Service area handover-oriented low earth orbit satellite cache active transfer method and device

Abstract

The application relates to the technical field of satellite communication, and provides a low-orbit satellite cache active transfer method and device for service area switching, wherein the low-orbit satellite cache active transfer method for service area switching comprises the following steps: determining a cache transfer-out satellite and a cache transfer-in satellite of a target service area in a target time period; determining a transfer distribution matrix according to target transfer-out cache content of each cache transfer-out satellite and target cache space of each cache transfer-in satellite; wherein the transfer distribution matrix is used for representing a distribution mapping relationship of the target transfer-out cache content of each cache transfer-out satellite to each cache transfer-in satellite; determining a global transfer start time according to a cache transfer deadline corresponding to each cache transfer-out satellite and a total data amount of the target transfer-out cache content of each cache transfer-out satellite; and sending the transfer distribution matrix and the global transfer start time to the cache transfer-out satellite. The application can effectively improve the cache hit rate and service continuity of an in-group satellite.

Description

Technical Field

[0001] This invention relates to the field of satellite communication technology, and in particular to a method and apparatus for active handover of low-Earth orbit satellite buffers for service area handover. Background Technology

[0002] In recent years, with the continuous deployment of low-Earth orbit (LEO) satellite constellations, LEO satellite networks are evolving from transparent forwarding systems into space edge networks with onboard storage and processing capabilities. Deploying the caching capabilities of content delivery networks (CDNs) to satellite nodes can effectively shorten content retrieval paths, reduce user access latency, and alleviate the pressure on the satellite-to-ground link back-to-origin process. Onboard caching has become a key technological direction for LEO satellite content distribution. However, the continuous high-speed movement of LEO satellite nodes relative to their ground service areas causes cached regional hotspot content on departing satellites to become invalid as they leave the constellation. Newly joined satellites are in a cold start state due to the lack of matching cache, resulting in decreased hit rates, increased latency, and increased back-to-origin pressure.

[0003] Among related technologies, there are various solutions to the caching problem in low-Earth orbit satellite handover scenarios. However, the core of all these solutions is to achieve cache sharing and cross-satellite retrieval within a satellite group serving the same ground area at the same time through inter-satellite links, or to preheat content based on single-satellite trajectory prediction. It is difficult to guarantee the cache hit rate and service continuity of the incoming satellites under the constraints of limited handover time and inter-satellite bandwidth.

[0004] Therefore, how to effectively improve the cache hit rate and service continuity of incoming satellites is a technical problem that urgently needs to be solved. Summary of the Invention

[0005] This invention provides a method and apparatus for proactive handover of low-Earth orbit satellite cache for service area handover, which addresses the aforementioned deficiencies in the prior art and effectively improves the cache hit rate and service continuity of incoming satellites.

[0006] This invention provides a method for proactive handover of low-Earth orbit satellite buffers for service area handover, comprising the following steps.

[0007] The process involves identifying the cache-transferring satellites and cache-receiving satellites within the target service area and the target time period; determining a handover allocation matrix based on the target outgoing cache content of each cache-transferring satellite and the target cache space of each cache-receiving satellite; wherein the handover allocation matrix represents the allocation mapping relationship between the target outgoing cache content of each cache-transferring satellite and the target cache-receiving satellite; determining the global handover start time based on the cache handover deadline time corresponding to each cache-transferring satellite and the total data volume of the target outgoing cache content of each cache-transferring satellite; and sending the handover allocation matrix and the global handover start time to the airborne controller, so that the airborne controller, based on the global handover start time, instructs each cache-transferring satellite to send the target outgoing cache content to the cache-receiving satellite according to the handover allocation matrix, and instructs the cache-receiving satellite to perform cache preheating based on the received target outgoing cache content.

[0008] According to the low-Earth orbit satellite cache active handover method for service area handover provided by the present invention, the step of determining the cache-transferring satellites and cache-transferring satellites in the target service area within a target time period includes: determining the set of outgoing satellites leaving the target service area within the target time period, and determining the cache handover deadline time corresponding to each outgoing satellite in the set of outgoing satellites; wherein, the cache handover deadline time is the time node at which the outgoing satellite can actively hand over cache content to the incoming satellite; determining the set of incoming satellites in the target service area within the target time period, and the entry time of each incoming satellite in the set of incoming satellites joining the target service area; and determining the cache-transferring satellites from the set of outgoing satellites and the cache-transferring satellites from the set of incoming satellites based on the cache handover deadline time corresponding to each outgoing satellite and the entry time of each incoming satellite joining the target service area.

[0009] According to the low-Earth orbit satellite buffer active handover method for service area handover provided by the present invention, determining the set of out-of-group satellites leaving the target service area within the target time period includes: determining the set of out-of-group satellites based on the orbital parameters of each satellite in the target service area at the current time step and the geographical boundary of the target service area.

[0010] According to the low-Earth orbit satellite buffer active handover method for service area handover provided by the present invention, determining the buffer handover deadline for each outgoing satellite in the outgoing satellite set includes: determining a first time when the outgoing satellite leaves the target service area based on the orbital parameters of the outgoing satellite at the current time step and the geographical boundary of the target service area; determining a second time when the outgoing satellite loses a valid inter-satellite link with other satellites in the target service area based on the orbital parameters of each outgoing satellite at the current time step and the inter-satellite links between satellites in the target service area; and determining the buffer handover deadline for each outgoing satellite based on the minimum value between the first time and the second time.

[0011] According to the low-Earth orbit satellite cache active handover method for service area handover provided by the present invention, the target transfer-out cache content of each cache transfer-out satellite is obtained in the following manner: For each cache transfer-out satellite, the following operations are performed: From the cache data of the cache transfer-out satellite, candidate transfer-out cache content that meets a first condition is selected; wherein, the first condition includes at least one of the following conditions: the popularity of the cache data is greater than a preset popularity threshold, and the cache data is a unique copy in the target service area; The value density of each cache object is determined according to the access frequency of each cache object in the candidate transfer-out cache content in the target service area and the data volume of the cache object; The target transfer-out cache content is selected from the candidate transfer-out cache content according to the value density of each cache object.

[0012] According to the low-Earth orbit satellite cache active handover method for service area handover provided by the present invention, the target cache space of each cache-receiving satellite is determined in the following manner: For each cache transfer satellite, the following operations are performed: obtain the first remaining available cache space of the cache transfer satellite; determine that the first remaining available cache space is greater than or equal to the size of the target transferred-out cache content; and determine the target cache space of the cache transfer satellite based on the first remaining available cache space.

[0013] According to the low-Earth orbit satellite cache active handover method for service area handover provided by the present invention, the method further includes: determining that the first remaining available cache space is less than the size of the target transferred-out cache content, and performing a value assessment on the existing cache objects of the cache-in satellite; based on the result of the value assessment, evicting low-value content from the existing cache objects; and determining the target cache space of the cache-in satellite based on the second remaining available cache space of the cache-in satellite after evicting the low-value content.

[0014] According to the low-Earth orbit satellite cache active handover method for service area handover provided by the present invention, the step of determining the global handover start time based on the cache handover deadline time corresponding to each cache handover satellite and the total data volume of the target handover cache content of each cache handover satellite includes: determining the total data volume of the target handover cache content for each cache handover satellite; and determining the latest start time for the handover task of the cache handover satellite based on the cache handover deadline time corresponding to the cache handover satellite, the total data volume of the target handover cache content, the inter-satellite link bandwidth of the cache handover satellite and its corresponding cache receiving satellite, the handover confirmation overhead, and the safety buffer time; and determining the global handover start time based on the latest start time for the handover task of all cache handover satellites.

[0015] This invention also provides a method for proactive handover of low-Earth orbit satellite buffers for service area handover, executed by a surface controller, the method comprising: The system receives a handover allocation matrix and a global handover start time. The handover allocation matrix represents the allocation mapping relationship between the target handover cache content of each cache-out satellite and each cache-in satellite. Based on the global handover start time, each cache-out satellite is instructed to send the target handover cache content to the cache-in satellite according to the handover allocation matrix. The cache-in satellite is instructed to perform cache preheating based on the received target handover cache content. The handover allocation matrix is ​​determined by the ground controller based on the target handover cache content of each cache-out satellite and the target cache space of each cache-in satellite within the target service area and target time period. The global handover start time is determined by the ground controller based on the corresponding cache handover deadline of each cache-out satellite and the total data volume of the target handover cache content of each cache-out satellite.

[0016] This invention also provides a low-Earth orbit satellite content distribution network, including a ground controller and a surface controller; wherein the ground controller and the surface controller perform the following interactive operations: the ground controller determines the cache transfer-out satellites and cache transfer-in satellites within a target time period; determines a handover allocation matrix based on the target transfer-out cache content of each cache transfer-out satellite and the target cache space of each cache transfer-in satellite; wherein the handover allocation matrix is ​​used to represent the allocation mapping relationship from the target transfer-out cache content of each cache transfer-out satellite to each cache transfer-in satellite; determines a global handover start time based on the cache handover deadline time corresponding to each cache transfer-out satellite and the total data volume of the target transfer-out cache content of each cache transfer-out satellite; the surface controller receives the handover allocation matrix and the global handover start time; based on the global handover start time, instructs each cache transfer-out satellite to send the target transfer-out cache content to the cache transfer-in satellite according to the handover allocation matrix; and instructs the cache transfer-in satellite to perform cache preheating based on the received target transfer-out cache content.

[0017] The present invention also provides a low-Earth orbit satellite buffer active handover device for service area handover, which is installed on a ground controller, the device comprising: The first determining module is used to determine the cache transfer-out satellites and cache transfer-in satellites within the target service area during the target time period; the second determining module is used to determine the handover allocation matrix based on the target transfer-out cache content of each cache transfer-out satellite and the target cache space of each cache transfer-in satellite; wherein, the handover allocation matrix is ​​used to represent the allocation mapping relationship from the target transfer-out cache content of each cache transfer-out satellite to each cache transfer-in satellite; the third determining module is used to determine the global handover start time based on the cache handover deadline time corresponding to each cache transfer-out satellite and the total data volume of the target transfer-out cache content of each cache transfer-out satellite; the sending module is used to send the handover allocation matrix and the global handover start time to the sky surface controller, so that the sky surface controller, based on the global handover start time, instructs each cache transfer-out satellite to send the target transfer-out cache content to the cache transfer-in satellite according to the handover allocation matrix, and instructs the cache transfer-in satellite to perform cache preheating based on the received target transfer-out cache content.

[0018] The present invention also provides a low-Earth orbit satellite buffer active handover device for service area handover, which is disposed on the air surface controller, the device comprising: A receiving module is used to receive a handover allocation matrix and a global handover start time; wherein, the handover allocation matrix is ​​used to represent the allocation mapping relationship between the target handover cache content of each cache handover-out satellite and each cache handover-in satellite; a first instruction module is used to instruct each cache handover-out satellite to send the target handover cache content to the cache handover-in satellite according to the handover allocation matrix based on the global handover start time; a second instruction module is used to instruct the cache handover-in satellite to perform cache preheating according to the received target handover cache content; wherein, the handover allocation matrix is ​​determined by the ground controller based on the target handover cache content of each cache handover-out satellite and the target cache space of each cache handover-in satellite in the target service area within the target time period; the global handover start time is determined by the ground controller based on the cache handover deadline corresponding to each cache handover satellite and the total data volume of the target handover cache content of each cache handover-out satellite.

[0019] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the low-Earth orbit satellite buffer active handover method for service area handover as described above.

[0020] The present invention also provides a non-transitory computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the low-Earth orbit satellite buffer active handover method for service area handover as described above.

[0021] The present invention also provides a computer program product, including a computer program that, when executed by a processor, implements the low-Earth orbit satellite buffer active handover method for service area handover as described above.

[0022] The present invention provides a method and apparatus for proactive handover of cached data for low-Earth orbit satellites in service area handover. The method identifies the cache-transferring satellites and cache-receiving satellites within a target service area and a target time period. It determines a handover allocation matrix based on the target cache content of each cache-transferring satellite and the target cache space of each cache-receiving satellite. By combining the cache handover deadline for each cache-transferring satellite with the total data volume of the target cache content, the global handover start time is deduced. Finally, the handover allocation matrix and the global handover start time are sent to the airborne controller. This allows the airborne controller to instruct each cache-transferring satellite to send the target cache content to the cache-receiving satellite according to the handover allocation matrix, and to instruct the cache-receiving satellite to perform cache preheating. This ensures that the incoming satellites have the cached content relevant to the current hotspot area when they officially take over service, avoiding the sudden drop in hit rate and sudden increase in access latency caused by cache cold start under passive preheating methods. This effectively improves the cache hit rate and service continuity of the incoming satellites. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0024] Figure 1 This is one of the flowcharts of the low-orbit satellite buffer active handover method for service area handover provided by the present invention.

[0025] Figure 2 This is the second flowchart of the low-orbit satellite buffer active handover method for service area handover provided by the present invention.

[0026] Figure 3 This is a schematic diagram of the architecture of the low-orbit satellite content distribution network provided by the present invention.

[0027] Figure 4 This is one of the structural schematic diagrams of the low-orbit satellite buffer active handover device for service area switching provided by the present invention.

[0028] Figure 5 This is the second schematic diagram of the low-orbit satellite buffer active handover device for service area switching provided by the present invention.

[0029] Figure 6 This is a schematic diagram of the structure of the electronic device provided by the present invention. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0031] The following is combined Figures 1 to 2 This invention describes a method for proactive handover of low-Earth orbit satellite buffers for service area handover.

[0032] Figure 1 This is one of the flowcharts of the low-orbit satellite buffer active handover method for service area handover provided by the present invention.

[0033] This method is executed by the ground controller. The ground controller is a ground device or system deployed on the ground that is responsible for remotely monitoring the satellite, issuing commands, and scheduling tasks, such as the ground telemetry and control station in a satellite communication system.

[0034] like Figure 1 As shown, the method includes the following steps.

[0035] Step 101: Determine the cached outgoing satellites and cached incoming satellites for the target service area within the target time period.

[0036] In some embodiments, a set of outgoing satellites that leave the target service area within a target time period is determined, and the cache handover deadline for each outgoing satellite in the outgoing satellite set is determined; a set of incoming satellites that enter the target service area within the target time period is determined, and the entry time of each incoming satellite in the incoming satellite set when it joins the target service area is determined; based on the cache handover deadline for each outgoing satellite and the entry time of each incoming satellite when it joins the target service area, cache-transfer-out satellites are determined from the outgoing satellite set, and cache-transfer-in satellites are determined from the incoming satellite set.

[0037] The cache handover deadline is the time when a departing satellite can actively hand over its cached content to a incoming satellite.

[0038] A satellite that leaves the target service area within the target time period is a satellite that leaves the target service area.

[0039] A satellite entering a satellite group is a satellite that enters the target service area and provides communication services within the target time period.

[0040] A cache-transfer satellite is a satellite that needs to actively transfer its cached content to other satellites.

[0041] A cache-in satellite is an incoming satellite that receives cached content transferred from an outgoing satellite.

[0042] In the specific implementation process, the set of satellites that can be removed from the target service area can be determined based on the orbital parameters of each satellite at the current time step and the geographical boundaries of the target service area.

[0043] For example, the ground controller acquires the orbital parameters of each satellite within the target service area at the current time step. The orbital parameters include parameters that describe the satellite's motion state, such as the satellite's position, velocity, and orbital inclination. Based on the orbital parameters, the predicted orbit of each satellite is determined. The predicted orbit of each satellite is compared with the geographical boundary of the target service area. When the predicted orbit of a satellite does not intersect with the geographical boundary of the target service area within the target time period, the satellite is included in the set of out-of-group satellites.

[0044] In the specific implementation process, the buffer handover deadline for each outgoing satellite in the outgoing satellite set can be determined in the following ways: Based on the orbital parameters of the outgoing satellites at the current time step and the geographical boundary of the target service area, determine the first moment when the outgoing satellites leave the target service area; based on the orbital parameters of each outgoing satellite at the current time step and the inter-satellite links between satellites within the target service area, determine the second moment when the outgoing satellites lose effective inter-satellite links with other satellites within the target service area; based on the minimum value between the first and second moments, determine the buffer handover deadline for each outgoing satellite.

[0045] For example, extrapolation can be performed based on the orbital parameters of the outgoing satellite to calculate the time of intersection between the outgoing satellite's nadir trajectory and the geographical boundary of the target service area, which is taken as the first moment. The relative distance and relative attitude between the outgoing satellite and other satellites can be calculated based on the orbital parameters of the outgoing satellite. When the relative distance exceeds the communication range of the inter-satellite link or the relative attitude causes the link to become unavailable, this moment is recorded as the second moment. For each outgoing satellite, the smaller value between the first moment and the second moment is taken as the buffer handover deadline for that outgoing satellite.

[0046] In the specific implementation process, the ground controller can extrapolate the orbital parameters of each satellite in the service area adjacent to the target service area at the current time step to calculate the intersection time of the ground point trajectory of each satellite with the geographical boundary of the target service area; when the predicted orbit of a satellite enters the geographical boundary of the target service area within the target time period, the satellite is included in the satellite group; the moment when the satellite enters the geographical boundary of the target service area is its entry time.

[0047] In the specific implementation process, the ground controller determines whether the deadline for the buffer transfer of the outgoing satellite is later than the entry time of the incoming satellite. When the deadline for the buffer transfer of the outgoing satellite is later than the entry time of the incoming satellite, it indicates that there is an overlap window between the two in time. If the overlap window is greater than a preset threshold, the outgoing satellite can be used as a buffer transfer-out satellite and the incoming satellite can be used as a buffer transfer-in satellite. The ground controller determines all outgoing satellites that meet the time overlap condition as buffer transfer-out satellites and all incoming satellites that meet the time overlap condition as buffer transfer-in satellites.

[0048] Step 102: Determine the handover allocation matrix based on the target outgoing cache content of each cached satellite and the target cache space of each cached incoming satellite.

[0049] The handover allocation matrix is ​​used to represent the allocation mapping relationship between the target outgoing cache content of each cache outgoing satellite and the cache incoming satellite. The handover allocation matrix describes which incoming satellite each cache content to be handed over should be sent to. For example, content A is handed over from satellite S1 to satellite T1, and content B is handed over from satellite S1 to satellite T2.

[0050] In the specific implementation process, the target transfer cache content of each cached transfer satellite can be obtained through the following methods: For each cached satellite to be transferred out, the following operations are performed: From the cached data of the cached satellite to be transferred out, candidate cached content to be transferred out that meets the first condition is selected; wherein, the first condition includes at least one of the following conditions: the popularity of the cached data is greater than a preset popularity threshold, and the cached data is a unique copy within the target service area; The value density of each cached object in the candidate cached content is determined based on the access frequency and data volume of each cached object within the target service area; The target cached content to be transferred out is selected from the candidate cached content based on the value density of each cached object.

[0051] Popularity is the number of times cached content is requested by users within a certain period of time. For example, a video that has been requested 500 times in the past hour has a higher popularity than a video that has only been requested 5 times.

[0052] The ground controller checks whether each cached object is a unique copy within the target service area. If a cached content exists only on the satellite from which it is transferred out and has no copy on other satellites within the target service area, then the cached object is included in the candidate transferred-out cache content.

[0053] Value density is used to characterize the value of a content service per unit of migration cost. For example, a 1MB video that is frequently accessed has a high value density.

[0054] In practice, the value density of each cached object can be determined by the ratio between the access frequency of each cached object in the target service area and the data volume of the cached object. This can be expressed by the following formula: ; in, This indicates the historical access frequency of the cached object in the target service region. This indicates the data size of the cached object. This value density allows for the prioritization of high-value cached objects that are small in size and frequently accessed.

[0055] In the specific implementation process, the cached objects in the candidate transfer-out cache content are sorted according to their value density from high to low to generate the target transfer-out cache content. If the ground controller determines that the total target transfer-out cache content exceeds the transmittable capacity within the switching window, the target transfer-out cache content is truncated to ensure that the total amount of the final target transfer-out cache content meets the transmittable capacity constraint.

[0056] In the specific implementation process, the target cache space for each cache to be transferred to the satellite can be determined in the following ways: For each cache transfer to a satellite, perform the following operations: Obtain the first remaining available cache space of the satellite; determine that the first remaining available cache space is greater than or equal to the size of the target transferred-out cache content; and determine the target cache space of the satellite based on the first remaining available cache space. For example, the first remaining available cache space can be used as the target cache space for the satellite transfer.

[0057] In the embodiments provided by the present invention, by using value density to filter target out cached content, it is possible to ensure that high-value content can be received first and preheated in advance under the condition that the incoming satellite cache resources are limited.

[0058] In some embodiments, if the first remaining available cache space is determined to be less than the size of the target transferred-out cache content, the existing cache objects of the cache transferred to the satellite are valued; based on the value assessment result, low-value content is evicted from the existing cache objects; and based on the second remaining available cache space of the cache transferred to the satellite after evicting the low-value content, the target cache space of the cache transferred to the satellite is determined.

[0059] Value assessment involves quantifying and scoring the service value of existing cached content on a satellite. Existing cached objects are sorted from lowest to highest service value score, and the lowest-scoring cached objects are evicted sequentially until sufficient space remains to accommodate the target content being moved out of the cache. Service value can be determined based on factors such as the relevance of the cached object to the target service area and its storage value.

[0060] The ground controller uses the above method to calculate the target cache space of each receiving satellite. For content objects in the target outgoing cache, they are preferentially allocated to receiving satellites with sufficient cache space, so that they can directly receive the target outgoing cache content without affecting the existing cache.

[0061] Based on the target cache space of each receiving satellite and the value density ranking results of the target transferring out cache content, the ground controller generates a mapping relationship between the target transferring out cache content and the receiving satellite, forming a handover allocation matrix. This is used to guide subsequent cross-satellite cache transfers.

[0062] In the embodiments provided by the present invention, the optimal allocation of high-value cached content to the limited cache space of the incoming satellite is achieved through the handover allocation matrix, which effectively improves the cache handover benefits under the conditions of limited handover window and limited inter-satellite bandwidth, and avoids the problem of bandwidth waste caused by blind transmission or the need to gradually replenish the cache by user requests after the handover is completed.

[0063] Step 103: Determine the global handover start time based on the handover deadline for each cached satellite and the total amount of data in the target cached content of each cached satellite.

[0064] In the specific implementation process, for each cache transfer-out satellite, the total amount of data in the target cache transfer-out content is determined; and based on the cache transfer deadline corresponding to the cache transfer-out satellite, the total amount of data in the target cache transfer-out content, the inter-satellite link bandwidth between the cache transfer-out satellite and its corresponding cache transfer-in satellite, the transfer confirmation overhead, and the safety buffer time, the latest start time for the cache transfer-out satellite to start the transfer task is determined; and based on the latest start time for the transfer task of all cache transfer-out satellites, the global transfer start time is determined.

[0065] As an example only, for each cached satellite... The statistics show the target cache content that is being migrated out by the entity responsible for the migration. and the total amount of data in the target cached content. .in, The cached content can be transferred from the target. The sum of the data sizes of each content object is obtained.

[0066] For each cache-transferred satellite Combined with its cache handover deadline The inter-satellite link bandwidth of the cache-transferring satellite and its corresponding cache-receiving satellite. Transfer and confirmation of expenses and safety buffer time By working backwards, we can deduce the latest start time of the handover mission for the satellite being transferred out of the cache. The calculation formula is as follows: ; Then, the minimum value of the latest start time of the handover mission for all cached satellites is taken to obtain the global handover start time. .

[0067] In the embodiments provided by the present invention, by using the global handover start time obtained by taking the minimum value of the latest start time of the handover task of all cached satellites, the entire cache active handover process can be completed before the disconnection of the outgoing satellite, so that the incoming satellite can have the cached content related to the current hot spot area when it officially takes over the service.

[0068] Step 104: Send the handover allocation matrix and the global handover start time to the air surface controller, so that the air surface controller, based on the global handover start time, instructs each buffer transfer-out satellite to send the target transfer-out buffer content to the buffer transfer-in satellite according to the handover allocation matrix, and instructs the buffer transfer-in satellite to perform buffer preheating according to the received target transfer-out buffer content.

[0069] A satellite antenna controller is a controller deployed on the antenna surface of a satellite that is responsible for issuing control commands to the satellite and coordinating inter-satellite operations. For example, it is a satellite terminal in a satellite communication ground station that is responsible for scheduling antenna pointing and distributing commands.

[0070] Cache preheating refers to loading popular content into the satellite cache in advance before the user actually requests the content. For example, popular videos are stored in the cache of the incoming satellites before the satellite takes over the service, so that when the user requests the content, it can be read directly from the cache without having to go back to the origin to the ground station.

[0071] In the specific implementation process, the ground controller can send the generated handover allocation matrix and the global handover start time to the space controller via the satellite-ground link; when the space controller determines that the current time has reached the global handover start time, it issues handover instructions to each cache handover satellite and each cache handover satellite: each cache handover satellite reads the target handover cache content according to the handover allocation matrix, and sends the target handover cache content to the corresponding cache handover satellite via the inter-satellite link; each cache handover satellite completes the writing and directory update of the target handover cache content according to the predetermined reception and replacement strategy, and stores the received target handover cache content into the local cache, thereby completing the cache preheating before the official service takeover.

[0072] Figure 2 This is the second flowchart illustrating the low-Earth orbit satellite buffer active handover method for service area handover provided by this invention. This method is executed by the sky surface controller, such as... Figure 2 As shown, the method includes the following steps.

[0073] Step 201: Receive the handover allocation matrix and the global handover start time; wherein, the handover allocation matrix is ​​used to represent the allocation mapping relationship between the target handover cache content of each cache handover satellite and the cache handover receiving satellite.

[0074] For a detailed description of the handover assignment matrix and the global handover start time, please refer to the relevant content in steps 102 and 103, which will not be repeated here.

[0075] Step 202: Based on the global handover start time, instruct each cache-out satellite to send the target cache-out content to the cache-in satellite according to the handover allocation matrix.

[0076] Step 203: Instruct the satellite to transfer the cache contents according to the received target and perform cache preheating.

[0077] This invention also provides a low-Earth orbit satellite content distribution network, such as... Figure 3 As shown, this low-Earth orbit satellite content delivery network includes a ground controller and a surface controller; the ground controller and surface controller perform the following interactive operations to complete the buffer handover between departing and incoming satellites: The ground controller determines the buffered outgoing and buffered incoming satellites within the target time period.

[0078] Based on the target outgoing cache content of each cache transfer-out satellite and the target cache space of each cache transfer-in satellite, a handover allocation matrix is ​​determined; wherein, the handover allocation matrix is ​​used to represent the allocation mapping relationship from the target outgoing cache content of each cache transfer-out satellite to each cache transfer-in satellite.

[0079] The global handover start time is determined based on the handover deadline for each cache transfer satellite and the total data volume of the target transfer cache content for each cache transfer satellite.

[0080] The rooftop controller receives the handover assignment matrix and the global handover start time.

[0081] Based on the global handover start time, each cache-out satellite is instructed to send the target cache-out content to the cache-in satellite according to the handover allocation matrix.

[0082] The satellite is instructed to transfer cached contents to the target and perform cache preheating.

[0083] The following describes the low-Earth orbit satellite buffer active handover device for service area handover provided by the present invention. The low-Earth orbit satellite buffer active handover device for service area handover described below can be referred to in correspondence with the low-Earth orbit satellite buffer active handover method for service area handover described above.

[0084] Figure 4 This is one of the structural schematic diagrams of the low-Earth orbit satellite buffer active handover device for service area handover provided by the present invention. Figure 4 As shown, the low-Earth orbit satellite buffer active handover device 400 for service area handover includes the following modules.

[0085] The first determining module 410 is used to determine the cached outgoing satellites and cached incoming satellites in the target service area within the target time period.

[0086] The second determining module 420 is used to determine the handover allocation matrix based on the target outgoing cache content of each cache outgoing satellite and the target cache space of each cache incoming satellite; wherein, the handover allocation matrix is ​​used to represent the allocation mapping relationship from the target outgoing cache content of each cache outgoing satellite to each cache incoming satellite.

[0087] The third determining module 430 is used to determine the global handover start time based on the handover deadline time corresponding to each cached satellite and the total data volume of the target handover cache content of each cached satellite.

[0088] The sending module 440 is used to send the handover allocation matrix and the global handover start time to the sky surface controller, so that the sky surface controller, based on the global handover start time, instructs each buffer handover satellite to send the target handover buffer content to the buffer handover satellite according to the handover allocation matrix, and instructs the buffer handover satellite to perform buffer preheating according to the received target handover buffer content.

[0089] Figure 5 This is the second schematic diagram of the low-Earth orbit satellite buffer active handover device for service area switching provided by the present invention. Figure 5 As shown, the low-Earth orbit satellite buffer active handover device 500 for service area handover includes the following modules.

[0090] The receiving module 510 is used to receive the handover allocation matrix and the global handover start time; wherein, the handover allocation matrix is ​​used to represent the allocation mapping relationship between the target handover cache content of each cache handover satellite and each cache handover receiving satellite.

[0091] The first instruction module 520 is used to instruct each cache-out satellite to send the target cache-out content to the cache-in satellite according to the handover allocation matrix, based on the global handover start time.

[0092] The second instruction module 530 is used to instruct the cache transfer satellite to perform cache preheating according to the received target transfer cache content.

[0093] The handover allocation matrix is ​​determined by the ground controller based on the target outgoing cache content of each cached outgoing satellite and the target cache space of each cached incoming satellite within the target service area during the target time period; the global handover start time is determined by the ground controller based on the cache handover end time corresponding to each cached outgoing satellite and the total data volume of the target outgoing cache content of each cached outgoing satellite.

[0094] Figure 6 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 6 As shown, the electronic device may include: a processor 610, a communications interface 620, a memory 630, and a communications bus 640, wherein the processor 610, the communications interface 620, and the memory 630 communicate with each other through the communications bus 640. The processor 610 can call logical instructions in the memory 630 to execute a low-Earth orbit satellite cache active handover method for service area handover. This method includes: determining the cache-transferring satellites and cache-receiving satellites for the target service area within a target time period; determining a handover allocation matrix based on the target cache content of each cache-transferring satellite and the target cache space of each cache-receiving satellite; wherein the handover allocation matrix represents the allocation mapping relationship from the target cache content of each cache-transferring satellite to each cache-receiving satellite; determining a global handover start time based on the cache handover deadline time corresponding to each cache-transferring satellite and the total data volume of the target cache content of each cache-transferring satellite; and sending the handover allocation matrix and the global handover start time to the airship controller, so that the airship controller, based on the global handover start time, instructs each cache-transferring satellite to send the target cache content to the cache-receiving satellite according to the handover allocation matrix, and instructs the cache-receiving satellite to perform cache preheating based on the received target cache content.

[0095] Furthermore, the logical instructions in the aforementioned memory 630 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0096] On the other hand, the present invention also provides a computer program product, which includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer is able to execute the low-Earth orbit satellite cache active handover method for service area handover provided by the above methods. The method includes: determining the cache-out satellites and cache-in satellites of the target service area within a target time period; determining a handover allocation matrix based on the target cache-out content of each cache-out satellite and the target cache space of each cache-in satellite; wherein the handover allocation matrix is ​​used to represent each The system establishes a mapping relationship between the target outgoing cache content of the outgoing satellite and the allocation of cache content to each incoming satellite. Based on the cache handover deadline for each outgoing satellite and the total data volume of the target outgoing cache content for each outgoing satellite, the system determines the global handover start time. The system then sends the handover allocation matrix and the global handover start time to the airborne controller, enabling the airborne controller to instruct each outgoing satellite to send the target outgoing cache content to the incoming satellite according to the handover allocation matrix, and to instruct the incoming satellite to perform cache preheating based on the received target outgoing cache content.

[0097] In another aspect, the present invention also provides a non-transitory computer-readable storage medium storing a computer program thereon. When executed by a processor, the computer program implements a method for proactive handover of low-Earth orbit satellite caches for service area handover provided by the methods described above. This method includes: determining cache-transferring satellites and cache-receiving satellites within a target service area and a target time period; determining a handover allocation matrix based on the target outgoing cache content of each cache-transferring satellite and the target cache space of each cache-receiving satellite; wherein the handover allocation matrix represents the allocation mapping relationship from the target outgoing cache content of each cache-transferring satellite to each cache-receiving satellite; determining a global handover start time based on the cache handover deadline time corresponding to each cache-transferring satellite and the total data volume of the target outgoing cache content of each cache-transferring satellite; and sending the handover allocation matrix and the global handover start time to a surface controller, so that the surface controller, based on the global handover start time, instructs each cache-transferring satellite to send the target outgoing cache content to the cache-receiving satellite according to the handover allocation matrix, and instructs the cache-receiving satellite to perform cache preheating based on the received target outgoing cache content.

[0098] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0099] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0100] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for proactive handover of low-Earth orbit satellite buffers for service area handover, characterized in that, The method, executed by a ground controller, includes: Identify the cached outgoing and cached incoming satellites for the target service area within the target time period; Based on the target outgoing cache content of each cache transfer-out satellite and the target cache space of each cache transfer-in satellite, a handover allocation matrix is ​​determined; wherein, the handover allocation matrix is ​​used to represent the allocation mapping relationship from the target outgoing cache content of each cache transfer-out satellite to each cache transfer-in satellite; The global handover start time is determined based on the handover deadline for each cache transfer satellite and the total data volume of the target transfer cache content for each cache transfer satellite. The handover allocation matrix and the global handover start time are sent to the air surface controller, so that the air surface controller, based on the global handover start time, instructs each buffer transfer-out satellite to send the target transfer-out buffer content to the buffer transfer-in satellite according to the handover allocation matrix, and instructs the buffer transfer-in satellite to perform buffer preheating according to the received target transfer-out buffer content.

2. The method for proactive handover of low-Earth orbit satellite buffers for service area handover as described in claim 1, characterized in that, The determination of cached outgoing and cached incoming satellites for the target service area within the target time period includes: The set of satellites leaving the target service area within the target time period is determined, and the cache handover deadline for each satellite in the set of satellites leaving the group is determined; wherein, the cache handover deadline is the time node at which the satellite leaving the group can actively hand over the cache content to the satellite joining the group; Determine the set of satellites joining the target service area within the target time period, and the joining time of each satellite in the set of satellites joining the target service area; Based on the cache transfer deadline for each departing satellite and the entry time of each incoming satellite into the target service area, cache-transfer-out satellites are determined from the set of departing satellites, and cache-transfer-in satellites are determined from the set of incoming satellites.

3. The method for proactive handover of low-Earth orbit satellite buffers for service area handover according to claim 2, characterized in that, The determination of the set of outgoing satellites that leave the target service area within the target time period includes: The set of out-of-group satellites is determined based on the orbital parameters of each satellite within the target service area at the current time step and the geographical boundaries of the target service area.

4. The method for proactive handover of low-Earth orbit satellite buffers for service area handover according to claim 2, characterized in that, Determining the buffer handover deadline for each out-of-group satellite in the out-of-group satellite set includes: Based on the orbital parameters of the outgoing satellite at the current time step and the geographical boundary of the target service area, determine the first moment when the outgoing satellite leaves the target service area; Based on the orbital parameters of each out-of-group satellite at the current time step and the inter-satellite links between satellites within the target service area, determine the second moment when the out-of-group satellite loses its effective inter-satellite link with other satellites within the target service area; The deadline for buffer handover of each outgoing satellite is determined based on the minimum value between the first time point and the second time point.

5. The method for proactive handover of low-Earth orbit satellite buffers for service area handover according to any one of claims 1 to 4, characterized in that, The target transfer cache content of each cached transfer satellite is obtained through the following methods: For each cached satellite being transferred out, perform the following operations: From the cached data of the satellite being transferred out, candidate transferred-out cached content that meets the first condition is selected; wherein, the first condition includes at least one of the following conditions: the popularity of the cached data is greater than a preset popularity threshold, or the cached data is a unique copy within the target service area; The value density of each cache object is determined based on the access frequency of each cache object in the candidate outgoing cache content within the target service area and the data volume of the cache object. Based on the value density of each cached object, the target cached content is selected from the candidate cached content to be transferred out.

6. The method for proactive handover of low-Earth orbit satellite buffers for service area handover according to any one of claims 1 to 4, characterized in that, The target cache space for each cache transferred to the satellite is determined using the following method: For each cached satellite, perform the following operations: Obtain the first remaining available cache space of the satellite to be transferred from the cache; The first remaining available cache space is determined to be greater than or equal to the size of the target outgoing cache content. Based on the first remaining available cache space, the target cache space for the cache to be transferred to the satellite is determined.

7. The method for proactive handover of low-Earth orbit satellite buffers for service area handover according to claim 6, characterized in that, The method further includes: If the first remaining available cache space is determined to be less than the size of the target transferred cache content, the value of the existing cache objects of the transferred satellite is evaluated. Based on the results of the value assessment, low-value content is evicted from the existing cached object; The target cache space for the satellite to be transferred is determined based on the second remaining available cache space of the satellite after the low-value content has been expelled.

8. The method for proactive handover of low-Earth orbit satellite buffers for service area handover according to claim 1, characterized in that, The process of determining the global handover start time based on the handover deadline for each cached satellite and the total data volume of the target handover cache content for each cached satellite includes: For each cache-transfer satellite, determine the total amount of data in its target cache-transfer content; and Based on the cache handover deadline corresponding to the cache transfer-out satellite, the total data volume of the target transferred-out cache content, the inter-satellite link bandwidth of the cache transfer-out satellite and its corresponding cache transfer-in satellite, the handover confirmation overhead, and the safety buffer time, the latest start time for the cache transfer-out satellite to initiate the handover task is determined. The global handover start time is determined based on the latest start time of the handover mission for all cached satellites.

9. A method for proactive handover of low-Earth orbit satellite buffers for service area handover, characterized in that, The method, executed by the rooftop controller, includes: Receive the handover allocation matrix and the global handover start time; wherein, the handover allocation matrix is ​​used to represent the allocation mapping relationship between the target handover cache content of each cache handover satellite and each cache handover receiving satellite; Based on the global handover start time, each cache-out satellite is instructed to send the target cache-out content to the cache-in satellite according to the handover allocation matrix; The satellite is instructed to perform cache preheating based on the received target cache content. The handover allocation matrix is ​​determined by the ground controller based on the target outgoing cache content of each cached outgoing satellite and the target cache space of each cached incoming satellite within the target service area during the target time period; the global handover start time is determined by the ground controller based on the cache handover end time corresponding to each cached outgoing satellite and the total data volume of the target outgoing cache content of each cached outgoing satellite.

10. A low-Earth orbit satellite content delivery network, characterized in that, It includes a ground controller and a rooftop controller; wherein the ground controller and the rooftop controller perform the following interactive operations: The ground controller determines the cached outgoing satellites and cached incoming satellites within the target time period; Based on the target outgoing cache content of each cache transfer-out satellite and the target cache space of each cache transfer-in satellite, a handover allocation matrix is ​​determined; wherein, the handover allocation matrix is ​​used to represent the allocation mapping relationship from the target outgoing cache content of each cache transfer-out satellite to each cache transfer-in satellite; The global handover start time is determined based on the handover deadline for each cache transfer satellite and the total data volume of the target transfer cache content for each cache transfer satellite. The rooftop controller receives the handover assignment matrix and the global handover start time; Based on the global handover start time, each cache-out satellite is instructed to send the target cache-out content to the cache-in satellite according to the handover allocation matrix; The satellite is instructed to perform cache preheating based on the received target cache content.

11. A low-Earth orbit satellite buffer active handover device for service area handover, characterized in that, The device, located on a ground controller, includes: The first determining module is used to determine the cached outgoing satellites and cached incoming satellites in the target service area within the target time period; The second determining module is used to determine the handover allocation matrix based on the target outgoing cache content of each cache outgoing satellite and the target cache space of each cache incoming satellite; wherein, the handover allocation matrix is ​​used to represent the allocation mapping relationship from the target outgoing cache content of each cache outgoing satellite to each cache incoming satellite; The third determining module is used to determine the global handover start time based on the handover deadline time corresponding to each cache transfer satellite and the total data volume of the target transfer-out cache content of each cache transfer satellite. The sending module is used to send the handover allocation matrix and the global handover start time to the sky controller, so that the sky controller, based on the global handover start time, instructs each buffer handover satellite to send the target handover buffer content to the buffer receiving satellite according to the handover allocation matrix, and instructs the buffer receiving satellite to perform buffer preheating according to the received target handover buffer content.

12. A low-Earth orbit satellite buffer active handover device for service area handover, characterized in that, The device, located on the rooftop controller, includes: The receiving module is used to receive the handover allocation matrix and the global handover start time; wherein, the handover allocation matrix is ​​used to represent the allocation mapping relationship between the target handover cache content of each cache handover satellite and each cache handover satellite. The first instruction module is used to instruct each cache-out satellite to send the target cache-out content to the cache-in satellite according to the cache allocation matrix, based on the global handover start time. The second instruction module is used to instruct the cache receiving satellite to perform cache preheating according to the received target cache content; The handover allocation matrix is ​​determined by the ground controller based on the target outgoing cache content of each cached outgoing satellite and the target cache space of each cached incoming satellite within the target service area during the target time period; the global handover start time is determined by the ground controller based on the cache handover end time corresponding to each cached outgoing satellite and the total data volume of the target outgoing cache content of each cached outgoing satellite.

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