This application claims priority to Korean Patent Applications No. 10-2022-0060363, filed on May 17, 2022, and Korean Patent Applications No. 10-2023-0051216, filed on Apr. 19, 2023, which is hereby incorporated by reference in its entirety.
The present disclosure relates to a technology for train control in a wireless communication system, and more particularly, to a technology for multiple accesses between a plurality of onboard train control terminals and a wayside device when configuring communication redundancy in a wireless communication system for train control.
Recently, wireless communication has been applied in train control, greatly reducing wayside infrastructures, such as track circuits for train control, and introduction of train signal control through moving blockage may remarkably increase line capacity. However, the stability and availability requirements of communication infrastructures for train control are as high as wired communication, and it is difficult to perfectly perform train control based on a single wireless communication infrastructure.
The present disclosure is directed to providing a method of configuring a redundancy network, a method of connecting an onboard terminal and a wayside device, and a method for multi-access and communication between multiple terminals and a wayside device with regard to implementing communication redundancy using a commercial Long-Term Evolution (LTE) network in a Long-Term Evolution-railway (LTE-R) based train control wireless communication.
According to an aspect of the present disclosure, there is provided a method of operating a network device for train control in a wireless communication system, the method including: generating control information for train control; providing a first control command to a first base station through a first interface based on the control information; and providing a second control command to a second base station through a second interface based on the control information, wherein the first control command or the second control command is provided to the first base station or the second base station through the first interface or the second interface via a first core network for train control, and one of the first base station and the second base station is connected to a second core network.
The first control command and the second control command may be generated by duplicating the control information.
The second core network may be a commercial network connected to the one of the first base station and the second base station through a commercial interface.
The method may further include: acquiring a third control command from the first base station through the first interface; acquiring a fourth control command from the second base station through the second interface; and determining whether the third control command and the fourth control command are abnormal, wherein the third control command and the fourth control command may be generated from another network device for train control.
The third control command may be acquired through a first router of the network device, the fourth control command may be acquired through a second router of the network device, and the first router and the second router may constitute virtual private network (VPN) tunneling.
The first control command may be provided to the first base station through the first router, the second control command may be provided to the second base station through the second router, and the first router and the second router may transmit or receive signals or data through tunneling with routers corresponding to the other network device.
The other network device may include two or more network devices, the first control command or the second control command may further include header information associated with one of the two or more network devices, and the method may further include providing the first control command or the second control command to a router device corresponding to one of the two or more network devices based on the header information.
According to an aspect of the present disclosure, there is provided a network device for train control in a wireless communication system, the network device including: a transceiver; and at least one controller operatively connected to the transceiver, wherein the at least one controller is configured to: generate control information for train control; provide a first control command to a first base station through a first interface based on the control information; and provide a second control command to a second base station through a second interface based on the control information, and wherein the first control command or the second control command is provided to the first base station or the second base station through the first interface or the second interface via a first core network for train control, and one of the first base station and the second base station is connected to a second core network.
The first control command and the second control command may be generated by duplicating the control information.
The second core network may be a commercial network connected to the one of the first base station and the second base station through a commercial interface.
The at least one controller may be further configured to: acquire a third control command from the first base station through the first interface; acquire a fourth control command from the second base station through the second interface; and determine whether the third control command and the fourth control command are abnormal, wherein the third control command and the fourth control command may be generated from another network device for train control.
The network device may further include a first router and a second router, wherein the first router acquires the third control command, and the second router may acquire the fourth control command, and the first router and the second router may constitute virtual private network (VPN) tunneling.
The first control command may be provided to the first base station through the first router, the second control command may be provided to the second base station through the second router, and the first router and the second router may transmit or receive signals or data through tunneling with routers corresponding to the other network device.
The other network device may include two or more network devices, the first control command or the second control command may further include header information associated with one of the two or more network devices, and the at least one controller may be configured to provide the first control command or the second control command to a router device corresponding to one of the two or more network devices based on the header information.
According to an aspect of the present disclosure, there is provided a system for train control in a wireless communication system, the system including: an onboard wireless communication device and a wayside wireless communication device, wherein the onboard wireless communication device is configured to: generate control information for train control; provide a first control command to a first base station through a first interface based on the control information; and provide a second control command to a second base station through a second interface based on the control information, and the wayside wireless communication device is configured to: acquire the first control command from the first base station through the first interface; acquire the second control command from the second base station through the second interface; analyze the first control command and the second control command to determine whether the first control command and the second control command are abnormal; and generate an operating signal corresponding to one of the first control command and the second control command that is determined to be normal.
The wayside wireless communication device and the onboard wireless communication device may provide or acquire the first control command or the second control command through virtual private network (VPN) tunneling.
The phrases “in some embodiments” or “in one embodiment” appearing in various places in this specification do not necessarily all refer to the same embodiments.
Some embodiments of the present disclosure may be represented by functional block configurations and various processing operations. Some or all of these functional blocks may be implemented with various numbers of hardware and/or software configurations that perform particular functions. For example, the functional blocks of the present disclosure may be implemented by one or more microprocessors, or by circuit configurations for a given function. Also, for example, the functional blocks of the present disclosure may be implemented in various programming or scripting languages. The functional blocks may be implemented with algorithms running on one or more processors. In addition, the present disclosure may employ conventional techniques for electronic configuration, signal processing, and/or data processing, and the like. Terms such as “mechanism,” “element,” “means,” and “configuration” and the like are widely used and are not limited to mechanical and physical configurations.
Also, the connection lines or connection members between the components shown in the drawings are merely illustrative of functional connections and/or physical or circuit connections. In actual devices, connections between components may be represented by various functional connections, physical connections, or circuit connections that can be replaced or added.
In general, communication infrastructures for train control require as high stability and availability as wired communication, so there are many difficulties in perfectly performing train control based on a single wireless communication infrastructure.
In order to resolve such a limitation, European train control systems have adopted a redundancy structure of train control wireless communication for global system for mobile communications-railway (GSM-R), as shown in
Referring to
GSM-R is assigned uplink and downlink bandwidths of 4 MHz and operates nineteen sub-channels each of 200 KHz, and the remaining 200 KHz is finely divided and used as a guard band between the sub-channels. Since GSM-R is based on a time division multiple access (TDMA) scheme, sub-channels used by each base station are not used by adjacent base stations, resulting in a frequency reuse rate set to 8 as shown in
In GSM-R, as a TDMA system, sub-channels are used without overlapping between base stations. However, in Long-Term Evolution (LTE), which is an orthogonal frequency domain multiple access (OFDMA) system, sub-channels are shared between base stations, so it is impossible to duplicate frequency coverage using the same frequency band without changing the wireless access specifications.
Referring to
Specifically, two LTE-railway (LTE-R) base stations using the same frequency band will inevitably have interference due to the nature of OFDMA using the same subcarrier, but when a commercial network system (e.g., LTE) is used, different frequency bands may be used so that redundancy of train control communication may be achieved.
The existing very high frequency (VHF) and trunked radio system (TRS)-based train communication method is being converted to use LTE-R, which is an LTE-based train communication network. As described above, there is a limitation in providing communication availability and stability for train control only with a single LTE-R communication due to the uncertainty of wireless communication.
Referring to the drawing illustrating redundancy of a train control system using LTE-R and commercial LTE, a communication path from wayside to onboard may be duplicated, so that when a certain apparatus on the communication path fails, the failure may be easily overcome through another path.
However, in this case, a railway communication network needs to be linked to a commercial LTE core network through an Internet interface. This violates the policy of operating the existing railway network as a closed network for safety and security. In addition, even when operating in such a structure, a strong security apparatus may need to be installed at the interface between the Internet network and the railroad network to protect the railroad network, which is a national security facility.
In order to construct a network structure that maintains train control communication in a closed network without linking to a commercial Internet network and additionally installing an apparatus, a base station sharing technology (radio access network sharing: RAN sharing) may be used. The base station sharing technology is a technology of sharing one base station to use in different core networks.
Referring to
Referring to
Wireless communication systems for train control may be divided into a wayside train control system and an onboard train control system depending on the installation location thereof. The wayside train control system or the onboard train control system may include a wayside wireless communication device or an onboard wireless communication device, or may be operatively connected to a wayside wireless communication device or an onboard wireless communication device to transmit or receive signals or data to or from the wayside wireless communication device or the onboard wireless communication device.
In
For example, train control data generated from an onboard train control system may be transferred to a redundancy device #1 through a switching hub #1, and the redundancy device #1 may copy and duplicate the train control data and transfer the duplicated train control data to each of a router #1 and a router #2. The router #1 having received the train control data may transfer the received train control data to a router #3 through an LTE-R terminal and an Internet service provider #1 (ISP #1) and the train control data may be transferred to a redundancy device #2. This is a transmission path through the LTE-R terminal. As for a transmission path through an LTE terminal, the duplicated train control data from the redundancy device #1 is transferred to the router #2, the router #2 transfers the train control data to a router #4 through the LTE terminal and an ISP #2, and then the train control data may be transferred to the redundancy device #2. The redundancy device #2 may be configured to inspect the two pieces of train control data transferred through different transmission paths for abnormalities, then select one of the pieces of train control data and transfer the selected train control data to a switching hub #2 so that the selected train control data is transferred to the wayside train control system.
First, virtual private network (VPN) tunneling may be configured between a router #1 (a router #2) and a router #3 (a router #4). The reason for configuring VPN tunneling for the section may be for virtualization and tunnel inter-component communication between the router #1 and the router #3 to maintain smooth communication even when Internet protocols (IPs) of the LTE-R terminal and the LTE terminal change. In general, LTE communication terminals may use a variable IP scheme. In other words, the IP may change from time to time with each network connection. In this case, when a call is disconnected during communication and reconnection is performed, the IP of the terminal may change, which causes a communication failure in the train control communication in which a communication session has previously been established. When a virtual network is configured through VPN tunneling, communication may be performable with a virtual address regardless of changes in the IP of the terminal, and data exchange between routers may be performed regardless of intermediate IP addresses through tunneling.
In
When the raw socket and VPN tunneling are used as described above, the packet structure {circle around (3)} and the packet structure {circle around (7)} become identical. This is taken to mean that the wireless communication network simply operates as a packet forwarding network, and the onboard train control system and the wayside train control system may be provided with convenience in independent network address management.
Here, multiple terminals may refer to a case in which the onboard wireless communication device or the wayside wireless communication device is provided in two or more units thereof. In train control communication, there may be cases in which a wayside wireless communication device needs to transmit train control data in linkage with multiple onboard wireless communication devices.
For example, when two onboard wireless communication devices are connected to a network, VPN tunneling may be configured as shown in
A wayside train control system may transfer train control data to a redundancy device #2 and perform data copy and SN insertion to transfer the received train control data along two routes. In addition, in response to confirming that the train control data is transmitted to an IP address of the onboard control system #1, the wayside train control system may configure data packets by adding an IP header having an IP address of the redundancy device #1 as a receiver, and transfer the data packets to each of the router #3 and the router #4.
The router #3 may check the received IP address header and determine whether to transfer the data through a tunnel of a first VLAN or a tunnel of a third VLAN. In this case, the wayside train control system may, upon checking that the packet is to be transferred to the redundancy device #1, transfer the data through the tunnel of the first VLAN.
The router #4 may check the received IP address header and determine whether to transfer the data through a tunnel of a second VLAN or a tunnel of a fourth VLAN. In this case, the wayside train control system may, upon checking that the packet is to be transferred to the redundancy device #1, transfer the data through the tunnel of the second VLAN.
At the router #1 and the router #2, the train control data transmitted to the respective tunnels may be transferred to the redundancy device #1, and the redundancy device #1 may discard one of the duplicated two packets of train control data based on the SN, and finally transmit the remaining train control data to the onboard train control system #1.
A wayside train control system may transfer train control data to a redundancy device #2 and perform data copy and SN insertion to transfer the received train control data along two routes. In addition, in response to confirming that the train control data is transmitted to an IP address of the onboard control system #2, the wayside train control system may configure data packets by adding an IP header having an IP address of the redundancy device #3 as a receiver, and transfer the data packets to each of the router #3 and the router #4. For the router #3, the wayside train control system may check the received IP address header and determine whether to transfer the data through a tunnel of the first VLAN or a tunnel of the third VLAN. In this case, the wayside train control system may, upon checking that the packet is to be transferred to the redundancy device #3, transfer the data through the tunnel of the third VLAN.
The router #4 may check the received IP address header and determine whether to transfer the data through a tunnel of the second VLAN or a tunnel of the fourth VLAN. In this case, the wayside train control system may, upon checking that the packet is to be transferred to the redundancy device #3, transfer the data through the tunnel of the fourth VLAN.
At the router #5 and the router #6, the train control data transmitted with the respective tunnels may be transferred to the redundancy device #3, and the redundancy device #3 may discard one of the duplicated two packets of train control data based on the SN, and finally transmit the remaining train control data to the onboard train control system #2.
Referring to
In operation S110, the network device generates control information for train control.
The control information may be basic information for generating at least one of a first control command or a second control command to be described below. In addition, according to an embodiment of the present disclosure, the control information may further include data. For example, the network device may generate or acquire data along with control information.
In operation S120, the network device provides a first control command to a first base station through a first interface based on the control information. A first control command or a second control command may be provided to a first base station or a second base station through a first interface or a second interface via a first core network for train control.
One of the first base station and the second base station may be connected to a second core network. Here, the second core network may be a commercial network connected to one of the first base station and the second base station through a commercial interface. For example, when the first core network is an LTE-R network, the second core network may be a commercial LTE network. In addition, the first control command and the second control command may be control commands generated by duplicating the control information.
The network device may provide data regarding the first base station along with the first control command to the first base station through the first interface.
In operation S130, the network device provides the second control command to the second base station through the second interface based on the control information.
The network device may provide data regarding the second base station along with the second control command to the second base station through the second interface.
The network device may further perform operations described below independently of the above-described operations.
The network device may acquire a third control command from the first base station through the first interface. In addition, the network device may acquire a fourth control command from the second base station through the second interface. Here, the third control command and the fourth control command may be control commands that are generated and provided through another network device.
The third control command may be acquired through a first router of the network device, the fourth control command may be acquired through a second router of the network device, and the first router and the second router may compose VPN tunneling.
In addition, the first control command may be provided to the first base station through the first router, the second control command may be provided to the second base station through the second router, and the first router and the second router may be configured to transmit or receive signals or data through tunneling with routers corresponding to the other network device.
Then, the network device may determine whether the third control command and the fourth control command are abnormal.
The above-described embodiment relates to an environment in which only one other network device is present, but there may be two or more other network devices according to various embodiments of the present disclosure.
In this case, the first control command or the second control command may further include header information associated with one of the two or more network devices, and the first control command or the second control command may be provided to a router device corresponding to one of the two or more network devices based on the header information.
As is apparent from the above, the present disclosure provides a solution to overcome security issues that can occur when communication redundancy is implemented in a wireless communication system for train control using a base station sharing method.
In addition, the present disclosure enables efficient and simple processing of transmitted and received input/output packets through a raw socket technique and a virtual private network (VPN) tunneling technique, and even with communication interruption and reconnection, overcomes communication issues through a virtual network using a variable terminal Internet protocol (IP).
In addition, the present disclosure proposes a method of determining a communication path based on packet header received IP information even in a multi-access communication environment of terminals, thereby providing a technology capable of enabling smooth uplink/downlink communication even in a multi-access environment.
As described above, the embodiment of the present invention is not implemented only through the above-described apparatus and/or method, but through a program for realizing a function corresponding to the configuration of the embodiment of the present invention, a recording medium on which the program is recorded, and the like.
Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements performed by those skilled in the art using the basic concepts of the present invention defined in the following claims also belong to the scope of rights of the present invention.
The above are specific embodiments for carrying out the present disclosure. The present disclosure will include not only the above-described embodiments, but also simple design changes or easily changeable embodiments. In addition, the present disclosure will include techniques that may be easily modified and implemented using the embodiments. Accordingly, the scope of the present disclosure should not be limited to the above-described embodiments, but should be defined by the claims and equivalents of the present invention as well as the claims to be described below.
Number | Date | Country | Kind |
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10-2022-0060363 | May 2022 | KR | national |
10-2023-0051216 | Apr 2023 | KR | national |