A time slot scheduling method based on Beidou timing

Abstract

The invention discloses a time slot scheduling method based on Beidou timing, and relates to the field of narrowband communication. The method is a dynamic time slot allocation method for channel multiplexing in a railway communication environment under the condition of shortage of channel resources. In actual use, the method is used by a single host in conjunction with multiple slaves. The host and the slave maintain time slot synchronization through Beidou timing and communicate through radio frequency signals. The host confirms the current number and working status of the slave according to the status report of the current slave, and dynamically distributes time slots to the slave. There is no need to configure or combine multiple devices in advance, and only the same frequency point needs to be written to realize the business scheduling of one master and multiple slaves. And there is no need to set up a base station, and only terminal communication equipment is needed to complete the communication, which has better flexibility. The method only needs a terminal to complete channel resource scheduling, 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 the field of narrowband communication, and in particular to a time slot scheduling method based on Beidou timing. The method is aimed at channel multiplexing in a railway communication environment when channel resources are scarce. 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. Although traditional narrowband walkie-talkies are low-cost, they cannot perform complex scheduling services under a single channel. Summary of the invention

[0003] In view of the problems existing in the prior art, the present invention provides a time slot scheduling method based on Beidou timing. The method is a dynamic time slot allocation method. In actual use, the method is often used by a single host in conjunction with multiple slaves. The host and the slave maintain time slot synchronization through Beidou timing and communicate through radio frequency signals. The host confirms the current number and working status of the slave according to the status report of the current slave, and dynamically distributes time slots to the slave.

[0004] The technical solution adopted by the present invention is: a time slot scheduling method based on Beidou timing is that after the system is started, the host starts broadcasting according to a preset broadcast cycle, when the slave is not started, the host only broadcasts and does not perform other operations; when the slave does not receive the broadcast, the slave does not perform other operations; when the host and the slave are both started, the following interactive process operations are performed: A1. The host broadcast contains data on life signal cycle, broadcast cycle, service allocation time slot, and service fault tolerance cycle.

[0005] A2. After receiving the broadcast from the host, the slave calculates the time slice when the slave should report the life signal according to the life signal cycle; the slave reports the slave identity information and service type.

[0006] A3. The host adds the received slave life signal to the list to be assigned and sorts the list.

[0007] A4. The host makes a priority judgment and allocates time slots to the slave with the highest priority. If the priorities are the same, they are allocated according to the first-in-first-out principle. Then the next slave allowed to transmit is selected and the time slot is allocated according to the service type.

[0008] A5. The host broadcasts a message with a life signal cycle, device information that allows transmission, and time slot allocation information.

[0009] A6. The slave receives the host broadcast. If the host broadcast commands the slave to transmit, the slave performs business communication within the specified time slot carried by the broadcast and executes the business communication process with the host.

[0010] A7. When the current business is not completed, a new business cycle begins and the slave sends a life signal to the master.

[0011] A8. After receiving the life signal from the slave that the service is not completed, the host broadcasts and continues to allocate time slots to the slave.

[0012] A9. The slave and the host continue to execute the business communication process.

[0013] A10. After the slave completes the service, it modifies the service status in the life signal and sends a life signal to the host.

[0014] A11. The slave service is completed, and the host deletes the current slave information from the list to be assigned.

[0015] When both the master and slave are started, the following startup and waiting operations are first performed: B1. The host and slave are powered on and started. The host and slave obtain Beidou timing and synchronize local time slots through Beidou timing.

[0016] B2. If Beidou timing is obtained, the host obtains the preset life signal cycle and communication cycle and fills in the broadcast frame; The host starts to send broadcasts, and the slave does not send; otherwise, it returns to step B1.

[0017] B3. If the slave receives the host broadcast, receives the broadcast frame, decodes the life signal cycle, and reports the life signal according to the cycle; otherwise, return to step B2.

[0018] B4. If the host receives the life signal from the slave, it enters the time slot distribution process, otherwise returns to step B2.

[0019] The time slot distribution process performs the following operations: C1. The host receives the life signal from the slave.

[0020] C2. If the host determines that the slave state is to apply for a time slot, the host adds the slave identity information to the queue; otherwise, the host returns to step C1.

[0021] C3. The host organizes the list of items to be transmitted, makes a priority judgment, and allocates time slots to the slave with the highest priority. If the priorities are the same, they are allocated according to the first-in-first-out principle.

[0022] C4. Fill the slave information and the allocated time slot into the broadcast.

[0023] C5. The host waits for the slave to perform business communication at the specified time slot.

[0024] C6. The slave determines whether its own business communication is completed. If completed, the slave sets the business status of the local machine to business completed, reports a life signal, and returns to step C1. If not completed, the slave sets the business status of the local machine to business incomplete, reports a life signal, and returns to step C1.

[0025] The beneficial effects of the present invention are: there is no need to configure or combine multiple devices in advance, and only the same frequency point needs to be written to realize the service scheduling of one master and multiple slaves. And there is no need to assume a base station, only the terminal communication equipment is needed to complete the communication, which has better flexibility. 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 method only needs the terminal to complete the channel resource scheduling, which has the advantages of low cost, high flexibility, and quick deployment, and is suitable for freight and passenger stations with frequent vehicle in and out. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of a typical application scenario of the present invention; Figure 2 It is a schematic diagram of time slice division in the present invention; Figure 3 It is a flow chart of the interaction between the host and the slave in the present invention; Figure 4 It is a flowchart of system startup and waiting in the present invention; Figure 5 It is a flow chart of system time slot allocation in the present invention. DETAILED DESCRIPTION

[0027] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0028] After the system is started, the host starts broadcasting according to the preset broadcast cycle. When the slave is not started, the host only broadcasts and does not perform other operations; when the slave does not receive the broadcast, the slave does not perform other operations; when both the host and the slave are started, the following interactive process operations are performed as follows Figure 3 As shown: A1. The host broadcast contains data on life signal cycle, broadcast cycle, service allocation time slot, and service fault tolerance cycle.

[0029] A2. After receiving the broadcast from the host, the slave calculates the time slice when the slave should report the life signal according to the life signal cycle; the slave reports the slave identity information and service type.

[0030] A3. The host adds the received slave life signal to the list to be assigned and sorts the list.

[0031] A4. The host makes a priority judgment and allocates time slots to the slave with the highest priority. If the priorities are the same, they are allocated according to the first-in-first-out principle. Then the next slave allowed to transmit is selected and the time slot is allocated according to the service type.

[0032] A5. The host broadcasts a message with a life signal cycle, device information that allows transmission, and time slot allocation information.

[0033] A6. The slave receives the host broadcast. If the host broadcast commands the slave to transmit, the slave performs business communication within the specified time slot carried by the broadcast and executes the business communication process with the host.

[0034] A7. When the current business is not completed, a new business cycle begins and the slave sends a life signal to the master.

[0035] A8. After receiving the life signal from the slave that the service is not completed, the host broadcasts and continues to allocate time slots to the slave.

[0036] A9. The slave and the host continue to execute the business communication process.

[0037] A10. After the slave completes the service, it modifies the service status in the life signal and sends a life signal to the host.

[0038] A11. The slave service is completed, and the host deletes the current slave information from the list to be assigned.

[0039] like Figure 4 As shown in the figure, when both the master and slave are started, the following startup and waiting operations are first performed: B1. The host and slave are powered on and started. The host and slave obtain Beidou timing and synchronize local time slots through Beidou timing.

[0040] B2. If Beidou timing is obtained, the host obtains the preset life signal cycle and communication cycle and fills in the broadcast frame; The host starts to send broadcasts, and the slave does not send; otherwise, it returns to step B1.

[0041] B3. If the slave receives the host broadcast, receives the broadcast frame, decodes the life signal cycle, and reports the life signal according to the cycle; otherwise, return to step B2.

[0042] B4. If the host receives the life signal from the slave, it enters the time slot distribution process, otherwise returns to step B2.

[0043] like Figure 5 As shown, the time slot distribution process performs the following operations: C1. The host receives the life signal from the slave.

[0044] C2. If the host determines that the slave state is to apply for a time slot, the host adds the slave identity information to the queue; otherwise, the host returns to step C1.

[0045] C3. The host organizes the list of items to be transmitted, makes a priority judgment, and allocates time slots to the slave with the highest priority. If the priorities are the same, they are allocated according to the first-in-first-out principle.

[0046] C4. Fill the slave information and the allocated time slot into the broadcast.

[0047] C5. The host waits for the slave to perform business communication at the specified time slot.

[0048] C6. The slave determines whether its own business communication is completed. If completed, the slave sets the business status of the local machine to business completed, reports a life signal, and returns to step C1. If not completed, the slave sets the business status of the local machine to business incomplete, reports a life signal, and returns to step C1.

[0049] Example: Typical application scenarios such as Figure 1 As shown, the system should have one host and multiple slaves (slave 1, slave 2, slave 3... slave N). If there is one host in the system and three slaves, record them as slave 1, slave 2, and slave 3. Before the host is running, the life signal cycle, broadcast cycle, service fault tolerance cycle and frequency should be configured. The slave should be equipped with a frequency, and the frequency of the host and slave should be consistent.

[0050] After the host is started, it reads the preset life signal cycle, broadcast cycle, service fault tolerance cycle and frequency, calculates the service cycle, and divides the system time slice. Figure 2 The complete service cycle of the system is from life signal - host broadcast - slave service - fault-tolerant processing.

[0051] At this time, the host has slave 1 and slave 2 in the waiting list, of which slave 1 has been waiting longer. At this time, a new service cycle begins, and slaves 1, 2, and 3 report their own life signals at random time slices within the life signal cycle. The host receives the life signals of slaves 1, 2, and 3, of which slaves 1 and 2 already exist in the information list, and slave 3 is a newly received device. The host adds slave 3 to the waiting list. Then the priority is determined. At this time, the priorities of slaves 1, 2, and 3 are the same, so the time slots are allocated according to the first-in-first-out principle.

[0052] The host fills the device information of slave 1 and the designated time slot for business operation into the broadcast, and transmits it in the broadcast cycle. Slaves 1, 2, and 3 all receive this broadcast. Slaves 2 and 3 interpret the device information in the broadcast as not belonging to the host, and then skip the current business cycle and wait for the new business cycle to report the life signal.

[0053] Slave 1 decodes the transmission permission information and time slot information in the broadcast, and then performs business communication in the specified time slot. Since the business data volume of slave 1 is large or there are many bit errors, it is not completed within the specified time slot and the subsequent fault-tolerant processing. Then slave 1 suspends the business and waits for the new business cycle to report the life signal.

[0054] At the beginning of a new service cycle, the host receives life signals from slaves 1, 2, and 3, and all of them are in the state of requesting time slots. Since slave 1 was assigned to communicate last time, and the life signal of slave 1 is still received in this cycle, it means that the service of slave 1 is not completed. At this time, its priority is the highest, so the designated time slot in the new cycle is still assigned to slave 1, and the time slot information is filled in the broadcast.

[0055] After receiving the broadcast, slave 1 completes its own service in the specified time slot, sets the service status in the life signal to completed, and reports it in a new service cycle.

[0056] A new service cycle begins, and the host receives life signals from slaves 1, 2, and 3. At this time, slave 1 no longer requests a time slot, so the host deletes slave 1 from the list to be allocated. At this time, there are still slaves 2 and 3 in the queue, and slave 2 has been waiting longer, so the next few time slots are allocated to slave 2 for service.

[0057] When the slave receives the broadcast, it obtains the life signal cycle divided in the current system, divides the time slices based on Beidou time, and reports the life signal in a random time slice within the life signal cycle.

[0058] After the host receives the life signal from the slave, it allocates the specified time slot to the slave for business communication according to the business type, and the allocation is sent through broadcast. When the slave receives the host broadcast and determines that the time slot in the current broadcast is allocated to it, it starts to perform its business. If the business transmission is completed, it will set the business status of the local machine to complete the communication in the next life signal, and no longer apply for time slots. If not completed, it will continue to apply for time slots until the business is completed.

[0059] The master and slave operate at the same frequency. Beidou timing is used to ensure time slot synchronization between the master and slave. After the system is running, Beidou positioning is first performed to obtain timing. If timing is not obtained, in order to ensure 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 a local timer. The master will carry the slave identity information in the broadcast data. The slave will determine whether it is the local time slot based on the identity information, otherwise it will continue to wait for the next broadcast. When the slave completes its own business, it will set the local state to complete the transmission. At this time, the transmission state in the life signal will also change synchronously. The host will no longer allocate time slots to the slave to save channel resources. If necessary, the slave can manually set the flag to the unsent state to reapply for the time slot.

Claims

1. A time slot scheduling method based on Beidou timing, characterized in that: After the system is started, the host starts broadcasting according to the preset broadcast cycle. When the slave is not started, the host only broadcasts and does not perform other operations; when the slave does not receive the broadcast, the slave does not perform other operations; when both the host and the slave are started, the following interactive process operations are performed: A1. The host broadcasts data including life signal cycle, broadcast cycle, service allocation time slot, and service fault tolerance cycle; A2. After receiving the broadcast from the host, the slave calculates the time slice in which the slave should report the life signal according to the life signal cycle; the slave reports the slave identity information and service type; A3. The host adds the received slave life signal to the list to be assigned and sorts the list; A4. The host determines the priority and allocates time slots to the slave with the highest priority. If the priorities are the same, they are allocated according to the first-in-first-out principle. Then the next slave allowed to transmit is selected and the time slot is allocated according to the service type. A5. The host broadcasts the life signal cycle, the device information allowed to transmit and the time slot allocation information; A6. The slave receives the host broadcast. If the host broadcast commands the slave to transmit, the slave performs business communication in the specified time slot carried by the broadcast and executes the business communication process with the host. A7. When the current service is not completed, a new service cycle begins and the slave sends a life signal to the master. A8. After receiving the life signal from the slave that the service is not completed, the host broadcasts and continues to allocate time slots to the slave; A9, the slave and the host continue to execute the business communication process; A10. After the slave service is completed, the service status in the life signal is modified and a life signal is sent to the host. A11. The slave service is completed, and the host deletes the current slave information from the list to be assigned.

2. A time slot scheduling method based on Beidou timing according to claim 1, characterized in that: When both the master and slave are started, the following startup and waiting operations are first performed: B1. The host and slave are powered on and started. The host and slave obtain Beidou timing and synchronize local time slots through Beidou timing. B2. If Beidou timing is obtained, the host obtains the preset life signal cycle and communication cycle and fills in the broadcast frame; The host starts to send broadcasts, but the slave does not send any; Otherwise, return to step B1; B3. If the slave receives the host broadcast, it receives the broadcast frame, decodes the life signal cycle, and reports the life signal according to the cycle; Otherwise, return to step B2; B4. If the host receives the life signal from the slave, it enters the time slot distribution process, otherwise returns to step B2.

3. A time slot scheduling method based on Beidou timing according to claim 2, characterized in that: The time slot distribution process performs the following operations: C1. The host receives the life signal from the slave; C2. If the host determines that the slave state is to apply for a time slot, the slave identity information is added to the queue; otherwise, it returns to step C1; C3. The host sorts out the list to be transmitted, makes a priority judgment, and allocates time slots to the slave with the highest priority. If the priorities are the same, they are allocated according to the first-in-first-out principle. C4, fill the slave information and the allocated time slot into the broadcast; C5, the host waits for the slave to perform business communication in the specified time slot; C6. The slave determines whether its own business communication is completed. If completed, the slave sets the business status of the slave to business completed, reports a life signal, and returns to step C1. If not completed, the slave sets the business status of the slave to business uncompleted, and then reports a life signal. Return to step C1.

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