A satellite-ground integrated network resource management and content collaborative caching method and system

Abstract

A method and system for resource management and content collaborative caching in a space-ground integrated network, belonging to the field of space communication technology, includes: dynamically sensing current space-ground integrated network information using a time-slot division method; in the application scenario of space-ground collaborative caching and content access, the end user sends content request information through access satellite nodes based on environmental perception. The access satellite nodes first search for current content cache information within their own nodes, then search for cached content on other satellite nodes in an inter-satellite collaborative manner, and finally search for cached content at the ground cloud center in a space-ground collaborative manner, and route and forward the request through inter-satellite links to achieve the fastest possible response to the requested content. This invention, by adopting a method based on satellite neighborhood search and space-ground collaborative access, realizes the fast access service capability of space-ground collaborative and inter-satellite collaborative content cache, effectively reducing the design complexity of the space-ground integrated network system and improving the operational efficiency of the space-ground integrated network.

Description

Technical Field

[0001] This invention relates to a method and system for resource management and content collaborative caching in a space-ground integrated network, belonging to the field of space communication technology. Background Art

[0002] With the development of wireless communication technology and the increasing number of smart devices, terrestrial networks with edge caching can provide internet services to end users, such as multimedia services, web services, and application services, to improve user experience and network efficiency. Cached content is located as close as possible to the user to reduce data transmission latency and network bandwidth costs. It's important to note that content caching servers are typically located at the edge nodes of the terrestrial network. However, due to high capital expenditures and harsh geographical environments, terrestrial networks do not yet cover more than 80% of land areas and more than 95% of ocean areas. In this situation, it is impossible to provide content services to remote end users outside terrestrial network coverage areas (such as oceans, deserts, and mountainous regions). As a supplement to terrestrial networks, large low Earth orbit (LEO) satellite constellations can provide global wireless communication and internet access services to end users and have become an important component of future communication systems.

[0003] Traditional satellite networks only offer data routing and forwarding capabilities, requiring end users to access internet services from the ground via satellite, leading to service latency and high network load costs. Leveraging the seamless global coverage and low latency of low Earth orbit satellite networks, satellite edge caching, as a new paradigm, places caching servers on satellites to enable edge caching services. However, satellite network onboard resources are very limited, and cannot meet the service demands of a large influx of end users. Combining the advantages of terrestrial and satellite networks to implement collaborative content caching in a space-ground integrated network, providing on-demand content services to end users in a flexible and efficient manner, is a promising approach. It is worth noting that unlike terrestrial networks with relatively static topologies and abundant resources, satellite networks, due to their dynamic nature, have topologies that change over time due to their strictly limited resources. Therefore, implementing collaborative caching and resource allocation strategies in a space-ground integrated network is a challenging problem.

[0004] Regarding space-ground integrated networks and cached content access technologies, a review of existing literature and patents reveals that current work has relatively simplified the complexity of collaborative caching and resource allocation in space-ground integrated networks, primarily considering space-ground collaborative caching in scenarios without inter-satellite communication. In this case, the lack of inter-satellite collaborative caching compromises user service experience and network operational efficiency. Furthermore, considering the inter-satellite communication capabilities of low-Earth orbit satellite networks, collaborative caching services between different satellites can be provided to end users. It is important to note that since the available links, bandwidth, and storage resources of satellite networks are limited, optimizing collaborative caching and resource allocation strategies can improve user service experience and network operational efficiency. However, existing work rarely discusses the joint optimization of data routing, network bandwidth, and onboard storage resources for collaborative caching in space-ground integrated networks. Moreover, as the number of satellites increases, the dimensionality of spatial state information also increases, posing challenges to global resource management in space-ground integrated networks. Further research is needed on collaborative caching architectures for space-ground integrated networks to simplify the system complexity of resource management and improve the real-time performance of decision-making. Summary of the Invention

[0005] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide a method and system for resource management and content collaborative caching in a space-ground converged network. It constructs a system model for space-ground collaborative caching and resource optimization, realizes the content service supply capability of space-ground collaboration and inter-satellite collaboration, effectively reduces the design complexity of the space-ground converged network system, and improves the operational efficiency of the space-ground converged network.

[0006] The technical solution of this invention is: a method for resource management and content collaborative caching in a satellite-ground converged network, comprising:

[0007] In the satellite-ground integrated network, each satellite node obtains random access request information from users in the current time slot in real time;

[0008] Based on the time-slot network model of the space-ground fusion network, network state information is sensed and acquired in each time slot;

[0009] Based on the acquired network status information and random access request information, the ground operation control center establishes a satellite-ground integrated network resource management and content collaborative access system model, and constructs a joint optimization mathematical model of network storage resources and network bandwidth resources under multiple physical constraints.

[0010] Based on the aforementioned satellite-ground converged network resource management and content collaborative access system model, and the joint optimization mathematical model, the satellite-ground collaborative caching and resource configuration optimization methods are used to determine the optimization strategies for satellite-ground collaborative caching, resource optimization configuration, and cached content access strategy selection, thereby minimizing the deployment cost of the satellite-ground network.

[0011] The space-ground converged network implements resource allocation and content caching deployment according to the optimization strategy, and provides users with collaborative access services for cached content.

[0012] Furthermore, the satellite node establishes a satellite-to-ground link only with user terminals within its coverage area and provides network access services to those user terminals.

[0013] Furthermore, the network status information includes current location, network topology, task running status, resource usage, cached content type, and task service requirements.

[0014] Furthermore, the establishment of the satellite-ground converged network resource management and content collaborative access system model includes the bandwidth usage cost of user u during content access.

[0015]

[0016] And the storage resources generated when user u accesses content at the current moment.

[0017]

[0018] Where, x u,w ={0,1} indicates whether user u accesses content w, where x u,w =1 indicates that user u accesses content w; otherwise, x u,w =0; This indicates whether user u used link e during content w access, where This indicates that user u used link e during the access process of content w; otherwise... The actual data rate at which user u accesses content w is represented as b. u ;a u,dc ={0,1} indicates whether user u accesses content from a terrestrial data center via a satellite network, a u,dc =1 indicates that content access is performed via satellite network to a ground data center; otherwise, a u,dc =0; y w,v ={0,1} indicates whether content w is deployed on satellite node v, where y w,v =1 indicates that content w is deployed on satellite node v; otherwise, y w,v =0; This indicates whether user u accesses content w through satellite node v, where This indicates that user u accesses content w; otherwise... Content w represents data size s w .

[0019] Furthermore, the constraints of the satellite-ground converged network resource management and content collaborative access system model include user access constraints.

[0020]

[0021] And the storage resource constraints of satellite nodes when accessing content cache.

[0022]

[0023] And the service latency for each user's content (w) does not exceed the maximum acceptable service latency.

[0024]

[0025] and the access service constraints provided by each satellite node to users.

[0026]

[0027] and bandwidth resource constraints

[0028]

[0029] and the in-degree and out-degree constraints of satellite nodes during data routing.

[0030]

[0031] and the in-degree and out-degree constraints of satellite nodes during data routing.

[0032]

[0033] Among them, y w,v Whether content w is deployed on satellite node v, Whether user u accesses content w, x via satellite node v u,w For user u, whether to access content w, a u,dc Let U be the user's task set, W be the set of accessible content, and s be the user's task set. The question asks whether user u accesses content via a satellite network to a terrestrial data center. w For task w, w∈W, the size of the content data. Let t be the storage resource capacity that a satellite node v, v∈V can provide. u,w The service latency for user u accessing content w. The maximum service latency for user u to access content w. This represents the maximum number of users that can access satellite v. To determine whether user u used link e during content w access, b u B represents the actual data rate at which user u accesses content w. e Let E represent the bandwidth resource capacity of inter-satellite links e, where e∈E, and E is the set of inter-satellite links between all satellite nodes. and Let v be the set of input degrees and the set of output degrees. Satellite V is considered as the access satellite of the cloud center DC. dc,a V is the set of satellite nodes, v u,a For access satellites of the cloud center DC.

[0034] Furthermore, the joint optimization mathematical model includes

[0035]

[0036] The objective function represents the average deployment cost per user, and the cost factors for network bandwidth usage cost and on-orbit storage resource usage cost are respectively expressed as: and Let U be the set of user tasks and M be the number of users.

[0037] Furthermore, in the aforementioned satellite-ground collaborative caching and resource configuration optimization method, each satellite node interacts with neighboring satellites to obtain current storage resources and content deployment information. If the storage resources of the current neighboring satellite nodes are insufficient, access is limited, or a ground data center is nearby, the user can directly obtain access content from the ground data center via inter-satellite links, including:

[0038] Each access satellite node obtains the operational status of the neighboring satellite subnetwork based on the network hop count, and obtains feasible strategies for content placement and routing paths by traversing the satellites and links in the neighboring subnetwork. In the initial layer, each user's access satellite is a unique root candidate. After searching for the root candidate, the neighboring satellites of the root candidate become new candidates for the next layer. Regardless of whether a feasible strategy is obtained in the current layer, the search for new candidate strategies in the next layer will continue until the current hop count in the subnetwork reaches the maximum.

[0039] Secondly, when there is insufficient available storage resources in the subnetwork, content services are limited, or the cloud center's access satellite is located in its neighboring subnetwork, the user's content services can be provided by the cloud center. In this case, the shortest path between the user's access satellite and the cloud center is traversed, and feasible routing paths are obtained based on descending order. In this situation, the feasible strategy with the lowest deployment cost will be regarded as the strategy for coordinating caching and resource allocation, including resource allocation, content caching, and access.

[0040] A satellite-ground converged network resource management and content collaborative caching system includes:

[0041] The user terminal, located in a multi-dimensional space encompassing land, sea, and air, sends service request information to servers located in the satellite edge cloud and central cloud to obtain the required content data in real time from the nearest location.

[0042] The ground-based operation control center can manage and control the satellite edge cloud and the ground center cloud in an integrated manner based on the space-ground cross-domain network. By monitoring the operation status of the satellite network and the ground center cloud and the current task execution status in real time, it can autonomously complete task orchestration and resource allocation according to the current access user requests and network status. It can also share with the satellite edge cloud and the ground center cloud through information interaction to complete resource configuration, task deployment and execution.

[0043] The satellite edge cloud module is used to interconnect each satellite node with four adjacent satellite nodes via inter-satellite links, forming a satellite neighborhood sub-network based on network hop count. In the satellite network, satellite nodes provide on-orbit storage services to users by carrying certain storage payloads, as well as on-demand content storage services. Satellite nodes transmit their operational status and mission execution status to the operation control center via inter-satellite and satellite-to-ground links according to time slots. The operation control center monitors the operational status of the satellite edge cloud in real time and uniformly orchestrates available resources.

[0044] The ground-based central cloud module, located far from the user end, works in conjunction with the satellite edge cloud module to provide users with storage resources and content caching services.

[0045] A computer-readable storage medium storing a computer program, wherein the computer program, when executed by a processor, implements the steps of the method for resource management and content collaborative caching in a space-ground converged network.

[0046] A satellite-ground converged network resource management and content collaborative caching device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the satellite-ground converged network resource management and content collaborative caching method.

[0047] The advantages of this invention compared to the prior art are:

[0048] (1) Ground-to-ground integrated network resource management architecture with ground-to-ground master control + satellite-to-satellite auxiliary control: To address issues such as low utilization of cross-domain network resources, poor system compatibility, and insufficient real-time decision-making, a ground-to-ground integrated network resource management architecture with ground-to-ground master control + satellite-to-satellite auxiliary control is established. The ground master control can achieve dynamic management of all resources in the integrated network, while satellite nodes have a certain degree of autonomy, enabling real-time monitoring of the operational status of sub-networks and autonomous content access. Based on user service needs and on-orbit cached content, users can quickly obtain cached content through inter-satellite collaboration or access ground cloud data through inter-satellite links, achieving integrated space-to-ground network resources, on-demand management, and timely service provision.

[0049] (2) A mathematical model based on satellite-ground collaborative caching and resource optimization is established to meet the service needs of satellite internet applications. This model, under multiple physical constraints, jointly reduces the cost of using on-orbit cache resources and satellite network bandwidth resources, effectively improving the operational efficiency of the satellite-ground integrated network and the user service experience. This mathematical model can be customized to achieve various problem model variations, such as cache resource optimization, network bandwidth resource optimization, and service time minimization.

[0050] (3) Neighborhood Search-Based Collaborative Caching and Resource Optimization Method: Considering that the proposed problem is NP-hard and finding the optimal strategy involves high computational complexity, a neighborhood search-based collaborative caching and resource optimization method is proposed. Access satellites can autonomously manage their neighborhood sub-networks, allocating cached resources and deploying cached content within these sub-networks. By traversing sub-network nodes, the current resource allocation, content cache location, and routing selection strategy can be quickly obtained. Employing a neighborhood search approach effectively reduces the current solution space size and rapidly enables the selection of collaborative caching and resource optimization strategies, making it suitable for large-scale satellite-ground integrated network applications. Attached Figure Description

[0051] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present invention. The same reference symbols are used throughout the drawings to represent the same components. In the drawings:

[0052] Figure 1 This is a schematic diagram of the architecture for the space-ground integrated network resource management system.

[0053] Figure 2 A schematic diagram of a satellite-ground collaborative content access model;

[0054] Figure 3 This is a schematic diagram of a satellite-ground collaborative caching and resource optimization method.

[0055] Figure 4 The results of collaborative caching and resource allocation under three different application scenarios are shown, where (a) is the storage cost, (b) is the bandwidth cost, and (c) is the total deployment cost.

[0056] Figure 5 The results of collaborative caching and resource optimization for three different algorithms are shown, where (a) represents storage cost, (b) represents bandwidth cost, and (c) represents total deployment cost. DETAILED DESCRIPTION

[0057] To better understand the above technical solutions, the technical solutions of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solutions of the present invention, rather than limitations on the technical solutions of the present invention. In the absence of conflict, the embodiments of the present invention and the technical features in the embodiments can be combined with each other.

[0058] The following description, in conjunction with the accompanying drawings, provides a more detailed explanation of the satellite-ground integrated network resource management and content collaborative caching method and system provided by the present invention. Specific implementation methods may include:

[0059] (1) Each satellite node obtains random access request information from the user terminal in the current time slot in real time;

[0060] (2) According to the time-slot network model, within each time slot, the network autonomously perceives status information including network topology, task running status, resource usage and task service requirements.

[0061] (3) Based on the network status and user access request information obtained, the ground operation and control center establishes a satellite-ground integrated network resource management and content collaborative access system model, and constructs a joint optimization mathematical model of network storage resources and network bandwidth resources under multiple physical constraints.

[0062] (4) The ground control center uses the satellite-ground collaborative caching and resource configuration optimization methods to complete satellite-ground collaborative caching, resource optimization configuration, and cache content access strategy selection, thereby minimizing the deployment cost of the satellite-ground network.

[0063] (5) The satellite-ground converged network implements resource configuration and content caching deployment according to the optimization strategy obtained in step (4), and provides users with collaborative access services for cached content.

[0064] Furthermore, in step (1), each satellite can only establish a satellite-to-ground link with the user terminal within its coverage area and provide network access services to that user terminal.

[0065] In one possible implementation, in step (2), the satellite-ground fusion network can autonomously obtain the network's operating status based on the time slot, including the current location, resource usage, cached content type, etc.

[0066] Optionally, in one possible implementation, step (3) establishes a satellite-ground integrated network resource management and content collaborative access system model and a joint optimization mathematical model. When a user accesses content in the satellite edge cloud, a certain network bandwidth usage cost is incurred, where the bandwidth usage cost for user u during content access is expressed as:

[0067]

[0068] Where, x u,w ={0,1} indicates whether user u accesses content w, where x u,w =1 indicates that user u is accessing content w; otherwise, x = 1. u,w =0. This indicates whether user u used link e during content w access, where This indicates that user u used link e during the access process of content w; otherwise... The actual data rate of the content w retrieved by user u is represented by b. u E represents the set of inter-satellite links between all satellite nodes;

[0069] Accessing content requires storage resources when deployed on satellite nodes. When different user tasks access the same content, that content can be deployed on a single satellite node, effectively reducing the number of storage resources used. For user u, if the current content is being deployed for the first time, then the storage resources for that content need to be considered; if the current content is not being deployed for the first time, then the storage resources for that content do not need to be considered. That is, the storage resources generated when user u accesses the content at the current moment can be represented as:

[0070]

[0071] Among them, a u,dc ={0,1} indicates whether user u accesses content from a terrestrial data center via a satellite network, a u,dc =1 indicates that content access is performed via satellite network to a ground data center; otherwise, a u,dc =0. y w,v ={0,1} indicates whether content w is deployed on satellite node v, where y w,v =1 indicates that content w is deployed on satellite node v; otherwise, y w,v =0. This indicates whether user u accesses content w through satellite node v, where This indicates that user u accesses content w; otherwise... Content w represents data size s w W is the set of accessible content.

[0072] In one possible implementation, considering both user service experience and satellite network operational efficiency, and taking into account the overall interests of user tasks and the satellite network, an optimization objective function for network bandwidth usage cost and on-orbit storage resource usage cost is established based on a weighted sum method. The joint optimization objective function can be expressed as:

[0073]

[0074] The objective function represents the average deployment cost per user, and the cost factors for network bandwidth usage cost and on-orbit storage resource usage cost are respectively expressed as: and Let U be the set of user tasks and M be the number of users.

[0075] Preferably, in step (3), various physical constraints such as satellite node resources, link bandwidth resources, and task deployment need to be met in the mathematical model of satellite-ground collaborative caching and content access.

[0076] When user u accesses content via satellite, each user accesses the current content on one satellite node. Considering that the accessed content can be deployed on multiple satellite nodes simultaneously, the user access constraint can be specifically expressed as follows:

[0077]

[0078] Since satellite node resources are limited, the currently available resources must be no less than the resources required for this access task. Therefore, the storage resource constraint of the satellite node when caching accessed content can be expressed as:

[0079]

[0080] Wherein, the storage resource capacity that satellite node v, v∈V can provide is represented as

[0081] Each user's content service latency t u,w Not exceeding the maximum acceptable service delay It can be represented as:

[0082]

[0083] Furthermore, the amount of content accessible to each satellite node is limited; the maximum number of users accessing satellite v is expressed as... At that time, the access service constraints provided by each satellite node to the user are expressed as follows:

[0084]

[0085] If the access satellite node resources are insufficient, the user needs to access content through other satellite nodes via a link. This means that the bandwidth required by the inter-satellite link e for routing data must not exceed the currently available bandwidth resource B. e The bandwidth resource constraint is then expressed as:

[0086]

[0087] When users access content through the satellite edge cloud, the data input and output of each satellite node must be consistent during the satellite network routing process, except for the satellite node storing the content and the access satellite node. and Let the input degree set and output degree set be the satellite v. The in-degree and out-degree constraints of the satellite nodes during data routing can be expressed as:

[0088]

[0089] In addition, it is generally necessary to ensure that the satellite's input and output degrees are equal. When binary auxiliary variables... This indicates that satellite v is considered as the access satellite v of the cloud center DC. dc,a ,otherwise The path selection constraints for user u and content w can then be:

[0090]

[0091] Preferably, in the satellite-ground integrated network resource management and content collaborative access optimization method in step (4), each satellite node interacts with neighboring satellites to obtain current storage resources and content deployment information. If the storage resources of the current neighboring satellite node are insufficient, access is limited, or a ground data center is nearby, the user can directly obtain access content from the ground data center through the inter-satellite link. The specific process is as follows:

[0092] First, each access satellite node obtains the operational status of its neighboring satellite subnetwork based on network hop count. It then traverses the satellites and links in the neighboring subnetworks to determine feasible strategies for content placement and routing paths. In the initial layer, each user's access satellite is a unique root candidate. After searching for the root candidate, the neighboring satellites of the root candidate become new candidates for the next layer. To obtain a feasible strategy with the lowest deployment cost, the search continues for new candidate strategies in the next layer, regardless of whether a feasible strategy is found in the current layer, until the current hop count in the subnetwork reaches its maximum.

[0093] Secondly, when there is insufficient available storage resources in a subnetwork, content services are limited, or the cloud center's access satellites are located in its neighboring subnetworks, the user's content services can be provided by the cloud center. In this case, the shortest paths between the user's access satellites and the cloud center can be traversed, and feasible routing paths can be obtained in descending order. In this scenario, the feasible strategy with the lowest deployment cost will be considered as the strategy for coordinating caching and resource allocation, including resource allocation, content caching, and service provisioning.

[0094] Preferably, in step (5), resource allocation, cache deployment, and content access services are implemented based on the optimization strategy obtained in step (4).

[0095] Secondly, embodiments of the present invention provide a satellite-ground converged network resource management and content collaborative caching system, comprising:

[0096] (1) User terminals located in land, sea and air multi-dimensional space send service request information to servers located in satellite edge cloud and central cloud, and obtain the required content data in real time nearby.

[0097] (2) The ground-based operation control center can manage the satellite edge cloud and the ground center cloud in an integrated manner based on the space-ground cross-domain network. By monitoring the operation status of the satellite network and the ground center cloud network and the current task execution status in real time, it can autonomously complete task orchestration and resource allocation according to the current access user requests and network status. It can share with the satellite edge cloud and the ground center cloud through information interaction to complete resource configuration, task deployment and execution.

[0098] (3) Each satellite node in the satellite edge cloud is interconnected with its four neighboring satellite nodes via inter-satellite links. Each satellite node forms a satellite neighborhood sub-network with its neighboring satellite nodes based on network hop count. In the satellite network, satellite nodes provide on-orbit storage services to users by carrying certain storage payloads. By constructing the satellite edge cloud, flexible management and efficient utilization of on-orbit resources are achieved, providing users with content storage services on demand. Satellite nodes send their operational status and mission execution status to the operation and control center via inter-satellite / satellite-to-ground links according to time slots. The operation and control center is responsible for real-time monitoring of the operational status of the satellite edge cloud and unified orchestration of available resources.

[0099] (4) Unlike the strictly limited storage resources in ground-based central clouds and satellite edge clouds, ground-based central clouds are located far from the user end but have sufficient storage and other resources, and can work with satellite edge clouds to provide content caching services for users.

[0100] In the solution provided in the embodiments of the present invention, to address the application requirements of satellite-ground collaborative caching services for satellite internet, a method such as... is first constructed. Figure 1 The illustrated space-ground integrated network resource management system architecture, which combines ground-based main control and on-board auxiliary control, includes several parts: user terminals located in multi-dimensional space, satellite edge clouds, ground-based operation control centers, and ground-based central clouds.

[0101] (1) User terminals located in land, sea and air multi-dimensional space send service request information to servers located in satellite edge cloud and central cloud, and obtain the required content data in real time nearby.

[0102] (2) The ground-based operation control center can manage the satellite edge cloud and the ground center cloud in an integrated manner based on the space-ground cross-domain network. By monitoring the operation status of the satellite network and the ground center cloud network and the current task execution status in real time, it can dynamically manage network resources in a centralized manner, autonomously complete task orchestration and resource allocation according to the current access user requests and network status, and share with the satellite edge cloud and the ground center cloud through information interaction to complete resource configuration, task deployment and execution.

[0103] (3) In the satellite edge cloud satellite network, satellite nodes provide on-orbit storage services to users by carrying certain storage payloads. By constructing a satellite edge cloud, flexible management and efficient utilization of on-orbit resources are achieved, providing users with content storage services on demand. Satellite nodes send their operating status and mission execution status to the operation and control center via inter-satellite / satellite-to-ground links according to time slots. The operation and control center is responsible for real-time monitoring of the satellite edge cloud's operating status and unified orchestration of available resources.

[0104] (4) Unlike the strictly limited storage resources in ground-based central cloud and satellite edge cloud, ground-based central cloud is located far from the user end but has sufficient storage and other resources, and can work with satellite edge cloud to provide content caching services for users.

[0105] To address the complex environment of dynamically changing satellite network topologies and random user task access, a quasi-static satellite network and user task model is established, referencing existing work on satellite networks. The satellite network topology remains constant within a time slot but dynamically changes across different time slots. User tasks maintain their state throughout their runtime, and their service requirements are consistently met. It is assumed that a batch of user tasks arrives at the satellite node simultaneously at the start of each time slot. The satellite node provides content access services to the currently accessing user tasks on demand, based on predefined content caching and access policies.

[0106] During satellite-ground collaborative content access, the user task first sends the access request information to the satellite edge cloud through the currently accessed satellite node. The satellite edge cloud synchronizes the current network and content storage status through information sharing and autonomously obtains the content access request. The satellite-ground collaborative caching and content access process can be divided into two stages: content collaborative caching and cached content collaborative access. In the content collaborative caching process, the satellite edge cloud selects content caching and access strategies based on the current edge cloud network status and user access requests, and completes cached content deployment through satellite-ground resource optimization methods. In the cached content access process, content access services are provided to users based on the content data deployed in stage one. It should be noted that, in order to effectively utilize satellite-ground cross-domain resources, the satellite-ground collaborative caching and content access stages use a joint optimization method to calculate their final strategies. Content access services can be provided to users by the access satellite and several adjacent satellite nodes, or by directly accessing the ground data center through inter-satellite links. The specific steps are as follows:

[0107] (1) Each satellite node obtains random access request information from the user terminal in the current time slot in real time;

[0108] (2) According to the time-slot network model, within each time slot, the network autonomously perceives status information including network topology, task running status, resource usage and task service requirements.

[0109] (3) Based on the network status and user access request information obtained, the ground operation and control center establishes a satellite-ground integrated network resource management and content collaborative access system model, and constructs a joint optimization mathematical model of network storage resources and network bandwidth resources under multiple physical constraints.

[0110] To better explain the integrated network resource management and content collaborative caching access method, the present invention establishes the following system model in conjunction with embodiments.

[0111] The satellite network is represented as a directed graph G(V,E), where V represents a set of N satellite nodes, and E represents a set of inter-satellite links between all satellite nodes, constructed based on a central satellite and the network hop count h. The storage resources supported by a satellite node are represented as mem. The resource capabilities that a satellite node v, v∈V, can provide are represented as... Each satellite node has four inter-satellite links with its neighboring satellite nodes. Two of these links originate from the same orbital plane, and the other two originate from adjacent orbital planes. The bandwidth resource capacity of each inter-satellite link e, e∈E, is represented by B. e Given the limited available resources of satellites, each satellite can only provide content services to a limited number of users. The maximum number of users accessing satellite v can be expressed as... The input degree set and output degree set of satellite v can be represented as follows: and In addition, the cloud center DC has ample available storage and satellite-to-ground bandwidth resources, and the cloud center is also connecting to satellite V. dc,a Within its coverage area.

[0112] In satellite-ground collaborative access application scenarios, users come from sensors and terminal devices located in multiple dimensions such as air, space, land, and sea. The set of user tasks is U, and the number of users is M. Considering that in remote areas lacking terrestrial networks, satellite nodes can only establish access links and communicate with users within their coverage area, users not covered by satellites cannot offload computing tasks to the satellite edge cloud through satellite nodes. All users are randomly located within the coverage areas of different satellite nodes and obtain the currently accessed content by communicating with the satellite nodes. Specifically, when satellite v provides content services to user u, the access satellite will be represented as access satellite v. u,a The actual data rate of the content w retrieved by user u is represented by b. u .

[0113] Let W be the set of accessed content, which includes Q pieces of content. For each piece of content w, w∈W, the data size and hotness level are represented by s, respectively. w and p w Each user task randomly selects content to access based on its popularity, with more popular content being more likely to be accessed. During content access, the user terminal needs to interact with satellite nodes via a satellite-to-ground link. When a user accesses a satellite node and the available resources of that node are insufficient, content access must be achieved through multi-node collaborative caching. Assume the maximum latency for user u accessing content w, w∈W, is expressed as...

[0114] Reference for Space-Ground Collaborative Caching and Content Access Model Figure 2 The diagram illustrates the satellite edge content access process for nine users. Each satellite node is equipped with a storage server and has a certain coverage area. Satellite nodes can directly interact with users within their coverage area via satellite-to-ground links. Based on received user task information and the current operational status of the satellite network, the current satellite-to-ground collaborative caching and user task content access strategy is determined. Specifically, given sufficient available resources at the current satellite node, User 1 directly accesses content data via Satellite 1, User 2 accesses content data from Satellite 1 via Satellite 4, and if the current satellite node's caching resources are insufficient, User 3 accesses content data from Satellite 3 via Satellite 2, while User 7 accesses content data from the ground data center via the inter-satellite link between Satellites 6 and 5. Users outside the coverage area of ​​the current satellite cannot access content services through the satellite edge cloud.

[0115] During user content access, different caching and access strategies have varying impacts on the overall operational performance of the satellite network and the user service experience. For user terminals, the content access process incurs a certain execution latency. Satellite nodes incur bandwidth and storage costs during content caching and data distribution. This invention balances user service experience and the overall performance of the satellite network in the process of satellite-ground collaborative caching and content access. Under constraints such as cached content deployment, collaborative access, and physical resource configuration, it establishes a joint minimization mathematical problem of network bandwidth usage and inter-satellite storage resource usage, and optimizes the objective function of the average total deployment cost per user.

[0116] The present invention establishes the following mathematical model in conjunction with embodiments.

[0117] To better abstract and express the mathematical problems of the above-mentioned satellite-ground collaborative caching, we first define the following binary decision variables and intermediate variables.

[0118] binary decision variable x u,w ={0,1} indicates whether user u accesses content w, where x u,w =1 indicates that user u is accessing content w; otherwise, x = 1. u,w =0.

[0119] Binary decision variable y w,v ={0,1} indicates whether content w is deployed on satellite node v, where y w,v =1 indicates that content w is deployed on satellite node v; otherwise, y w,v =0.

[0120] Binary decision variables This indicates whether user u accesses content w through satellite node v, where This indicates that user u accesses content w; otherwise...

[0121] Binary decision variables This indicates whether user u used link e during content w access, where This indicates that user u used link e during the access process of content w; otherwise...

[0122] binary decision variable a u,dc ={0,1} indicates whether user u accesses content from a terrestrial data center via a satellite network, where a u,dc =1 indicates that content access is performed via satellite network to a ground data center; otherwise, a u,dc =0.

[0123] When a user accesses content in the satellite edge cloud, a certain network bandwidth usage cost is incurred. The bandwidth usage cost for user u during content access can be expressed as:

[0124]

[0125] Furthermore, deploying accessed content on satellite nodes requires certain storage resources. When different user tasks access the same content, that content can be deployed on a single satellite node, effectively reducing the number of storage resources used. For user u, if the current content is being deployed for the first time, then the storage resources for that content need to be considered; if the current content is not being deployed for the first time, then the storage resources for that content do not need to be considered. That is, the storage resources generated when user u accesses the content at the current moment can be represented as:

[0126]

[0127] From the perspectives of user service experience and satellite network operational efficiency, and taking into account both user missions and the overall interests of the satellite network, optimization objective functions for network bandwidth usage cost and on-orbit storage resource usage cost are established based on a weighted sum method. These objective functions represent the average deployment cost per user. It is assumed that the cost factors for network bandwidth usage cost and on-orbit storage resource usage cost are expressed as follows: and Therefore, for users accessing content, the joint optimization objective function can be expressed as:

[0128]

[0129] During the process of satellite-ground collaborative caching and content access, various physical constraints such as satellite node resources, link bandwidth resources, and task deployment need to be met. The specific constraints are as follows.

[0130] When user u accesses content via satellite edge cloud, each user accesses the current content on one satellite node. Considering that the accessed content can be deployed on multiple satellite nodes simultaneously, the user access constraints can be specifically expressed as follows:

[0131]

[0132] Since satellite node resources are limited, the currently available resources must be no less than the resources required for this access task. Therefore, the storage resource constraint of the satellite node when caching accessed content can be expressed as:

[0133]

[0134] At the same time, ensuring that the content service latency for each user does not exceed the maximum acceptable service latency can be expressed as:

[0135]

[0136] Furthermore, considering that the amount of content accessible by each satellite node is limited, the access service constraints provided by each satellite node to users can be expressed as follows:

[0137]

[0138] If the access satellite node resources are insufficient, the user needs to access content through other satellite nodes via a link. This means that the bandwidth resources required for routing data via the inter-satellite link must not exceed the currently available bandwidth resources. Therefore, the bandwidth resource constraint can be expressed as:

[0139]

[0140] When a user accesses content through the satellite edge cloud, the data routing process in the satellite network must ensure that the data input and output of each satellite node, except for the content storage satellite node and the access satellite node, are consistent. That is, the in-degree and out-degree constraints of the satellite nodes during data routing can be expressed as:

[0141]

[0142] Furthermore, it ensures that the input and output degrees of each satellite are typically equal. (When binary auxiliary variables...) This indicates that satellite v is considered as the access satellite v of the cloud center DC. dc,a ,otherwise The path selection constraints for user u and content w can then be:

[0143]

[0144] (4) The ground control center uses the satellite-ground collaborative caching and resource configuration optimization methods to complete satellite-ground collaborative caching, resource optimization configuration, and cache content access strategy selection, thereby minimizing the deployment cost of the satellite-ground network.

[0145] Considering that the constructed problem model belongs to the NP-hard problem, in order to reduce the computational complexity of solving the problem model, this invention first divides the satellite network into several interdependent sub-networks, and then performs caching strategies, content deployment and user access process execution based on satellite-ground collaborative caching and resource optimization methods.

[0146] Considering the problems of huge network status synchronization overhead, high control complexity and poor real-time decision-making when large-scale satellite constellations manage and schedule storage, link and bandwidth resources in a global manner, each satellite node in this invention can only interact with neighboring satellites to obtain current storage resources and content deployment. If the storage resources of the current neighboring satellite nodes are insufficient, the access volume is limited, or the ground data center is nearby, the user can directly obtain access content from the ground data center through the inter-satellite link, assuming that the storage resources of the ground data center are sufficient and the user's access volume is unlimited.

[0147] When a user requests random access to the satellite edge cloud, the satellite node first autonomously updates and obtains the available storage resources and deployed access content from neighboring satellite nodes. Based on the current network operating status, it selects the optimal content deployment and access strategy for the user. It's important to note that, considering multiple users may be accessing the same content, access content data can be shared among multiple users, effectively reducing the cost of on-orbit storage resource usage. Furthermore, obtaining access content from neighboring nodes closest to the accessing satellite can effectively reduce network bandwidth usage.

[0148] For satellite networks, the first step is to determine the hop count h. sub Each satellite (v) is assigned a neighboring subnetwork, and each satellite is treated as an intelligent agent with environmental awareness, autonomy, and social behavior, autonomously responsible for resource management, content caching, and access services within its neighboring subnetwork. Due to limited onboard storage resources, different satellites within the subnetwork can provide collaborative caching services to users through inter-satellite links to improve user experience and network efficiency. When available storage resources in a subnetwork are insufficient or service provision is limited, users will collaboratively obtain the required content from the cloud center through the satellite network.

[0149] Furthermore, content-sharing technology improves the utilization of onboard storage resources, allowing different users with the same service needs to access the same content deployed on satellites. Considering that more popular cached content is more easily accessed, all users accessing each satellite can be sorted by content popularity from highest to lowest, and user-coordinated caching and resource allocation strategies can be formulated, deployed, and implemented accordingly.

[0150] Specifically, for each user's content service, a neighborhood search approach is used. This involves traversing satellites and links in neighboring subnetworks to obtain feasible strategies for content placement and routing paths. In the initial layer, each user's access satellite is considered a unique root candidate. If the required content has already been deployed or available storage resources are sufficient to cache the content, the root candidate is searched first to obtain a feasible strategy. After a root candidate is found, its neighboring satellites become new candidates for the next layer. It's important to note that a satellite in the subnetwork with the required content might provide content services to the user; in this case, the storage resource usage for the user's content service can be considered zero. Therefore, to obtain the feasible strategy with the lowest deployment cost, the search continues for new candidate strategies in the next layer, regardless of whether a feasible strategy is found in the current layer, until the current hop count in the subnetwork is maximized.

[0151] When there is insufficient available storage resources in a subnetwork, content services are limited, or the cloud center's access satellite is located in its neighboring subnetwork, the user's content services can be provided by the cloud center. In this case, L shortest paths between user u's access satellite and the cloud center dc can be traversed. Feasible routes are obtained in descending order. In this case, the feasible strategy with the lowest deployment cost will be considered as the strategy for collaborative caching and resource allocation, including resource allocation, content caching, and service provisioning.

[0152] To further describe the operation of the proposed method, refer to... Figure 3 Let's take an example to illustrate. First, establish satellite v0 in h sub =1 and h sub The neighborhood subnetworks when = 2 are represented by green and red lines, respectively. Then, a neighborhood search method is used to obtain feasible strategies h for collaborative caching and resource allocation of content services in the neighboring subnetworks with minimal deployment cost. sub =2. Specifically, for a user, the initial layer root candidate is first searched, i.e., accessing satellite v0. However, due to insufficient storage resources, a feasible content service strategy cannot be provided. Then, the candidate satellites {v1,v2,v3,v4} of the next layer are traversed, resulting in two feasible strategies, namely strategy 1 and strategy 2. For strategy 1, satellite v1 has sufficient storage resources to deploy the required content, and the content can be routed via the path v1→v0. For strategy 2, since the required content is deployed on satellite v4, it only needs to be routed via the path v4→v0, and the deployment cost can only come from network bandwidth consumption. In addition, the search continues for candidate schemes in the third layer {v5,v6,…,v4}. 12 The proposed strategy is Strategy 3, where the required content is also deployed on satellite v8, and the content service can be provided simply through the routing path v8→v3→v0. Therefore, considering that Strategy 3 has a higher network consumption than Strategy 2, Strategy 2 is superior to both Strategy 1 and Strategy 3, and will be considered the feasible strategy with the lowest deployment cost.

[0153] In a dynamic environment, the operations control center autonomously senses changes in the surrounding environment by collecting information such as business needs and network operating status in each time slot, and then formulates collaborative caching and resource allocation strategies for new users one by one. When a user's inactivity time exceeds the maximum threshold, cached content on the satellite will be released to reduce storage resource usage. However, in practical applications, considering the real-time nature of user content services, content services can be provided to users based on the content caching strategy generated in the previous time slot, and then the performance of collaborative caching and resource allocation can be improved based on the user's current service needs.

[0154] This invention analyzes the performance of the proposed method in a network simulation application scenario.

[0155] Based on the STK software, orbital parameters of the existing Iridium II satellite constellation were obtained, and a Walker constellation with 66 LEO satellites was established. This constellation comprises six orbital planes, each containing 11 LEO satellites at an altitude of 780 km. Each satellite has 1000 Mbits of storage resources, a maximum of 30 user tasks can access the system, and 100 Mbps of inter-satellite link bandwidth. A satellite subnetwork with a network hop count of 2 is established using the 5th satellite in orbit 4 as the access satellite node. The ground data center is located within the coverage area of ​​the 5th satellite in orbit 6. The available storage resources of the cloud center and the available bandwidth resources between the cloud and the access satellites are considered sufficient. The path count between the cloud center and the access satellites is indicated as 4. Furthermore, the hop count of each adjacent subnetwork is considered to be 1.

[0156] Furthermore, it is assumed that users can be randomly deployed within satellite coverage. For each piece of content, the data size and content popularity can be generated from [100, 500] Mbits and [1, 10], respectively. It is assumed that the service latency for each user to obtain content is less than the maximum service latency, and the storage resource usage cost coefficient and network bandwidth consumption cost coefficient are 0.4 and 0.6, respectively.

[0157] Under the conditions of 4 accessed satellites, Q=5 and M={200,210,…,300}, the performance of content services in three different scenarios—collaborative caching, edge caching, and cloud center—was experimentally analyzed. Figure 4 As shown.

[0158] The average storage cost for each user service in the three scenarios is shown above. Figure 4As shown in (a), for cloud centers, all content services for users are provided by the cloud center, and the satellite network without edge caching is only responsible for data routing. For edge caching, considering that user content services are only provided by satellite networks with edge caching, more content services can be provided to users as the amount of content deployed on satellites increases. Furthermore, for collaborative caching, user collaborative content services can be provided by a satellite-ground collaborative network. Considering the limited supply of edge services and limited storage resources, the terrestrial cloud center can provide content services to users through the satellite network. Therefore, the average storage cost per user service for edge caching is higher than that for collaborative caching. Compared to edge caching, the average storage cost per user service for collaborative caching can be reduced by 30.37%.

[0159] The average bandwidth cost for each user service under the three scenarios is shown in the figure above. Figure 4 As shown in (b), the average bandwidth cost is highest in the cloud center, followed by collaborative caching, and then edge caching. This is because the cloud center can provide content services to all users in the cloud center and a few users in the collaborative cache, while the other users of the collaborative cache and all users of the edge cache will have their content services provided by the satellite network of the edge cache. It is worth noting that cloud-based content services lead to increased network bandwidth consumption compared to edge-based content services. On average, the bandwidth cost per user service of collaborative caching is reduced by 83.9% in the case of cloud center, while it only increases by 32.36% in the case of edge caching.

[0160] also, Figure 4 (c) The average total deployment cost per user service is provided, where the total deployment cost consists of storage resource usage and network bandwidth consumption based on a weighted summation method. It can be observed that the three schemes have different impacts on storage and bandwidth costs. However, the total deployment cost per user service of the collaborative cache is lower than that of both cloud center and edge cache, with the total deployment cost per user service of the edge cache also being lower than that of the cloud center. Compared to cloud center and edge cache, the average total deployment cost per user service of the collaborative cache is reduced by 56.3% and 15.79%, respectively, indicating that the collaborative cache outperforms cloud center and edge cache in reducing total deployment costs.

[0161] Furthermore, experiments were conducted to compare the performance of the proposed method with two baseline algorithms, Greedy and BFS, in content service. For the Greedy algorithm, a greedy search is performed on neighboring sub-networks to obtain the joint strategy for collaborative caching and resource allocation, continuing until the first feasible strategy is found. However, for BFS, the joint strategy for collaborative caching and resource allocation is based on a multi-priority BFS search, where all candidate strategies in one search layer are sorted from high to low according to content caching, storage resource consumption, and service latency. Figure 5 Experimental results for various user services under the proposed method, Greedy, and BFS algorithms are provided, including storage cost, bandwidth cost, and total deployment cost.

[0162] Figure 5 (a) describes the average storage cost for each user service of the proposed method, Greedy, and BFS. For the Greedy algorithm, user collaborative caching services are provided greedily; that is, if the content a user needs is not yet deployed on the traversed satellites, the first available satellite with sufficient storage resources can be used to cache the required content. In this case, the storage cost per user service increases. However, for BFS, when traversing candidate content in a search layer, content sharing methods are prioritized to improve the utilization of onboard storage resources, thereby obtaining a collaborative caching and resource allocation strategy that minimizes storage costs. Furthermore, for the proposed method, when providing user content services, content sharing methods among all satellites in the neighboring subnetwork can be prioritized. Therefore, the average storage cost per user service is highest for Greedy, followed by BFS, and then the proposed method. It is worth noting that as the number of users increases, content sharing methods can provide content services to more users, which will correspondingly reduce the storage cost per user service. On average, the proposed method reduces storage costs per user service by 25.96% compared to Greedy and by 20.61% compared to BFS.

[0163] Figure 5 (b) Shows the average bandwidth cost per user service for the proposed method, Greedy, and BFS. It can also be observed that the average bandwidth cost per user service for Greedy and BFS is close to the results of the proposed method. Compared to Greedy and BFS, the proposed method reduces the bandwidth cost per user service by an average of 3.3% and 2.34%, respectively.

[0164] also, Figure 5 (c) Describes the average total deployment cost for each user service of the proposed method, Greedy, and BFS. Considering that Greedy can greedily provide content services to users, it cannot guarantee that as many content services as possible will be provided through content sharing, which may result in the highest total deployment cost for each user service. For BFS, content sharing can prioritize all candidates within a search layer, but it cannot guarantee that all candidates across different search layers will receive content sharing. Therefore, the average total deployment cost per user service is lower than that of Greedy. For CCRA, it can be guaranteed that all satellites in adjacent subnetworks will prioritize content sharing. Therefore, the average total deployment cost per user service of the proposed method is lower than that of Greedy and BFS.

[0165] Based on the optimization strategy obtained in step (4), resource allocation, cache deployment and content access services are implemented in the space-ground converged network.

[0166] This invention provides a computer-readable storage medium storing computer instructions that, when executed on a computer, cause the computer to perform... Figure 1 The method described.

[0167] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage and optical storage) containing computer-usable program code.

[0168] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0169] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0170] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0171] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

[0172] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A method for resource management and content collaborative caching in a satellite-ground integrated network, characterized in that, include: In the satellite-ground integrated network, each satellite node obtains random access request information from users in the current time slot in real time; Based on the time-slot network model of the space-ground fusion network, network state information is sensed and acquired in each time slot; Based on the acquired network status information and random access request information, the ground operation control center establishes a satellite-ground integrated network resource management and content collaborative access system model, and constructs a joint optimization mathematical model of network storage resources and network bandwidth resources under multiple physical constraints. Based on the aforementioned satellite-ground converged network resource management and content collaborative access system model, and the joint optimization mathematical model, the satellite-ground collaborative caching and resource configuration optimization methods are used to determine the optimization strategies for satellite-ground collaborative caching, resource optimization configuration, and cached content access strategy selection, thereby minimizing the deployment cost of the satellite-ground network. The space-ground converged network implements resource allocation and content caching deployment according to the optimization strategy, and provides users with collaborative access services for cached content. The establishment of the satellite-ground integrated network resource management and content collaborative access system model includes the bandwidth usage cost of user u during content access. And the storage resources generated when user u accesses content at the current moment. Where, x u,w ={0,1} indicates whether user u accesses content w, where x u,w =1 indicates that user u accesses content w; otherwise, x u,w =0; This indicates whether user u used link e during content w access, where This indicates that user u used link e during the access process of content w; otherwise... The actual data rate at which user u accesses content w is represented as b. u ;a u,dc ={0,1} indicates whether user u accesses content from a terrestrial data center via a satellite network, a u,dc =1 indicates that content access is performed via satellite network to a ground data center; otherwise, a u,dc =0; y w,v ={0,1} indicates whether content w is deployed on satellite node v, where y w,v =1 indicates that content w is deployed on satellite node v; otherwise, y w,v =0; This indicates whether user u accesses content w through satellite node v, where This indicates that user u accesses content w; otherwise... Content w represents data size s w .

2. The method for resource management and content collaborative caching in a satellite-ground integrated network according to claim 1, characterized in that, The satellite node establishes a satellite-to-ground link only with the user terminal within its coverage area and provides network access services to that user terminal.

3. The method for resource management and content collaborative caching in a satellite-ground integrated network according to claim 1, characterized in that, The network status information includes current location, network topology, task running status, resource usage, cached content type, and task service requirements.

4. The method for resource management and content collaborative caching in a satellite-ground integrated network according to claim 1, characterized in that, The constraints of the satellite-ground integrated network resource management and content collaborative access system model include user access constraints. And the storage resource constraints of satellite nodes when accessing content cache. And the service latency for each user's content (w) does not exceed the maximum acceptable service latency. and the access service constraints provided by each satellite node to users. and bandwidth resource constraints and the in-degree and out-degree constraints of satellite nodes during data routing. and the in-degree and out-degree constraints of satellite nodes during data routing. Among them, y w,v Whether content w is deployed on satellite node v, Whether user u accesses content w, x via satellite node v u,w For user u, whether to access content w, a u,dc Let U be the user's task set, W be the set of accessible content, and s be the user's task set. The question asks whether user u accesses content via a satellite network to a terrestrial data center. w For task w, w∈W, the size of the content data. Let t be the storage resource capacity that a satellite node v, v∈V can provide. u,w The service latency for user u accessing content w. The maximum service latency for user u to access content w. This represents the maximum number of users that can access satellite v. To determine whether user u used link e during content w access, b u B represents the actual data rate at which user u accesses content w. e Let E represent the bandwidth resource capacity of inter-satellite links e, where e∈E, and E is the set of inter-satellite links between all satellite nodes. and Let v be the set of input degrees and the set of output degrees. Satellite V is considered as the access satellite of the cloud center DC. dc,a V is the set of satellite nodes, v u,a For access satellites of the cloud center DC.

5. The method for resource management and content collaborative caching in a satellite-ground integrated network according to claim 1, characterized in that, The joint optimization mathematical model includes The joint optimization mathematical model is represented by the average deployment cost per user, and the cost factors for network bandwidth usage cost and on-orbit storage resource usage cost are respectively represented as: and Let U be the set of user tasks and M be the number of users.

6. The method for resource management and content collaborative caching in a satellite-ground integrated network according to claim 1, characterized in that, In the aforementioned satellite-ground collaborative caching and resource configuration optimization method, each satellite node interacts with neighboring satellites to obtain current storage resources and content deployment information. If the storage resources of the current neighboring satellite nodes are insufficient, access is limited, or a ground data center is nearby, the user can directly obtain access content from the ground data center via inter-satellite links, including: Each access satellite node obtains the operational status of the neighboring satellite subnetwork based on the network hop count, and obtains feasible strategies for content placement and routing paths by traversing the satellites and links in the neighboring subnetwork. In the initial layer, each user's access satellite is a unique root candidate. After searching for the root candidate, the neighboring satellites of the root candidate become new candidates for the next layer. Regardless of whether a feasible strategy is obtained in the current layer, the search for new candidate strategies in the next layer will continue until the current hop count in the subnetwork reaches the maximum. Secondly, when there is insufficient available storage resources in the subnetwork, content services are limited, or the cloud center's access satellite is located in its neighboring subnetwork, the user's content services can be provided by the cloud center. In this case, the shortest path between the user's access satellite and the cloud center is traversed, and feasible routing paths are obtained based on descending order. In this situation, the feasible strategy with the lowest deployment cost will be regarded as the strategy for coordinating caching and resource allocation, including resource allocation, content caching, and access.

7. A satellite-ground integrated network resource management and content collaborative caching system, characterized in that, include: The user terminal, located in a multi-dimensional space encompassing land, sea, and air, sends service request information to servers located in the satellite edge cloud and central cloud to obtain the required content data in real time from the nearest location. The ground-based operation control center can manage and control the satellite edge cloud and the ground center cloud in an integrated manner based on the space-ground cross-domain network. By monitoring the operation status of the satellite network and the ground center cloud and the current task execution status in real time, it can autonomously complete task orchestration and resource allocation according to the current access user requests and network status. It can also share with the satellite edge cloud and the ground center cloud through information interaction to complete resource configuration, task deployment and execution. The satellite edge cloud module is used to interconnect each satellite node with four adjacent satellite nodes through inter-satellite links, and form a satellite neighborhood sub-network with adjacent satellite nodes based on the network hop count. In the satellite network, satellite nodes provide on-orbit storage services to users by carrying certain storage payloads, as well as on-demand content storage services to users; satellite nodes send the operating status and mission execution status of each node to the operation control center through inter-satellite and satellite-to-ground links according to time slots; the operation control center monitors the operating status of the satellite edge cloud in real time and uniformly arranges the available resources. The ground-based central cloud module, located far from the user end, works in conjunction with the satellite edge cloud module to provide users with storage resources and content caching services; The model for establishing a satellite-ground converged network resource management and content collaborative access system includes the bandwidth usage cost for user u during content access. And the storage resources generated when user u accesses content at the current moment. Where, x u,w ={0,1} indicates whether user u accesses content w, where x u,w =1 indicates that user u accesses content w; otherwise, x u,w =0; This indicates whether user u used link e during content w access, where This indicates that user u used link e during the access process of content w; otherwise... The actual data rate at which user u accesses content w is represented as b. u ;a u,dc ={0,1} indicates whether user u accesses content from a terrestrial data center via a satellite network, a u,dc =1 indicates that content access is performed via satellite network to a ground data center; otherwise, a u,dc =0; y w,v ={0,1} indicates whether content w is deployed on satellite node v, where y w,v =1 indicates that content w is deployed on satellite node v; otherwise, y w,v =0; This indicates whether user u accesses content w through satellite node v, where This indicates that user u accesses content w; otherwise... Content w represents data size s w .

8. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method as described in any one of claims 1 to 6.

9. A satellite-ground converged network resource management and content collaborative caching device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, it implements the steps of the method as described in any one of claims 1 to 6.

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