CN102497429B - Multi-redundancy processing method for train-ground data transmission in rail transit - Google Patents
Multi-redundancy processing method for train-ground data transmission in rail transit Download PDFInfo
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Abstract
The invention discloses a multi-redundancy processing method for train-ground data transmission in rail transit. The method is characterized in that: a redundancy design is adopted for all hardware related to security transmission, wherein 1, dual wireless network cards are used for a trackside access point (AP) and vehicular stations (STA); 2, a vehicular STA is configured at each of the head and tail of a train, and the STAs at the head and tail of the train are connected with each other through a special train line to realize mutual hot backup; 3, a central communication gateway is subjected to redundancy configuration to realize the mutual hot backup of the two STAs; 4, the redundancy design is adopted for a trackside data transmission network; and 5, wireless signals can realize complete redundancy coverage. Four copies are made by the central communication gateway for a downlink data message which is transmitted to a vehicular application host by a ground application host, transmitted to a destination train through four different wireless links, verified by an STA corresponding to a vehicular destination host and transmitted to the destination host; and an uplink data message in an opposite direction is subjected to the same processing. By the multi-redundancy processing method, identical data can be transmitted through a plurality of different links at the same time, the influence of a single point failure on data transmission quality in a system is avoided, the packet loss rate of the system reaches 10<-6> magnitude, and data transmission security is high.
Description
Technical field
The present invention relates to car-ground transfer of data multiple redundancy treatment mechanism in a kind of track traffic, especially a multi-chain circuit transmission technology that provides the car-ground double-direction radio data communication of high reliability, high availability to design for urban track traffic CBTC system, specifically a kind of multi-redundancy processing method for train-ground data transmission in rail transit.
Background technology
As everyone knows, early stage railway signal system mainly utilizes interlock device to guarantee that train is safe by assigned direction on fixing track, operation effectively.Current, along with developing rapidly of computer, communication and the automatic technology of controlling, city rail traffic signal system has developed into an advanced automatic control system---and be train automatic controlling system (being called for short ATC system), it is the principal security of train safe, efficient operation.ATC system develops into current movable block system by early stage fixed blocking system---based on communication Train Control (CBTC), data communication system (DCS) is intended to solve the key issue in car-ground transmission in CBTC system, in train high-speed mobile process, guarantees that train is connected with trackside network reliable and stable.Transmission CBTC high security message can not produce packet loss phenomenon, and any Single Point of Faliure of simultaneity factor does not affect the transmission of CBTC safe packet.
The reliabilty and availability of at present conventional raising transfer of data, the mode that redundant ability is provided is mainly to set up A, two wireless networks of B simultaneously.
Summary of the invention
The object of the invention is, according to the demand of high security and high reliability request in CBTC transfer of data, to invent a kind of multi-redundancy processing method for train-ground data transmission in rail transit.
Technical scheme of the present invention is:
A multi-redundancy processing method for train-ground data transmission in rail transit, is characterized in that the hardware relevant with safe transmission all to adopt Redundancy Design, and described hardware redundancy design comprises: in trackside AP and vehicle-mounted STA, use two wireless network cards 1.; 2. at headstock and the tailstock, all configure vehicle-mounted STA, and headstock and tailstock STA all interconnect by professional train line, realize hot standby each other; 3. make the configuration of center to center communications gateway redundancy, hot standby each other; 4. trackside data transmission network adopts Redundancy Design; 5. wireless signal fully redundance covers; The downlink data message that Ground Application main frame mails to vehicular applications main frame is copied after four parts by center to center communications gateway, by four different wireless links, mail to object train, then issue destination host after four parts of messages being verified to processing by STA corresponding to vehicle-mounted destination host; Rightabout uplink data messages is also passed through same processing; Therefore, CBTC application message, simultaneously via four different link transmission, guarantees to transmit not packet loss, and intrasystem any Single Point of Faliure does not affect the transmission of data.
Described trackside data transmission network adopts Redundancy Design for adopting double-core+high-performance optical fiber looped network.
Mono-of described headstock and tailstock STA are at headstock, and another is at the tailstock; The default gateway of vehicular applications main frame all points to STA direct-connected with it, and therefore first the data from In-vehicle networking arrive corresponding vehicle-mounted STA; This STA copy data also adds the fields such as timestamp, sequence number, and calling data forwarding module, by radio port, mails to communication gate through the AP of trackside on the one hand; On the other hand, data pass to opposite end STA by special-purpose train line, by opposite end STA, according to the wireless link connection of self, mail to communication gate independently via trackside AP; Therefore, all ATC applied business data are transferred to ground application system by these two STA simultaneously, same, and the data of ground application system are transferred to vehicular applications system via two STA simultaneously; Two STA provide the full redundancy to communication link, with the redundancy of equipment and link, have guaranteed reliabilty and availability.
Beneficial effect of the present invention:
1, many different links of redundancy treatment mechanism of the present invention transmit identical data simultaneously, and the Single Point of Faliure in system does not affect data transmission quality, and the system packet loss of making reaches 10
-6magnitude;
2, redundancy treatment mechanism of the present invention had both been applicable to 3 and gets 2 vehicular applications main frame and be also applicable to 2 and take advantage of 2 to get 2 vehicular applications main frame, flexible configuration;
3, redundancy treatment mechanism of the present invention can effectively be protected the threats such as " deletion ", " insertion ", " repetition ";
4, redundancy treatment mechanism energy of the present invention and the combination of ipsec encryption authentication framework, realize the high security of transfer of data.
Accompanying drawing explanation
Fig. 1 is system topology figure of the present invention.
Fig. 2 is transfer of data schematic diagram of the present invention.
Fig. 3 is CG flow chart of the present invention.
Fig. 4 is STA flow chart of the present invention.
Fig. 5 is that MAC Address of the present invention is obtained and forwarding process figure.
Embodiment
Below in conjunction with drawings and Examples, the present invention is further illustrated.
As Figure 1-5.
A kind of multi-redundancy processing method for train-ground data transmission in rail transit, crucial the hardware relevant with safe transmission is all adopted to Redundancy Design, described hardware redundancy design comprises: 1. in trackside AP(Access Point WAP (wireless access point)) and vehicle-mounted STA(Station radio station) in use pair wireless network cards; 2. at headstock and the tailstock, all configure vehicle-mounted STA, and headstock and tailstock STA all interconnect by professional train line, realize hot standby each other; 3. make the configuration of center to center communications gateway redundancy, hot standby each other; 4. trackside data transmission network adopts Redundancy Design (as adopted double-core+high-performance optical fiber looped network); 5. wireless signal fully redundance covers; The downlink data message that Ground Application main frame mails to vehicular applications main frame is copied after four parts by center to center communications gateway, by four different wireless links, mail to object train, then issue destination host after four parts of messages being verified to processing by STA corresponding to vehicle-mounted destination host; Rightabout uplink data messages is also passed through same processing; Therefore, CBTC application message, simultaneously via four different link transmission, guarantees to transmit not packet loss, and intrasystem any Single Point of Faliure does not affect the transmission of data.Although in physical connection, there is more loop in system, adopt transmission end to end, eliminate 2 layer loops and 3 layer loops, make system works stable, there is not broadcast storm problem.
Data retransmission comprises data uplink and descending two parts.Data uplink refers to vehicular applications main frame applied host machine transmission data earthward, through STA, AP, communication gate, arrives destination host; Data downstream refers to that data arrive vehicular applications main frame from Ground Application main frame via communication gate, AP and STA.
On two STA of same train, one at headstock, and another is at the tailstock.The default gateway of vehicular applications main frame all points to STA direct-connected with it, and therefore first the data from In-vehicle networking arrive corresponding vehicle-mounted STA; This STA copy data also adds the fields such as timestamp, sequence number, and calling data forwarding module, by radio port, mails to communication gate through the AP of trackside on the one hand; On the other hand, data pass to opposite end STA by special-purpose train line, by opposite end STA, according to the wireless link connection of self, mail to communication gate independently via trackside AP.Therefore, all ATC applied business data are transferred to ground application system by these two STA simultaneously, same, and the data of ground application system are transferred to vehicular applications system via two STA simultaneously.Therefore, two STA provide the full redundancy to communication link, with the higher reliabilty and availability of redundancy acquisition of equipment and link.Work signal as shown in Figure 2.
As shown in Figure 1, its chief component equipment has data communication system simplified network topological structure:
1. be communication gate CG(Communication Gateway communication gate) terrestrial interface equipment, management is simultaneously all STA completely.To being forwarded to the data of vehicular applications main frame except increasing the information such as timestamp, sequence number, also increase the information word of routing, guarantee that data accurately mail to object train and destination host.The train receiving is mail to the data message of ground host machine, carry out, after redundancy processing and checking, mailing to ground destination host.
2. vehicle-mounted STA is vehicle-mounted interface equipment, and to being forwarded to the data of Ground Application main frame, vehicle-mounted STA increases the information such as timestamp, sequence number, by 4 different space links, is transmitted to corresponding communication gate, forwards ground data in the other direction to corresponding mobile unit.In each train head and the tailstock, respectively have a chassis to carry STA, each unit has two wireless network cards that are operated in different channels, sets up associated respectively from different trackside AP.
3. the effect of trackside AP is the wired and wireless network of bridge joint, for vehicle-mounted STA provides wireless link access, by rational system, guarantee that trackside wireless signal fully redundance covers, two STA of headstock (or tailstock) are the different AP of associated trackside respectively, and such train has just had 4 different links.The adjacent AP of trackside has line end to be connected with communication gate by different switches or optical networking, and when the cable network connecting at single AP or its lost efficacy, each train and communication gate still have 2 above or links existence of 2.
The redundancy of hardware link also needs software to coordinate to realize effective utilization of resource, otherwise not only waste resource, also may affect system and normally works, and produces as network generation loop, end-to-endly receives the problems such as duplicate packages, time delay be excessive.
When data retransmission layer adopts link redundancy mechanism, the flow process that transmits an IP grouping from Ground Application main frame to vehicular applications main frame is as follows:
1. communication gate is intercepted and captured the IP grouping that Ground Application main frame mails to on-vehicle host.
2. to IP, ID, time stamp and route selection information are added in grouping, and new IP divides into groups as the packet of data communication system inside, and adds forwarding queue to.
4 parts of the new packet copies in forwarding queue and use UDP(User Datagram Protocol User Datagram Protoco (UDP)) 4 links by corresponding train are transmitted to vehicle-mounted STA.
4., if vehicle-mounted STA receives and mails to and the own grouping that is directly connected vehicular applications main frame, first according to ID and time stamp, check whether had this grouping in forwarding data bag buffer memory: if exist, abandon this grouping; If do not exist, add the ID of this grouping and time stamp to buffer memory, and forward initial IP and be grouped into corresponding on-vehicle host.If vehicle-mounted STA receives the grouping of mailing to same train opposite end, by train head and the tail wire link, be transmitted to opposite end.
5. vehicular applications main frame receives this grouping.
The flow process that transmits a grouping from vehicular applications main frame to Ground Application main frame is similar with the former, vehicle-mounted STA intercept and capture IP grouping that vehicular applications main frame mails to Ground Application main frame afterwards redundant forwarding to ground communication gateway, then be transmitted to corresponding ground applied host machine.
Key technology mainly contains link redundancy configuration, the processing of packet redundancy, the control of MAC(Media Access Control medium access) address dynamic process and Data acquisition and caching process etc.
Adopt redundant transmission mechanism to improve the reliability of data retransmission, but still need to add corresponding treatment mechanism and reduce the impact of redundant transmission on application, otherwise can produce, end-to-endly receive duplicate packages and the serious problems such as forward delay is excessive.
The data retransmission redundancy handling process of communication gate and vehicle-mounted STA as shown in Figure 3, Figure 4.
Communication gate and vehicle-mounted STA are in carrying out the process of data retransmission, if do not take other measures, from receiving that data are to sending the data processing the memory copying operation needing for several times, this will cause larger impact on forwarding performance.In order to reduce the impact of memory copying on forwarding performance, adopted the measure that reduces as much as possible internal memory operation, specific as follows:
1. owing to adding the contents such as ID and time stamp before the raw data packets of intercepting and capturing, it is carried out to encapsulation operation, so when using Packet Socket intercepted data frame, be not it to be stored in to the original position of free core, but be that ID and time stamp etc. add the reserved enough memory headrooms of content above.Then directly before raw data packets, add the information words such as ID and time stamp, while forwarding the packet after encapsulation by UDP Socket, can directly send, do not need additional other memory copying operation, greatly reduced taking of CPU and memory source, improved forwarding performance.
2. while forwarding raw data packets by Packet Socket to applied host machine, exist respective hosts MAC Address not in the situation of cache list, Dynamic Acquisition MAC Address need to spend the regular hour, at this moment need packet to dump in the queue of ARP data buffer storage, after receiving arp reply, could forward raw data packets, the whole raw data packets of unloading also will certain CPU and the memory source of cost, and especially when traffic carrying capacity burdensome, this is huge cost to system resource.In order to reduce impact, the whole raw data packets of our not unloading, but its internal memory first address and data package size are deposited in the queue of ARP data buffer storage, has reduced the taking of CPU and memory source, and has improved to a certain extent forwarding performance.
3. when forwarding raw data packets by Packet Socket to applied host machine, be not that raw data packets is dumped to other region of memory yet, but the size of directly skew the is added information such as ID and time stamp is directly usingd this first address as the parameter that will send data.
Communication gate and vehicle-mounted STA need to obtain the MAC Address of respective hosts when applied host machine sends initial data frame, in order to improve flexibility and the portability of system, have taked Dynamic Acquisition MAC Address method and relevant treatment mechanism, as shown in Figure 5.
ARP agreement is according to network layer address, to obtain the agreement of respective hosts data-link layer address, is mainly according to the MAC Address of IP address acquisition respective hosts herein.Owing to asking to receive that from sending ARP arp reply need to expend the regular hour, although generally in 1ms, but still can cause impact definitely to forwarding performance, so ARP request list (depositing the ARP request having sent) and ARP data buffer storage queue (depositing the initial data frame that does not get MAC Address but sent ARP request) on the basis of MAC Address list, have been increased.Actual data retransmission divides for 3 kinds of situations:
1. the destination host MAC Address that need to forward initial data frame exists in MAC cache list, directly forwards this Frame.
2. corresponding MAC Address does not exist in cache list, and does not send the request of corresponding MAC Address, sends the ARP request of corresponding MAC Address, and request is added to ARP request list, and initial data frame is dumped to the queue of ARP data buffer storage.
3. corresponding MAC Address does not exist in cache list, but has sent the request of corresponding MAC Address, directly initial data frame is dumped to the queue of ARP data buffer storage.
The part that the present invention does not relate to all prior art that maybe can adopt same as the prior art is realized.
Claims (2)
1. a multi-redundancy processing method for train-ground data transmission in rail transit, is characterized in that the hardware relevant with safe transmission all to adopt Redundancy Design, and described hardware redundancy design comprises: in trackside AP and vehicle-mounted STA, use two wireless network cards 1.; 2. at headstock and the tailstock, all configure vehicle-mounted STA, and headstock and tailstock STA all interconnect by special-purpose train line, realize hot standby each other; 3. make the configuration of center to center communications gateway redundancy, hot standby each other; 4. trackside data transmission network adopts Redundancy Design; 5. wireless signal fully redundance covers; The downlink data message that Ground Application main frame mails to vehicular applications main frame is copied after four parts by center to center communications gateway, by four different wireless links, mail to object train, then issue vehicular applications main frame after four parts of messages being verified to processing by STA corresponding to the vehicular applications main frame on object train; Rightabout uplink data messages is also passed through same processing; Therefore, CBTC application message, simultaneously via four different link transmission, guarantees to transmit not packet loss, and intrasystem any Single Point of Faliure does not affect the transmission of data; Mono-of described headstock and tailstock STA are at headstock, and another is at the tailstock; The default gateway of vehicular applications main frame all points to STA direct-connected with it, and therefore first the data from In-vehicle networking arrive corresponding vehicle-mounted STA; This STA copy data also adds timestamp and sequence number field, and calling data forwarding module, by radio port, mails to center to center communications gateway through the AP of trackside on the one hand; On the other hand, data pass to opposite end STA by special-purpose train line, by opposite end STA, according to the wireless link connection of self, mail to center to center communications gateway independently via trackside AP; Therefore, all ATC applied business data are transferred to ground application system by these two STA simultaneously, same, and the data of ground application system are transferred to vehicular applications system via two STA simultaneously; Two STA provide the full redundancy to communication link, with the redundancy of equipment and link, have guaranteed reliabilty and availability.
2. multi-redundancy processing method for train-ground data transmission in rail transit according to claim 1, is characterized in that described trackside data transmission network adopts Redundancy Design for adopting double-core+high-performance optical fiber looped network.
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| CN102811415B (en) * | 2012-07-17 | 2014-11-05 | 北京交通大学 | Train-ground communication method of urban railway transportation |
| CN103179131A (en) * | 2013-04-09 | 2013-06-26 | 北京锦鸿希电信息技术股份有限公司 | Communication method, device and system for train control |
| CN105703891B (en) * | 2014-11-28 | 2019-09-17 | 电信科学技术研究院 | A kind of method and apparatus carried out data transmission |
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| CN106506271A (en) * | 2016-11-04 | 2017-03-15 | 北京锦鸿希电信息技术股份有限公司 | Data communications method and device |
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| CN109005554A (en) * | 2018-08-13 | 2018-12-14 | 武汉智慧地铁科技有限公司 | A kind of rail traffic link backup system and its backup method |
| DE102018009823A1 (en) * | 2018-12-14 | 2020-06-18 | Diehl Metering S.A.S. | Process for collecting data, sensor and supply network |
| CN110798818B (en) * | 2019-07-26 | 2022-05-13 | 北京锦鸿希电信息技术股份有限公司 | Train information transmission method and system for urban rail transit |
| CN110789569B (en) * | 2019-10-17 | 2022-04-22 | 北京全路通信信号研究设计院集团有限公司 | Column control DMI data redundancy control method and system |
| CN110808816A (en) * | 2019-11-05 | 2020-02-18 | 中国铁道科学研究院集团有限公司通信信号研究所 | Railway train-ground redundant wireless data communication method |
| CN110912655B (en) * | 2019-12-24 | 2023-01-20 | 瑞斯康达科技发展股份有限公司 | Data redundancy backup method, device, equipment and medium |
| CN111010705B (en) * | 2019-12-25 | 2024-03-12 | 迈普通信技术股份有限公司 | Method and system for synchronizing wireless access point and wireless controller address in cascading scene |
| CN111405524B (en) * | 2020-03-25 | 2022-07-12 | 卡斯柯信号有限公司 | Multi-vehicle-ground wireless communication system and communication method thereof |
| CN113721447B (en) * | 2020-05-26 | 2023-08-25 | 北京机械设备研究所 | Vehicle control system based on redundancy reconfiguration and control method |
| CN112078630B (en) * | 2020-08-25 | 2022-10-18 | 通号城市轨道交通技术有限公司 | Train control system |
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