Completely buried space near-electric field coupled wireless networking communication system and method

Abstract

This invention belongs to the field of near-field communication technology, and specifically relates to a near-electric field coupled wireless networking communication system and method for completely buried spaces. It includes: a plurality of slave communication nodes for collecting environmental data of the surrounding space; these slave communication nodes are spaced apart on a metal cable in the goaf and communicate with other nodes via near-field coupling through the metal cable, forming a wireless network with each slave communication node and its corresponding metal cable; and a main communication node for aggregating environmental data from each slave communication node and connecting to a host computer to achieve goaf environmental monitoring. The main communication node is located at the coal face, with one end of the metal cable connected to the main communication node and the other end extending longitudinally through the goaf and into the completely buried space. This invention uses symmetrical electric dipole antennas of the communication nodes to couple electric field signals to the metal cable or to sense electric field signals fed back from other nodes on the metal cable for wireless networking communication. Under completely buried conditions, it can ensure the communication quality of communication nodes near the metal cable.

Description

Technical Field

[0001] This invention belongs to the field of near-field communication technology, and specifically relates to a fully buried space near-electric field coupled wireless networking communication system and method. Background Technology

[0002] According to the relevant provisions of the Coal Mine Safety Regulations on mine fire prediction and monitoring, mines with spontaneous combustion hazards should regularly check the levels of CO and other harmful gases; establish a coal mine spontaneous combustion monitoring system to determine the indicator gases and critical values ​​for spontaneous combustion in coal seams; and analyze the temperature and gas composition within the fire zone during the sealing, management, and unsealing processes.

[0003] Existing technologies for monitoring fires in goaf areas mainly include the bundled tube method and the fiber optic thermometry method. The former provides early warning by indirectly monitoring gas concentration but cannot pinpoint the fire location, while the latter suffers from a high false alarm rate due to fiber compression, rendering it unreliable. Temperature-based prevention technology for high-temperature points in coal mine goaf areas is the most promising approach for goaf fire control. Networking goaf temperature acquisition nodes via wireless communication is the most promising method. However, due to the unique environment of goaf areas, communication nodes can be buried by conductive media such as fallen coal chunks, coal gangue, sandstone, and even groundwater (5-10 meters thick, with a small gap between them and the overlying sandstone), posing a significant challenge to the design of wireless communication systems. Existing wireless networking methods mainly include Bluetooth, ZigBee, Wi-Fi, and LoRa. Bluetooth and Wi-Fi operate in the 2.4 GHz band, ZigBee operates in multiple bands including 2.4 GHz, 868 MHz, and 915 MHz, and LoRa operates in 433 MHz, 868 MHz, and 915 MHz. It can be seen that the communication frequencies of these wireless networking methods are all above 400 MHz. In a completely buried environment, electromagnetic waves face severe absorption in semiconductor media such as coal, sand, and seawater, hindering long-distance propagation. A team from North China University tested communication distances under burial conditions in a mined-out area using a 170 MHz frequency, finding the longest distance to be less than 5 meters. When the frequency exceeds 400 MHz, achieving longer distances becomes difficult. Therefore, the aforementioned existing wireless networking communication methods are unsuitable for the wireless networking communication needs in completely buried spaces. The system and method for through-the-ground (TTE) communication proposed by Marshall Radio Telemetry, Inc. of the United States is used to wirelessly transmit signals through the ground between transmitting and receiving antennas. It generates significant far-field radiation through the communication antenna and interacts primarily through the emission and absorption of electromagnetic radiation, except for magnetic coupling. It typically selects frequencies much higher than those conventionally used for TTE communication. This method can operate in the 0.1MHz–3MHz frequency range, but due to the large antenna size and the need for pre-planned clearance around the antenna, it is not suitable for completely buried environments. Summary of the Invention

[0004] Therefore, the present invention provides a fully buried space near-electric field coupled wireless networking communication system and method, which can ensure high penetration while supporting a large communication bandwidth to meet the needs of multi-node networking.

[0005] According to the design scheme provided by the present invention, a fully buried space near-electric field coupled wireless networking communication system is provided, comprising the following:

[0006] Several slave communication nodes are used to collect data on the spatial environment. The slave communication nodes are arranged at intervals on the metal cable in the goaf area and are near-field coupled to communicate with the corresponding metal cable segment. Each slave communication node and the corresponding metal cable segment form a wireless network.

[0007] The main communication node is used to collect environmental data from each slave communication node and connect to the host computer to realize environmental monitoring of the goaf area. The main communication node is set on the working face of the goaf area, and one end of the metal cable is connected to the main communication node, while the other end runs longitudinally through the goaf area and extends to the completely buried space.

[0008] As a fully buried space near-electric field coupled wireless networking communication system of the present invention, the communication node further includes: a sealed cabin, a sensor module disposed in the sealed cabin for collecting ambient gas and temperature data, a main control circuit module connected to the sensor module, a communication module for wireless communication networking with other nodes, a battery module for providing voltage to the node, and a power management module for converting and outputting the voltage of the battery module.

[0009] As a fully buried space near-electric field coupled wireless networking communication system in this invention, the cabin further includes: a cylindrical shell made of stainless steel, a breathable and waterproof valve disposed on one end face of the cylindrical shell, and a sealing connector disposed on the other end face of the cylindrical shell for connecting an external communication antenna; and an anti-burial filter screen is also provided on the cylindrical shell to prevent the breathable and waterproof valve from being blocked.

[0010] As a fully buried space near-electric field coupled wireless networking communication system in this invention, the power management module is further provided with a clock module for providing sleep and wake-up signals for both the communication module and the sensor module, and the sleep or wake-up signals provided by the clock module are used to turn off or on the power supply of the communication module and the sensor module.

[0011] As a fully buried space near-electric field coupled wireless networking communication system of the present invention, the communication module further includes: a communication antenna, an impedance matching circuit, a power amplifier drive circuit, a filter circuit, an analog-to-digital conversion circuit, a modulation and decoding circuit, a control circuit, a digital-to-analog conversion circuit, and a signal amplification circuit. The communication antenna is installed on the sealed cabin and connected to the power drive circuit and the signal amplification circuit through the impedance matching circuit. The communication antenna is used to send the radio frequency signal of the communication node to the metal cable through a near-distance coupling method, and the metal cable receives the induced signal to realize wireless communication networking with other communication nodes.

[0012] As a fully buried space near-electric field coupled wireless networking communication system of the present invention, the communication antenna further adopts a symmetrical electric dipole antenna.

[0013] As a fully buried space near-electric field coupled wireless networking communication system of the present invention, the communication nodes are further wrapped with an insulating outer sheath, and the communication nodes are placed around the metal cable or fixed on the metal cable.

[0014] Furthermore, based on the above system, the present invention also provides a fully buried space near-electric field coupled wireless networking communication method, comprising:

[0015] The antenna length of the communication node is set according to the communication carrier frequency of the application scenario, and the matching parameters of the communication node are adjusted. The metal cable laid longitudinally in the goaf area is used as the wireless communication channel. Each communication node pre-set in the goaf area and coupled in the near field with the metal cable is connected to other nodes through cable-borne communication to build a wireless communication network.

[0016] A communication node connected to the working face end of the metal cable is set as the main communication node, and other communication nodes on the metal cable are set as slave communication nodes. The environmental data of the goaf collected by the slave communication nodes is aggregated to the main communication node of the working face using a wireless communication network. The host computer connected to the main communication node of the working face analyzes and processes the received environmental data to achieve monitoring of the environment of the completely buried space.

[0017] As a wireless networking communication method in this case, each communication node is placed around the metal cable or electrically insulated from and fixed to the metal cable, and adjacent communication nodes are deployed at predetermined distances according to the application scenario.

[0018] The beneficial effects of this invention are:

[0019] This invention uses a metal cable as a channel. A certain frequency electric field signal is coupled to the metal cable via a symmetrical electric dipole antenna of the communication node, or an electric field signal fed back from other nodes is sensed from the cable, enabling wireless network communication. Under completely buried conditions, this ensures stable and reliable wireless communication between multiple communication nodes fixed near the cable. It can be used for wireless network communication in extreme environments such as completely buried underground spaces or underwater. Furthermore, the communication node utilizes a breathable, waterproof, and impact-resistant cabin structure to protect the circuitry and batteries from damage by sand and gravel left in the mining area or from water flooding. A breathable and waterproof valve is introduced, and a metal filter is added to ensure that gas can enter the cabin while water is isolated under completely buried conditions. The power management module uses a "sleep-wake" working mode, that is, the power to the communication module and sensor module is turned off during sleep mode and turned on during wake-up. The system optimizes the power supply for the communication and sensor modules, reducing system power consumption and extending system battery life. Furthermore, it utilizes a small-size, low-cost symmetrical electric dipole antenna, which is insulated from the surrounding medium and connected to the back-end drive or amplifier circuit via a matching circuit to ensure high conversion efficiency. Employing a master-slave networking mode, it can use OFDM technology at the physical layer and BPSK modulation, resulting in strong noise and burst interference resistance, suitable for communication in highly interference-prone underground environments. At the MAC layer, it can be implemented based on TDMA, providing a collision avoidance mechanism and supporting concurrent communication of multiple nodes. At the network layer, based on dynamic routing and multi-path addressing, a single master node can support up to 300 slave nodes, providing crucial support for underground goaf fire monitoring and underwater wireless networking communication. Attached image description:

[0020] Figure 1 This is a schematic diagram illustrating the principle of near-electric field coupling wireless networking communication in a completely buried space, as shown in the embodiment.

[0021] Figure 2 This is a schematic diagram illustrating the connection between the communication node and the metal cable in the embodiment.

[0022] Figure 3 This is a schematic diagram of the communication node structure in the embodiment;

[0023] Figure 4 This is a schematic diagram of the cabin principle in the embodiment;

[0024] Figure 5 This is a schematic diagram of the cabin structure in the embodiment;

[0025] Figure 6 This is a schematic diagram of the "sleep-wake" working mode in the embodiment;

[0026] Figure 7 This is a schematic diagram of the communication module structure in the embodiment;

[0027] Figure 8This is a schematic diagram of the network structure in the embodiment;

[0028] Figure 9 This is a schematic diagram of an underwater test scenario in the embodiment;

[0029] Figure 10 This is a schematic diagram of the received signal spectrum and waterfall in the embodiment;

[0030] Figure 11 The demodulation results are illustrated in the example.

[0031] In the diagram, the labels are as follows: label 1 represents the master communication node, label 2 represents the slave communication node, label 3 represents the buried medium, label 4 represents the metal cable, label 5 represents the hull, label 51 represents the shell, label 52 represents the sealing connector, label 53 represents the ventilated and waterproof valve, and label 54 represents the anti-buried filter. Detailed implementation method:

[0032] To make the objectives, technical solutions, and advantages of this invention clearer and more understandable, the invention will be further described in detail below with reference to the accompanying drawings and technical solutions.

[0033] Magnetoelectric near-field coupling wireless penetration communication technology has solved the problem of wireless communication in completely buried spaces, enabling point-to-point data transmission. However, it suffers from problems such as the large size of the magnetic induction antenna leading to difficulties in the design of anti-collision protection in the goaf area, and the low magnetoelectric conversion efficiency of the induction coil resulting in high power consumption, making large-scale deployment difficult. This invention provides a near-electric field coupling wireless networking communication system for completely buried spaces, comprising the following:

[0034] Several slave communication nodes are used to collect data on the spatial environment. The slave communication nodes are arranged at intervals on the metal cable in the goaf area and are near-field coupled to communicate with the corresponding metal cable segment. Each slave communication node and the corresponding metal cable segment form a wireless network.

[0035] The main communication node is used to collect environmental data from each slave communication node and connect to the host computer to realize environmental monitoring of the goaf area. The main communication node is set on the working face of the goaf area, and one end of the metal cable is connected to the main communication node, while the other end runs longitudinally through the goaf area and extends to the completely buried space.

[0036] Using metal cables laid in the goaf as wireless communication channels, the cables are laid longitudinally along the goaf. Communication nodes are near-field coupled to the metal cables via symmetrical electric dipole antennas, and establish wireless communication networks with other nodes through cable-borne wireless communication. The communication nodes primarily perform functions such as collecting goaf temperature and gas data, information encoding, communication modulation and demodulation, and generating and parsing wireless networking protocols between multiple nodes. All nodes pre-installed in the goaf periodically aggregate the collected data to the main node at the coal face via the network, providing crucial support for underground goaf fire monitoring and underwater wireless networking communication.

[0037] See Figure 1 As shown, multiple coal mine safety certified metal cables run longitudinally through the goaf. One end of the cable is located at the coal face and connected to the main communication node, while the other end extends deep into the goaf (buried by residual coal and sand). Multiple communication nodes are fixed to each metal cable through an insulation layer. The communication nodes use their own symmetrical electric dipole antennas to interact with the cables through near-electric field coupling. The nodes communicate with each other wirelessly to form a network. Each node is equipped with temperature and gas sensors for CO, methane, oxygen, acetylene, and ethylene. All nodes periodically aggregate data to the main node. The main node has the same structure as the communication nodes, but the network permissions are different. The communication nodes use their built-in temperature and gas sensors to acquire surrounding environmental parameters. These parameters are then encoded, modulated, and fed to a symmetrical electric dipole antenna via a drive circuit at a specific carrier frequency. The dipole antenna senses the near-electric field on a metal cable. The dipole antenna at the far-end node senses and receives the signal from the cable, amplifies, demodulates, and decodes it to achieve wireless communication of the data. Each communication node sends and receives specified data according to a communication protocol, thus enabling environmental monitoring of the goaf area.

[0038] Among them, the metal cable can be regarded as a wireless communication channel artificially constructed in the goaf. Its material can be a high-strength metal cable that meets coal mine safety certification, or other conductive metal materials. The cable can be bare or wrapped with insulating fire-resistant rubber. When using bare cable, the cable will be in direct contact with the surrounding medium. Especially when water is present, the high conductivity will greatly attenuate the communication signal, requiring greater communication transmission power and limiting the communication bandwidth, thus affecting the networking efficiency. Compared with the former, the latter has less path loss, requires only less transmission power to achieve long-distance communication, and supports a wider channel bandwidth, but the deployment cost and complexity are slightly higher than the former.

[0039] See Figure 2As shown, the metal cable and communication nodes are coupled together, meaning the communication nodes are not electrically connected to the metal cable; they only need to be fixed near the cable. The cable's main function is to sense the electromagnetic waves radiated by the node's antenna and couple them to other nodes at a distance. The communication node's antenna is wrapped in an insulating sheath and placed around the metal cable (often fixed to it, electrically insulated from each other). Multiple communication nodes are arranged at a certain distance along the metal cable to cover the goaf area. Reliable communication is maintained even if the cable is broken by falling rocks. To reduce communication path loss, the metal cable must be wrapped in insulating material to insulate it from the surrounding medium, while the cable's ends can either contact the surrounding medium or remain insulated.

[0040] Furthermore, in the embodiments of this case, see Figure 3 As shown, the communication node includes: a sealed chamber, a sensor module installed inside the sealed chamber for collecting ambient gas and temperature data, a main control circuit module connected to the sensor module, a communication module for wireless communication networking with other nodes, a battery module for providing voltage to the node, and a power management module for converting and outputting the voltage of the battery module.

[0041] As a preferred embodiment, the cabin further comprises: a cylindrical shell made of stainless steel, a breathable and waterproof valve disposed on one end face of the cylindrical shell, and a sealing connector disposed on the other end face of the cylindrical shell for connecting an external communication antenna; and an anti-burial filter screen is also provided on the cylindrical shell to prevent the breathable and waterproof valve from being blocked.

[0042] See Figure 4 and 5 As shown, the hull can be a watertight structure made of high-strength stainless steel, designed to prevent other modules inside from being damaged by falling rocks or from flooding. The overall structure can be cylindrical, with a venting and waterproof valve on one end to allow gas in while preventing water ingress. The other end has a sealing connector for connecting the internal circuitry to the external communication antenna. A burial-proof filter, made of perforated stainless steel tubing, is connected to the stern to prevent sand or coal debris from clogging the venting and waterproof valve.

[0043] Furthermore, the power management module is equipped with a clock module for providing sleep and wake-up signals for both the communication module and the sensor module, and the power supply of the communication module and the sensor module is turned off or on using the sleep or wake-up signals provided by the clock module.

[0044] The battery module consists of lithium batteries or dry cell batteries, providing a voltage range of 5-7V. Batteries with a self-discharge time greater than one year are required. The power management module converts the battery module's voltage, outputting 3.3V to the main control module and communication module while meeting the explosion-proof requirements of this coal mine project, ensuring no fire occurs under short-circuit conditions. To ensure the system can operate continuously for several months under battery power, in this embodiment, the power management module adopts a "sleep-wake" operating mode, such as... Figure 6 As shown, based on the clock, the power supply to the communication module and sensor module is turned off during sleep and turned on during wake-up, thereby maximizing system power saving.

[0045] Further, see Figure 7 As shown, the communication module includes: a communication antenna, an impedance matching circuit, a power amplifier drive circuit, a filter circuit, an analog-to-digital converter circuit, a modulation and decoding circuit, a control circuit, a digital-to-analog converter circuit, and a signal amplification circuit. The communication antenna is mounted on the sealed cabin and connected to the power drive circuit and the signal amplification circuit through the impedance matching circuit. The communication antenna transmits the radio frequency signal of the communication node to a metal cable via close-range coupling, and the metal cable receives the induced signal to achieve wireless communication networking with other communication nodes. Furthermore, the communication antenna is a symmetrical electric dipole antenna.

[0046] A symmetrical electric dipole antenna is used as the communication antenna and is connected to the power drive and signal amplification circuits through an impedance matching circuit. This antenna is connected to the internal circuit board via a sealed connector in the cabin and feeds the radio frequency communication signal to the metal cable or receives the induced signal through the cable using a close-range coupling (non-electrical connection) method, enabling wireless communication networking between this communication node and other nodes. The sensor module in the communication node can consist of sensors for CO, O2, methane, acetylene, ethylene, and temperature, used to collect environmental gas and temperature parameters.

[0047] In a preferred embodiment, the communication node is further encased in an insulating outer sheath and is placed around or fixed to the metal cable. The communication nodes are placed along the metal cable, and different spacing distances can be designed according to actual needs. The antenna of the communication node is closely coupled to the metal cable, typically requiring no electrical connection; energy exchange is achieved through near-electric field coupling to transmit information. If conditions permit, the antenna and the metal cable can also be electrically connected to further extend the communication distance.

[0048] For a goaf area 200 meters wide and 3000 meters deep, 200 to 400 communication nodes are needed to achieve full coverage. For details on establishing a wireless communication network between nodes, please refer to [link / reference needed]. Figure 8As shown, all communication nodes adopt a master-slave networking method. At the physical layer, OFDM technology and BPSK modulation can be used. At the MAC layer, a collision avoidance mechanism based on TDMA can be provided, supporting concurrent communication of multiple nodes. At the network layer, a one-master-many-slave networking mode can be implemented based on dynamic routing, multi-path addressing, etc., with a single master node supporting up to 300 slave nodes.

[0049] Furthermore, based on the above system, this embodiment of the invention also provides a fully buried space near-electric field coupled wireless networking communication method, comprising:

[0050] The antenna length of the communication node is set according to the communication carrier frequency of the application scenario, and the matching parameters of the communication node are adjusted. The metal cable laid longitudinally in the goaf area is used as the wireless communication channel. Each communication node pre-set in the goaf area and coupled in the near field with the metal cable is connected to other nodes through cable-borne communication to build a wireless communication network.

[0051] A communication node connected to the working face end of the metal cable is set as the main communication node, and other communication nodes on the metal cable are set as slave communication nodes. The environmental data of the goaf collected by the slave communication nodes is aggregated to the main communication node of the working face using a wireless communication network. The host computer connected to the main communication node of the working face analyzes and processes the received environmental data to achieve monitoring of the environment of the completely buried space.

[0052] The communication node uses its own symmetrical electric dipole antenna to couple with the cable in a near-electric field, feeding electromagnetic waves of a preset carrier frequency to the metal cable or receiving signals transmitted by other communication nodes; among multiple communication nodes, the nodes form a network in a master-slave mode to realize data interaction.

[0053] Furthermore, each communication node is placed around the metal cable or electrically insulated from and fixed to the metal cable, and adjacent communication nodes are deployed at predetermined intervals according to the application scenario. Different intervals can be designed according to actual needs.

[0054] Wireless communication frequencies typically range from 2MHz to 8MHz to ensure high penetration and a large communication bandwidth. In scenarios requiring long-distance communication with minimal antenna size constraints, frequencies from 0.1MHz to 0.5MHz can also be used. After determining the antenna size of the communication node, the impedance matching parameters of the communication module circuit within the communication node are adjusted according to the communication frequency. Metal cables and communication nodes are deployed in the buried layer within a fully buried space, while main control nodes are deployed at the coal face. The communication nodes utilize their built-in temperature and gas sensors to acquire surrounding environmental parameters. These parameters are then encoded, modulated, and fed to a symmetrical electric dipole antenna via a drive circuit at a specific carrier frequency. The dipole antenna senses the near-field electric field in the metal cable. The dipole antenna at the far-end node receives this signal from the cable, amplifies, demodulates, and decodes it, enabling wireless data communication. Each communication node sends and receives data to designated addresses according to a communication protocol.

[0055] To verify the effectiveness of this solution, the following explanation is based on experimental data:

[0056] Using a lake as the test scenario, such as Figure 9 As shown, the water depth is 3 meters, the lake bottom is muddy, and the experiment uses two communication nodes, one located at the bottom of the lake and the other at the surface, with a horizontal distance of 100 meters between them. The communication transmission power is 500mW, the communication rate is 9600bit / s, and the communication interval is 1s.

[0057] By selecting a communication frequency f and setting the parameters of a symmetrical electric dipole antenna and its matching circuit at that frequency, the dipole antenna, consisting of a coaxial cable with an outer shield and watertight end faces, is tested. The communication module cyclically sends 10 bytes of the sequence "0x11 0x33 0x55 0x77 0x99 0xAA 0xCC 0xBB 0x66 0x88" at 1-second intervals. A Cat6 cable (10mm diameter, 150m long, with insulation) is used as the metal cable. One end of the cable is tied to a communication node and submerged in the lake, while the other end extends above the water and is in close contact with another communication node (ensuring a certain distance is sufficient, but physical contact is not required). The surface communication node is then connected to a computer and a spectrum analyzer to observe whether the signal transmitted underwater can be received and demodulated / decoded.

[0058] Experimental results are as follows Figure 10 and 11 As shown, from Figure 10 The spectrum diagram shows the signal is above 20dB, while the waterfall plot shows an evenly spaced signal transmission rhythm. From... Figure 11The demodulation results show that the surface communication node can accurately demodulate the data sent by the underwater communication node. Based on the above data, it can be concluded that the proposed solution can be used to solve the problem of wireless networking communication under completely buried conditions such as coal mine goaf areas or deep-sea underwater environments.

[0059] Unless otherwise specifically stated, the relative steps, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention.

[0060] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to the method section.

[0061] The units and method steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of each example have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations are not considered to be beyond the scope of this invention.

[0062] Those skilled in the art will understand that all or part of the steps in the above methods can be implemented by a program instructing related hardware, and the program can be stored in a computer-readable storage medium, such as a read-only memory, a disk, or an optical disk. Optionally, all or part of the steps in the above embodiments can also be implemented using one or more integrated circuits. Accordingly, each module / unit in the above embodiments can be implemented in hardware or as a software functional module. This invention is not limited to any particular combination of hardware and software.

[0063] Finally, it should be noted that the above-described embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and not to limit it. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the technical scope disclosed in the present invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A fully buried space near electric field coupling type wireless networking communication system, characterized by, Comprise: a plurality of slave communication nodes for collecting space environment data, the plurality of slave communication nodes are arranged on the metal cable in the goaf and communicate with the corresponding metal cable segment in near field coupling, and a wireless networking network is formed between each slave communication node and the corresponding metal cable segment; and a master communication node for collecting the environment data of each slave communication node and realizing the monitoring of the goaf environment by connecting with the host computer, the master communication node is arranged on the working face of the goaf, and one end of the metal cable is connected with the master communication node, and the other end longitudinally penetrates the goaf and extends to the completely buried space; The communication node comprises: a sealed cabin body, and a sensor module arranged in the sealed cabin body for collecting environmental gas and temperature data, a master control circuit module connected with the sensor module, a communication module for wireless communication networking with other nodes, a battery module for providing voltage for the node, and a power management module for converting and outputting the voltage of the battery module; the communication module comprises: a communication antenna, an impedance matching circuit, a power amplifier driving circuit, a filter circuit, an analog / digital conversion circuit, a modulation and decoding circuit, a control circuit, a digital / analog conversion circuit and a signal amplification circuit, the communication antenna is installed on the sealed cabin body and connected with the power driving circuit and the signal amplification circuit through the impedance matching circuit, and the communication antenna sends the radio frequency signal of the communication node to the metal cable in a near field coupling mode, and the metal cable receives the induced signal to realize wireless communication networking with other communication nodes; the communication antenna adopts a symmetrical electric dipole antenna.

2. The fully buried space near electric field coupled wireless mesh networking communication system according to claim 1, wherein, The cabin body comprises: a cylindrical shell made of stainless steel, a breathable waterproof valve arranged on one end face of the cylindrical shell, and a sealed plug-in connector arranged on the other end face of the cylindrical shell for connecting an external communication antenna, and a buried prevention filter screen is further arranged on the cylindrical shell for preventing the breathable waterproof valve from being blocked.

3. The fully buried space near electric field coupled wireless mesh networking communication system according to claim 1, wherein, The power management module is provided with a clock module for providing sleep and wake-up signals of both the communication module and the sensor module, and the sleep or wake-up signals provided by the clock module are used to close or open the power supply of the communication module and the sensor module.

4. The fully buried space near electric field coupled wireless mesh networking communication system according to claim 1, wherein, The communication node is further wrapped with an insulating outer skin, and the communication node is placed around or fixed on the metal cable.

5. A method for completely buried space near electric field coupling type wireless networking communication, characterized in that, Based on the system implementation of claim 1, the following is contained: According to the application scenario, the communication node antenna length is set and the communication node matching parameters are adjusted according to the communication carrier frequency; the metal cable longitudinally laid in the goaf is used as a wireless communication channel, and each communication node prearranged in the goaf and in near field coupling with the metal cable constructs a wireless communication networking network with other nodes through cable communication; The communication node connected with the working face end of the metal cable is set as the master communication node, and the other communication nodes on the metal cable are set as slave communication nodes, the wireless communication networking network is used to collect the goaf environment data collected by the slave communication nodes to the working face master communication node, and the host computer connected with the working face master communication node is used to analyze and process the received environment data to realize the monitoring of the completely buried space environment.

6. The fully buried space near electric field coupling type wireless networking communication method according to claim 5, wherein, The communication nodes are placed around the periphery of the metal cable or fixed electrically insulated from the metal cable, and the adjacent communication nodes are arranged at a predetermined distance according to the application scene.

7. The fully buried space near electric field coupling type wireless networking communication method according to claim 5 or 6, characterized by, The communication carrier frequency according to the application scene adopts a scene frequency interval of 2MHz-8MHz or a scene frequency interval of 0.1MHz-0.5MHz.

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