阅读说明：本技术 一种核电站通信基于无线光的以太网透传方法 (Wireless light-based Ethernet transparent transmission method for nuclear power station communication ) 是由 陈晓 马志才 汤智超 钟林秀 刘鑫 廖亮 路璐 张婷婷 于 2020-06-22 设计创作，主要内容包括：本发明公开了一种核电站通信的基于无线光的以太网透传方法；该方法包括：以太网芯片、发光二极管、光电二极管、跨阻放大器、现场可编程逻辑门阵列；在发射端通过现场可编程逻辑门阵列,将以太网芯片输出的并行信号转变成串行信号,并插入具有低自相关系数的起始帧和结束帧,然后驱动发光二极管生成无线光信号；在接收端,通过光电二极管和跨阻放大器,将无线光信号转换成电信号,再通过现场可编程逻辑门阵列,将起始帧和结束帧识别,恢复成以太网芯片的串行信号。本发明以太网节点设备无需做任何软硬件修改,系统的兼容性强；不依赖电磁波传输,因此不会对电磁敏感设备产生干扰；不依赖中央处理器等控制单元,结构简单易集成。(The invention discloses a wireless light-based Ethernet transparent transmission method for nuclear power station communication; the method comprises the following steps: the device comprises an Ethernet chip, a light emitting diode, a photodiode, a trans-impedance amplifier and a field programmable gate array; converting parallel signals output by an Ethernet chip into serial signals at a transmitting end through a field programmable logic gate array, inserting a start frame and an end frame with low autocorrelation coefficients, and then driving a light emitting diode to generate a wireless optical signal; at a receiving end, a wireless optical signal is converted into an electric signal through a photodiode and a trans-impedance amplifier, and then a start frame and an end frame are identified through a field programmable gate array to be recovered into a serial signal of an Ethernet chip. The Ethernet node equipment does not need to make any software and hardware modification, and the system has strong compatibility; the electromagnetic wave transmission is not relied on, so that the electromagnetic sensitive equipment is not interfered; the device does not depend on control units such as a central processing unit and the like, and is simple in structure and easy to integrate.)

1. The Ethernet transparent transmission method based on wireless light for nuclear power station communication is characterized by comprising an Ethernet chip, a light emitting diode, a photodiode, a transimpedance amplifier and a field programmable logic gate array, and comprises the following steps:

and (3) network cable connection: connecting the Ethernet chip MDI interface of the transmitting end with a router or a switch through a network cable;

and (3) generating a serial frame: performing parallel-serial conversion on output vectors RXD [3:0] and RX _ DV of the MII interface of the Ethernet chip at a transmitting end to generate a serial frame;

and generating a frame data stream: inserting a start frame with a low autocorrelation coefficient before the serial frame and inserting an end frame with a low autocorrelation coefficient after the serial frame by a special frame inserter to generate a frame data stream;

generating a visible light signal: driving the light emitting diode to emit light according to the frame data stream, wherein a bit 1 is correspondingly bright, and a bit 0 is correspondingly dark, so as to generate a visible light signal;

and restoring the frame data stream: recovering the frame data stream through the photodiode and the transimpedance amplifier at a receiving end;

and (3) recovering the serial frame: removing a start frame and an end frame in the frame data stream by a special frame deleter to recover a serial frame;

and (3) serial-parallel conversion: performing serial-to-parallel conversion on the serial frame to generate MII interface vectors TXD [3:0] and RX _ DV, and accessing the generated TXD [3:0] and RX _ DV to the Ethernet chip at a receiving end;

user access: and connecting the MDI interface of the Ethernet chip at the receiving end with the user equipment through a network cable.

2. The wireless light-based Ethernet transparent transmission method for nuclear power plant communication according to claim 1, wherein RXD [3:0] and RX _ DV signals of the ethernet chip at a receiving end are transmitted to TXD [3:0] and TX _ EN pins of the ethernet chip at a transmitting end, so as to implement bidirectional communication.

3. The wireless light-based ethernet transparent transmission method for nuclear power plant communication as claimed in claim 1, wherein said ethernet chip can adopt RTL8211EG or other ethernet chips supporting MII interface.

4. The wireless light-based ethernet transparent transmission method for nuclear power plant communication as claimed in claim 1, wherein said light emitting diode is driven by CMOS transistor or triode.

5. The wireless-light-based ethernet transparent transmission method for nuclear power plant communication according to claim 1, wherein the output voltage of said transimpedance amplifier should conform to FPGA interface standard.

Technical Field

The invention belongs to the technical field of wireless communication, and particularly relates to the technical field of nuclear power station communication Ethernet transparent transmission.

Background

In order to ensure the safety of equipment, an electromagnetic radiation free area exists in the nuclear power station. In these areas, conventional radio frequency communication cannot be applied. The wireless optical communication system has the characteristics of high speed and no electromagnetic radiation, so that the wireless optical communication system is suitable for nuclear power station scenes. Most of the existing wireless optical internet access methods aim at specific protocols, such as TCP/IP or UDP, and the universality of the system is limited; or the system is complex in structure, a central processing unit and a Field Programmable Gate Array (FPGA) need to be used simultaneously, and difficulty is caused in miniaturization and low power consumption of equipment.

Disclosure of Invention

The invention mainly solves the technical problems that the existing wireless optical network access system has low universality, complex structure and difficult volume reduction. The Ethernet node equipment can realize the Internet access function without any software and hardware modification based on an Ethernet chip, a light emitting diode, a photodiode, a transimpedance amplifier and a field programmable logic gate array, and is suitable for any Ethernet protocol.

A nuclear power station communication wireless light-based Ethernet transparent transmission method comprises an Ethernet chip, a light emitting diode, a photodiode, a trans-impedance amplifier and a field programmable logic gate array, and comprises the following steps:

and (3) network cable connection: connecting the Ethernet chip MDI interface of the transmitting end with a router or a switch through a network cable;

and (3) generating a serial frame: performing parallel-serial conversion on output vectors RXD [3:0] and RX _ DV of the MII interface of the Ethernet chip at a transmitting end to generate a serial frame;

and generating a frame data stream: inserting a start frame with a low autocorrelation coefficient before the serial frame and inserting an end frame with a low autocorrelation coefficient after the serial frame by a special frame inserter to generate a frame data stream;

generating a visible light signal: driving the light emitting diode to emit light according to the frame data stream, wherein a bit 1 is correspondingly bright, and a bit 0 is correspondingly dark, so as to generate a visible light signal;

and restoring the frame data stream: recovering the frame data stream through the photodiode and the transimpedance amplifier at a receiving end;

and (3) recovering the serial frame: removing a start frame and an end frame in the frame data stream by a special frame deleter to recover a serial frame;

and (3) serial-parallel conversion: performing serial-to-parallel conversion on the serial frame to generate MII interface vectors TXD [3:0] and RX _ DV, and accessing the generated TXD [3:0] and RX _ DV to the Ethernet chip at a receiving end;

user access: and connecting the MDI interface of the Ethernet chip at the receiving end with the user equipment through a network cable.

Preferably, RXD [3:0] and RX _ DV signals of the Ethernet chip at a receiving end are transmitted to TXD [3:0] and TX _ EN pins of the Ethernet chip at a transmitting end, so that bidirectional communication is realized.

Preferably, the ethernet chip may adopt RTL8211EG or other ethernet chips supporting MII interfaces.

Preferably, the driving of the light emitting diode can adopt a CMOS tube or a triode.

Preferably, the output voltage of the transimpedance amplifier should comply with the FPGA interface standard.

The Ethernet node device adopts the Ethernet chip, the light emitting diode, the photodiode, the transimpedance amplifier and the FPGA to realize the Ethernet transparent transmission based on the wireless optical signal, so that the Ethernet node device can realize the wireless Internet function without any software and hardware modification and electromagnetic radiation. Compared with the prior art, the method has the advantages of strong compatibility, suitability for any Ethernet communication protocol, few chip types, simple structure, small volume and low power consumption.

Drawings

Fig. 1 is a schematic diagram of hardware connections.

Fig. 2 shows the conversion process of the MII interface vector into a frame data stream.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.

Hardware connection as shown in fig. 1, first, an ethernet chip MDI interface of a transmitting end and a router or a switch are connected by a network cable, which may be an RJ45 network cable, and the ethernet chip may be an RTL8211EG or other ethernet chips supporting an MII interface.

Then, output vectors RXD [3:0] and RX _ DV of an MII interface of the transmitting end Ethernet chip are connected to the FPGA, the FPGA carries out parallel-serial conversion on the RXD [3:0] and the RX _ DV to generate a data stream, and the serial bits are in the sequence of [ RX _ DV, RXD [3], RXD [2], RXD [1] and RXD [0], namely serial frames. The output vector of the MII interface versus the serial frame is shown in fig. 2. The FPGA chip can adopt Xilinx Spartan 6 series or other similar chips with sufficient IO ports.

Then, the point in the serial frame where RX _ DV changes is detected by the FPGA. When RX _ DV makes a transition from low level to high level, the first high level RX _ DV is replaced with the start frame. The starting frame can be freely designed, but a sharp peak of the autocorrelation function is ensured so as not to be confused with communication data. For example, a pseudo-random m-sequence or a barker code may be employed as the starting frame. When the high level is transited to the low level, the first low level RX _ DV is replaced with the end frame. The design criteria for the end frame are the same as for the start frame.

For example, the following start and end frames may be employed:

starting a frame: +++++ - - ++ - + - +

And (4) ending the frame: +++ - - - + - - + -

We call the serial frame with the start frame and the end frame added, the frame data stream. The relationship between serial frames and frame data streams is shown in fig. 2.

Then, the LED is driven to emit light according to the frame data stream, the bit 1 corresponds to bright, the bit 0 corresponds to dark, and a visible light signal is generated. The LED can be driven by a CMOS tube or a triode so as to ensure that the driving current is large enough. For example, a CMOS transistor may be selected from AO3400 or similar products.

The frame data stream is then recovered at the receiving end by means of a photodiode and a transimpedance amplifier. The photodiode may be selected from PDB-C156 or the like. The output voltage of the trans-impedance amplifier should conform to the FPGA interface standard, such as 3.3V output at high level and 0V output at low level. The transimpedance amplifier can be selected from OPA847, OPA657 and the like.

Then, the start frame and the end frame are detected by a special frame remover, and then the start frame and the end frame in the frame data stream are removed to recover the serial frame. Here, there are many frame detection methods, for example, autocorrelation detection may be adopted to perform sliding correlation between the standard frame and the received data stream, and if the result of the sliding correlation is greater than a custom threshold, it is considered that a special frame appears.

And finally, performing serial-to-parallel conversion on the serial frame, extracting MII interface vectors RXD [3:0] and RX _ DV according to the bit sequence of the serial frame in the figure 2, and accessing the extracted RXD [3:0] and RX _ DV signals to TXD [3:0] and TX _ EN of the Ethernet chip at the receiving end.

Then, the MDI interface of the receiving ethernet chip and the user equipment are connected through the RJ45 network cable.

If bidirectional communication is required, RXD [3:0] and RX _ DV signals of the receiving Ethernet chip can be transmitted to TXD [3:0] and TX _ EN pins of the transmitting Ethernet chip in the same way.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is intended to include such modifications and variations. The foregoing examples or embodiments are merely illustrative of the present invention, which may be embodied in other specific forms or in other specific forms without departing from the spirit or essential characteristics thereof. The described embodiments are, therefore, to be considered in all respects as illustrative and not restrictive. The scope of the invention should be indicated by the appended claims, and any changes that are equivalent to the intent and scope of the claims should be construed to be included therein.