Content caching method for satellite terrestrial integrated network with differentiated interest and access mode

Patent metadata

Field	Value
Publication number	US-12192556-B2
Application number	US-202418592565-A
Country	US
Kind code	B2
Filing date	Mar 1, 2024
Priority date	Mar 9, 2023
Publication date	Jan 7, 2025
Grant date	Jan 7, 2025

Abstract

A content caching method for a satellite terrestrial integrated network with differentiated interests and access modes, including: collecting user proportion information, content popularity distribution information, cache capacity information, and link delay information in the satellite terrestrial integrated network; determining a content caching problem of the collaboration of base stations and a satellite for a delay optimization based on differentiated user interests and differentiated access modes; solving the content caching problem to obtain a content caching strategy of the collaboration of the base stations and the satellite; and based on the obtained content caching strategy, caching contents in the base stations and the satellite to provide a content service for base station access users and satellite access users in the satellite terrestrial integrated network.

First claim

What is claimed is:

1. A content caching method for a satellite terrestrial integrated network with differentiated interests and access modes, comprising:
step (1), collecting user proportion information, content popularity distribution information, cache capacity information, and link delay information in the satellite terrestrial integrated network, wherein the satellite terrestrial integrated network comprises base stations, a satellite, base station access users, satellite access users, a ground station, and a cloud server; and a cover area of the satellite terrestrial integrated network is divided into multiple regions, and different regions have different local content popularity distributions;
wherein the user proportion information comprises proportion information of the base station access users and the satellite access users in the satellite terrestrial integrated network, and proportion information of users in different regions covered by the satellite terrestrial integrated network;
the content popularity distribution information is local content popularity distribution information of different regions covered by the satellite terrestrial integrated network;
the cache capacity information comprises base station cache capacity information and satellite cache capacity information; and
the link delay information comprises link delay information from the base stations to the base station access users, link delay information from the satellite to the base stations, link delay information from the satellite to the satellite access user, link delay information from the ground station to the satellite, and link delay information from the cloud server to the ground station;
step (2), determining a content caching problem of a collaboration of the base stations and the satellite for a delay optimization based on differentiated user interests and differentiated access modes, wherein the delay optimization refers to minimizing an average content retrieval delay of all users in the satellite terrestrial integrated network; and the step (2) comprises:
sub-step (2.1), for each region covered by the satellite terrestrial integrated network, calculating, based on a local content popularity distribution in the region, content storage probabilities of a requested content in the base stations, the satellite, the ground station, and the cloud server when the base station access users in the region request any content; and
for each region covered by the satellite terrestrial integrated network, calculating, based on the local content popularity distribution in the region, content storage probabilities of the requested content in the satellite, the ground station, and the cloud server when the satellite access users in the region request any content;
sub-step (2.2), for each region covered by the satellite terrestrial integrated network, calculating an average content retrieval delay of the base station access users and an average content retrieval delay of the satellite access users, respectively, based on the content storage probabilities and the link delay information;
sub-step (2.3), performing weighted summation on the average content retrieval delays of all users in all regions within a coverage area of the satellite terrestrial integrated network to obtain a network average content retrieval delay; and
sub-step (2.4), obtaining the content caching problem by taking a content caching strategy of the collaboration of the base stations and the satellite as an optimization variable, minimization of the network average content retrieval delay as an optimization target, and cache capacities of the base stations and the satellite as an optimization limitation condition;
step (3), solving the content caching problem to obtain the content caching strategy of the collaboration of the base stations and the satellite;
sub-step (3.1), equivalently converting the average content retrieval delay of the satellite access users in different regions into the average content retrieval delay of all the satellite access users under a global content popularity distribution, in such a manner to reduce a calculation complexity of the average content retrieval delay of the satellite access users;
sub-step (3.2), reducing a solution space size and reducing a search complexity of the content caching strategy based on solution space analysis;
sub-step (3.3), converting the content caching problem into a maximization problem of a delay reduction gain, wherein the delay reduction gain refers to a reduction amount of an average content retrieval delay of the users under a current content caching strategy when no content is cached by the base stations and the satellite; and
sub-step (3.4), solving the converted maximization problem of the delay reduction gain to obtain the content caching strategy of the collaboration of the base stations and the satellite; and
step (4), caching, based on the obtained content caching strategy, contents in the base stations and the satellite to provide a content service for the base station access users and the satellite access users in the satellite terrestrial integrated network.

2. The content caching method for a satellite terrestrial integrated network with differentiated interests and access modes according to claim 1 , wherein the sub-step (3.2) further comprises:
sub-step (3.2.1), for each region, calculating fixedly cached contents and selectively cached contents of the base stations in the region based on the local content popularity distribution information, the cache capacity information and the link delay information of the region, wherein the fixedly cached contents refer to contents necessarily cached in the content caching strategy obtained by solving the content caching problem, and the selectively cached contents refer to contents possibly cached in the content caching strategy obtained by solving the content caching problem; and
calculating fixedly cached contents and selectively cached contents of the satellite based on the user proportion information, global content popularity distribution information, and the cache capacity information; and
sub-step (3.2.2), for each region, reducing a solution space of the content caching strategy of the base stations in the region to a union set of the fixedly cached contents and the selectively cached contents of the base stations in the region, and reducing a search space of the content caching strategy of the base stations in the region to a set of the selectively cached contents of the base stations in the region; and
reducing a solution space of the content caching strategy of the satellite to a union set of the fixedly cached contents and the selectively cached contents of the satellite, and reducing a search space of the content caching strategy of the satellite to a set of the selectively cached contents of the satellite.

3. The content caching method for a satellite terrestrial integrated network with differentiated interests and access modes according to claim 2 , wherein the sub-step (3.4) comprises the following iterative sub-steps:
sub-step (3.4.1), initializing a satellite iterative solution into a set of the fixedly cached contents of the satellite;
sub-step (3.4.2), initializing all contents in the set of the selectively cached contents of the satellite to be in an unselected state;
sub-step (3.4.3), selecting unselected content from the set of the selectively cached contents of the satellite, and updating a satellite candidate solution corresponding to the unselected content into a union of the satellite iterative solution and selected content;
sub-step (3.4.4), calculating, for each region, a content caching strategy when the base stations obtain a maximum delay reduction gain under a satellite candidate solution corresponding to the selected content;
sub-step (3.4.5), c

Assignees

• Zhejiang Lab

Inventors

• Zhu Xiangming
• Liu Shanyun
• Hao Nan

Classifications

• H04N21/2183 Primary

  Cache memory {(caches in web servers or browsers G06F16/9574; intermediate storage and caching in data networks H04L67/568)} · CPC title

• H04N21/252

  Processing of multiple end-users' preferences to derive collaborative data · CPC title

• H04N21/2668

  Creating a channel for a dedicated end-user group, e.g. insertion of targeted commercials based on end-user profiles {(information retrieval from the Internet by querying with filtering and personalisation G06F16/9535; arrangements for replacing or switching information during the broadcast H04H20/10; push services over packet-switching network H04L12/1859; adaptation of message content in packet-switching networks H04L51/063)} · CPC title

• H04N21/23106

  involving caching operations (prefetching while addressing of a memory level in which the access to the desired data or data block requires associative addressing means within memory systems or architectures G06F12/0862; caching at an intermediate stage in a data network H04L67/568) · CPC title

• H04N21/6143

  involving transmission via a satellite · CPC title