A Deterministic Path Set Planning Method for Low-Earth Orbit Satellite Networks Based on the Space Domain

Abstract

This invention discloses a deterministic path set planning method for low-Earth orbit (LEO) satellite networks based on the spatial domain. Based on predictable LEO satellite topology information, a shortest path algorithm is used to obtain a set of lateral paths that meet the deterministic service transmission delay requirements. The lateral path set within the j-th time slice is compared with the lateral path set within the (j+1)-th time slice. The path with the most overlapping inter-satellite links is selected as the path in the (j+1)-th time slice corresponding to a path in the j-th time slice, and so on, to obtain the set of longitudinal paths within the complete service time. The impact of different longitudinal path sets on transmission delay is measured to obtain an optimal deterministic path set. This invention determines the path search range by dividing the spatial domain and extended domain, maintaining path consistency, and reducing the number of path switching times within the service transmission time while ensuring that deterministic services meet the delay threshold, thereby reducing the overall transmission delay within the complete service time and improving the deterministic service capability.

Description

Technical Field

[0001] This application relates to the technical field of networks and information processing, and in particular to a deterministic path set planning method for low-Earth orbit satellite networks based on the space domain. Background Technology

[0002] With the further integration of low-Earth orbit (LEO) satellite networks and terrestrial networks, there is a need for onboard systems to meet the high reliability and time determinism requirements of deterministic services during transmission and distribution. Due to the unique characteristics of my country's LEO satellite constellation construction, information backhaul beyond a certain range requires multi-hop paths within the LEO satellite network. This increases both the difficulty of path selection and the uncertainty of service information backhaul. Looking towards future massive LEO satellite networks, if the range of path selection options is too large when deterministic services are transmitted via LEO satellite inter-satellite links, it can easily lead to path non-convergence, and the path selection algorithm will be inefficient.

[0003] If a deterministic service cannot be transmitted within the duration of a single path, an indefinite number of path switching is required during the transmission process. Even if the selected transmission path has the minimum latency each time, frequent path switching during the complete transmission of the service, as well as too many inter-satellite links that need to be switched when the path changes, will affect the overall transmission latency and path consistency of the service. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, a deterministic path set planning method for low-Earth orbit satellite networks based on spatial domain partitioning is proposed. This method narrows the scope of path requests through domain partitioning. A deterministic path set planning method is also proposed, which, based on the predictable information of the low-Earth orbit satellite constellation topology, maximizes the duration of paths and reduces path switching while meeting the delay threshold of deterministic services, so that the paths have consistency and service continuity during the complete transmission time of deterministic services.

[0005] Firstly, a deterministic path set planning method for low-Earth orbit satellite networks based on the space domain is provided, including:

[0006] Based on the deterministic service transmission request message sent by initiator A to destination B, the deterministic service transmission delay threshold τ is obtained. s The service duration Ts indicates the set of J time slices, Ts = {T1, T2, ..., T...}. J};

[0007] Determine the physical satellite node S corresponding to the initiator A in the j-th time slice. A The physical satellite node S corresponding to the destination B. B , j = 1 ~ J;

[0008] Within the defined spatial search domain, calculate the path link combination within the j-th time slice. and from path link combination The latency threshold τ that satisfies deterministic business requirements is determined in the middle. s The paths of demand form a set of horizontal paths.

[0009] Based on the horizontal path set Obtain multiple vertical path sets under all J time slices within the complete service transmission time Ts. These multiple vertical path sets include a first vertical path set and a second vertical path set. The first vertical path set includes the horizontal path R. j-1,1 and lateral path R j,1 The second set of vertical paths includes the horizontal path R. j-1,2 and lateral path R j,2 Horizontal path R j-1,1 and lateral path R j-1,2 The set of lateral paths belonging to the (j-1)th time slice lateral path R j,1 and lateral path R j,2 The set of lateral paths belonging to the j-th time slice lateral path R j,1 From the lateral path R j-1,1 Switching to the desired horizontal path R j,1 For the set of horizontal paths Middle and lateral path R j-1,1 The path with the highest overlap is the lateral path R. j,2 From the lateral path R j-1,2 Switching to the desired horizontal path R j,2 For the set of horizontal paths Middle and lateral path R j-1,2 The path with the highest overlap;

[0010] The set of paths with the shortest delay is determined from the multiple sets of vertical paths as the preferred set of paths.

[0011] In conjunction with the first aspect, in some implementations of the first aspect, when j=1, or when the starting satellite node in the (j-1)th time slice cannot be used in the jth time slice, the determination of the physical satellite node S corresponding to the initiator A in the jth time slice... A ,include:

[0012] Using the geocentric perpendicular method, the vector connecting the geocenter to the initiating point A is extended and intersected with the satellite orbital altitude plane to obtain the virtual satellite node A′ of the initiating point A;

[0013] Within the j-th time slice when the service begins to transmit, the coverage area of ​​the neighboring satellites of the virtual satellite node A′ is counted, and the ground coverage area that the neighboring satellites can cover is projected onto the low-Earth orbit satellite orbital plane.

[0014] Within the low-Earth orbit plane, count all satellite nodes that can cover the virtual satellite node A′ to obtain the initial satellite node set {S}. A1 ,S A2 ,...,S An};

[0015] Using the known constellation ephemeris, obtain the duration {Tc} of the virtual satellite node A′ covered by different satellites in the initial satellite node set. A1 ,Tc A2 ,...,Tc An};

[0016] Select max(Tc) Ai The corresponding satellite node is the physical satellite node S mapped by the virtual starting node A′. A .

[0017] In conjunction with the first aspect, in some implementations of the first aspect, when j=1, or when the desired satellite node in the (j-1)th time slice cannot be used in the jth time slice, the determination of the physical satellite node S corresponding to the destination B in the jth time slice... B ,include:

[0018] Using the geocentric perpendicular method, the vector connecting the geocenter to the target end B is extended and intersected with the satellite orbital altitude plane to obtain the virtual satellite node B′ of the target end B;

[0019] Within the j-th time slice when the service begins to transmit, the coverage area of ​​the neighboring satellites of the virtual satellite node B′ is counted, and the ground coverage area that the neighboring satellites can cover is projected onto the low-Earth orbit satellite orbital plane.

[0020] Within the low-Earth orbital plane, count all satellite nodes that can cover the virtual satellite node B′ to obtain the target satellite node set {S}. B1 ,S B2 ,...,S Bm};

[0021] Using the known constellation ephemeris, obtain the duration {Tc} of the virtual satellite node B′ covered by different satellites in the target satellite node set. B1 ,Tc B2 ,...,Tc Bn};

[0022] Select max(Tc) BiThe corresponding satellite node is the physical satellite node S mapped to the virtual expected node B′. B .

[0023] In conjunction with the first aspect, in some implementations of the first aspect, the calculation of the path link combination within the j-th time slice... include:

[0024] Based on the satellite link connectivity status in the constellation ephemeris at that moment, the shortest path Dijkstra algorithm is used to obtain the path from satellite node S. A To satellite node S B Shortest path set

[0025] In conjunction with the first aspect, in some implementations of the first aspect, when all shortest paths within the initial search domain in the j-th time slice fail to satisfy the time delay threshold τ... s In the case of demand, the spatial search domain is an extended search domain. The initial search domain is determined based on the starting satellite node and the desired satellite node. The extended search domain is obtained by expanding the initial search domain outwards. The lateral path set... All paths satisfy the condition that there are satellite nodes on the path that are located within the extended search domain but outside the initial search domain.

[0026] In conjunction with the first aspect, in some implementations of the first aspect, the extended search domain range extends from the starting satellite node S. A The satellite node S is located in a north-south or east-west direction, away from the desired satellite node. B By expanding by one satellite node,

[0027] And / or,

[0028] The expanded search domain ranges from the desired satellite node S B Deviating from the starting satellite node S in the north-south or east-west direction A This is achieved by expanding by one satellite node.

[0029] In conjunction with the first aspect, in some implementations of the first aspect, the lateral path set The path in the path satisfies any of the following:

[0030] Starting satellite node S in the lateral path A The next hop is satellite node S A ', Satellite Node S A 'For the starting satellite node S A The satellite node S is located in a north-south or east-west direction, away from the desired satellite node. B The next hop node;

[0031] Desired satellite node S in the lateral pathB The previous hop is satellite node S B ', Satellite Node S B 'For the desired satellite node S B Deviating from the starting satellite node S in the north-south or east-west direction A The previous hop node.

[0032] In conjunction with the first aspect, in some implementations of the first aspect, determining the set of paths with the shortest latency from the plurality of vertical path sets as the preferred path set includes:

[0033] The weights of the vertical path set are calculated based on the transmission path delay weight function, which satisfies the following:

[0034]

[0035] TC LC N is the propagation delay of all links contained in the vertical path set. LC T is the number of distinct links for each path in different time slices within the vertical path set compared to the previous path. LC It is the latency required for different links in the path to be established and switched, and K is the number of paths in the vertical path set.

[0036] In a second aspect, a communication method is provided for transmitting deterministic service transmission messages, wherein the satellite nodes traversed by the deterministic service transmission messages are determined by the method described in any of the implementations of the first aspect above.

[0037] Thirdly, an electronic device is provided, characterized in that the electronic device is used to perform the method described in any one of the implementations of the first to second aspects described above.

[0038] Compared with the prior art, the solution provided in this application has at least the following beneficial technical effects:

[0039] (1) The present invention divides the low-orbit satellite network space corresponding to the deterministic business area into three regions: “starting domain”, “search domain” and “expected domain”, and determines the path search range.

[0040] (2) The present invention obtains the required optimized path set, and under the premise of satisfying the deterministic service delay constraint, reduces the number of path switching times during the service transmission time, reduces the overall transmission delay during the complete service time, and improves the deterministic service capability of the path set.

[0041] (3) The present invention proposes a method for expanding the spatial domain path search range, reducing the variation of the path search range and maintaining path consistency. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the "starting domain" / "desired domain" in space.

[0043] Figure 2 A schematic diagram of the initial region for "finding the domain" in space.

[0044] Figure 3 A schematic diagram of the expanded area for "finding the domain" in space.

[0045] Figure 4 This is a flowchart for planning deterministic path sets based on the spatial domain. Detailed Implementation

[0046] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0047] Based on the known location information of the ground terminal, the entire transmission process via the low-Earth orbit (LEO) satellite network can be divided into three spatial regions: the "starting domain," the "search domain," and the "desired domain." Since the LEO satellite network is highly dynamic compared to the ground, analyzing the motion patterns of the ground terminal and the LEO satellite reveals that the ground terminal's speed is much lower than the LEO satellite's speed. Therefore, within a certain timeframe, a ground terminal can be considered quasi-static relative to the LEO satellite. Mapping the ground terminal onto the LEO satellite's orbital altitude plane as a fixed point, the spatial domain division method narrows the search path range. Furthermore, by using minimum and scalable regions, a relatively stable path range can be obtained, reducing the time required for path search. Moreover, under the premise of time slicing, path associations between different time slices are established, and paths for different time periods within the complete service transmission time are planned to obtain an overall optimized path set.

[0048] End-to-end latency typically consists of four parts: transmission latency, propagation latency, processing latency, and queuing latency. When deterministic services are transmitted in low-Earth orbit (LEO) satellite networks, each satellite node prioritizes transmission for these services. Through techniques such as traffic shaping, resource reservation, and deterministic scheduling, the transmission latency, processing latency, and queuing latency of deterministic services within each node are minimized and made deterministic. Therefore, the main factor affecting end-to-end latency in LEO satellite networks is the propagation latency on the link. The fewer the number of hops in the link, the lower the propagation latency. Path switching causes large fluctuations in the link, affecting the stability and consistency of the path. Therefore, from this perspective, shorter propagation latency in a given time slice is not always better. Instead, while meeting the latency threshold for deterministic services, maximizing the path's duration and minimizing path switching are crucial to ensuring consistency and service continuity throughout the complete transmission time of the deterministic service.

[0049] In this invention, taking into account the high dynamics and topology plannable characteristics of low-Earth orbit satellite networks, the transmission requirements are planned in advance. While ensuring that the path delay meets the requirements, the number of inter-satellite links that need to be switched is reduced, and the balance of services such as delay and bandwidth between different paths is guaranteed, thereby improving the reliability and service continuity of deterministic services.

[0050] Figure 4 This application illustrates a deterministic path set planning method for low-Earth orbit satellite networks based on the space domain. Taking the Walker constellation as an example, a specific embodiment is shown below.

[0051] (1) Obtain the geographical location information of the ground deterministic service sender A and the destination B, determine the position information of the corresponding virtual satellite nodes A′ and B′ in the orbital plane of the low-Earth orbit satellite network, and obtain the deterministic service transmission delay threshold τ by the deterministic service transmission request message sent by the initiator A to the destination B. s And the duration of the business, Ts.

[0052] (2) Convert the business duration Ts into a set of time slices Ts = {T1, T2, ..., Ts} according to certain criteria. J Within a time slice, the path can be considered static, and any time slice is represented as... Assuming the time slices are divided at equal intervals, denoted as Δt, and the orbital period of the low-Earth orbit satellite is T, then the number of time slices is... A dynamic path can be converted into a static path under certain constraints. In this embodiment, Ts = 10Δt, which is less than the orbital period T of the low-Earth orbit satellite, so the number of time slices J = Ts / Δt = (10Δt) / Δt = 10.

[0053] (3) Define the spatial "starting domain" and obtain the starting satellite node set {S}. A1 ,S A2 ,...,S An}, determine the physical satellite node S mapped to the virtual starting node. A ,like Figure 1 As shown.

[0054] (3a) Using the geocentric perpendicular method, the line vector connecting the geocenter to the ground initiating end A is extended and intersected with the satellite orbital altitude plane to obtain the virtual satellite node A′ of the ground initiating end A.

[0055] (3b) In the j-th time slice (initially set to j=1) when the service begins to transmit Within, the coverage area of ​​neighboring satellites of virtual satellite node A′ is statistically analyzed, and the ground area covered by the neighboring satellites is projected onto the low-Earth orbit satellite orbital plane.

[0056] (3c) Count all satellite nodes that can cover the virtual satellite node A′ within the low Earth orbit plane to obtain the initial satellite node set {S}. A1 ,S A2 ,...,S An}

[0057] (3d) Using the known constellation ephemeris, obtain the duration {Tc} of the virtual satellite node A′ covered by different satellites in the initial satellite node set. A1 ,Tc A2 ,...,Tc An}

[0058] (3e) Select max(Tc) Ai The corresponding satellite node is the physical satellite node S mapped by the virtual starting node A′. A .like Figure 2 As shown, in the j=1th time slice S A =S 10 .

[0059] (3f) Similarly, the judgment is made in the 2nd to 10th time slices of the service, and the starting satellite nodes obtained in the 10 time slices are as follows:

[0060] {S 10 (T1),S 10 (T2),S 10 (T3),S 10 (T4),S 11 (T5),S 11 (T6),S 11 (T7),S 11 (T8),S 12 (T9),S 12 (T 10 )}

[0061] Where the starting satellite node in the (j-1)th time slice cannot be used in the jth time slice, the starting satellite node in the jth time slice is obtained by executing (3b) to (3e) above. Specifically, in the jth time slice where service transmission begins... Within, determine the previous time slice T. j-1 Selected physical satellite node S A Is the connection with the ground-initiating terminal valid? If valid, maintain S. A If unchanged; if invalid, repeat steps (3b)-(3e) to obtain a new starting satellite node S. A .

[0062] (4) Define the spatial "desired domain" and obtain the desired satellite node set {S}. B1,S B2 ,...,S Bm}, determine the physical satellite node S mapped to the virtual expected node. B .

[0063] (4a) Obtain the virtual satellite node B′ of the ground initiator B (refer to step (3a) above);

[0064] (4b) In the j-th time slice (initially set to j=1) when the service begins to transmit Within, the coverage area of ​​neighboring satellites of virtual satellite node B′ is statistically analyzed, and the ground area covered by the neighboring satellites is projected onto the low-Earth orbit satellite orbital plane.

[0065] (4c) Count all satellite nodes that can cover the virtual satellite node B′ within the low Earth orbit plane to obtain the target satellite node set {S}. B1 ,S B2 ,...,S Bm}

[0066] (4d) Using the known constellation ephemeris, obtain the duration {Tc} of the virtual satellite node B′ covered by different satellites in the target satellite node set. B1 ,Tc B2 ,...,Tc Bn}

[0067] (4e) Select max(Tc) Bi The corresponding satellite node is the physical satellite node S mapped to the virtual expected node B′. B In the j=1th time slice, S B =S 42 .

[0068] (4f) Similarly, the judgment is made in the 2nd to 10th time slices of the service, and the expected satellite nodes obtained in the 10 time slices are as follows:

[0069] {S 42 (T1),S 42 (T2),S 42 (T3),S 42 (T4),S 42 (T5),S 43 (T6),S 43 (T7),S 43 (T8),S 43 (T9),S 43 (T 10 )}.

[0070] Where the desired satellite node in the (j-1)th time slice cannot be used in the jth time slice, the desired satellite node in the jth time slice is obtained by performing steps (4b) to (4e) above. In the jth time slice where service transmission begins... Within, determine the previous time slice T. j-1 Selected physical satellite node S B Is the connection with the ground destination terminal valid? If valid, maintain S. B If unchanged; if invalid, repeat steps (4b)-(4e) to obtain the new desired satellite node S. B .

[0071] (5) Define the spatial search domain range under the current time slice. The method for defining the spatial "search domain" range is to use the starting node set S A and expected node S B The orbital plane of the node is taken as one side, and the perpendicular line between the node and the orbital plane is taken as the other side. A rectangular area is delineated in the orbital plane of the low Earth orbit satellite network, which is the mapped spatial "search domain". For example... Figure 2 As shown, assume node S A With S B Satellites are distributed across three orbital planes, excluding retrograde slots and polar orbits. Satellites are equally spaced across each orbital plane.

[0072] (6) Within each time slice, calculate the time slices j = 1 to 10 respectively within the defined spatial search domain. Internal path link combination

[0073] The paths are composed of different satellite links. In this embodiment, all the paths are coded according to the different inter-satellite links they contain, and there are a total of 33 paths.

[0074] (6a) In the first time slice T1, based on the satellite link connectivity status in the constellation ephemeris at that moment, the shortest path (Dijkstra) algorithm is used to obtain the path from S A To S B Shortest path set The inter-satellite links included in each path are shown in Equation (1), and the positional relationships between nodes are shown in [reference needed]. Figure 2 .

[0075]

[0076] Inter-satellite links are mainly divided into two types: intra-orbit ISLs between satellites in the same orbit and inter-orbit ISLs between satellites in different orbits. In intra-orbit ISLs, the relative positions of two satellites remain constant; in inter-orbit ISLs, the distance between two satellites in adjacent orbits moving in the same direction changes over time. In inter-orbit ISLs with opposite directions, due to the reverse orbital motion, the visible stars in the other orbit continuously change for one satellite, making the inter-satellite link not constant. Therefore, there are instances of inter-orbit link interruptions in polar regions and reverse gaps in inter-satellite links between the two hemispheres, requiring advance planning.

[0077] Based on the starting node and desired node time of the path and the search domain range, the link combination of the path within time slice T2 to T4 is obtained as shown in Equation (1), the link combination of the path within time slice T5 is shown in Equation (2), and the link combination of the path within time slice T6 to T8 is shown in Equation (3).

[0078]

[0079]

[0080] Time slices T9 to T 10 Inside, assuming due to link Unable to connect normally, proceed to step (6b).

[0081] (6b) In the 9th to 10th time slices, the required path link combination cannot be obtained in the search domain obtained above. link Connection unsuccessful; search domain needs to be expanded. Explanation: Inter-satellite links within the orbital plane are continuously maintained throughout satellite operation, which can be viewed as a ring revolving around the Earth. However, inter-satellite links between orbital planes are visible for a limited time. Therefore, when expanding, two principles apply: first, only one hop should be added at both the starting and destination ends; second, the number of links within the orbital plane should be increased as much as possible to extend the overall path's duration. Therefore, this embodiment uses a north-south expansion. For more complex expansion methods, if the required links cannot be met in the north-south direction, the next step can be to expand in the east-west direction.

[0082] In this embodiment, the expansion strategy is to first extend the starting node S... A The projection direction (north-south) of the orbital plane is along S. B →S A The direction is used to obtain the starting node S. A The next hop node S A '; then at the desired node S B The projection direction (north-south) of the orbital plane is along S. A →S B The direction yields the desired node S BThe next hop node S B '; Finally, with S A 'and S B The orbital plane has two sides, with S as the boundary. A 'and S B The perpendicular lines to the orbital plane are the other two sides, which map the orbital elevation surface of the low Earth orbit satellite network into a rectangular region, thus obtaining an extended search domain.

[0083] In time slices T9 to T 10 Within, after step (6b) to expand the search domain, the path link combination is calculated, as shown in equation (4).

[0084]

[0085] (7) Within the j=1 to 10th time slices, based on the known satellite status information and link information, the obtained path set is... Transmission delay τ for each path c The latency threshold requirement τ for this deterministic business request s Comparisons are made to ensure that the latency threshold τ for deterministic business operations is met. s The paths of demand form a set of horizontal paths. Each path in the aforementioned lateral path set consists of different links and link nodes. This can be labeled as... Where M1, M2, ..., M k It serves as an intermediate satellite node.

[0086] Assume that in the first time slice, τ cR1 , τ cR2 , τ cR7 Delay threshold τ for deterministic business operations s Demands, and their corresponding paths, form a set of horizontal paths:

[0087] The set of lateral paths in time slices 2 to 4 and They are the same, both being {R1,R2,R7}.

[0088] Within the 5th time slice, its lateral path set

[0089] The set of lateral paths within time slices 6 to 8

[0090] Within the 9th to 10th time slices, its lateral path set

[0091] (8) Obtain the set of vertical paths under all time slices within the complete service transmission time Ts.

[0092] (8a) The first time slice when the service begins transmission The set of horizontal paths within This is called the initial path set. The initial path set is the set of horizontal paths for the first time slice. The final set of vertical paths The path in the initial path set is used as the starting path. The specific link combination of the initial path set is shown in equation (1).

[0093] Within the second time slice T2 when the service begins transmission, each path R in the initial path set is used respectively. i Starting from the first path, compare it with all paths in the path set within time slice T2 in chronological order, and select the path with the most overlapping links as the path in the second time slice T2 to connect with R. 11 The corresponding path.

[0094] (8b) And so on, in the j-th time slice T when the service begins to transmit j Within each slice, obtain the value corresponding to the previous time slice T. j-1 The corresponding paths are set within the inner lateral path set. During the complete transmission time of the service, the initial path set is used. Using different paths as the first path, we can obtain a set of K paths, called the vertical path set, which can be expressed as: K is the number of paths in the initial path set. Any vertical path can be represented as:

[0095] In this embodiment of the application, during the 2nd to 4th time slices T2 to T4 when the service starts transmitting, since the starting node and the expected node are the same as those in the 1st time slice, and the "spatial domain" range and link status are the same, the selected lateral path does not change and remains {R1,R2,R7}.

[0096] In this embodiment of the application, the starting node changes within the fifth time slice, from the previous S 10 Change to S 11 This results in a path switch. Referring to equation (2), the path with the highest overlap with the path of the previous time slice is taken as the path of the current time slice. In the vertical path set... The process involves switching from path R1 to path R. 11 , Switch from R2 to path R 11 , Switch from R7 to path R 14 Its lateral path is {R}. 11 ,R 11 ,R 14}

[0097] In this embodiment of the application, within the 6th to 8th time slices, compared to the 5th time slice, the desired node changes, from the previous S... 42 Change to S 43 This results in a path switch. Referring to equation (3), the path with the highest overlap with the path of the previous time slice is taken as the path of the current time slice. In the vertical path set... The middle is the path R 11 Switch to path R 15 , R 11 Switch to path R 15 , R 14 Switch to path R 21 Its lateral path is {R}. 15 ,R 15 ,R 21}

[0098] In this embodiment of the application, within the 9th to 10th time slices, compared to the 8th time slice, the starting node and the "spatial domain" change; the starting node changes from the previous S... 11 Change to S 12 The "spatial domain" expands accordingly, resulting in a path switch. Referring to equation (4), the path with the highest overlap with the previous time slice is taken as the path for the current time slice. In the vertical path set R... V1 The middle is the path R 15 Switch to path R 25 , R 15 Switch to path R 25 , R 21 Switch to path R 33 Its lateral path is {R}. 25 ,R 25 ,R 33}

[0099] Therefore, the set of longitudinal paths corresponding to the 10 time slices is shown in Equation (5).

[0100]

[0101] (9) Calculate R based on the transmission path delay weight function. V Weights of different path sets in the middle:

[0102]

[0103] This function represents the total transmission delay of the transmission path under different time slices contained in each longitudinal path set. This function mainly includes inter-satellite link propagation delay and path switching delay, but does not include satellite processing delay and queuing delay. TC LC N is the propagation delay of all links contained in the vertical path set. LC T is the number of distinct links for each path in different time slices within the vertical path set compared to the previous path. LC It is the latency required for different links in the path to be established and switched.

[0104] Calculate the time delay weight function for different longitudinal path sets, sort the longitudinal path sets according to the magnitude of the time delay weights, and select the longitudinal path set with the smallest weight as the preferred path set.

[0105] Assuming the current transmission delay of a single satellite link is τ0, and the establishment and handover delays of different links are... Delay weight:

[0106]

[0107]

[0108] Delay weight:

[0109]

[0110] Delay weight:

[0111]

[0112] Based on τ0 and The specific values ​​are used to perform a final optimization sort on the path set, resulting in the optimal path set in this example.

[0113] This application also provides a communication method for transmitting deterministic service transmission messages, wherein the satellite nodes through which the deterministic service transmission messages pass are determined by the above method.

[0114] This application also provides an electronic device for performing the methods provided in the embodiments of this application described above.

[0115] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope defined in the claims of the present invention.

Claims

1. A deterministic path set planning method for low-Earth orbit satellite networks based on the space domain, characterized in that, include: According to the initiator To the destination The deterministic service transmission request message sent obtains the deterministic service transmission delay threshold for this transmission. and business duration Business duration A set used to indicate J time slices ; Determine the initiator in the j-th time slice Corresponding physical satellite nodes and destination Corresponding physical satellite nodes , j=1~J; Within the defined spatial search domain, calculate the path link combination within the j-th time slice. and from path link combination Determine the latency threshold that satisfies deterministic business requirements. The paths of demand form a set of horizontal paths. ; Based on the horizontal path set Get the duration of the service Multiple vertical path sets under all J time slices, where each vertical path set includes the target vertical path set, and the target vertical path set includes the lateral path R. j-1,1 and lateral path R j,1 Horizontal path R j-1,1 The set of lateral paths belonging to the (j-1)th time slice Horizontal path R j,1 The set of lateral paths belonging to the j-th time slice Horizontal path R j,1 From the lateral path R j-1,1 Switching to the desired horizontal path R j,1 For the set of horizontal paths Middle and lateral path R j-1,1 The path with the highest overlap; The set of paths with the shortest latency is determined from the multiple sets of vertical paths as the preferred set of paths; The step of determining the set of paths with the shortest delay from the plurality of vertical path sets as the preferred path set includes: The weights of the vertical path set are calculated based on the transmission path delay weight function, which satisfies the following: ， It is the propagation delay of all links contained in the vertical path set. It represents the number of distinct links for each path in different time slices within the vertical path set compared to the previous path. It is the latency required for different links in the path to be established and switched, and K is the number of paths in the vertical path set; During the complete transmission time of the service, with the initial path set Using different paths as the first path, we can obtain a set of K paths, called the vertical path set, which can be expressed as: K is the number of paths in the initial path set. Any vertical path can be expressed as: , 1≤i≤K.

2. The method according to claim 1, characterized in that, When j=1, or when the starting satellite node in the (j-1)th time slice cannot be used in the jth time slice, the determination of the initiating end in the jth time slice... Corresponding physical satellite nodes ,include: Using the geocentric perpendicular method, the distance from the center of the earth to the starting point is... The connecting vector is extended to intersect the satellite orbital altitude plane to obtain the initiating point. Virtual satellite nodes ; Within the j-th time slice after the service begins transmission, count the virtual satellite nodes. The coverage area of ​​neighboring satellites projects the ground area covered by neighboring satellites onto the orbital plane of the low-Earth orbit satellites; Statistical analysis of coverable virtual satellite nodes within the low Earth orbit plane Obtain the initial set of satellite nodes from all satellite nodes. ; Using the known constellation ephemeris, obtain the virtual satellite nodes covered by different satellites in the initial satellite node set. Durable duration ; choose The corresponding satellite node serves as the virtual starting node. Mapped physical satellite nodes .

3. The method according to claim 1, characterized in that, When j=1, or when the desired satellite node in the (j-1)th time slice cannot be used in the jth time slice, the determination of the destination in the jth time slice... Corresponding physical satellite nodes ,include: Using the geocentric perpendicular method, the distance from the Earth's center to the destination is... The line vector connecting the points is extended to intersect the satellite orbital altitude plane to obtain the target end. Virtual satellite nodes ; Within the j-th time slice after the service begins transmission, count the virtual satellite nodes. The coverage area of ​​neighboring satellites projects the ground area covered by neighboring satellites onto the orbital plane of the low-Earth orbit satellites; Statistical analysis of coverable virtual satellite nodes within the low Earth orbit plane Obtain the target satellite node set from all satellite nodes. ; By using the known constellation ephemeris, obtain the virtual satellite nodes covered by different satellites in the target satellite node set. Durable duration ; choose The corresponding satellite nodes serve as virtual expected nodes. Mapped physical satellite nodes .

4. The method according to claim 1, characterized in that, The calculation of path link combinations within the j-th time slice ,include: Based on the current connectivity status of satellite links in the constellation ephemeris, the shortest path Dijkstra algorithm is used to obtain the path from the satellite nodes. To satellite node Shortest path set .

5. The method according to claim 1, characterized in that, When all shortest paths within the initial search domain in the j-th time slice fail to meet the time delay threshold In the case of demand, the spatial search domain is an extended search domain. The initial search domain is determined based on the starting satellite node and the desired satellite node. The extended search domain is obtained by expanding the initial search domain outwards. The lateral path set... All paths satisfy the condition that there are satellite nodes on the path that are located within the extended search domain but outside the initial search domain.

6. The method according to claim 5, characterized in that, The expanded search domain ranges from the starting satellite node. Deviating from the desired satellite node in the north-south or east-west direction. By expanding by one satellite node, And / or, The expanded search domain ranges from the desired satellite nodes. Deviating from the starting satellite node in the north-south or east-west direction This is achieved by expanding by one satellite node.

7. The method according to claim 6, characterized in that, The lateral path set The path in the path satisfies any of the following: Starting satellite node in the lateral path The next hop is a satellite node. Satellite nodes Starting satellite node Deviating from the desired satellite node in the north-south or east-west direction. The next hop node; Desired satellite nodes in the lateral path The previous hop is a satellite node. Satellite nodes For desired satellite nodes Deviating from the starting satellite node in the north-south or east-west direction The previous hop node.

8. A communication method, characterized in that, The communication method is used to transmit deterministic service transmission messages, wherein the satellite nodes through which the deterministic service transmission messages pass are determined by the method described in any one of claims 1 to 7.

9. An electronic device, characterized in that, The electronic device is used to perform the method as described in any one of claims 1 to 8.

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