CN1247404C - Wireless locomotive signal system preset polling optimized control method - Google Patents

Abstract

The invention discloses an autonomous polling optimization control method for a wireless locomotive signaling system, which is used in the wireless locomotive signaling system. The method includes the following steps: (1) when the train passes the transponder, the vehicle-mounted data transmission station obtains the registration address and frequency information of the station from the proximity transponder; (2) the vehicle-mounted data transmission station detects the (3) After the registration is completed, the station control center performs polling control on each registered train in the way of calling; (4) The train passes the station and responds After the device is connected, the station control center will log it out. Using this method can guarantee the integrity of each communication process; using interweaving technology and three-dimensional control technology in the polling and registration process can effectively shorten the locomotive signal response time and ensure safe and reliable signal transmission, thereby greatly improving the entire locomotive signal system. operational safety and efficiency.

Description

Self-discipline polling optimization control method for wireless locomotive signaling system

technical field

The invention relates to a method for autonomously polling locomotives entering and leaving stations in a wireless locomotive signal system, effectively shortening the response time of locomotive signals, and ensuring reliable transmission of information, belonging to the technical field of railway signals.

Background technique

The existing railway signaling system is commonly referred to as the general signaling system, which is a wired system based on the ground track circuit, which cannot meet the actual needs in some special environments, special regions and future high-speed railways. For this reason, the applicant has developed a locomotive signaling system based on a wireless data transmission network.

The wireless locomotive signaling system is very different from the general locomotive signaling. First, the transmission media are different. The wireless locomotive signaling system is based on wireless channels, while the general locomotive signaling system is based on track circuits. Secondly, the signal types are different. The control signals of the wireless locomotive signaling system are digital, while the general locomotive signaling system uses analog signals. In addition, the control mechanisms of the two are also different. The wireless locomotive signal system is a centralized control method, that is, the wireless locomotive signal ground equipment uses time division multiplexing or frequency division multiplexing to simultaneously control multiple trains, while the general locomotive signal is A distributed control method, the on-board control equipment can only receive the information in the track circuit where the car is located, and it has a one-to-one correspondence with the track circuit. Therefore, for the wireless locomotive signaling system, many control methods used in the wired signaling system are no longer applicable, and new control methods must be developed according to its characteristics.

According to the actual needs of the project, the conditions to be met by the wireless data transmission network as the basis of the wireless locomotive signaling system include the following:

(1) Meet the real-time requirements of data transmission, ensure the response time of wireless locomotive signals, ensure the maximum number of trains controlled by the station, and ensure the time required for redundant measures in the process of information transmission.

(2) Satisfy the requirements of the amount of information transmitted.

(3) Establish a unique and definite wireless channel between the station and the designated train.

(4) Meet the bit error rate and reliability requirements of data transmission.

(5) It is satisfied that the trains under the jurisdiction of the station are all within the field strength coverage.

Contents of the invention

The object of the present invention is to provide a control method suitable for the wireless locomotive signaling system. The method can realize self-discipline polling of the locomotives entering and leaving the station, so as to identify and control the locomotives in real time. In the self-discipline polling process, it can effectively shorten the response time of the locomotive signal through various technical means, and can ensure the reliability and safety of information transmission.

For realizing above-mentioned purpose of the invention, the present invention adopts following technical scheme:

A wireless locomotive signal system self-discipline polling optimization control method, used in the wireless locomotive signal system, the system includes a station control center and at least one vehicle-mounted equipment; The balise and the outbound balise, the proximity balise and the outbound balise are respectively located on the track sides on both sides of the station, and are characterized in that:

The method comprises the steps of:

(1) When the train passes the transponder, the on-board data transmission station obtains the registration address and frequency information of the station from the transponder;

(2) After the vehicle-mounted data transmission station detects the registration time slot in the polling period, it seeks registration from the station control center in the form of calling;

(3) After the registration is completed, the station control center performs polling control on each registered train in the form of calling;

(4) After the train passes the outbound transponder, the station control center will log it out.

The self-discipline polling optimization control method of the wireless locomotive signaling system described in the invention can fully meet the actual needs of the control of the wireless locomotive signaling system. It adopts the polling method for the radio communication between the on-board equipment and the ground, which ensures the integrity of each communication process; in the whole control process, it also uses interweaving technology and three-dimensional control technology to effectively shorten the locomotive signal response time and ensure the signal The transmission is safe and reliable, thereby greatly improving the safety and efficiency of the entire locomotive signaling system operation.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

Fig. 1 is a system structure block diagram of the whole wireless locomotive signaling system.

Fig. 2 is a schematic diagram of the frequency configuration in which stations use different frequencies to control up/down trains respectively in the wireless locomotive signaling system.

Fig. 3 is a flow chart of the self-discipline polling optimization control method of the wireless locomotive signaling system according to the present invention.

Figure 4 is a time slot allocation diagram when the station control center adopts time division multiplexing to control the train.

Figure 5 is a schematic diagram of the interweaving technology used in the wireless data transmission process between the station control center and the vehicle radio.

Fig. 6 is a schematic diagram of time slot allocation when the variable period method is used to shorten the response time of the wireless locomotive signal in the method of the present invention.

Detailed ways

The self-discipline polling optimization control method of the wireless locomotive signaling system described in the present invention is applied in the wireless locomotive signaling system. As shown in Figure 1, the system includes a station control center and at least one vehicle-mounted device; the vehicle-mounted device is installed on the locomotive, including a vehicle-mounted host, a vehicle-mounted query device, a vehicle-mounted signal and a data transmission station, and the vehicle-mounted host computer and the data transmission station on the locomotive The station control center is installed in the station, including the station control host, digital radio, proximity transponder and outbound transponder, and the station control host is connected with the digital radio and station interlocking host connect.

The above-mentioned wireless locomotive signal system adopts a digital transmission station to form a wireless data transmission network. By setting up the vehicle-mounted radio station on each locomotive, and setting up the base station at each station, and uniformly set the station number according to regulations. The base radio station and the on-board radio station of the train form a star network structure, in which the station radio station is the network center, and the on-board radio station is the network node. Stations and trains in the network use the same frequency, and channel resources are utilized in a time-division multiplexing manner. This wireless locomotive signaling system is a near-continuous wireless locomotive signal, that is, when a train runs from one station to another, it only has a locomotive signal at an adjacent station, which is determined by the semi-automatic block driving mode of the railway. This type only has wireless signal field strength coverage around the station, so it is suitable for realization by ordinary digital radio stations. The wireless network used in the wireless locomotive signaling system has the following technical characteristics:

1. Possess dynamic networking capabilities and network mobility

Since the trains are constantly moving along the railway, the number and members of the network at each station at different times are uncertain, and it is a process of dynamic combination and separation. Therefore, the composition of the network is open and dynamic. At the same time, the overall network formed by the stations along the line has mobility.

2. Inter-station frequency alternate setting

In order to avoid co-channel interference, the radio stations use cross-frequency at each station. As shown in Figure 2, each station uses two radio stations with different frequencies to control up/down trains respectively. Among them, F2, F4, and F6 are the operating frequencies of uplink trains, and F1, F3, and F5 are the operating frequencies of downlink trains. The up/down trains use different frequencies, which can prevent the data sent to the up train from being received by the down train and avoid unnecessary conflicts.

In the wireless locomotive signaling system, every three stations alternately use a set of different frequencies to avoid co-frequency interference between stations. The on-board host of the train senses the ground transponder data to obtain the frequency used by the radio station at the next station, and automatically resets the working frequency of the on-board radio to keep it corresponding to the ground. Ensure the normal communication between the vehicle and the ground.

3. Site selection method

The data transmission station in the wireless locomotive signaling system adopts the site selection method. Since all radio stations in the same station work at the same frequency, each can receive the information sent by the other, which is likely to cause communication confusion. Therefore, add address information according to the station number in the transmitted data frame. After receiving a frame of information, the station will compare the address in the information frame with its own number. If they are the same, it will confirm that it is its own information and send it to the control host. Automatically discard if different.

4. Avoid transmission frame collision and communication blocking

The wireless locomotive signal system prevents frame collisions in the transmission network through time-division multiplexing communication methods and communication protocols. The communication protocol strictly defines the communication time slots, stipulates the communication sequence of the corresponding time slots, and the active and passive relationship between the station and the train. In this way, the orderly communication between the station and the train is ensured, and the frame collision in the transmission process is avoided. During the communication process, the vehicle radio or station radio may be locked due to interference and other reasons. In order to prevent communication interruption, the radio needs to have functions such as timeout detection and reset.

5. Variable frame structure

In order to ensure the real-time and reliability of wireless locomotive signals, the information transmitted wirelessly is divided into three types. The first type of information (I): the basic information of the train control signal; the second type of information (II): including the number of connecting/departing lanes, train number, actual speed and maximum allowable speed of the train, and the position of the train, etc. In addition, the third type of non-safety information (III) can also be transmitted under the premise that the transmission delay allows: different content information including public affairs, electrical affairs, and machine affairs. Standard formats of long, medium and short message cycles can be selected according to different needs.

As shown in Figure 3, the self-discipline polling optimization control method of the present invention includes the following steps:

(1) When the train passes the transponder, the on-board data transmission station obtains the registration address and frequency information of the station from the transponder.

When a train passes an approaching transponder, the train needs to request registration into the network. If the train sends registration information immediately at this time, it will not only disrupt other communications, but also fail to register. Therefore, we have added a registration time slot in a polling control cycle. When there is one train at the station, one control cycle is one communication time slot and one registration time slot; when there are two trains at the station, one control cycle is two communication time slots. slot and a registration slot, and so on. The train obtains the registration address and frequency information of the station from the approaching transponder to form a registration information frame, but if it is not in the registration time slot, the registration information will not be sent immediately, and the registration information will be sent only when the registration time slot is detected.

(2) After the on-board data transmission station detects the registration time slot in the polling cycle, it seeks registration from the station control center in the way of calling.

The train determines whether it is in the registration time slot by detecting the carrier. The on-board equipment performs a carrier detection every 20 milliseconds. If there is no signal for 3 consecutive times, it is judged as the registration time slot and starts to send a registration request. If the first registration fails, the second time can be performed. , the third time, until the registration is successful. This train registration process is completed in the mode that the main train calls the station to answer.

(3) After the registration is completed, the station control center performs polling control on each registered train by means of calling.

As shown in Figure 4, in the wireless locomotive signaling system, the station control center uses time division multiplexing to control each train in the management. It calls each train according to the order of the trains in the registry, assigns time slots to each train, each time slot includes two parts of sending and receiving, polls all trains again and adds a registration time slot to complete a communication cycle , the communication period changes with the number of trains in the tube. In this communication process, since all radio stations in a station work on the same frequency, one of the radio stations sends out information and all other radio stations can receive it. When two radio stations are in the process of communication, the third radio station will disrupt the normal communication of the first two radio stations. Therefore, the control of each train at the station must be carried out in strict polling order, and each train must be self-disciplined, and can only respond when it is its turn, otherwise it can only wait. Therefore, this communication mode belongs to a kind of communication mode in which the station master calls the train to answer, which is opposite to the above-mentioned registration process, so the wireless locomotive signal system is a kind of master-slave variable self-discipline polling work mode. This method can not only ensure the needs of normal polling communication, but also enable the registration of trains approaching the station.

The above-mentioned master-slave variable polling mode specifies the active-passive relationship between the station and the train at different times, so as to ensure the orderly communication between the station and the train and avoid frame conflicts in the transmission process.

(4) After the train passes the outbound transponder, the station control center will log it out.

In addition to providing the above-mentioned variable master-slave polling method, the present invention also proposes technical measures to reduce the response time of the locomotive signal in the polling process and improve the reliability of data transmission according to the needs of actual work, so as to further optimize the method . This is explained below.

The response time of the locomotive signal refers to the time it takes for the ground equipment to send a signal to the on-board equipment to receive it and display it on the on-board signal machine. The response time of the locomotive signal is related to the number of trains controlled, the amount of information transmitted, the transmission speed, the signal system, and the redundancy measures. Response time is an important index of locomotive signal, which directly affects the driving efficiency and driving safety. The shorter the response time, the more efficient the driver can maneuver the train. The higher the speed of the train, the shorter the response time of the locomotive signal is required. At present, the response time for general locomotive signals to receive frequency-shifted signals is about 1.7 seconds to 2.3 seconds, and the response time for receiving signals of other systems is even longer. Since the general locomotive signal adopts a distributed control method in which a section of track circuit corresponds to a piece of on-board equipment, the problem of response time is relatively easy to solve. The wireless locomotive signal adopts a one-to-many centralized control method. A set of ground equipment controls all the trains in the station and adjacent stations at the same time. Therefore, it is necessary to divide a control cycle into several control time slots, and complete the corresponding control in each time slot. The signal processing of the train, therefore, a control cycle is the strain time of the wireless locomotive signal. In order to shorten this response time, the following technical measures can be adopted:

1. Use interleaving technology to shorten the response time of wireless locomotive signals

Since increasing the baud rate of wireless transmission will lead to an exponentially increasing bit error rate, it is unrealistic to shorten the response time of wireless locomotive signals by increasing the baud rate of transmission. The data show that the wireless locomotive signal is mainly affected by burst errors caused by fast fading, which leads to repeated requests for wireless data transmission. Therefore, the wireless data transmission in the wireless locomotive signal should adopt the short message frame structure and forward error correction (FEC) method. The short information frame can effectively avoid fast fading interference and reduce the efficiency drop caused by retransmission. Forward error correction can make the bit error rate meet the specified requirements.

The so-called interleaving technology is shown in Fig. 5, and its specific content is as follows: on a variable parameter channel such as mobile communication, bit errors often occur in series. This is due to the fact that a deep fading trough that lasts longer will affect successive strings of bits. However, channel coding is only effective for detecting and correcting single errors and not too long error trains. In order to solve this problem, it is possible to disperse the successive bits in a message, that is, the successive bits in a message are sent in a non-sequential manner. In this way, even if a series of errors occurs during the transmission process, when the message of a continuous bit string is restored, the error becomes single (or very short in length), and then the channel coding error correction function is used to correct the error and restore the original information.

Interweaving technology is generally used to improve voice quality. It achieves the purpose of improving voice quality by equalizing bit errors, but it cannot reduce bit errors. However, we can improve the efficiency of FEC error correction by using interleaving technology, save the time of wireless data transmission in the air, and thus achieve the purpose of shortening the response time. Redundant coding (n, k) must set the ratio of effective information k and redundant information (nk) according to the local maximum fading, and there must be enough redundant information to achieve the effect of forward error correction. If the transmitted information is interleaved before this, the local large fading is dispersed, so that less redundant information (nk) can be used to achieve the same error correction effect. Because the amount of information transmitted in the air is reduced, the wireless transmission time is shortened, and the interleaving and deinterleaving processes are completed by the internal hardware of the computers at both ends, so the interleaving time can be ignored. Shortening the wireless transmission time is equivalent to shortening the control time slot, that is, shortening the response time. For example, under the premise of ensuring that the same burst error can be corrected, FEC without interleaving technology needs to use the BCH (31, 16) code that can correct the burst length _lb≤7bits for error correction, and the coding efficiency is only 0.52; and After FEC using interleaving technology, only the RS (16, 12) code that can correct the burst length l _b ≤ 3 bits can be used for error correction, and the coding efficiency is 0.75. If the transmission baud rate is 2400b/s, and the effective information transmission is 160bit, the FEC using interleaving technology can increase the transmission efficiency by 31%, and save the air wireless transmission time by 20 milliseconds. For the wireless locomotive signal system controlling 5 trains, the overall The strain time was shortened by 1 second, and the effect was very noticeable.

2. Shorten the response time of the wireless locomotive signal by changing the control cycle

The station control host adopts time-division multiplexing polling method to control all trains in the station and adjacent stations. Divide the control cycle T into n control time slots t ₁ , t ₂ ... t _n , corresponding to the processing time of each train respectively. A control time slot includes the time when the station control host receives interlocking information, generates locomotive signal time according to interlocking conditions, locomotive number and train position, sends locomotive signal and other information to the corresponding train and receives train position and speed sent by on-board equipment and the wireless transmission time used for information such as locomotive signal receipts. One control cycle T=t ₁ +t ₂ +...+t _n .

The station control host is designed according to the maximum number of trains n that need to be controlled, that is, one control cycle is fixedly set to n time slots. Since the number of trains at a station is uncertain at a certain moment, in fact, most of the time, a station only has half of the maximum number of controlled trains. Controlling the train with a fixed period is a waste of time, which not only affects the efficiency, but also prolongs the response time of the locomotive signal.

As shown in Figure 6, in the method of the present invention, the control period is determined by means of train registration, and several control time slots are set for several registered vehicles. The control cycle is dynamically changed during the whole train control process. This method can not only meet the maximum number of trains that need to be controlled, but also shorten the locomotive signal response time to the greatest extent at most times.

3. Shorten the response time of wireless locomotive signals by changing the sequence of time slots

In the wireless locomotive signaling system, the station control host computer reads the interlocking data according to the specified time interval, and through the analysis of the interlocking data, it is found that if the signal of a certain train changes, it will immediately set the processing of the train as the highest priority, and Change the original polling sequence, that is, the train processing time slot with the highest priority is placed at the front of the control cycle. When the ground signal changes, the on-board wireless locomotive signal immediately follows the change. In this way, the train whose signal changes can be processed in time without waiting for the train to be polled. As a result, the response time of the wireless locomotive signal is greatly shortened.

Whether it is wireless locomotive signaling or general locomotive signaling based on track circuits, the reliability and safety of the system are crucial. The reliability of wireless data transmission in wireless locomotive signals is the key. According to the needs of train safety control and in combination with the characteristics of wireless data transmission, the present invention proposes a three-dimensional control method, which can ensure the reliability and safety of transmitting train control data through wireless channels .

The so-called three-dimensional control means that the information content is valid only if it satisfies the requirements of address code, time stamp and registry information at the same time:

(1) In the wireless locomotive signaling system, each station and on-board equipment has a fixed address, and the sending and receiving of information is strictly carried out according to the address. For the information with the wrong address, its "mailbox" will refuse to receive it.

(2) Timestamp of information transmission. The time-division multiplexing method is used in the wireless locomotive signal for information transmission, which may be subject to intentional or unintentional interference and attacks at any time, so a time stamp is specially set in the system, that is, any information transmission is marked with the starting time. , valid information aborted.

(3) Train registration system. Trains within the dispatching jurisdiction have unique train number codes. The train number is issued by the section dispatching center with the highest authority according to the travel plan. The train number corresponds to the registration number. Any running train can only be registered after it is registered. Efficient information transmission in wireless channels.

The above-mentioned three-dimensional control method using address, time stamp and registration makes the two-way communication subject to strict security guarantees, that is, the information content is only valid if it satisfies the three-dimensional conditions at the same time.

In addition, in the wireless locomotive signal system, the information transmission between the station control center and the on-board equipment not only adopts a closed-loop method, that is, the two-party response confirmation method, but also adopts a highly reliable method of two out of three in the transmission and decoding of information content To be done. There is CRC error detection in the sending code, which can improve the anti-interference performance of the system, thereby also improving the reliability of information transmission. In the process of information transmission, the radio station also adopts its own error detection and error correction control technology, which is another measure to improve the anti-interference performance in the high frequency band.

The foregoing specific embodiments have been described for purposes of illustrating the practice of the invention. It should be understood that other variations and modifications of the present invention will be apparent to those skilled in the art and that the invention is not limited to the specific embodiments described. Therefore, any/all modifications, changes or equivalent transformations within the scope of the true essence and basic principles of the disclosed content of the present invention belong to the protection scope of the claims of the present invention.

Claims (9)

1. a wireless cab signal system self-discipline poll optimal control method is used for wireless cab signal system, and this system comprises station control center and at least one mobile unit; Mobile unit comprises data radio station, comprises data radio station in the station control center, near responser and departures responser, lays respectively at the track limit of both sides, station near responser and departures responser, it is characterized in that:

This method comprises the steps:

When (1) train crosses near responser, registered address and the frequency of utilization information of vehicle-mounted data radio station from obtain this station near responser;

(2) vehicle-mounted data radio station is sought registration in the main mode of exhaling to station control center after detecting the interior discovery timeslot of polling cycle;

(3) after registration was finished, station control center was carried out poll control in the main mode of exhaling to each train of registering;

(4) after train crossed the departures responser, station control center was nullified it.

2. wireless cab signal system self-discipline poll optimal control method as claimed in claim 1 is characterized in that:

In the wireless communication procedure between described station control center and the mobile unit, the information content adopts the short message frame structure.

3. wireless cab signal system self-discipline poll optimal control method as claimed in claim 1 is characterized in that:

Adopt forward error correction mode in the wireless communication procedure between described station control center and the mobile unit.

4. wireless cab signal system self-discipline poll optimal control method as claimed in claim 3 is characterized in that:

Before adopting described forward error correction mode, earlier institute's information transmitted is interweaved.

5. wireless cab signal system self-discipline poll optimal control method as claimed in claim 1 is characterized in that:

The middle station control center of described step (3) is carried out the cycle of poll control and is dynamically determined according to the quantity of train to each train of registering.

6. wireless cab signal system self-discipline poll optimal control method as claimed in claim 1 is characterized in that:

In the described step (3), if wherein certain train signal changes, will handle this train immediately and be set at highest priority, and change original polling sequence, the train that preceence is the highest is handled time slot and is come the control cycle foremost.

7. wireless cab signal system self-discipline poll optimal control method as claimed in claim 1 is characterized in that:

The information content between described station control center and the mobile unit meets the requirement of address code, timestamp and registration three aspects simultaneously.

8. wireless cab signal system self-discipline poll optimal control method as claimed in claim 1 is characterized in that:

In the wireless communication procedure between described station control center and the mobile unit, two mode is got in the transmission of the information content and decoding employing three.

9. wireless cab signal system self-discipline poll optimal control method as claimed in claim 1 is characterized in that:

In the described step (2), train determines whether to be in discovery timeslot by the detected carrier mode, and mobile unit carries out the primary carrier detection for per 20 milliseconds, and continuous 3 no signals just are judged to be discovery timeslot, begin to send the registration request.

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