on the quality of millimeter wave wireless communication. ADC303 is responsible for sampling and measuring the output voltage of the power detector 302; the microprocessor 304 reads the calibration coefficient written in advance by the memory 305 according to the sampling data obtained by ADC303, calibrates and calculates the millimeter wave power, and finally outputs a voltage control signal, which is sent to the millimeter wave VGA205 after the DAC306 completes the digital-to-analog conversion.

[0056] This embodiment takes the first device as an example to describe in detail the method for realizing Ethernet millimeter wave full-duplex wireless communication by the above-mentioned vehicle-mounted Ethernet millimeter wave full-duplex wireless communication device for rail transit, such as Figure 4 As shown, the following steps are included:

[0057] S1, the first device is powered on and starts sending Ethernet signals;

[0058] S2. Determine the bandwidth of the electrical port module (which must be greater than Rb), and the electrical port module starts to receive the Ethernet signal sent by the switch and converts it into an OOK baseband signal output by the RF coaxial interface;

[0059] S2, set the cutoff frequency f of the first baseband low-pass filter and the second baseband low-pass filter LPF , should satisfy f LPF >Rb; use the first baseband low-pass filter to limit the baseband OOK signal;

[0060] S3, setting the frequency of the millimeter wave local oscillator source of the first device to f1, and generating a carrier frequency of f1 through the millimeter wave local oscillator source c_N Millimeter wave sine wave signal;

[0061] S4. Select a millimeter wave upconverter. The operating frequency range of the millimeter wave upconverter must cover the signal bandwidth [f1-Rb, f1+Rb]. The millimeter wave upconverter modulates the millimeter wave sinusoidal signal according to the received band-limited OOK baseband signal to obtain a frequency range of [f c_N -Rb,f c_NMillimeter-wave amplitude-modulated signal of +Rb

[0062] S5. Set the gain of the millimeter-wave VGA (G VGA ), the gain of the millimeter-wave power amplifier (G PA ), and the output power (P out ); Set the polarization direction of the antenna (horizontal or vertical) to transmit the millimeter-wave signal; Use the millimeter-wave VGA and the millimeter-wave power amplifier to amplify the power of the millimeter-wave amplitude-modulated signal, and then use the millimeter-wave duplexer for filtering processing. Finally, the filtered millimeter-wave amplitude-modulated signal is radiated into free space by the transmitting end of the millimeter-wave antenna;

[0063] S5. Set the polarization direction of the antenna (horizontal or vertical) to receive the millimeter-wave signal. Use the receiving end of the millimeter-wave antenna to receive the millimeter-wave amplitude-modulated signal from free space and transmit it to the millimeter-wave duplexer for filtering. It should be noted that: the receiving and transmitting polarization directions of the same device are orthogonal to each other, and the receiving and transmitting polarization directions of the same wireless link are the same;

[0064] S6. Set the gain of the millimeter-wave low-noise amplifier to G LNA , and set the coupling degree of the directional coupler to C. First, use the millimeter-wave low-noise amplifier to amplify the filtered millimeter-wave amplitude-modulated signal, and then the directional coupler simultaneously transmits the amplified millimeter-wave amplitude-modulated signal to the envelope detector and the power control device;

[0065] S6. The power control device is equipped with a power detector and a microprocessor. Use the power detector to detect the power of the millimeter-wave amplitude-modulated signal coupled by the directional coupler:

[0066] (1) First, use the power detector to convert the amplified millimeter-wave amplitude-modulated signal into voltage and measure the output voltage Vout of the power detector;

[0067] (2) In the microprocessor, calculate the actual received power Pr = Vout / Slope + Intercept + C - Ga - G LNA according to the output voltage Vout, the known slope Slope and intercept Intercept of the power detector;

[0068] (3) Perform power decision (|Pr - P SET (dBm)| < M?) according to the set expected received power P SET and the allowable error M (dB): If so, perform envelope detection; If not, output a control signal to the millimeter-wave VGA and continuously adjust the transmission power until the received power is within the allowable error M;

[0069] S7. The envelope detector performs envelope detection on the millimeter wave signal directly passed through the directional coupler to obtain a baseband OOK signal, which is then restored to an Ethernet signal through the electrical port module after passing through a second baseband low-pass filter, thereby finally realizing full-duplex wireless communication of the Ethernet millimeter wave signal.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be regarded as equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. An on-vehicle Ethernet millimeter wave full-duplex wireless communication device for rail transit, comprising: The first device, the second device, the third device, and the fourth device are characterized in that: The first device, the second device, the third device, and the fourth device are all configured to realize full-duplex wireless transmission of Ethernet-millimeter wave-Ethernet, wherein the antenna polarization directions of the first and second devices are the same, forming a first wireless link of full-duplex communication; the antenna polarization directions of the third and fourth devices are the same, forming a second wireless link of full-duplex communication; the polarization directions of the first and second devices and the third and fourth devices have two selectable states, vertical and horizontal, but cannot be in the same state at the same time, so as to ensure that the polarization directions of the millimeter wave signals transmitted by the first wireless link and the second wireless link are orthogonal to each other and isolated from each other, thereby realizing redundant transmission or expanding communication capacity.

2. According to claim 1, a vehicle-mounted Ethernet millimeter wave full-duplex wireless communication device for rail transit, characterized in that: The first device, the second device, the third device and the fourth device all include an electrical port module, a millimeter wave transmission link and a millimeter wave receiving link; The electrical port module receives an externally input Ethernet signal or a baseband signal provided by a millimeter wave receiving link, converts the Ethernet signal into an OOK baseband signal and outputs it to the millimeter wave transmitting link, and restores the baseband signal provided by the millimeter wave receiving link into an Ethernet signal for output; The millimeter wave transmission link includes: a first baseband low-pass filter, a millimeter wave local oscillator source, a millimeter wave up-converter, a millimeter wave VGA, a millimeter wave power amplifier, a millimeter wave duplexer and a millimeter wave antenna; the first baseband low-pass filter receives the OOK baseband signal provided by the electrical interface module and transmits it to the millimeter wave up-converter after performing band limiting processing; the millimeter wave local oscillator source is used to provide a millimeter wave sine wave signal for the millimeter up-converter; the millimeter wave up-converter modulates the millimeter wave sine wave signal according to the band-limited OOK baseband signal to obtain a millimeter wave amplitude modulation signal and transmits it to the millimeter wave VGA; after the millimeter wave VGA is cascaded with the millimeter wave power amplifier, the amplitude of the millimeter wave amplitude modulation signal is regulated, and the regulated millimeter wave amplitude modulation signal is filtered by the millimeter wave duplexer and transmitted to the millimeter wave antenna; the millimeter wave antenna radiates the filtered millimeter wave amplitude modulation signal into free space; The millimeter wave receiving link comprises: a millimeter wave antenna, a millimeter wave duplexer, a millimeter wave low noise amplifier, a directional coupler, a power control device, an envelope detector, and a second baseband low pass filter; the millimeter wave antenna receives a millimeter wave amplitude modulated signal propagating in free space and transmits it to the millimeter wave duplexer; the millimeter wave duplexer is used to filter the received millimeter wave amplitude modulated signal and transmit the filtered millimeter wave amplitude modulated signal to the millimeter wave low noise amplifier; the millimeter wave low noise amplifier amplifies the power of the filtered millimeter wave amplitude modulated signal and transmits it to the input end of the directional coupler; the coupling of the directional coupler The combined end is connected to a power control device, and the through end is connected to an envelope detector; the power detection device is used to detect the millimeter-wave power coupled by the directional coupler in real time, and generate a voltage control signal according to the detected millimeter-wave power and transmit it to the millimeter-wave VGA to adjust the transmission power in real time; the envelope detector demodulates the millimeter-wave amplitude modulated signal using a non-coherent demodulation method, and obtains an OOK baseband signal that is transmitted to the second baseband low-pass filter for filtering. The second baseband low-pass filter transmits the filtered OOK baseband signal to the electrical port module for signal conversion, and finally restores it to an Ethernet signal.

3. The vehicle-mounted Ethernet millimeter wave full-duplex wireless communication device for rail transit according to claim 2, characterized in that: The power control device includes: a millimeter wave amplifier, a power detector, an ADC, a microprocessor, a memory, and a DAC; The input end of the millimeter wave amplifier is connected to the coupling end of the directional coupler, and is used to amplify the coupled millimeter wave amplitude modulation signal and transmit it to the power detector; The power detector is used to convert the amplified millimeter wave amplitude modulation signal into a voltage output; The ADC is responsible for sampling and measuring the output voltage of the power detector, and transmitting the sampled data obtained by sampling and measuring to the microprocessor; The microprocessor reads the calibration coefficient written in advance in the memory according to the sampling data obtained by the ADC, calibrates and calculates the millimeter wave power, and finally outputs a voltage control signal to be transmitted to the DAC; The DAC performs digital-to-analog conversion on the received voltage control signal and sends the result to the millimeter wave VGA.

4. The vehicle-mounted Ethernet millimeter wave full-duplex wireless communication device for rail transit according to claim 3, characterized in that: The power detector is an RMS detector or a logarithmic detector operating in the millimeter wave frequency band.

5. The vehicle-mounted Ethernet millimeter wave full-duplex wireless communication device for rail transit according to claim 2, characterized in that: The bandwidth of the electrical port module must be greater than the Ethernet bandwidth R b ; The cut-off frequency f of the first baseband low-pass filter and the second baseband low-pass filter LPF Should be greater than R b .

6. The vehicle-mounted Ethernet millimeter wave full-duplex wireless communication device for rail transit according to claim 2, characterized in that: The millimeter wave duplexer is composed of a first waveguide filter, a second waveguide filter and a waveguide common end; in a millimeter wave transmitting link, the first waveguide filter is connected to the output port of a millimeter wave power amplifier; the first waveguide filter is connected to the input port of a millimeter wave low noise amplifier, and the waveguide common end is connected to the waveguide port of a millimeter wave antenna; in a millimeter wave receiving link, the first waveguide filter is connected to the input port of the millimeter wave low noise amplifier, the second waveguide filter is connected to the output port of the millimeter wave power amplifier, and the waveguide common end is connected to the waveguide port of the millimeter wave antenna.

7. According to any one of claims 1 to 6, a vehicle-mounted Ethernet millimeter wave full-duplex wireless communication device for rail transit, wherein the method for implementing Ethernet millimeter wave full-duplex wireless communication comprises the steps of: S1, power on the Nth device, and the electrical port module of the device starts to receive the Ethernet signal sent by the switch and converts it into an OOK baseband signal output by the RF coaxial interface; N is 1, 2, 3 or 4; S2, using the first baseband low-pass filter to limit the baseband OOK signal; S3, transmitting the millimeter wave sinusoidal wave signal generated by the millimeter wave local oscillator to the millimeter wave up-converter, and the millimeter wave up-converter modulates the millimeter wave sinusoidal wave signal according to the band-limited OOK baseband signal to obtain a millimeter wave amplitude modulated signal; S4, first cascade the millimeter wave VGA and the millimeter wave power amplifier, use the cascaded combination to amplify the power of the millimeter wave amplitude modulation signal, and then use the millimeter wave duplexer to filter and process it, and finally the millimeter wave antenna transmitting end radiates the processed millimeter wave amplitude modulation signal into the free space; S5, using the millimeter wave antenna receiving end to receive the millimeter wave amplitude modulation signal from the free space, then using the millimeter wave duplexer to filter the millimeter wave amplitude modulation signal, and then using the millimeter wave low noise amplifier to amplify the filtered millimeter wave amplitude modulation signal, and then using the directional coupler to simultaneously transmit the amplified millimeter wave amplitude modulation signal to the envelope detector and the power control device; S6. The power control device has a power detector and a microprocessor inside, and uses the power detector to detect the power of the millimeter wave amplitude modulation signal coupled by the directional coupler: (1) First, use a power detector to convert the amplified millimeter-wave amplitude modulated signal into a voltage and measure its output voltage Vout; (2) The power Pr of the millimeter-wave amplitude modulation signal actually received is calculated in the microprocessor based on the output voltage Vout, the slope Slope and the intercept Intercept of the known power detector: Pr=Vout / Slope+Intercept+C-Ga-G LNA ; (3) According to the expected received power P SET And the allowable error M is used to make a power decision, that is, to determine |Pr-P SET |Is it less than M: If so, perform envelope detection; if not, output a control signal to the millimeter wave VGA to continuously adjust the transmit power until the received power is within the allowable error M; S7. Use an envelope detector to perform envelope detection on the millimeter-wave amplitude modulated signal directly passed through the directional coupler to obtain a baseband OOK signal. After passing through a second baseband low-pass filter, it is finally restored to an Ethernet signal through an electrical port module, thereby finally realizing full-duplex wireless communication of Ethernet millimeter-wave signals.

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