Low earth orbit constellation time-sensitive networking span transmission method

Abstract

The application discloses a kind of low-orbit constellation time-sensitive service span transmission methods, comprising the following steps: in the low-orbit constellation based on laser interconnection, obtain each satellite IP address and laser connection information table;Each satellite node carries out adjacent satellite connection initialization and plans route, according to traffic weight and strongly connected algorithm carries out sketch, and the whole satellite constellation is divided into several parallel subnets;According to the VLAN label that traffic transmission time source node is arranged on data packet frame header, carry out fast arrangement;High priority time-sensitive service is exported by two controllable doors of periodic exchange opening and closing;Finally, according to the traffic re-planning route, the cross long-distance connection of time-sensitive service is realized.According to the low-orbit constellation time-sensitive service span transmission method of the application, the situation that time-sensitive service transmission delay is too high and uncontrollable caused by congestion that appears when transmitting traffic under parallel subnet structure is optimized, and the result of time-sensitive service transmission meets controllable, predictable and low-delay conditions.

Description

Technical Field

[0001] This invention relates to transmission scheduling methods, and more particularly to a method for long-distance transmission of time-sensitive services in a low-orbit constellation. Background Technology

[0002] Current research on satellite networking methods is mainly based on existing microwave communication transmission technologies, focusing on small-scale networking and satellite-to-ground communication. Link scheduling schemes are not suitable for the current context of large-scale low-Earth orbit constellations with inter-satellite laser interconnection. With the surge in the number of satellites and the expansion of network scale, and the anticipated use of laser communication between satellites, the increased routing hops and latency after dense satellite networking, especially with tens of thousands of satellites, negate the advantages of laser communication. Currently, traditional satellite networking schemes cannot fully leverage the ultra-low latency advantages of networking tens of thousands of satellites and inter-satellite laser communication. Simultaneously, the increasing complexity of space communication missions and the growing demand for time-sensitive services pose new challenges to information transmission. On the one hand, high bandwidth, reliability, and real-time performance are required within satellite systems; on the other hand, inter-satellite communication via wireless links also needs low latency and high reliability. However, when service data is transmitted jointly through wired links within satellites and wireless links between satellites, node congestion and uncontrollable transmission latency may occur, making it impossible to guarantee the real-time transmission of time-sensitive services. Summary of the Invention

[0003] In view of the aforementioned shortcomings of the prior art, the technical problem to be solved by the present invention is that existing time-sensitive service transmission methods are not suitable for mega-satellite constellations. With tens of thousands of satellites, dense satellite networking increases the number of routing hops and latency, failing to meet the requirements of low latency and controllable latency for time-sensitive services. Therefore, the present invention provides a method for long-distance transmission of time-sensitive services in low-Earth orbit constellations: based on a parallel subnet structure, it ensures controllable inter-satellite transmission latency while meeting transmission latency requirements; and achieves controllable and predictable latency throughout the entire process through queuing and forwarding scheduling of service data packets within the satellite.

[0004] To achieve the above objectives, the present invention provides a method for long-distance transmission of time-sensitive services in a low-Earth orbit constellation, comprising the following steps:

[0005] Obtain the IP addresses of each satellite and the laser connection information table; based on the laser connection information table, each satellite node initializes the connection between adjacent satellites and plans routes according to the traditional path algorithm. After filtering the initial important links by the set threshold, the entire satellite constellation is divided into several parallel subnets according to the traffic weight and strong connectivity algorithm.

[0006] Traffic routing is performed in the constructed parallel subnets, where each data packet includes basic information required for transmission and features related to priority ordering;

[0007] Based on the VLAN tag attached to the header of the data packet by the source node during traffic transmission, a coarse classification is first performed, and then a weighted priority scheduling algorithm is used for fast sorting to further refine the priority ranking.

[0008] The periodic forwarding mechanism in the 802.1Qch protocol is used to output high-priority time-sensitive services through two controllable gates that are periodically switched on and off.

[0009] Finally, routes are replanned based on traffic to achieve long-distance connectivity and predictable transmission latency for time-sensitive services.

[0010] Furthermore, each satellite has a laser connection information table, which records the satellites currently connected to each satellite, the satellite IPs within the laser's reachable range at the current moment, and their logical addresses. The satellite IPs within the laser's reachable range are the satellite IPs that each satellite can connect to by adjusting its laser, and the logical addresses are the current location information of all satellites that each satellite can connect to. The laser connection information table is continuously updated as the satellite's position changes.

[0011] Furthermore, the satellite logical addresses in the laser connection information table are used to locate the satellites in the same orbit before and after each satellite, as well as the satellites in adjacent orbits to the left and right, thereby completing the connection initialization of each satellite, with the initial overhead of each link being equal; based on the connection status of each link after initialization, the traditional Dijkstra algorithm is used to plan routes for various communication requests, obtain the traffic status of each inter-satellite link, and calculate the overhead of each link; important links are selected and traffic directions based on important links are created.

[0012] Furthermore, traffic routing is performed based on multiple parallel subnets, which are simulated traffic considering real-world communication needs and large-scale satellite constellation routing.

[0013] Furthermore, each satellite scheduling data service has specific requirements for latency, bandwidth, jitter, and VLAN tags.

[0014] Furthermore, for these data packets carrying transmission requirement information, in order to meet the transmission requirements of time-sensitive services during cross-subnet transmission, the positions of the data packets in the node buffer queue need to be adjusted according to their service priorities.

[0015] Furthermore, based on the VLAN tags, the priority of the VLAN tags for all services stored on the sending port is determined, typically set to P. i=0-7. These data packets are first sorted according to label priority, with higher priority packets sent first. For data packets of the same priority, a weighted priority algorithm is used for a second sorting. Its basic principle is linear weighting, prioritizing packets based on the impact of key parameters carried by the data packets on transmission. Assume that at time t, the data packets in the buffer queue of congested node i are S1, S2, ..., S... with different priorities. n The labels have already been sorted by priority, where S is assumed to be... n S n-1 S n-2 The tags have the same priority. This invention considers several factors that significantly affect the transmission of time-sensitive service data packets: transmission delay constraint D, transmission bandwidth constraint B, and transmission distance constraint J. i The influence factor. The formula for the subdivision priority of the weighted priority ranking algorithm is:

[0016] P t =e1·D+e2·B+e3·J.

[0017] Furthermore, two thresholds η1 and η2 are defined, where η1 is the "send as soon as possible" threshold and η2 is the "congestion retransmission" threshold. After adjusting the positions of services in the buffer queue, low-priority services located after the congestion retransmission threshold are discarded, and a message is sent to the source node of the discarded low-priority service to reselect a route for it. High-priority time-sensitive services located before the "send as soon as possible" threshold are prepared for long-distance transmission. For high-priority time-sensitive services, a periodic cyclic scheduling and forwarding mechanism is used for forwarding and scheduling.

[0018] Furthermore, the satellite physical layer responsible for the forwarding function also includes a TSN switch (SW) capable of handling time-sensitive service transmission. Utilizing the characteristics of the SW, gating scheduling based on odd-even time intervals and with time protection segments is performed for the transmission of time-sensitive services.

[0019] Furthermore, the timer module in the switch (SW) is used to control the opening and closing of the transmission gates on the forwarding port. This invention uses queues Q7 and Q6 of the SW forwarding port to transmit the highest priority time-sensitive service. Assuming the timer starts counting at time T0, queue Q7 in the SW is open for transmitting data and closed for writing data, while queue Q6 is open for writing data and closed for transmitting data. After a time period d, the timer module reaches the threshold T0+d, at which point the states of the two queues are reversed: queue Q7 is open for writing data and closed for transmitting data, while queue Q6 is closed for writing data and open for transmitting data. Considering that in some cases, TSN packets may be transmitted after the next lower priority service, and excessively large next lower priority packets may fail to meet the transmission delay requirements of the time-sensitive service, or even cause congestion. To address this, this invention extends the time period by a small additional time d before the time-sensitive service is about to be transmitted. offset (Generally, this is the transmission time of a standard Ethernet frame), during which no low-priority services can be transmitted. Therefore, the time point for the transmission gate opening and closing switch becomes T0+d+d. offset .

[0020] Furthermore, by introducing a parallel subnet structure, a weighted priority sorting algorithm, and an even / odd gated cyclic queuing forwarding mechanism, this invention achieves controllable latency for long-distance transmission between time-sensitive service subnets. First, when time-sensitive service data packets and secondary priority data packets arrive at the transmission port of the subnet's transmission satellite, the time overhead for sorting these data packets is D. S The worst-case latency for periodic queuing and forwarding at the transmission port is D. Q =2d+d offset The jitter is 0 to 2d+d offset When transmitting over long distances via a parallel subnet, the transmission delay D can be calculated using the laser transmission information table. T Therefore, we can derive the controllable delay for long-distance transmission as:

[0021] D Total =D S +D Q +D T .

[0022] Furthermore, end-to-end cross-distance transmission is achieved through a parallel subnet structure to fulfill service transmission requirements.

[0023] Technical effect

[0024] With the current large-scale constellation deployment, the scale has expanded, and laser communication is expected to be used between satellites. However, the increased routing hops and latency after dense satellite networking negate the advantages of laser communication. A multi-parallel subnet structure compensates for the lack of ultra-low latency advantages that traditional satellite networking schemes cannot maintain. It can be applied to long-distance transmission scenarios for time-sensitive services. Furthermore, by optimizing the hardware and forwarding mechanisms of the satellites in the parallel subnet, the combination of these two aspects can ensure that latency meets requirements while maintaining controllable and predictable conditions.

[0025] This invention discloses a method for long-distance transmission of time-sensitive services in a low-Earth orbit constellation. By employing a parallel subnet structure, simulated real-time traffic service routing, weighted priority algorithm for rapid service segmentation, periodic gated forwarding mechanism, and inter-subnet long-distance laser transmission, this method optimizes the situation where congestion during traffic transmission under a parallel subnet structure leads to excessively high and uncontrollable transmission delays for time-sensitive services. The transmission results of time-sensitive services meet the conditions of controllability, predictability, and low latency.

[0026] The following will further explain the concept, specific structure, and technical effects of the present invention in conjunction with the accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of a preferred embodiment of a low-orbit constellation time-sensitive service long-distance transmission method according to the present invention;

[0028] Figure 2 This is a schematic diagram of the parallel subnet structure division in a low-orbit constellation time-sensitive service span transmission method according to a preferred embodiment of the present invention;

[0029] Figure 3 This is a schematic diagram illustrating the weighted priority algorithm for arranging services in a preferred embodiment of a low-orbit constellation time-sensitive service long-distance transmission method according to the present invention.

[0030] Figure 4 This is a schematic diagram of a gated scheduling method based on odd-even time period rotation and with time protection segments in a low-orbit constellation time-sensitive service cross-distance transmission method according to a preferred embodiment of the present invention. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the example figures. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] like Figure 1As shown, this embodiment of the invention provides a method for long-distance transmission of time-sensitive services in a low-Earth orbit constellation, comprising the following steps:

[0033] Step 100: Each satellite has a laser connection information table, which records the satellites currently connected to each satellite, the satellite IPs within the laser's reachable range at the current moment, and their logical addresses. The satellite IPs within the laser's reachable range are the satellite IPs that each satellite can connect to by adjusting its laser, and the logical addresses are the current location information of all satellites that each satellite can connect to. The laser connection information table is continuously updated as the satellite's position changes. Using the satellite logical addresses in the laser connection information table, satellites in the same orbit and adjacent orbits are located to initialize the connection of each satellite. The initial overhead of each link is equal. Based on the connection status of each link after initialization, the traditional Dijkstra algorithm is used to plan routes for various communication requests, obtain the traffic status of each link between satellites, calculate the overhead of each link, and define DFN[U] as the order number (timestamp) of the depth search of node U, and LOW[U] as the smallest order number that can be found with U or its subtree. The algorithm starts the depth-first search in the order of node input. The derivation conditions are: ① For each new node X found, DFN[X] = LOW[X]; ② When node Y is connected to node Z, if Z is not in the stack at time DFN[Y], LOW[Y] = min(LOW[Y], LOW[Z]); ③ When node Y and node Z are not in the stack, LOW[Y] = min(LOW[Y], DFN[Z]); Important links are selected and traffic is directed based on important links.

[0034] Step 200: Set a link cost threshold. Compare the cost of each link with the threshold. Links exceeding the threshold are considered important links, and all important links are added to the directed graph. Low-volume services do not need to be included in the directed graph. A strong connectivity algorithm is used on the traffic directed graph created by important links to calculate the strongly connected components. Any pair of satellite nodes in a strongly connected component of the entire network is connected. Each strongly connected component is planned as a parallel subnet, and the subnet is shrunk to the nodes of the directed graph using a graph shrinking method. Routing replanning is then performed. For services within each subnet, the original routing method is used, and the cost of each link within the subnet is calculated. For cross-subnet services, long-distance links are used, connecting satellite nodes across long distances in the two subnets.

[0035] Step 300: Each satellite-scheduled data service has specific requirements for latency, bandwidth, jitter, and VLAN tags. For these data packets carrying transmission requirement information, during inter-subnet transmission, to meet the transmission needs of time-sensitive services, the positions of data packets in the node buffer queue need to be adjusted according to their service priorities. Based on the VLAN tags, the priority of the VLAN tags for all services stored on the sending port is determined, typically set to 0-7.

[0036] Step 400: First, sort these data packets according to their tag priority, with higher priority packets sent first. For data packets of the same priority, a weighted priority algorithm is used to sort them a second time. The basic principle is a linear weighting method, prioritizing packets based on the impact of key parameters carried by the data packets on transmission. Assume that at time t, the data packets in the buffer queue of congested node i are S1, S2, ..., S... packets with different priorities. n The labels have already been sorted by priority, where S is assumed to be... n S n-1 S n-2 The tags have the same priority. This invention considers several factors that significantly affect the transmission of time-sensitive service data packets: transmission delay constraint D, transmission bandwidth constraint B, and transmission distance constraint J. i The influence factor. The formula for the subdivision priority of the weighted priority ranking algorithm is:

[0037] P t =e1·D+e2·B+e3·J.

[0038] Two thresholds, η1 and η2, are defined: η1 is the threshold for sending as soon as possible, and η2 is the threshold for blocking retransmissions. The general priority standard for these thresholds is as follows:

[0039] η1 = 4; η1 = 2.

[0040] After adjusting the positions of services in the buffer queue, low-priority services that are below the congestion retransmission threshold are discarded, and a message is sent to the source node of the discarded low-priority service to reselect a route for it. High-priority time-sensitive services that are below the immediate transmission threshold are prepared for long-distance transmission. For high-priority time-sensitive services, a periodic cyclic scheduling and forwarding mechanism is used for forwarding and scheduling.

[0041] Step 500: The satellite physical layer responsible for forwarding also includes a TSN switch (SW) capable of handling time-sensitive service transmission. Utilizing the characteristics of the SW, gating scheduling based on odd-even time intervals and with time protection segments is implemented for time-sensitive service transmission. The opening and closing of the transmission gates on the forwarding port is controlled using a timer module in the SW. This invention uses queues R7 and Q6 on the SW forwarding port to transmit the highest-priority time-sensitive service. Assuming the timer starts counting at time T0, queue Q7 in the SW is open for transmitting data and closed for writing data, while queue Q6 is open for writing data and closed for transmitting data. After a time interval d, the timer module reaches the threshold T0+d, at which point the states of the two queues are reversed: queue Q7 is open for writing data and closed for transmitting data, while queue Q6 is closed for writing data and open for transmitting data. Considering that in some cases, TSN data packets may be transmitted after lower-priority services, and excessively large lower-priority data packets may fail to meet the transmission delay requirements of time-sensitive services, or even cause congestion. To address this, this invention extends the time interval by a small period d before the time-sensitive service is about to be transmitted. 0ffset (Generally, this is the transmission time of a standard Ethernet frame), during which no lower-priority services can be transmitted. Therefore, the formula for the timing of the transmission gate opening and closing switch is:

[0042] T c =T0+d+d offset .

[0043] This invention, by introducing a parallel subnet structure, a weighted priority sorting algorithm, and an even / odd gated cyclic queuing forwarding mechanism, achieves controllable latency for long-distance transmission between time-sensitive service subnets. First, when time-sensitive service data packets and secondary priority data packets arrive at the transmission port of the subnet's transmission satellite, the time overhead for sorting these data packets is D. S The worst-case latency for periodic queuing and forwarding at the transmission port is D. Q =2d+d offset The jitter is 0 to 2d+d offset When transmitting over long distances via a parallel subnet, the transmission delay D can be calculated using the laser transmission information table. T Therefore, we can derive the formula for the controllable delay of long-distance transmission as follows:

[0044] D Total =D S +D Q +D T .

[0045] Step 600: Re-route based on traffic to enable long-distance transmission of time-sensitive services.

[0046] The method of the present invention will be described below with specific embodiments.

[0047] Based on steps 100 and 200, assume there are currently 12 satellites communicating with each other, and these 14 satellites are numbered AL. According to step 100, each satellite has a laser connection information table. For example, for satellite A, assuming its laser can connect to satellite BK but not to satellite LN, then satellite A is currently connected to satellite B. The IP address and logical address of the satellite within the laser's reach range at the current moment are recorded for satellite BK. This connection information table will be continuously updated as the satellites move. Simultaneously, a simple satellite network based on laser links has been initialized, as shown in the following figure. Figure 2 As shown in (a). After rerouting and constructing subnets according to the strong connectivity algorithm, the resulting satellite network structure is as follows. Figure 2 As shown in (b).

[0048] According to step 300, assuming many data packets are transmitted from satellite B to satellite M, in order to meet the transmission requirements of time-sensitive services, it is necessary to use satellites B and I for cross-network data transmission through parallel subnets. Each satellite-scheduled data service has specific requirements regarding latency, bandwidth, jitter, and VLAN tags. For these data packets carrying transmission requirement information, during cross-subnet transmission, in order to meet the transmission requirements of time-sensitive services, the positions of the data packets in the node buffer queues need to be adjusted according to their service priorities.

[0049] According to step 400, these data packets are first sorted according to label priority, with higher priority packets sent first. For data packets of the same priority, a weighted priority algorithm is used to sort them a second time. The basic principle is linear weighting, prioritizing packets based on the impact of key parameters carried by the data packets on transmission. Two thresholds, η1 and η2, are defined: η1 is the "send as soon as possible" threshold, and η2 is the "congestion retransmission" threshold. After adjusting the positions of services in the buffer queue, low-priority services below the congestion retransmission threshold are discarded, and a message is sent to the source node of the discarded low-priority service to reselect a route for it. High-priority time-sensitive services above the "send as soon as possible" threshold are prepared for long-distance transmission. For high-priority time-sensitive services, a periodic cyclic scheduling and forwarding mechanism is used for forwarding. The priority-based service scheduling and forwarding process is as follows: Figure 3 As shown.

[0050] According to step 500, leveraging the characteristics of the Switch (SW), gating scheduling based on odd-even time intervals and with time protection segments is implemented for the transmission of time-sensitive services. The timer module in the SW controls the opening and closing of the transmission gates on the forwarding port. This invention uses queues R7 and R6 of the SW forwarding port to transmit the highest-priority time-sensitive services. Assuming the timer starts counting at time T0, queue R7 in the SW opens for data transmission and closes for data writing, while queue R6 opens for data writing and closes for data transmission. After a time interval d, the timer module reaches the threshold T0+d, at which point the states of the two queues are reversed: queue Q7 opens for data writing and closes for data transmission, while queue Q6 closes for data writing and opens for data transmission. Considering that in some cases, TSN packets may be transmitted after lower-priority services, and excessively large lower-priority packets may fail to meet the transmission delay requirements of time-sensitive services, or even cause congestion. To address this, this invention extends the time interval of the time-sensitive service transmission by a small additional time d before the scheduled transmission time. offset (Generally, this is the transmission time of a standard Ethernet frame), during which no low-priority services can be transmitted. Therefore, the time point for the transmission gate opening and closing switch becomes T0+d+d. offset The switching process and timeline of gate scheduling are as follows: Figure 4 As shown.

[0051] According to step 600, satellite B is selected to connect to satellite I within subnet ⑦, and then satellite I is routed to satellite M. This realizes long-distance inter-satellite connection, reduces the multi-hop delay of data transfer from subnet ③ to subnet ⑤ and then to subnet ⑦, and ensures efficient inter-regional transmission.

[0052] Finally, the total delay for all "send-forward-receive" processes from the subnet's input / output ports is calculated. First, the time complexity of the linear weighted priority algorithm in this invention is n log n. In real time, D is calculated... S The delay is approximately several hundred microseconds, depending on the number of packets in the buffer. Next, the latency in gating scheduling is calculated using the worst-case scenario: the maximum latency plus the maximum jitter. Assuming a gating switch slot is 200µs and a standard Ethernet frame takes 12.44µs to transmit, the latency D for this transmission process is... Q Approximately 825µs. Finally, regarding the transmission delay based on the parallel subnet structure, assuming a constellation with 1500 satellites, in the worst-case scenario, the transmission delay D via laser transmission... T The maximum is 80ms. Therefore, according to D... Total =D S +D Q +D TThe total latency is 81.824ms, which achieves both controllable latency and meets the low latency requirements of general time-sensitive services.

[0053] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A method for long-distance transmission of time-sensitive services in a low-Earth orbit constellation, characterized in that, Includes the following steps: Obtain the IP addresses and laser connection information tables for each satellite. Each satellite has its own laser connection information table, which records the satellites currently connected to each satellite, the IP addresses of satellites within the laser's reachable range at the current moment, and their logical location addresses. The satellite IP addresses within the laser's reachable range are the satellite IP addresses that each satellite can connect to by adjusting its laser. The logical location addresses are the current location information of all satellites that each satellite can connect to. The laser connection information table is continuously updated as the satellite's location changes. According to the laser connection information table, each satellite node initializes the connection between adjacent satellites and plans routes according to the traditional path algorithm. After filtering the initial important links by the set threshold, the entire satellite constellation is divided into several parallel subnets according to the traffic weight and strong connectivity algorithm. Traffic routing is performed in the constructed parallel subnets, where each data packet includes basic information required for transmission and features related to priority ordering; Based on the VLAN tag attached to the header of the data packet by the source node during traffic transmission, a coarse classification is first performed, and then a weighted priority scheduling algorithm is used for fast sorting to further refine the priority ranking. The periodic forwarding mechanism in the 802.1Qch protocol is used to output high-priority time-sensitive services through two controllable gates that are periodically switched on and off. Finally, routes are replanned based on traffic to achieve long-distance connectivity and predictable transmission latency for time-sensitive services.

2. The method for long-distance transmission of time-sensitive services in a low-orbit constellation as described in claim 1, characterized in that, Using the satellite logical addresses in the laser connection information table, the satellites in front and behind each other in the same orbit and the satellites in the adjacent orbits are found, thereby completing the connection initialization of each satellite. The initial cost of each link is equal. Based on the connection status of each link after initialization, the traditional Dijkstra algorithm is used to plan routes for various communication requests, obtain the traffic status of each link between satellites, and calculate the cost of each link. Important links are selected and traffic is directed based on important links.

3. The method for long-distance transmission of time-sensitive services in a low-orbit constellation as described in claim 2, characterized in that, Traffic routing is performed in multiple constructed parallel subnets, where the traffic is simulated traffic for real-world communication needs and large-scale satellite constellation routing.

4. The method for long-distance transmission of time-sensitive services in a low-orbit constellation as described in claim 3, characterized in that, Each satellite scheduling data service has specific requirements for latency, bandwidth, jitter, and VLAN tags.

5. A method for long-distance transmission of time-sensitive services in a low-orbit constellation as described in claim 4, characterized in that, For data packets carrying transmission requirements, when transmitting data across subnets, the positions of the data packets in the node buffer queue need to be adjusted according to their service priorities.

6. A method for long-distance transmission of time-sensitive services in a low-orbit constellation as described in claim 5, characterized in that, First, based on the VLAN tags, determine the priority of the VLAN tags for all services stored on the sending port, setting them from 0 to 7. Then, sort the data packets according to their tag priority, with higher priority packets sent first. For data packets of the same priority, use a weighted priority algorithm to sort them a second time. Assume that at time t, the data packets in the buffer queue of congested node i have different priorities. The tags have already been sorted by priority, where it is assumed that... The tags have the same priority; the influencing factors during the transmission of time-sensitive service data packets include transmission delay constraint D, transmission bandwidth constraint B, and transmission distance constraint J. The influence factor is the weighted priority ranking algorithm, where the formula is: 。 7. A method for long-distance transmission of time-sensitive services in a low-orbit constellation as described in claim 6, characterized in that, Define two thresholds and , To send the threshold as quickly as possible, To block the retransmission threshold, the positions of services in the buffer queue are adjusted. Low-priority services located after the blocking retransmission threshold are discarded, and a message is sent to notify the source node of the discarded low-priority service to reselect a route for it. High-priority time-sensitive services located before the immediate transmission threshold are prepared for cross-distance transmission. For high-priority time-sensitive services, a periodic cyclic scheduling and forwarding mechanism is used for forwarding and scheduling.

8. A method for long-distance transmission of time-sensitive services in a low-orbit constellation as described in claim 7, characterized in that, The satellite physical layer responsible for forwarding functions also includes TSN switches (SWs) capable of handling time-sensitive service transmission. Utilizing the characteristics of SWs, time-sensitive service transmission is subject to gating scheduling based on odd-even time intervals and with time protection segments.

9. A method for long-distance transmission of time-sensitive services in a low-orbit constellation as described in claim 8, characterized in that, The opening and closing of the transmission gates on the forwarding port are controlled using the timer module in the Switch (SW). Specifically, the forwarding port of the Switch (SW) is used... queues and The queue is used to transmit the highest priority time-sensitive services; assuming the timer is in... The timer starts now, and at this moment, in SW... The queue number is open for transmitting data and closed for writing data. The queue is open for writing data and closed for transmitting data; within a time period The timer module reaches the threshold At this point, the states of the two queues are reversed. The queue number is open for writing data and closed for sending data. Queue number 1 is closed for writing data and open for transmitting data; Extend the time slightly before the time-sensitive service is about to be transmitted. The transmission time is the time it takes for a standard Ethernet frame to pass through. During this time period, no lower-priority services can be transmitted. Therefore, the timing of the transmission gate opening / closing switch becomes... .

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