A satellite edge cache network content distribution and resource management algorithm and device

Abstract

The present invention discloses a device for satellite edge cache network content distribution and resource management algorithm, including a communication module, a storage module, a content distribution module, a billing module and a resource management module; the communication module is responsible for satellite-to-ground / inter-satellite signaling and data transmission; the storage module is responsible for storing some content files in the network. In the present invention, the multi-orbit and multi-level structural characteristics of the satellite network and the satellite storage capacity are fully utilized, and the advanced edge cache technology of the ground network is used for reference. The caching capacity of the satellite is used to cache hot files in each satellite node, thereby realizing the sinking of network content and functions, forming a satellite edge cache network, and using the different communication and processing capabilities of high and low orbit satellites to build a multi-level network cache, which increases the flexibility of content acquisition and further reduces the service delay of the satellite network.

Description

Technical Field

[0001] The present invention relates to the field of satellite edge cache network content distribution and resource management technology, and in particular to a satellite edge cache network content distribution and resource management algorithm and device. Background Art

[0002] In recent years, the development of low-orbit constellations has been changing with each passing day. Compared with high-orbit satellites, low-orbit satellites can significantly shorten the satellite-to-ground propagation time, bring users more agile service response and data transmission delay, and provide more possibilities for satellite hosting of time-sensitive services. However, due to the weight, size and power consumption of low-orbit satellites, the storage and processing functions of low-orbit satellites are significantly different from those of high-orbit satellites. In order to achieve complementary advantages, high-orbit and low-orbit joint networking has become a general trend. On the other hand, with the continuous enhancement of on-board capabilities, satellites will have certain storage and computing capabilities. In the future, processing satellites will gradually replace transparent forwarding satellites and become the mainstream. The upgrade of satellite node capabilities and the evolution of satellite networking methods make on-board applications of edge cache networks possible.

[0003] At present, the existing satellite communication network is not flexible enough in acquiring network content, and there is a certain network delay during the transmission process. It cannot effectively utilize satellite storage capacity, improve satellite network service delay, and enhance service performance for time-sensitive services.

[0004] The edge cache network adopts the idea of ​​in-network caching. The basic idea of ​​CCN is to adopt in-network caching and cache file data in the intermediate node of the network between the content provider and the user terminal. Therefore, the user's content request can be terminated at a node in the network that caches the target content, without having to be transmitted to the content provider, thereby increasing the flexibility of content acquisition and reducing service delays. By utilizing the caching capacity of the satellite, hot files are cached in each satellite node, which can realize the sinking of network content and functions, form a satellite edge cache network, and further reduce the service delay of the satellite network. Therefore, based on the edge cache network, the present invention proposes a satellite edge cache network content distribution and resource management algorithm and device. Summary of the invention

[0005] The purpose of the present invention is to propose a satellite edge cache network content distribution and resource management algorithm and device in order to solve the above problems.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A device for satellite edge cache network content distribution and resource management algorithm, including a communication module, a storage module, a content distribution module, a billing module and a resource management module;

[0008] Communication module: responsible for satellite-to-ground / inter-satellite signaling and data transmission;

[0009] Storage module: responsible for storing some content files in the network;

[0010] Content distribution module: responsible for responding to user content requests and retrieving corresponding content files from appropriate locations in the network according to the cache status of each node and sending them to users;

[0011] Billing module: responsible for charging service fees to users or paying to the upper-level cache node;

[0012] Resource management module: Make decisions on each user's content request, user access satellite and allocated bandwidth to maximize its own benefits.

[0013] Preferably, the resource management module includes an information collection module and a calculation and decision module. The information collection module is responsible for collecting the cache status of each low-orbit satellite node and high-orbit satellite node in the collaboration group, the link status data from the user to each low-orbit satellite node in the collaboration group, and calculating the access satellite decision variable. Bandwidth allocation variables The value of k is determined and the decision result is notified to the selected access satellite k through the communication module.

[0014] A satellite edge cache network content distribution and resource management algorithm includes the following steps:

[0015] S1. Satellites with partially overlapping or similar coverage areas are divided into several edge cooperation groups, and the satellites in the cooperation group jointly provide access services for users in the coverage area;

[0016] S2. Each low-orbit satellite can be connected to a high-orbit satellite via an intersatellite link to request or return content;

[0017] S3. Ground content providers will access high-orbit satellites through gateways. Ground content providers, high-orbit satellites, and low-orbit satellites will form a multi-level edge cache network to provide content services for the entire network.

[0018] Preferably, the method for implementing step S1 specifically comprises the steps of:

[0019] S11. Store all the content files of the network in the data center of the content provider. The data center contains F files, the size of the file is Q bits, and the probability of the fth file being requested is q f ;

[0020] S12. Each low-orbit and high-orbit satellite in the network has storage capacity and can cache the popular files in step S11 in the network according to its own capacity to form an edge cache network. The cache state of satellite k is represented by a binary variable β kf Instructions, β kf =1 means that a copy of file f is cached in satellite k, β kf =0 means that satellite k does not cache file f, where the low-orbit satellite is the first-level access node of the network, providing access services for users.

[0021] Preferably, the method for implementing step S2 specifically comprises the following steps:

[0022] S21. The user initiates a request for a content file and sends a content request packet to the network;

[0023] S22. When the edge collaboration group in low orbit receives a user application in this area, it will select the best access satellite k to allocate access bandwidth to the user and provide content services based on the user's request content, service quality requirements and link quality. Indicates whether satellite k is selected to respond to and provide services for "user u requesting file f", where It means that satellite k establishes a connection with user u and transfers file f, otherwise it means that satellite k does not respond to this request;

[0024] S23. Satellite k first checks its own cache resources. If the corresponding content copy is stored, it directly feeds back to the user and applies to the operator to purchase the corresponding bandwidth allocation variable. Used to transfer file f for user u; otherwise, satellite k records the name of the content in its pending request table and forwards the request to the next level service node, i.e., the high-orbit satellite, according to the record in the forwarding information base.

[0025] Preferably, the method for implementing step S3 specifically comprises the following steps:

[0026] S31. The high-orbit satellite repeats the process of step S2 above until the target content is found in its own cache or at the content provider, and the target content will be sent to the user along the reverse path of the content request data packet, thereby forming a tree-shaped multi-level cache architecture;

[0027] S32. Under the tree-shaped multi-level cache architecture, when satellite k is selected to respond to user u's request for file f, that is, Satellite k purchases a certain amount of bandwidth from the operator based on the latency requirements of user u If we provide service to user u, the delay experienced by the user is:

[0028]

[0029] Among them, Q is the size of the file data, c is the speed of light; R uk , R Gk , R G0 are the spectrum efficiencies of the wireless links between user u and low-orbit satellite k, low-orbit satellite k and high-orbit satellite, and high-orbit satellite and terrestrial content providers, respectively. uk、 L Gk , L G0 are the distances between user u and low-orbit satellite k, low-orbit satellite k and high-orbit satellite, and high-orbit satellite and ground content provider, respectively. Gk , B G0 are the bandwidths of the wireless links between the low-orbit satellite k and the high-orbit satellite, and between the high-orbit satellite and the terrestrial content provider, respectively. Gf Indicates whether the high-orbit satellite stores a copy of file f;

[0030] S33. Users pay for the content services provided by the access satellite. Each edge collaboration group in the low-orbit constellation earns revenue by serving users in the coverage area. At the same time, its service costs include: 1) purchasing bandwidth allocation variables from the operator when serving each user The required cost, the unit price is φ; 2) When the service satellite k does not cache the file f requested by the user, it needs to request the file f from the high-orbit satellite and pay for the file By providing services to users, the net benefit that satellite k can obtain is

[0031] Preferably, the satellite decision variable in step S33 Bandwidth allocation variables The solution method includes the following steps:

[0032] S331. The maximum delay that the user can tolerate is D th , and the edge cooperation group of each low-orbit satellite only serves requests that can generate positive net benefits, then the access satellite decision variable of the edge cooperation group is Bandwidth allocation variables The process is to solve the following optimization problem:

[0033]

[0034] stCl:

[0035] C2:

[0036] C3:

[0037] C4:

[0038] Among them, constraint C1 means that for each content request of user u, the LEO satellite edge collaboration group will only select one member to serve it, D th Describes the user's service quality requirements, indicating the maximum delay that the user can tolerate when requesting content files. Constraint C2 guarantees the service quality requirements of each user. Constraint C3 indicates that satellite k will respond to a request only when the net benefit of serving a request is greater than zero, otherwise the request will be rejected by satellite k. Constraint C4 defines the value range of the satellite selection variable.

[0039] S332. The process of solving the value range of the above constraint condition C4 is:

[0040]

[0041]

[0042] in, where ∈ is a small non-zero positive number,

[0043]

[0044] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0045] In this application, full use is made of the multi-orbit and multi-level structural characteristics of the satellite network and the satellite storage capacity, and the advanced edge caching technology of the ground network is borrowed. The caching capacity of the satellite is used to cache hot files in each satellite node, thereby realizing the sinking of network content and functions, forming a satellite edge caching network, and utilizing the different communication and processing capabilities of high and low orbit satellites to build a multi-level network cache, which increases the flexibility of content acquisition and further reduces the service latency of the satellite network. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 A schematic diagram of a network architecture provided according to an embodiment of the present invention is shown;

[0047] Figure 2 A schematic diagram of the device composition of a satellite edge cache network content distribution and resource management algorithm provided according to an embodiment of the present invention is shown;

[0048] Figure 3 A schematic diagram of the network tree-shaped multi-level cache architecture provided in an embodiment of the present invention is shown;

[0049] Figure 4 A schematic diagram of the structure of a satellite content distribution and resource management process provided according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0050] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] See also Figure 1-4 , the present invention provides a technical solution:

[0052] A device for satellite edge cache network content distribution and resource management algorithm, including a communication module, a storage module, a content distribution module, a billing module and a resource management module;

[0053] Communication module: responsible for satellite-to-ground / inter-satellite signaling and data transmission;

[0054] Storage module: responsible for storing some content files in the network;

[0055] Content distribution module: responsible for responding to user content requests and retrieving corresponding content files from appropriate locations in the network according to the cache status of each node and sending them to users;

[0056] Billing module: responsible for charging service fees to users or paying to the upper-level cache node;

[0057] Resource management module: Make decisions on the user's access satellite and allocated bandwidth for each user's content request to maximize its own benefits;

[0058] The resource management module includes an information collection module and a calculation and decision module. The information collection module is responsible for collecting the cache status of each low-orbit satellite node and high-orbit satellite node in the collaboration group, the link status data from the user to each low-orbit satellite node in the collaboration group, and calculating the access satellite decision variable. Bandwidth allocation variables The value of the decision is then communicated to the selected access satellite through the communication module.

[0059] A satellite edge cache network content distribution and resource management algorithm includes the following steps:

[0060] S1. Satellites with partially overlapping or similar coverage areas are divided into several edge cooperation groups, and the satellites in the cooperation group jointly provide access services for users in the coverage area;

[0061] The method for implementing step S1 specifically comprises the steps of:

[0062] S11. Store all the content files of the network in the data center of the content provider. The data center contains F files. The size of the file is Q bits. The popularity of the file follows the Zipf distribution. The probability of the fth file being requested is;

[0063] S12. Each low-orbit and high-orbit satellite in the network has storage capacity and can cache the popular files in step S11 in the network according to its own capacity to form an edge cache network. The cache status of satellite k is indicated by a binary variable, β kf =1 means that a copy of file f is cached in satellite k, β kf =0 means that satellite k does not cache file f, where the low-orbit satellite is a primary access node of the network, providing access services to users;

[0064] S2. Each low-orbit satellite can be connected to a high-orbit satellite via an intersatellite link to request or return content;

[0065] The method for implementing step S2 specifically includes the following steps:

[0066] S21. The user initiates a request for a content file and sends a content request packet to the network;

[0067] S22. When the edge collaboration group in low orbit receives a user application in this area, it will select the best access satellite k to allocate access bandwidth to the user and provide content services based on the user's request content, service quality requirements and link quality. Indicates whether satellite k is selected to respond to and provide services for "user u requesting file f", where It means that satellite k establishes a connection with user u and transfers file f, otherwise it means that satellite k does not respond to this request;

[0068] S23. Satellite k first checks its own cache resources. If the corresponding content copy is stored, it directly feeds back to the user and applies to the operator to purchase the corresponding bandwidth allocation variable. Used to transfer file f for user u; otherwise, satellite k records the name of the content in its pending request table and forwards the request to the next level service node, i.e., the high-orbit satellite, according to the record in the forwarding information base;

[0069] S3. Ground content providers will access high-orbit satellites through gateways. Ground content providers, high-orbit satellites, and low-orbit satellites will form a multi-level edge cache network to provide content services for the entire network.

[0070] The method for implementing step S3 specifically includes the following steps:

[0071] S31. The high-orbit satellite repeats the process of step S2 above until the target content is found in its own cache or at the content provider, and the target content will be sent to the user along the reverse path of the content request data packet, thereby forming a tree-shaped multi-level cache architecture;

[0072] S32. Under the tree-shaped multi-level cache architecture, when satellite k is selected to respond to user u's request for file f, that is, Satellite k purchases a certain amount of bandwidth from the operator based on the latency requirements of user u If we provide service to user u, the delay experienced by the user is:

[0073]

[0074] Among them, Q is the size of the file data, c is the speed of light; R uk , R Gk , R G0 are the spectrum efficiencies of the wireless links between user u and low-orbit satellite k, low-orbit satellite k and high-orbit satellite, and high-orbit satellite and terrestrial content providers, respectively. uk , L Gk , L G0 are the distances between user u and low-orbit satellite k, low-orbit satellite k and high-orbit satellite, and high-orbit satellite and ground content provider, respectively. Gk , B G0 are the bandwidths of the wireless links between the low-orbit satellite k and the high-orbit satellite, and between the high-orbit satellite and the terrestrial content provider, respectively. Gf Indicates whether the high-orbit satellite stores a copy of file f;

[0075] S33. Users pay for the content services provided by the access satellite. Each edge collaboration group in the low-orbit constellation earns revenue by serving users in the coverage area. At the same time, its service costs include: 1) purchasing bandwidth allocation variables from the operator when serving each user The required cost, the unit price is φ; 2) When the service satellite k does not cache the file f requested by the user, it needs to request the file f from the high-orbit satellite and pay for the file By providing services to users, the net benefit that satellite k can obtain is

[0076] Satellite decision variables in step S33 Bandwidth allocation variables The solution method includes the following steps:

[0077] S331. The maximum delay that the user can tolerate is D th , and the edge cooperation group of each low-orbit satellite only serves requests that can generate positive net benefits, then the access satellite decision variable of the edge cooperation group is Bandwidth allocation variables The process is to solve the following optimization problem:

[0078]

[0079] st·C1:

[0080] C2:

[0081] C3:

[0082] C4:

[0083] Among them, constraint C1 means that for each content request of user u, the LEO satellite edge collaboration group will only select one member to serve it, D th Describes the user's service quality requirements, indicating the maximum delay that the user can tolerate when requesting content files. Constraint C2 guarantees the service quality requirements of each user. Constraint C3 indicates that satellite k will respond to a request only when the net benefit of serving a request is greater than zero, otherwise the request will be rejected by satellite k. Constraint C4 defines the value range of the satellite selection variable.

[0084] S332. The process of solving the value range of the above constraint condition C4 is:

[0085]

[0086]

[0087] in, where ∈ is a small non-zero positive number, Thus, the satellite decision variable is obtained Bandwidth allocation variables The value of .

[0088] In summary, the present embodiment provides a satellite edge cache network content distribution and resource management algorithm. When a user u needs a certain file content f, he can send a service request to indicate his target file and delay requirement D. th , and pay for the content service ρ. After receiving the user request, the collaboration group first makes a resource management decision, that is, selects the satellite decision variable for the access node Bandwidth allocation variables The calculation method is:

[0089]

[0090]

[0091] in, where ∈ is a small non-zero positive number, Satellite k is the satellite selected to provide access service for user u, and its characteristics are If all If both are 0, the user's request is rejected; then satellite k responds to user u's request. Satellite k first checks its own cache resources. If the corresponding content copy is stored, it directly feeds back to the user and applies to the operator to purchase the corresponding bandwidth resources. It is used to transfer file f for user u and pay for the bandwidth at a unit price of φ; otherwise, satellite k records the name of the content in its pending request table and forwards the request to the high-orbit satellite according to the record in the forwarding information base, and pays the high-orbit satellite. The high-orbit satellite repeats the above process until it finds the target content in its own cache or at the content provider, and the target content will be sent to the user along the reverse path of the content request data packet;

[0092] Each satellite node in the network caches certain content files according to its own caching capacity. Among them, low-orbit satellites serve as the first-level access nodes of ground user terminals. Low-orbit satellites covering the same area form an edge cooperation group to jointly provide access services to users in the area. High-orbit satellites serve as second-level access nodes and can accept content requests from low-orbit satellites or forward requests from low-orbit nodes to ground content service providers. Each low-orbit edge cooperation group selects satellite nodes that provide access services to users based on content requests, latency requirements and link conditions proposed by users, and allocates link bandwidth to them. If the access node has cached the user's requested content, the content file can be directly sent to the user, and the user pays the service satellite for content and bandwidth resources; otherwise, the access satellite will obtain the content from the high-orbit satellite and pay the high-orbit satellite. For the high-orbit satellite, if it has the target content file cached, the file will be returned directly, otherwise the request will be forwarded to the ground content service provider, and the ground content provider will send the content file.

[0093] The above description of the embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A satellite edge cache network content distribution and resource management algorithm, characterized in that: A satellite edge cache network content distribution and resource management device, including a communication module, a storage module, a content distribution module, a billing module and a resource management module; Communication module: responsible for satellite-to-ground / inter-satellite signaling and data transmission; Storage module: responsible for storing some content files in the network; Content distribution module: responsible for responding to user content requests and retrieving corresponding content files from appropriate locations in the network according to the cache status of each node and sending them to users; Billing module: responsible for charging service fees to users or paying to the upper-level cache node; Resource management module: Make decisions on the user's access satellite and allocated bandwidth for each user's content request to maximize its own benefits; The resource management module includes an information collection module and a calculation and decision module. The information collection module is responsible for collecting the cache status of each low-orbit satellite node and high-orbit satellite node in the collaboration group, the link status data from the user to each low-orbit satellite node in the collaboration group, and calculating the access satellite decision variable. Bandwidth allocation variables The value of , and inform the selected access satellite k of the decision result through the communication module, The specific steps include: S1. Satellites with partially overlapping or similar coverage areas are divided into several edge cooperation groups, and the satellites in the cooperation group jointly provide access services for users in the coverage area; S2. Each low-orbit satellite is connected to a high-orbit satellite via an intersatellite link to request or return content; The method of step S2 specifically comprises the following steps: S21. The user initiates a request for a content file and sends a content request packet to the network; S22. When the edge collaboration group in the low orbit receives a user application in this area, it will select the best access satellite k to allocate access bandwidth and provide content services to the user according to the user's request content, service quality requirements and link quality. The satellite decision variable Indicates whether satellite k is selected to respond to and provide services for "user u requesting file f", where It means that satellite k establishes a connection with user u and transfers file f, otherwise it means that satellite k does not respond to this request; S23. Satellite k first checks its own cache resources. If the corresponding content copy is stored, it directly feeds back to the user and applies to the operator to purchase the corresponding bandwidth allocation variable. Used to transfer file f for user u; otherwise, satellite k records the name of the content in its pending request table and forwards the request to the next level service node, i.e., the high-orbit satellite, according to the record in the forwarding information base; S3. Ground content providers will access high-orbit satellites through gateways. Ground content providers, high-orbit satellites, and low-orbit satellites will form a multi-level edge cache network to provide content services for the entire network. The method of step S3 specifically comprises the following steps: S31. The high-orbit satellite repeats the process of step S2 above until the target content is found in its own cache or at the content provider, and the target content will be sent to the user along the reverse path of the content request data packet, thereby forming a tree-shaped multi-level cache architecture; S32. Under the tree-shaped multi-level cache architecture, when satellite k is selected to respond to user u's request for file f, that is, Satellite k purchases a certain amount of bandwidth from the operator based on the latency requirements of user u If we provide service to user u, the delay experienced by the user is: Among them, Q is the size of the file data, c is the speed of light; R uk , R Gk , R G0 are the spectrum efficiencies of the wireless links between user u and low-orbit satellite k, low-orbit satellite k and high-orbit satellite, and high-orbit satellite and terrestrial content providers, respectively. uk , L Gk , L G0 are the distances between user u and low-orbit satellite k, low-orbit satellite k and high-orbit satellite, and high-orbit satellite and ground content provider, respectively. Gk , B G0 are the bandwidths of the wireless links between the low-orbit satellite k and the high-orbit satellite, and between the high-orbit satellite and the terrestrial content provider, respectively. Gf Indicates whether the high-orbit satellite stores a copy of file f; S33. Users pay for the content services provided by the access satellite. Each edge collaboration group in the low-orbit constellation earns revenue by serving users in the coverage area. Its service costs include: 1) purchasing bandwidth allocation variables from the operator when serving each user The required cost, the unit price is φ; 2) When the service satellite k does not cache the file f requested by the user, it needs to request the file f from the high-orbit satellite and pay for the file By providing services to users, the net benefit that satellite k can obtain is 2. A satellite edge cache network content distribution and resource management algorithm according to claim 1, characterized in that: The method of step S1 specifically comprises the following steps: S11. Store all the content files of the network in the data center of the content provider. The data center contains F files, the size of the file is Q bits, and the probability of the fth file being requested is q f ; S12. Each low-orbit and high-orbit satellite in the network has storage capacity and can cache the popular files in step S11 in the network according to its own capacity to form an edge cache network. The cache state of satellite k is represented by a binary variable β kf Instructions, β kf =1 means that a copy of file f is cached in satellite k, β kf =0 means that satellite k does not cache file f, where the low-orbit satellite is the first-level access node of the network, providing access services for users.

3. A satellite edge cache network content distribution and resource management algorithm according to claim 1, characterized in that: The satellite decision variables in step S3 Bandwidth allocation variables The solution method includes the following steps: S331. The maximum delay that the user can tolerate is D th , and the edge cooperation group of each low-orbit satellite only serves requests that can generate positive net benefits, then the access satellite decision variable of the edge cooperation group is Bandwidth allocation variables The process is to solve the following optimization problem: Among them, constraint C1 means that for each content request of user u, the LEO satellite edge collaboration group will only select one member to serve it, D th Describes the user's service quality requirements, indicating the maximum delay that the user can tolerate when requesting content files. Constraint C2 guarantees the service quality requirements of each user. Constraint C3 indicates that satellite k will respond to a request only when the net benefit of serving a request is greater than zero, otherwise the request will be rejected by satellite k. Constraint C4 defines the value range of the satellite selection variable. S332. The process of solving the value range of the above constraint condition C4 is as follows: in, where ∈ is a small non-zero positive number,

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