A synchronous narrowband communication system between ground and locomotive based on Beidou timing

Abstract

The present invention discloses a ground and locomotive synchronous narrowband communication system based on Beidou timing. The system includes a ground station radio and a locomotive radio, and both the ground station radio and the locomotive radio include an antenna unit, a baseband unit, a receiving unit, a transmitting unit and an auxiliary unit. Both the ground station radio and the locomotive radio contain working procedures, and the working procedures of the ground station radio include three processes: starting and waiting, time slot distribution and data communication; the working procedures of the locomotive radio include three processes: starting and waiting, applying for time slots and data communication. The present invention solves the problem that the narrowband technical solution currently used in the railway 400 MHz is limited by the frequency band and cost, and cannot be quickly deployed and constructed. This system only needs a terminal to complete the communication between locomotives and platforms and the channel resource scheduling between multiple vehicles. It has the advantages of low cost, high flexibility and fast deployment, and is suitable for freight and passenger stations with frequent vehicle entry and exit.

Description

Technical Field

[0001] The present invention relates to data communication between a ground station radio station and a locomotive radio station in railway transportation, and in particular to a ground and locomotive synchronous narrowband communication system based on Beidou timing. Background Art

[0002] In the current railway wireless communication environment, due to frequency band limitations, it is impossible to deploy too many channel resources at the same station, and it is often necessary to expand service capacity through base station scheduling or channel reuse. In actual use, base stations have disadvantages such as difficult deployment, complex operation, high cost and inconvenient mobility. Most traditional narrowband walkie-talkies only support voice services, and some walkie-talkies that support services such as packet data also have small data volume and poor real-time performance, which cannot meet the current needs of real-time data such as vehicle location information transmission between vehicles and the ground. Summary of the invention

[0003] In view of the problems existing in the prior art, the present invention provides a ground and locomotive synchronous narrowband communication system based on Beidou timing. The narrowband communication system is compatible with DMR and PDT protocols, and can collect locomotive radio and ground station radio information in real time and transmit it in data form.

[0004] The technical solution adopted by the present invention is: a ground and locomotive synchronous narrowband communication system based on Beidou timing includes a ground station radio and a locomotive radio, and the ground station radio and the locomotive radio both include an antenna unit for receiving and transmitting radio frequency signals of the ground station radio and the locomotive radio; include a baseband unit containing a CPU and a FLASH, which is used to complete protocol processing and configuration storage; include a receiving unit containing a receiving path 1, a receiving path 2 and a branch circuit, which is used to receive the radio frequency signal transmitted by the antenna unit and demodulate it to form a baseband signal of a corresponding type; include a transmitting unit containing a transmitting path 1, a transmitting path 2 and a combining circuit, which is used to Modulate the baseband signal of the relay station to form a corresponding RF signal and amplify and output it to the antenna unit; include an auxiliary unit including an Ethernet interface, a Beidou module and a power supply; wherein the receiving unit and the transmitting unit of the ground station radio station and the locomotive radio station are respectively connected to the antenna unit through a branch circuit and a combining circuit; the antenna unit is connected to the Beidou module; the Beidou module, the Ethernet port and other peripheral interfaces, the receiving path 1, the receiving path 2, the transmitting path 1, the transmitting path 2 are respectively connected to the CPU, and the CPU is connected to the FLASH; the ground station radio station is connected to the station dispatching center through the Ethernet interface, and the locomotive radio station is connected to the locomotive operation display terminal through the Ethernet interface.

[0005] The ground station radio and locomotive radio of the communication system both contain working procedures. The ground station radio working procedures include three processes: starting and waiting, time slot distribution and data communication; the locomotive radio working procedures include three processes: starting and waiting, time slot application and data communication.

[0006] The ground station radio start-up and waiting process performs the following operations:

[0007] A1. The user configures the ground station radio frequency F1, F2 and identity information, and connects to the station command center; after the ground station radio is powered on, the frequency, communication cycle, life signal sending cycle, detention alarm time and identity information are loaded, and Beidou positioning is performed to obtain Beidou timing. After obtaining the timing, the local time slot is synchronized, the startup is completed, and it enters the standby state.

[0008] A2. The station dispatching center configures differential data and broadcast data, sends them to the CPU of the baseband unit through the Ethernet peripheral interface, and periodically broadcasts the platform data on the ground station radio frequency F1.

[0009] A3. The CPU of the baseband unit controls the receiving path 2 in the receiving unit, waiting on the ground station radio frequency F2, waiting to receive the life signal from the locomotive radio.

[0010] The ground station radio time slot distribution process performs the following operations:

[0011] A4. When the baseband unit receives the life signal from the locomotive radio, it records the train number, distance and communication status information of the life signal.

[0012] A5. The baseband unit determines whether the communication status in the life signal of the locomotive radio station is no communication. If yes, the recorded train number is added to the list to be communicated. Otherwise, the recorded life signal information is discarded.

[0013] A6. After receiving the current round of life signals, the baseband unit sorts the train numbers in the communication list and first selects the train that has been stranded the longest in the queue. If there are multiple trains, the closest one is selected for allocation, and the train number is recorded, waiting for the next broadcast cycle.

[0014] A7. When the baseband unit is waiting for the next broadcast cycle, if it receives a request from the station dispatch center to communicate with a designated train number, it clears the currently assigned train number, ends the time slot distribution process, and jumps to step A11 of the ground station radio data communication process.

[0015] A8. The baseband unit fills the train number and the allocated time slot number allowed to be sent into the platform broadcast data, which is modulated by the baseband unit and broadcasted at the F1 frequency through the transmitting unit.

[0016] A9. The ground station radio station waits at the F2 frequency for the locomotive radio station of the designated train to send data. If the locomotive radio station data is received, the data communication process is entered. If the locomotive radio station data is not received within a data communication cycle, the process returns to step A4 to re-judge.

[0017] The ground station radio data communication process performs the following operations:

[0018] A10. The baseband unit performs CRC check on the data sent by the locomotive radio. If the check passes, the data is reported to the station dispatching center through the Ethernet interface, and then the process goes to step A11. If the check fails, the locomotive radio of the designated train is notified to resend through signaling. If the number of retransmission failures exceeds the preset upper limit of the number of retransmissions, the process returns to the ground station radio time slot distribution process. If the retransmission succeeds, the data is reported to the station dispatching center through the Ethernet interface, and then the process goes to step A11.

[0019] A11. The ground station radio obtains the response message from the station dispatching center, modulates it through the baseband unit, and sends it to the locomotive radio at the F2 frequency, waiting for the locomotive radio's signaling response.

[0020] A12. If the baseband unit analyzes the locomotive radio and displays a successful reception, the current data communication process ends and the next round of data communication process begins. Otherwise, the process returns to step A11.

[0021] The locomotive radio station startup and waiting process performs the following operations:

[0022] B1. The user configures the locomotive radio frequency F1, F2 and identity information, and connects the locomotive operation display terminal; after the locomotive radio is powered on, the frequency and identity information are loaded, and Beidou positioning is performed to obtain Beidou timing. After obtaining the timing, the local time slot is synchronized, the startup is completed, and it enters the standby state.

[0023] B2. The locomotive radio station waits at the F1 frequency point, waiting to receive broadcast data from the ground station radio station, and sends life signal information with the train number and communication status to the ground station radio station at a random time slot period within a fixed time period on the F2 frequency point.

[0024] The locomotive radio station time slot application process performs the following operations:

[0025] B3. The locomotive radio obtains the communication status and train number from the station dispatching center, and after modulation by the baseband unit, sends it to the ground station radio periodically at the F2 frequency.

[0026] B4. After the locomotive radio receives the broadcast from the ground station radio, the baseband unit demodulates the broadcast data, parses the time slot distribution information, and transmits the broadcast payload to the locomotive operation display terminal through the Ethernet port; if the parsed time slot distribution information indicates that the locomotive radio can perform data communication, the data communication process is entered, otherwise the B4 step is executed repeatedly.

[0027] B5. If the locomotive radio receives platform data from the ground station radio without being allocated a time slot, jump to step B8.

[0028] The locomotive radio data communication process performs the following operations:

[0029] B6. The baseband unit obtains the locomotive information payload to be sent from the locomotive operation display terminal, modulates it and transmits it at frequency F2 through the transmitting unit, and then waits for the reception response from the ground station radio station.

[0030] B7. After the locomotive radio receives the feedback from the ground station radio, the baseband unit parses the feedback signaling. If the ground station radio receives the data successfully, it waits for the ground station radio data at the F2 frequency point and then enters step B8. Otherwise, it enters the retransmission process and executes step B6 until the preset number of transmissions is exceeded.

[0031] B8. After the locomotive radio receives the ground station radio data, the baseband unit performs a CRC check on the ground station radio data. If the check fails, the ground station radio is informed through signaling, and then the ground station radio is waited for at the F2 frequency to resend the ground station radio response data, and step B8 is repeated; if the check passes, the ground station radio response data is transmitted to the locomotive operation display terminal.

[0032] B9. The baseband unit determines whether the locomotive radio station has sent locomotive data. If locomotive data has been sent, the data transmission status of the locomotive radio station is set to communicated, and the transmission status is synchronized to the locomotive operation display terminal through the Ethernet interface to end the data communication process. If the station data is received directly and the locomotive data has not been sent, the transmission status will not be updated and the data communication process will end.

[0033] The beneficial effects of the present invention are as follows: multiple locomotives and multiple stations do not need to be configured or combined in advance, and only the same F1 and F2 frequencies need to be written (only the F1 frequency needs to be written in the single-frequency working mode) to realize the reciprocating communication between multiple locomotives at different stations. And there is no need to assume a base station, only terminal communication equipment is needed to complete the communication, which has better flexibility. It solves the problem that the current narrowband technology solution used in the railway 400 MHz is limited by the frequency band and cost, and cannot be deployed and constructed quickly. This system only needs a terminal to complete the communication between locomotives and stations and the channel resource scheduling between multiple vehicles. It has the advantages of low cost, high flexibility, and quick deployment. It is suitable for freight and passenger stations with frequent vehicle entry and exit. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a schematic diagram of a typical application scenario of the present invention;

[0035] Figure 2 A block diagram of the connection principle of a synchronous narrowband communication system according to an embodiment of the present invention;

[0036] Figure 3 for Figure 2Schematic diagram of time slice division in the single-frequency working mode of the medium-synchronous narrowband communication system;

[0037] Figure 4 for Figure 2 Schematic diagram of time slice division in the synchronous narrowband communication system in dual-frequency working mode;

[0038] Figure 5 A flowchart of starting and waiting for a ground station radio station in an embodiment of the present invention;

[0039] Figure 6 A flow chart of time slot distribution of a ground station radio station in an embodiment of the present invention;

[0040] Figure 7 It is a data communication flow chart of a ground station radio station in an embodiment of the present invention;

[0041] Figure 8 The present invention is a flowchart of starting and waiting for a locomotive radio station in an embodiment of the present invention;

[0042] Fig. 9 A flow chart of applying for time slots of a locomotive radio station in an embodiment of the present invention;

[0043] Fig.10 1 is a data communication flow chart of a locomotive radio station in an embodiment of the present invention. DETAILED DESCRIPTION

[0044] The present invention is further described below with reference to the accompanying drawings and implementation examples.

[0045] like Figure 2 As shown, the ground and locomotive synchronous narrowband communication system based on Beidou timing includes a ground station radio and a locomotive radio. Both the ground station radio and the locomotive radio include an antenna unit for receiving and transmitting radio frequency signals of the ground station radio and the locomotive radio; include a baseband unit containing a CPU and FLASH, which is used to complete protocol processing and configuration storage; include a receiving unit containing a receiving path 1, a receiving path 2 and a branch circuit, which is used to receive the radio frequency signal transmitted by the antenna unit and demodulate it to form a baseband signal of a corresponding type; include a transmitting unit containing a transmitting path 1, a transmitting path 2 and a combining circuit, which is used to modulate the baseband of the relay station The signal forms a corresponding RF signal and is amplified and output to the antenna unit; it includes an auxiliary unit containing an Ethernet peripheral interface, a Beidou module and a power supply; among them, the receiving unit and the transmitting unit of the ground station radio and the locomotive radio are respectively connected to the antenna unit through a branch circuit and a combining circuit; the antenna unit is connected to the Beidou module; the Beidou module, the Ethernet port and other peripheral interfaces, the receiving path 1, the receiving path 2, the transmitting path 1, and the transmitting path 2 are respectively connected to the CPU, and the CPU is connected to the FLASH; the ground station radio is connected to the station dispatching center through the Ethernet interface, and the locomotive radio is connected to the locomotive operation display terminal through the Ethernet interface.

[0046] The baseband unit has configuration storage capabilities and can store vehicle and station identity information, frequency information, broadcast cycle and data communication cycle, etc. The baseband unit is responsible for protocol processing, can parse the information received by the receiving unit, determine whether the current vehicle station has the conditions for transmission, and has the ability to control the transmitting unit to select the frequency and time slot for transmission.

[0047] The output end of the transmitting unit is connected to the antenna unit to modulate the vehicle and platform baseband signals to form corresponding radio frequency signals and amplify and output them to the antenna unit.

[0048] The input end of the receiving unit is connected to the antenna unit, and is used to receive the RF signal transmitted by the antenna unit and demodulate it to form a baseband signal of the corresponding type; the receiving unit has a branch circuit and two independent receiving paths. The branch circuit is used to divide the received signal into two paths. The branch circuit has a protection capability to prevent high-power signals from entering the receiving path. Receive RF signals of two frequencies and convert them into baseband signals.

[0049] The antenna unit is used to receive / transmit radio frequency signals.

[0050] Typical application scenarios such as Figure 1 As shown, there is a platform (ground station radio) BS1 deployed in the station, four locomotives are stationed in the station, each equipped with a station (locomotive radio) MS1-MS4, and a locomotive is entering outside the station, equipped with a station MS5.

[0051] Before the typical platform BS1 works, it needs to be pre-connected to the station dispatching center, and the locomotive identity information, station number, frequency points F1 and F2, working mode, broadcast, life signal and data communication cycles are configured through the station dispatching center to match the different broadcast data volumes of different stations. Before the stations MS1-MS5 work, it needs to be pre-connected to the locomotive operation display terminal, configure the locomotive identity information and frequency points F1 and F2, the locomotive radio frequency points F1 and F2 should be consistent with the platform, and configure the working mode. The broadcast, life signal and data communication cycles are issued by the platform broadcast. After the locomotive radio receives the platform's broadcast information for the first time each time it enters the station, it will configure the parsed cycles to the locomotive radio.

[0052] When locomotive 5 has not entered the station yet, there are only locomotive radio stations MS1-MS4 in the station. At this time, locomotive radio stations MS1 and MS2 have stayed in the station for 5 cycles, and locomotive radio station MS3 has stayed for 1 cycle. At this time, station radio station BS1 has just completed the communication with locomotive radio station MS4 and started to distribute time slots for a new cycle. The station BS1 baseband unit determines that the locomotive radio stations MS1 and MS2 have stayed longer than locomotive radio station MS3 based on the information in the waiting communication list, and communication opportunities should be allocated to MS1 and MS2 first. At this time, locomotive radio station MS1 ​​is 1200 meters away from the station, and locomotive radio station MS2 is 1500m away from the station. Therefore, this round of communication opportunities is allocated to locomotive radio station MS1 ​​which is closer.

[0053] At this time, locomotive 5 enters the station and receives the broadcast from platform BS1. According to the broadcast information, it obtains the life signal reporting cycle and starts reporting the life signal. The life signal contains locomotive information and communication status identification for the station radio to distinguish and allocate time slots. At this time, the station dispatching center shows that there are five locomotives MS1-MS5 in the station, and the platform starts a new round of time slot distribution. Since locomotive radio MS4 and locomotive radio MS1 have completed communication, platform BS1 deletes these two locomotives from the list of non-communication, and the communication flag bit in the life signal reported by locomotive radio MS1 and MS4 is in the communication state, so platform BS1 no longer adds these two trains to the list. At this time, there are locomotive radios MS2, MS3 and MS5 in the list. According to the distribution rules, it should communicate with locomotive radio MS2 next. But at this time, platform BS1 has information to send to locomotive radio MS1. It manually selects locomotive radio MS1 on the station dispatching center and sends data. Therefore, this broadcast no longer distributes time slots, but directly communicates data with locomotive radio MS1. After completing this communication, time slot distribution is performed again.

[0054] After completing the communication, locomotive radio MS4 finds that the locomotive data has changed and needs to communicate with the station radio again. It applies for communication on the locomotive operation display terminal. At this time, locomotive radio MS4 changes the communication status indicator in the life signal to no communication. After receiving it, station BS1 will add locomotive radio MS4 to the no communication list again and distribute time slots when the opportunity arises.

[0055] When locomotive 4 leaves the station and does not receive the station broadcast for a period of time, locomotive radio station MS4 resets its communication status flag to no communication and suspends sending life signals until a new station broadcast is received again.

[0056] The present invention contains three key points. The first is that the system synchronizes time slots through Beidou timing to ensure that the transmission and reception between different terminals remain synchronized and prevent signaling collisions. The second is the randomly sent life signal and the adjustable life signal sending interval, which ensures that the life signal sent by the later-entering train without scheduling has a chance to be received by the platform. The third is the data communication cycle configured by the platform broadcast to ensure the adaptive ability of the same train in different station environments.

[0057] Both the ground station radio and locomotive radio of the ground and locomotive synchronous narrowband communication system based on Beidou timing contain working procedures. The ground station radio working procedures include three processes: starting and waiting, time slot distribution and data communication; the locomotive radio working procedures include three processes: starting and waiting, time slot application and data communication.

[0058] like Figure 5 As shown, the ground station radio station startup and waiting process performs the following operations:

[0059] A1. The user configures the ground station radio frequency F1, F2 and identity information, and connects to the station command center; after the ground station radio is powered on, the frequency, communication cycle, life signal sending cycle, detention alarm time and identity information are loaded, and Beidou positioning is performed to obtain Beidou timing. After obtaining the timing, the local time slot is synchronized, the startup is completed, and it enters the standby state.

[0060] A2. The station dispatching center configures differential data and broadcast data, sends them to the CPU of the baseband unit through the Ethernet peripheral interface, and periodically broadcasts the platform data on the ground station radio frequency F1.

[0061] A3. The CPU of the baseband unit controls the receiving path 2 in the receiving unit, waiting on the ground station radio frequency F2, waiting to receive the life signal from the locomotive radio.

[0062] like Figure 6 As shown, the ground station radio time slot distribution process performs the following operations:

[0063] A4. When the baseband unit receives the life signal from the locomotive radio, it records the train number, distance and communication status information of the life signal.

[0064] A5. The baseband unit determines whether the communication status in the life signal of the locomotive radio station is no communication. If yes, the recorded train number is added to the list to be communicated. Otherwise, the recorded life signal information is discarded.

[0065] A6. After receiving the current round of life signals, the baseband unit sorts the train numbers in the communication list and first selects the train that has been stranded the longest in the queue. If there are multiple trains, the closest one is selected for allocation, and the train number is recorded, waiting for the next broadcast cycle.

[0066] A7. When the baseband unit is waiting for the next broadcast cycle, if it receives a request from the station dispatch center to communicate with a designated train number, it clears the currently assigned train number, ends the time slot distribution process, and jumps to step A11 of the ground station radio data communication process.

[0067] A8. The baseband unit fills the train number and the allocated time slot number allowed to be sent into the platform broadcast data, which is modulated by the baseband unit and broadcasted at the F1 frequency through the transmitting unit.

[0068] A9. The ground station radio station waits at the F2 frequency for the locomotive radio station of the designated train to send data. If the locomotive radio station data is received, the data communication process is entered. If the locomotive radio station data is not received within a data communication cycle, the process returns to step A4 to re-judge.

[0069] like Figure 7 As shown, the ground station radio data communication process performs the following operations:

[0070] A10. The baseband unit performs CRC check on the data sent by the locomotive radio. If the check passes, the data is reported to the station dispatching center through the Ethernet interface, and then the process goes to step A11. If the check fails, the locomotive radio of the designated train is notified to resend through signaling. If the number of retransmission failures exceeds the preset upper limit of the number of retransmissions, the process returns to the ground station radio time slot distribution process. If the retransmission succeeds, the data is reported to the station dispatching center through the Ethernet interface, and then the process goes to step A11.

[0071] A11. The ground station radio obtains the response message from the station dispatching center, modulates it through the baseband unit, and sends it to the locomotive radio at the F2 frequency, waiting for the locomotive radio's signaling response.

[0072] A12. If the baseband unit analyzes the locomotive radio and displays a successful reception, the current data communication process ends and the next round of data communication process begins. Otherwise, the process returns to step A11.

[0073] like Figure 8 As shown, the locomotive radio station startup and waiting process performs the following operations:

[0074] B1. The user configures the locomotive radio frequency F1, F2 and identity information, and connects the locomotive operation display terminal; after the locomotive radio is powered on, the frequency and identity information are loaded, and Beidou positioning is performed to obtain Beidou timing. After obtaining the timing, the local time slot is synchronized, the startup is completed, and it enters the standby state.

[0075] B2. The locomotive radio station waits at the F1 frequency point, waiting to receive broadcast data from the ground station radio station, and sends life signal information with the train number and communication status to the ground station radio station at a random time slot period within a fixed time period on the F2 frequency point.

[0076] like Fig. 9 As shown, the locomotive radio station applies for a time slot by performing the following operations:

[0077] B3. The locomotive radio obtains the communication status and train number from the station dispatching center, and after modulation by the baseband unit, sends it to the ground station radio at the F2 frequency period.

[0078] B4. After the locomotive radio receives the broadcast from the ground station radio, the baseband unit demodulates the broadcast data, parses the time slot distribution information, and transmits the broadcast payload to the locomotive operation display terminal through the Ethernet port; if the parsed time slot distribution information indicates that the locomotive radio can perform data communication, the data communication process is entered, otherwise the B4 step is executed repeatedly.

[0079] B5. If the locomotive radio receives platform data from the ground station radio without being allocated a time slot, jump to step B8.

[0080] like Fig.10 As shown, the locomotive radio data communication process performs the following operations:

[0081] B6. The baseband unit obtains the locomotive information payload to be sent from the locomotive operation display terminal, modulates it and transmits it at frequency F2 through the transmitting unit, and then waits for the reception response from the ground station radio station.

[0082] B7. After the locomotive radio receives the feedback from the ground station radio, the baseband unit parses the feedback signaling. If the ground station radio receives the data successfully, it waits for the ground station radio data at the F2 frequency point and then enters step B8. Otherwise, it enters the retransmission process and executes step B6 until the preset number of retransmissions is exceeded.

[0083] B8. After the locomotive radio receives the ground station radio data, the baseband unit performs a CRC check on the ground station radio data. If the check fails, the ground station radio is informed through signaling, and then the ground station radio is waited for at the F2 frequency to resend the ground station radio response data, and step B8 is repeated; if the check passes, the ground station radio response data is transmitted to the locomotive operation display terminal.

[0084] B9. The baseband unit determines whether the locomotive radio station has sent locomotive data. If locomotive data has been sent, the data transmission status of the locomotive radio station is set to communicated, and the transmission status is synchronized to the locomotive operation display terminal through the Ethernet interface to end the data communication process. If the station data is received directly and the locomotive data has not been sent, the transmission status will not be updated and the data communication process will end.

[0085] In the single-frequency working mode, the working process of the vehicle and station is roughly the same as that of the dual-frequency mode. The only difference is that in the single-frequency working mode, broadcasting, life signals and data communications are all completed on the same frequency point. It is used in situations where channel resources are scarce and the air interface rate requirements are not too high. The detailed process is not described here. See the time slice division of the single-frequency working mode for details. Figure 3 , dual-frequency working mode time slice division see Figure 4 .

[0086] The F1 frequency and F2 frequency of the train and station are the same. Beidou timing is used to ensure the time slot synchronization between the train and the station. When the device is turned on, Beidou positioning should be performed first to obtain timing. If timing is not obtained, in order to ensure the normal transmission and reception of other devices in the system, transmission should not be performed. If the Beidou signal is lost after obtaining timing, the time slot synchronization can be maintained for a period of time through the local timer. When the station distributes time slots, a message with the train number and time slot information will be carried in the broadcast data. After the train receives the message that this identifier allows this train to transmit, it starts to transmit, otherwise it continues to wait for the next broadcast. When the train completes a round of data transmission, the state of the machine will be set to complete transmission. At this time, the transmission state in the life signal will also change synchronously. The platform will no longer allocate time slots to the train to save channel resources. If necessary, the locomotive terminal can manually set the flag to the unsent state to regain communication authority.

Claims

1. A ground and locomotive synchronous narrowband communication system based on Beidou timing, characterized in that: The communication system includes a ground station radio station and a locomotive radio station, and both the ground station radio station and the locomotive radio station include an antenna unit for receiving and transmitting radio frequency signals of the ground station radio station and the locomotive radio station; includes a baseband unit containing a CPU and a FLASH, which is used to complete protocol processing and configuration storage; includes a receiving unit containing a receiving path 1, a receiving path 2 and a branch circuit, which is used to receive the radio frequency signal transmitted by the antenna unit and demodulate it to form a corresponding type of baseband signal; includes a transmitting unit containing a transmitting path 1, a transmitting path 2 and a combining circuit, which is used to modulate the baseband signal of the relay station to form a corresponding radio frequency signal and amplify and output it to the antenna unit; includes an auxiliary unit containing peripheral interfaces such as an Ethernet port, a Beidou module and a power supply; Among them, the receiving unit and transmitting unit of the ground station radio and locomotive radio are connected to the antenna unit through the branch circuit and the combining circuit respectively; the antenna unit is connected to the Beidou module; the Beidou module, Ethernet port and other peripheral interfaces, receiving channel 1, receiving channel 2, transmitting channel 1, transmitting channel 2 are connected to the CPU respectively, and the CPU is connected to the FLASH; the ground station radio is connected to the station dispatching center through the Ethernet interface, and the locomotive radio is connected to the locomotive operation display terminal through the Ethernet interface; The ground station radio and locomotive radio of the communication system both have working procedures. The ground station radio working procedures include three processes: starting and waiting, time slot distribution and data communication; the locomotive radio working procedures include three processes: starting and waiting, time slot application and data communication; The ground station radio start-up and waiting process performs the following operations: A1. The user configures the ground station radio frequency F1, F2 and identity information, and connects to the station command center; after the ground station radio is powered on, the frequency, communication cycle, life signal sending cycle, detention alarm time and identity information are loaded, and Beidou positioning is performed to obtain Beidou timing. After obtaining the timing, the local time slot is synchronized, the startup is completed, and it enters the standby state; A2. The station dispatching center configures differential data and broadcast data, sends them to the CPU of the baseband unit through the Ethernet interface, and periodically broadcasts the platform data on the ground station radio frequency F1; A3, the CPU of the baseband unit controls the receiving path 2 in the receiving unit, waiting on the ground station radio frequency F2, waiting to receive the life signal from the locomotive radio; The ground station radio time slot distribution process performs the following operations: A4. When the baseband unit receives the life signal from the locomotive radio, it records the train number, distance and communication status information of the life signal; A5. The baseband unit determines whether the communication status in the life signal of the locomotive radio station is no communication. If yes, the recorded train number is added to the list to be communicated. Otherwise, the recorded life signal information is discarded. A6. After receiving the life signal in this round, the baseband unit sorts the train numbers in the communication list, first selects the train that has been stranded the longest in the queue, and if there are multiple trains, selects the train that is closest to it for distribution, records the train number, and waits for the next broadcast cycle; A7. When the baseband unit is waiting for the next broadcast cycle, if it receives a request from the station dispatch center to communicate with the designated train number, it clears the currently assigned train number, ends the time slot distribution process, and jumps to step A11 of the ground station radio data communication process; A8, the baseband unit fills the train number and the allocated time slot number allowed to be sent into the platform broadcast data, which is modulated by the baseband unit and broadcasted at the F1 frequency through the transmitting unit; A9, the ground station radio station waits at the F2 frequency point for the locomotive radio station of the designated train number to send data. If the locomotive radio station data is received, the data communication process is entered. If the locomotive radio station data is not received within a data communication cycle, the process returns to step A4 for re-judgment. The ground station radio data communication process performs the following operations: A10, the baseband unit performs CRC check on the data sent by the locomotive radio. If the check passes, the data is reported to the station dispatching center through the Ethernet interface, and then enters step A11; if the check fails, the locomotive radio of the specified train is notified to resend through signaling. If the number of retransmission failures exceeds the preset retransmission limit, it returns to the ground station radio time slot distribution process. If the retransmission is successful, the data is reported to the station dispatching center through the Ethernet interface, and then enters step A11; A11, the ground station radio receives the response message from the station dispatching center, modulates it through the baseband unit, and sends it to the locomotive radio at the F2 frequency, waiting for the locomotive radio's signaling response; A12. If the baseband unit analyzes the locomotive radio and displays a successful reception, the current data communication process ends and the next round of data communication process begins. Otherwise, the process returns to step A11. The locomotive radio station startup and waiting process performs the following operations: B1. The user configures the locomotive radio frequency F1, F2 and identity information, and connects the locomotive operation display terminal; after the locomotive radio is powered on, the frequency and identity information are loaded, and Beidou positioning is performed to obtain Beidou timing. After obtaining the timing, the local time slot is synchronized, the startup is completed, and the locomotive enters the standby state; B2, the locomotive radio station waits at the F1 frequency point, waiting to receive the broadcast data from the ground station radio station, and sends the life signal information with the train number and communication status to the ground station radio station at the random time slot period within the fixed time period on the F2 frequency point; The locomotive radio station time slot application process performs the following operations: B3, the locomotive radio obtains the communication status and train number from the station dispatching center, modulates it through the baseband unit, and sends it to the ground station radio at the F2 frequency periodically; B4. After the locomotive radio receives the broadcast from the ground station radio, the baseband unit demodulates the broadcast data, analyzes the time slot distribution information, and transmits the broadcast payload to the locomotive operation display terminal through the Ethernet port; if the analyzed time slot distribution information indicates that the locomotive radio can perform data communication, the data communication process is entered, otherwise the B4 step is executed repeatedly; B5. If the locomotive radio receives the station data sent by the ground station radio without being allocated a time slot, jump to step B8; The locomotive radio data communication process performs the following operations: B6, the baseband unit obtains the locomotive information payload to be sent from the locomotive operation display terminal, modulates it and transmits it at frequency F2 through the transmitting unit, and then waits for the reception response from the ground station radio station; B7. After the locomotive radio receives the reply from the ground station radio, the baseband unit parses the reply signaling. If the ground station radio receives the data successfully, it waits for the ground station radio data at the F2 frequency point and then enters step B8. Otherwise, it enters the retransmission process and executes step B6 until the preset retransmission times are exceeded. B8. After the locomotive radio receives the data from the ground station radio, the baseband unit performs a CRC check on the data from the ground station radio. If the check fails, the baseband unit notifies the ground station radio through signaling, and then waits for the ground station radio to resend the ground station radio response data at the F2 frequency point, and repeats step B8; if the check passes, the baseband unit transmits the ground station radio response data to the locomotive operation display terminal; B9. The baseband unit determines whether the locomotive radio station has sent locomotive data. If locomotive data has been sent, the data transmission status of the locomotive radio station is set to communicated, and the transmission status is synchronized to the locomotive operation display terminal through the Ethernet interface to end the data communication process. If the station data is received directly and the locomotive data has not been sent, the transmission status will not be updated and the data communication process will end.

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