KR100921818B1 - High speed roaming and duplexing system in subway radio image transmission unit - Google Patents

Abstract

PURPOSE: A high-speed roaming and duplexing system in a subway radio image transmission apparatus is provided to perform the roaming to the same channel through a mesh ad hoc based on the RSSI of a basic method. CONSTITUTION: A high-speed roaming and duplexing system in a subway radio image transmission apparatus comprises the first wired communication module(210), the first wireless communication module(220), the second wireless communication module(280), the first switch(240), and a controller. The first wired communication module connects to an AP of a different ground device(200) or a platform through an optical cable to perform the radio communication with other ground devices.

Description

HIGH SPEED ROAMING AND DUPLEXING SYSTEM IN SUBWAY RADIO IMAGE TRANSMISSION UNIT}

The present invention relates to a high speed roaming and duplication system in a subway wireless image transmission apparatus, and a high speed roaming and duplication system in a subway wireless image transmission apparatus that can be provided without loss of bidirectional data to the wireless image transmission apparatus.

The subway wireless video transmission device is used by an engineer operating a subway train to monitor the platform in front of the driver's cab for hundreds of meters of history, proactively responding to various platform safety accidents such as falling from a suicide or inadvertent passengers and falling onto the screen door. It is a system to cope with.

In the history situation room, two to six CCTV images are displayed on one screen for the situation check of the platform, and the real-time monitoring and control is performed by transmitting the room status and operation status in the subway to the situation room. Through communication, you can check the safe operation of the subway in real time, and can communicate with each other in case of disaster, and provide additional services such as finding lost children, finding lost items, and broadcasting announcements of destinations.

In addition, it is designed to secure a large data rate to enable broadcasting, internet, and advertising services in train and train cabins. In other words, it can be designed to enable various services when the frequency bandwidth is extended.

In the conventional subway wireless video transmission device, when a large amount of data such as CCTV is wirelessly serviced by a means of transportation (bus, subway, high speed train, etc.) traveling at high speed, a delay occurs when a ground device requests roaming to the next ground device. There may be situations where communication is lost.

This is because the LCX cable is used to connect to the AP (Access Point, or AP) connected to the optical cable through the optical terminal box (FDF) in a point-to-point communication method or to increase the stability, but at the connection point of the cable without providing roaming When it is disconnected, it is impossible to check, and communication failure may occur.

In addition, when a vehicle moving at high speed transmits platform image and other content information to a wireless transmission device at 18Ghz during operation, communication loss may occur due to a defect of 18Ghz band equipment.

Since the conventional method uses the AP, the link may be interrupted because a breakage phenomenon occurs for the time difference when the channel is changed.

Products currently on the market use RSSI as a default parameter to roam, resulting in inter-channel interference when using adjacent channels simultaneously, and delays when switching from the ground device in service to the channel of the next ground device when the train moves. I had a problem that could be missing.

In general, the subway (railroad) has a frequency for the wireless video transmission device, a time division duplex (TDD) transmission and reception device capable of large-capacity transmission in the wireless video transmission device and 2.4Ghz of the ISM band when roaming, 5Ghz and 18Ghz bands are available.

Accordingly, the present invention is to solve the above-mentioned conventional problems, an object of the present invention is to use a MAC address translator method for supporting uninterrupted high-speed roaming, mesh based on RSSI of the basic method when high-speed roaming By roaming to the same channel through ad hoc, there is no time difference when changing from on-board to the channel of the next terrestrial device, and by using the same channel, it is possible to perform roaming at high speed without interference between channels in the overlapping section with adjacent ground equipment. To provide a high-speed roaming and redundancy system in the subway wireless video transmission apparatus.

In the present invention, when an abnormality occurs in the optical cable and the optical box when connecting the terrestrial devices (MP), it is immediately switched to 5 GHz, and is connected to the adjacent terrestrial device according to the mesh ad hoc to maximize the backhaul redundancy effect, as well as the 18 GHz band. If there is a communication interruption during data and video transmission, the MP (ground and onboard equipment) is immediately switched to the 5GHz band, and the redundancy effect can be prevented and the stability is secured. To provide a roaming and redundancy system.

In addition, since the present invention uses two bands of frequency, the same effect as that of constructing redundant transceiver equipment can be achieved, and the TCP / IP port is provided as four ports in the MP (ground and in-vehicle device) to further interwork multiple devices. To provide a high-speed roaming and redundancy system in the subway wireless video transmission device capable of.

And the present invention is to provide a high-speed roaming and redundancy system in the subway wireless video transmission apparatus that can easily find and maintain the wireline backhaul failure point in the communication failure state due to the mesh ad hoc technology in the control room.

According to an aspect of the high-speed roaming and redundancy system in the subway wireless video transmission apparatus according to an embodiment of the present invention for achieving the above object, the first wired communication module for connecting to the AP of the other ground apparatus or platform via an optical cable; A first wireless communication module for performing wireless communication with the other terrestrial or on-vehicle device through a first data transmission band, and a second wireless communication module for performing wireless communication with the on-vehicle device and a second data transmission band; A first switch for switching the transmitted / received data to the first wired communication module, the first wireless communication module, or the second wireless communication module; It may include a terrestrial device having a control unit for switching to the first wireless communication module through the first switch when the communication of the first wired communication module occurs.

When the RSSI transmitted / received through the first wireless communication module is lower than a predetermined value, the controller of the terrestrial device switches to the second wireless communication module to perform data communication.

Here, the on-vehicle device comprises: a third wireless communication module for performing data communication with the terrestrial device through a first data transmission band; A fourth wireless communication module for performing data communication with the terrestrial device through a second data transmission band; A second switch for switching the third wireless communication module and the fourth wireless communication module; And a monitoring module for monitoring data transmitted / received through the second switch to a user, and mounted in front and rear cabs of the electric vehicle.

The on-vehicle devices are independently operated in front and rear cabs of an electric vehicle, and each NVR (Network) is assigned an independent IP address and performs digital conversion for data received through the third or fourth wireless communication module. Video Recorder) may be further included.

In addition, the on-vehicle device, at least one room, a display module;

CCTV cameras to view room conditions; And a third switch interlocked with the display module and the CCTV camera and connected with a second switch of the cab.

The on-vehicle device is generated when an input signal of more than a reference value allowed for the LNA is introduced into a low noise amplifier (LNA) of the receiver by increasing radio signal density and received signal strength when adjacent to the ground apparatus in a closed tunnel space. It may further include a transmission power controller (TPC) to prevent the phenomenon of RF saturation.

Meanwhile, the ground apparatus and the onboard apparatus perform handoff through the IEEE 802.11S protocol.

In addition, the on-vehicle device provides a DMB TV, advertisement, or Internet service through a display module installed in a guest room.

In addition, the above ground and on-vehicle devices operate by separating the frequency and the channel by uploading the heating and the cabin transmission, downloading the train monitoring and the platform information transmission, and the bandwidth of the frequency is 24Mbps.

As described above, according to the high-speed roaming and redundancy system in the subway wireless image transmission apparatus according to the present invention, even if an abnormality occurs in the image of the platform and the line transmitted to the electric vehicle, the image may be provided in a frequency band having good signal strength. There is an excellent effect that the driver of the electric vehicle can always check the interior of the platform and the image of the track.

In addition, the present invention has another effect that can realize high-speed roaming by reducing the time difference caused by the change by changing the same frequency channel using a mesh ad hoc method.

In addition, the present invention can monitor not only the platform image but also the train control signal through the network connecting the history, the general command room and the communication branch, so that the operation status of various onboard equipments can be integrated and monitored and managed. The ability to manage devices and onboard devices in both directions has another outstanding effect that can significantly improve the safety and reliability of the surveillance system.

Hereinafter, a preferred embodiment of a high speed roaming and redundancy system in a subway wireless image transmission apparatus according to the present invention will be described in detail with reference to the accompanying drawings. At this time, it will be understood by those of ordinary skill in the art that the system configuration described below is a system cited for the purpose of the present invention and does not limit the present invention to the following system.

1 is a view showing the configuration of a high speed roaming and redundancy system in a subway wireless video transmission apparatus according to an embodiment of the present invention, the high speed roaming and redundancy system in the subway wireless video transmission apparatus according to the present invention IT management center (100) , At least one ground device 200, and the on-vehicle device 300.

Here, the IT management center 100 is a place capable of backing up the data required for operating the train as an operating server, EMS server, storage server, streaming server, wireless monitoring server, integrated control device, and storage without a reference number It may be configured as, and may further include an existing backbone and a new backbone.

On the other hand, 2-6 CCTV cameras are installed in the platform to capture the status of the platform.

The history communication machine room can store the video information of the platform, and is equipped with a VDA and an encoder for compressing. The video information and data are stored through the Access Gateway and connected to each terrestrial device 200 through an optical cable. It consists of an optical terminal box (FDF).

The terrestrial device 200 configures each redundancy through a wireless network, a wired-wireless network, and a wired network to enable stable data transmission even in the event of a component failure. By simultaneously supporting the 5Ghz band to switch to the 5Ghz band when 18Ghz failure, the ground apparatus 200 is the first wired communication module 210, the first wireless communication module 220, the second as shown in FIG. The wireless communication module 230, the first switch 240, and the controller 250 are included.

The first wired communication module 210 of the ground apparatus 200 may be connected to another ground apparatus 200 or an AP 20 of a platform via an optical cable to transmit / receive data.

In addition, the first wireless communication module 220 of the ground apparatus 200 performs wireless communication with the other ground apparatus 200 or the on-vehicle apparatus 300 through a first data transmission band.

In addition, the second wireless communication module 230 of the terrestrial device 200 performs wireless communication with the on-vehicle device 300 through a second data transmission band.

The first switch 240 of the terrestrial device 200 switches the data transmitted / received to the first wired communication module 210, the first wireless communication module 220, or the second wireless communication module 230. Here, the first switch 240 may be an L2 switch, and may further include a surge protector that is supplied with power through an AC / DC converter and protects 80KA to a single-phase 220V for protecting lightning and ground faults.

In addition, the controller 250 of the ground apparatus 200 switches to the first wireless communication module 220 through the first switch 240 when a failure occurs in the communication of the first wired communication module 210. When the RSSI transmitted / received through the communication module 220 becomes lower than or equal to a preset value, the RSSI is transferred to the second wireless communication module 230 to perform data communication.

In addition, the on-vehicle device 300 performs wireless communication with the ground apparatus 200 through the first data transmission band and the second data transmission band, and is interlocked with a train control system capable of receiving each passenger car monitoring and train operation information. 3 and 4, the on-vehicle device 300 includes a third wireless communication module 310, a fourth wireless communication module 320, a second switch 330, an NVR 340, and a monitoring module. It includes 350, and the carriage is connected to the second switch 330 through a third switch.

The third wireless communication module 310 of the on-vehicle device 300 performs data communication with the terrestrial device 200 through a first data transmission band.

In addition, the fourth wireless communication module 320 of the on-vehicle device 300 performs data communication with the terrestrial device 200 through a second data transmission band.

The second switch 330 of the on-vehicle device 300 switches the third wireless communication module 310 and the fourth wireless communication module 320 and transmits / receives data with the monitoring module 350. In this case, the second switch 230 is an L3 switch, which supports Layer 3 function, and manages L2 such as copper Gigabit 4 port, SFP 2 port, VLAN, QoS, and Rmon.

In addition, the monitoring module 350 of the on-vehicle device 300 monitors the data received through the ground device 200 or each passenger car through the second switch 330 to the user or the driver.

Meanwhile, the NVRs 340 of the on-vehicle device 300 operate independently from each other in the front and rear cabs of the electric vehicle, and are assigned an independent IP address and are provided through the third wireless communication module 310 or the fourth wireless communication module 320. Perform digital conversion on the received data. Here, the NVR 340 is capable of splitting 32 channel IP inputs 1, 4, 8, and 32 texts, and has a touch screen, and functions as a storage and a display.

Here, each cabin of the on-vehicle device 300 includes a display module, and may provide DMB TV, advertisements, or Internet services through the display module installed in the cabin.

In addition, the CCTV cameras in each room of the on-vehicle device 300 provide room situation information.

The third switch of each room of the on-vehicle device 300 is interlocked with the display module and the CCTV camera, and is connected with the second switch 330 of the cab, Copper Gigabit 4 Port, SFP 2 Port, VLAN, QoS, Rmon, etc. It consists of L2 management.

Meanwhile, when the TPC of the on-vehicle device 300 is adjacent to the terrestrial device 200 in an enclosed tunnel space, the radio signal density and the received signal strength are increased, and an input signal of more than a reference value allowed for the LNA is introduced into the LNA of the receiver. Prevents RF saturation from occurring.

Here, the ground apparatus 200 and the on-vehicle apparatus 300 perform a handoff through the IEEE 802.11S protocol.

As shown in FIG. 5, the ground apparatus 200 and the on-vehicle apparatus 300 operate by separating the frequency bands and channels of the merchant ship and the shipowner, and uploading of heating and cabin transmissions, train monitoring and platform information transmission. By downloading and operating the frequency and channel separately, it is possible to simultaneously provide merchants, ships, uploads and downloads. That is, the time division duplex (TDD) method for large capacity transmission and the 2.4GHz, 5GHz, and 18GHz bands of the ISM band are used when roaming.

At this time, the frequency and channel separation is divided into six channels in the 18.86 ~ 18.92 GHz band and six channels in the 19.20 ~ 19.26 GHz band according to the frequency distribution notice for the wireless video transmission device to prevent crosstalk and interference, respectively The bandwidth of the frequency is 24Mbps.

Here, the terrestrial device 200 and the on-vehicle device 300 uses a communication standard IEEE802.11S mesh protocol, the communication modulation method is capable of data transmission in BPSK, QPSK, 16QAM using OFDM and 20MHz bandwidth Up to 64QAM is supported. Ethernet can be transmitted at 10 / 100Mbps, and it is equipped with 4 ports so that VoIP and other interworking devices can be added as needed.

General functions and detailed operations of the above-described elements will be omitted, and the operations will be described based on operations corresponding to the present invention.

First, as shown in FIG. 6, a tunnel wireless environment is implemented to implement a seamless video transmission between a vehicle apparatus 200 installed in a train moving at 80 km / h in a tunnel in a subway and a ground apparatus 200 installed in a tunnel. Considering this, we select the optimal installation location and derive the installation interval by calculating the coverage to guarantee the data bandwidth.

In addition, by applying IEEE802.11s, a communication protocol that can implement seamless handoff, it supports fast dynamic automatic connection / reconnection and consists of self-forming and self-Healing protocol network load control and data transmission congestion control protocol. It provides zero packet loss between wireless transmitters and receivers, and supports mobility for real-time video / high quality voice (VoIP).

Therefore, the network is designed to allow 16QAM or more modulation by OFDM modulation as shown in FIG. 7, and the communication radius that can guarantee a data rate of 8Mbps or more with a rated output of 100mW is about 500m, and the interval between stations is 1Km on average. Therefore, an average of two ground apparatuses 200 in one direction (upper or lower vessel) per station is required, and additional ground apparatuses 200 are required depending on the propagation environment such as obstacles in a curved section and a tunnel.

It also provides 8 ~ 12Mbps throughput with 10MHz bandwidth for scalability and 20 ~ 24Mbps throughput when using 20MHz bandwidth. Automatic mesh network is set up when wireless transmitter (node) is added.

As illustrated in FIG. 8, at least one or more terrestrial devices 200 may be configured to provide redundant data through a wireless network, a wired-wireless network, and a wired network, so that stable data transmission may occur even when a component failure occurs. Wireless network redundancy is dual-radio application and supports 18Ghz band and 5Ghz band at the same time. In other words, when the problem occurs due to the commercial use of 18GHz of the "frequency distribution plan for subway wireless video transmission" and "transit safety and public purpose" notice issued by the Ministry of Information and Communication (2007.9.20), it operates at 5GHz without replacing the system. Can have the advantage that can be implemented as a redundant system.

Therefore, the first wired communication module 210 of the ground apparatus 200 is connected to the AP 20 of the other ground apparatus 200 or the platform through an optical cable.

Also, the first wireless communication module 220 of the ground apparatus 200 may perform wireless communication with another ground apparatus 200 or the on-vehicle apparatus 300 through a first data transmission band.

The second wireless communication module 230 of the terrestrial device 200 may perform wireless communication with the on-vehicle device 300 through a second data transmission band.

In this state, when the communication of the first wired communication module 210 occurs as shown in FIG. 8, the controller 250 of the ground apparatus 200 receives the first wired communication module 210 through the first switch 240. The communication with the other terrestrial device 200 is transferred to the first wireless communication module 220 to maintain data communication between the terrestrial devices 200.

Meanwhile, when the RSSI transmitted / received with the on-vehicle device 300 through the first wireless communication module 220 is lowered below a preset value, the controller 250 of the terrestrial device 200 receives another communication module, that is, the second communication module. Transfer to the wireless communication module 230 to maintain data communication with the on-vehicle device 300.

Meanwhile, during the channel setting and changing, the frequency channel setting and changing of the first wireless communication module 210 and the second wireless communication module 220 can be changed remotely using NMS S / W and installed in all stations in the same direction ( The first wireless communication module 210 and the second wireless communication module 220 of the upper line or the lower line are uniformly used in one channel, and operate (mesh routing) by mesh networking instead of interference in the wireless transmission / reception period.

Meanwhile, the third wireless communication module 310 of the on-vehicle device 300 performs data communication with the terrestrial device 200 through a first data transmission band, and the fourth wireless communication module 320 is the ground device 200. And data communication through a second data transmission band, and the second switch 330 switches the third wireless communication module 310 and the fourth wireless communication module 320 and transmits data to the monitoring module 350. / Receiving, the monitoring module 350 monitors the data transmitted and received via the second switch 330 to the user or driver. In this case, the NVR 340 is independently operated in the front and rear cab of the electric vehicle, the independent IP address is assigned to the digital for the data received through the third wireless communication module 310 or the fourth wireless communication module 320 You can perform the conversion.

Here, each cabin of the on-vehicle device 300 includes a display module, and provides a DMB TV, an advertisement, or an Internet service through the display module installed in the cabin.

And the CCTV camera of each room of the on-vehicle device 300 provides room status information.

The third switch of each cabin of the on-vehicle device 300 is interlocked with the display module and the CCTV camera and connected with the second switch 330 of the cab.

As shown in FIG. 9, the on-vehicle device 300 is configured to have an optimal communication environment since negotiation that needs to be changed to a corresponding channel is eliminated whenever entering each station.

As shown in FIG. 10, when the TPC of the on-vehicle device 300 is adjacent to the terrestrial device 200 in an enclosed tunnel space, the radio signal density and the received signal strength are increased, so that the LNA of the receiver is above the reference value allowed for the LNA. It is possible to prevent the RF saturation caused by the input signal.

Here, the ground apparatus 200 and the on-vehicle apparatus 300 perform a handoff through the IEEE 802.11S protocol.

It integrates the platform image and contents data installed in the history and train operation information and transmits it wirelessly to the train, and integrates the operation status of various equipment in the history as well as the platform image through the network connecting the history, general command room and communication branch. It can manage and monitor the train control information in both directions and securely modify the transmission of only one-way video, and monitor the station's platform status in dual way by the train driver and the general command room to view various accidents in the urban railway. It is possible to build a stable monitoring system that can effectively prevent, transmit train control signals more stably, and respond immediately to the occurrence of historical equipment failures.

Although the present invention has been described in detail only with respect to the specific embodiments described, it will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the present invention, and such modifications and modifications belong to the appended claims. .

1 is a view showing the configuration of a high-speed roaming and redundancy system in the subway wireless image transmission apparatus according to the present invention.

FIG. 2 is a functional block diagram illustrating a detailed configuration of a terrestrial device among high-speed roaming and redundancy systems in the subway wireless video transmitting apparatus according to FIG. 1.

3 is a view showing the configuration of a vehicle in the high-speed roaming and redundancy system in the subway wireless image transmission apparatus according to FIG.

FIG. 4 is a diagram illustrating a detailed configuration of an on-vehicle device among high-speed roaming and redundancy systems in the subway wireless video transmitting apparatus according to FIG. 1.

FIG. 5 is a view illustrating a state in which frequency bands and channels of merchant ships and ships are separated and operated in a high-speed roaming and duplication system in the subway wireless video transmitting apparatus according to FIG. 1; FIG.

FIG. 6 is a view illustrating a link setup between a terrestrial device and a car-mounted device in a high speed roaming and redundancy system in the subway wireless video transmission device according to FIG. 1.

FIG. 7 is a view showing a ground apparatus installed in a subway in a high speed roaming and redundancy system in the subway wireless video transmitting apparatus according to FIG. 1.

FIG. 8 is a view illustrating duplication between terrestrial devices or between terrestrial devices and on-vehicle devices in a high-speed roaming and redundancy system in the subway wireless video transmitting apparatus according to FIG. 1;

FIG. 9 is a view illustrating a channel change between a terrestrial device and an onboard device in a high speed roaming and redundancy system in the subway wireless image transmission device of FIG. 1; FIG.

FIG. 10 is a diagram illustrating a TPC technology in a high speed roaming and redundancy system in the apparatus for transmitting subway wireless video according to FIG. 1.

<Explanation of symbols for the main parts of the drawings>

100: IT Management Center

200: at least one or more ground apparatuses 210: first wired communication module

220: first wireless communication module 230: second wireless communication module

240: first switch 250: control unit

300: on-vehicle device 310: third wireless communication module

320: fourth wireless communication module 330: second switch

340: NVR 350: monitoring module

Claims (10)

A high speed roaming and redundancy system in a subway wireless video transmission device that communicates with an IT management center, at least one ground device, and at least one onboard device, A first wired communication module connecting the AP with another ground apparatus or platform through an optical cable; A first wireless communication module for performing wireless communication with the other terrestrial or on-vehicle device through a first data transmission band, and a second wireless communication module for performing wireless communication with the on-vehicle device and a second data transmission band; A first switch for switching the transmitted / received data to the first wired communication module, the first wireless communication module, or the second wireless communication module; High speed roaming and redundancy system in a subway wireless video transmitting apparatus including a ground device having a control unit for switching to the first wireless communication module through the first switch when a communication failure of the first wired communication module occurs. The method of claim 1, The control unit of the ground device, When the RSSI transmitted / received through the first wireless communication module becomes lower than a preset value, high speed roaming and duplexing in the subway wireless video transmitting apparatus is characterized in that the data transfer is performed by switching to the second wireless communication module. system. The method of claim 2, The on-vehicle device, A third wireless communication module for performing data communication with the terrestrial device through a first data transmission band; A fourth wireless communication module for performing data communication with the terrestrial device through a second data transmission band; A second switch for switching the third wireless communication module and the fourth wireless communication module; And a monitoring module configured to monitor data transmitted and received through the second switch to a user, wherein the high speed roaming and redundancy system is mounted in a front and rear cab of an electric vehicle. The method of claim 3, wherein The on-vehicle device, Each of the front and rear cabs of the electric vehicle is independently operated, and further includes an NVR (Network Video Recorder) which is assigned an independent IP address and performs digital conversion on the data received through the third wireless communication module or the fourth wireless communication module. High speed roaming and redundancy system in the subway wireless video transmission device, characterized in that. The method of claim 4, wherein The on-vehicle device, A display module in at least one room; CCTV cameras to view room conditions; And High speed roaming and redundancy system in the subway wireless video transmission device interlocking with the display module and the CCTV camera, the third switch connected to the second switch of the front and rear cab. The method of claim 5, The on-vehicle device, When adjacent to ground equipment in an enclosed tunnel space, the radio signal density and the received signal strength are increased to prevent the RF saturation caused by the inflow of the input signal above the reference value allowed for the LNA into the LNA (Low Noise Amplifier) of the receiver. High speed roaming and redundancy system in a subway wireless video transmission device further comprising a transmission power controller (TPC). The method of claim 1, The above ground device and the onboard device, A high speed roaming and redundancy system in a subway wireless video transmission device, characterized in that handoff is performed through the IEEE 802.11S protocol. The method of claim 5, The on-vehicle device, A high-speed roaming and redundancy system in a subway wireless video transmission device, characterized by providing a DMB TV, advertisement, or Internet service through a display module installed in a guest room. The method of claim 1, The above ground device and the onboard device, A high speed roaming and redundancy system in a subway wireless video transmission apparatus, characterized in that the frequency and channel are separated and operated by uploading heat transfer transmission and cabin transmission, and downloading train monitoring and platform information transmission. The method of claim 9, The bandwidth of the frequency is a high speed roaming and redundancy system in the subway wireless video transmission device, characterized in that 24Mbps.

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