CN-122001948-A - Asynchronous coded cache file distribution method and device

CN122001948ACN 122001948 ACN122001948 ACN 122001948ACN-122001948-A

Abstract

The invention provides a file distribution method and device for asynchronous coding cache, the method comprises the steps of establishing user QoE constraint on delivery delay and service preferential price, determining base station profit according to the difference between service income of a base station and service cost of the base station, constructing base station profit maximization problem based on the user QoE constraint and with maximized base station profit as an objective function, solving the base station profit maximization problem to obtain optimal delivery delay of each user and corresponding optimal service preferential price which enable the base station profit to be maximized, and enabling the base station to delay delivery of file requests of corresponding users according to the obtained optimal delivery delay. The method maximizes the profit of the base station while guaranteeing the QoE of the user, thereby realizing the balance of the QoE of the user and the profit of the base station.

Inventors

ZHOU YIQING
CAO MENGHUA
SHI JINGLIN
LIU LING

Assignees

中国科学院计算技术研究所

Dates

Publication Date: 20260508
Application Date: 20241105

Claims (12)

1. The file distribution method based on asynchronous code cache is characterized by comprising the following steps: Establishing a user QoE constraint on the delivery delay and the service offer price, wherein the user QoE constraint comprises a first sub-constraint based on the delivery delay and a second sub-constraint based on the service offer price, and the second sub-constraint considers the price satisfaction degree of each user to the corresponding service offer price when the file request of each user is given the delivery delay; Determining a profit of the base station according to the difference between the service income of the base station and the service cost of the base station, wherein the service income of the base station is determined according to the service preferential price, and the service cost of the base station is determined according to the delivery delay; Constructing a base station profit maximization problem by taking the profit of the base station as an objective function to be maximized based on the QoE constraint of the user; Solving the problem of maximization of the profit of the base station to obtain the optimal delivery delay and the corresponding optimal service preferential price of each user which enables the profit of the base station to be maximized; And when responding to the file requests of the users, the base station waits for the corresponding optimal delivery delay for each file requested by the user to deliver.
2. The method of claim 1, wherein solving the base station profit maximization problem further comprises: solving the candidate delivery delays meeting the QoE constraint of the user to obtain a candidate delivery delay set of each user; And combining the candidate delivery delay set of each user, converting the base station profit maximization problem into an active user set allocation problem, and solving the active user set allocation problem to obtain the optimal delivery delay and the corresponding service preferential price for maximizing the base station profit.
3. The method according to claim 2, characterized by comprising: constructing a first function according to the difference between the user QoE constraint and a given minimum user QoE; If the first function corresponding to the delivery delay threshold is smaller than or equal to zero, enumerating all delivery delays meeting the first function of larger than or equal to zero as candidate delivery delays for a range of which the delivery delay is smaller than or equal to the delivery delay threshold; And for the range that the delivery delay is greater than the delivery delay threshold, the delivery delay is increased by taking one as a step length, the corresponding first function is calculated, when the first function is greater than or equal to zero, the corresponding delivery delay is taken as the candidate delivery delay, and if the first function is less than or equal to zero, the enumeration is ended.
4. The method of claim 3, wherein the delivery delay threshold is a delivery delay corresponding to a maximum price discount allowed for a given market, and wherein the user QoE constraint is a decreasing function of the delivery delay when the delivery delay is greater than the delivery delay threshold.
5. The method of any one of claims 1-4, wherein the first sub-constraint is expressed as Wherein Q d (τ k ) represents a first sub-constraint, τ k is a delivery delay of a file requested by user k, and alpha, beta, gamma are all influencing parameters, and alpha, beta, gamma >0.
6. The method of claim 5, wherein the price satisfaction is related to a service offer price and a user subjective desired price, the price satisfaction being expressed as Wherein, the Representing a service offer price requested by a user k file given a delivery delay τ k , the service offer price being a difference between a service original price and a service discount; representing subjective expected price of user, delta k is satisfaction degree of user to price Delta k is related only to user k itself, is independent of delivery delay τ k , and delta k >0; The second sub-constraint is expressed as Wherein, the And g, h is a fixed parameter, g, h >0.
7. The method according to any of claims 1-4, wherein the service revenues of the base station are expressed as Where R BS (p pref ) represents the service revenue of the base station, p pref is a service offer price vector, The service preferential price is the service original price p 0 and the service discount Is a difference in (2); The service cost of the base station is expressed as Wherein C BS (τ) represents the cost of service of the base station, the delivery delay vector τ= [ τ 1 ,...,τ k ,...,τ K ],L d (τ) is the delivery load of the given delivery delay vector τ, The cost required for unit load transfer. The profit of the base station is expressed as P BS (p pref ,τ)＝R BS (p pref )-C BS (τ), Where P BS (p pref , τ) represents the base station profit.
8. The method of claim 2, wherein translating the base station profit maximization problem into an active user set allocation problem comprises: According to the time slot of each user's file request reaching the base station and the delivery delay of the base station to the file request, obtaining the delivery time slot of the file request, dividing the users belonging to the same delivery time slot into the same active user set; And calculating the utility of the active user set of each delivery time slot, and decomposing the profit of the base station into the sum of the effects corresponding to the active user sets of all the delivery time slots to obtain the allocation problem of the active user set, wherein the utility is the difference between the service income and the service cost which can be obtained by file delivery provided by the base station for the users in the active user set of the delivery time slot.
9. The method of claim 8, wherein solving the active user set allocation problem to obtain an optimal delivery delay and corresponding service benefit price that maximizes base station profit comprises: Dividing the active user set allocation problem into a plurality of sub allocation problems by adopting a dynamic programming method; And determining the maximum base station profit corresponding to the allocation problem of the active user set and the corresponding optimal delivery delay vector by solving the maximum utility corresponding to each sub allocation problem, and obtaining the optimal delivery delay and the corresponding service preferential price corresponding to each user.
10. An asynchronously encoded cached file distribution apparatus comprising: A user QoE constraint construction module, configured to establish a user QoE constraint on a delivery delay and a service offer price, where the user QoE constraint includes a first sub-constraint based on the delivery delay and a second sub-constraint based on the service offer price, where the second sub-constraint considers a price satisfaction of a user with respect to the corresponding service offer price for each user's file request given the corresponding delivery delay; The base station profit determining module is used for determining the profit of the base station according to the difference between the service income of the base station and the service cost of the base station, wherein the service income of the base station is determined according to the service preferential price, and the service cost of the base station is determined according to the delivery delay; The base station profit maximization problem determination module is used for constructing a base station profit maximization problem by taking the maximization of the profit of the base station as an objective function based on the QoE constraint of the user; The solving and optimizing module is used for solving the problem of maximizing profit of the base station and obtaining the optimal delivery delay and the corresponding optimal service preferential price of each user which maximizes profit of the base station; And the delivery execution module is used for responding to the file requests of the users, and the base station waits for the corresponding optimal delivery delay for each user file request to deliver.
11. A computer readable storage medium, on which a computer program is stored, characterized in that the computer program, when being executed by a processor, implements the steps of the method of any of claims 1-9.
12. A computer program product comprising a computer program, characterized in that the computer program, when executed by a processor, implements the steps of the method of any of claims 1-9.

Description

Asynchronous coded cache file distribution method and device Technical Field The present invention relates to the field of wireless communications, and in particular, to a method and an apparatus for distributing an asynchronously encoded cache file. Background The ever-increasing video file transmission demands for future 6G network everything interconnection and cloud network side resource sharing bring huge pressure to the capacity of the mobile cellular network. How to reduce the load pressure of communication transmission and meet the explosive demands of traffic is one of the key research directions to be explored. The caching mechanism stores part of video to the network edge in advance in the low peak period of the traffic, and is a widely applied method for reducing traffic load in the peak period. In general, the file delivery process of a cache-enabled wireless communication system consists of two phases, a content placement phase and a file delivery phase. In the content placement phase, the base station pre-caches part of the file in the user's local storage. In the file delivery phase, if a user's file request is hit by its local store, content may be directly extracted from its local store. Otherwise, the base station delivers the user file request through the wireless network. In order to relieve the load pressure of wireless communication transmission, the prior art adopts a coding buffer mechanism. In the file delivery phase, the code caching mechanism delivers the file request of the user through a transmission mode of code multicasting. The coding multicast process is that based on the network coding mode, the base station firstly builds the coding multicast message between users by creating the coding multicast opportunity between users, and then transmits the built coding multicast message to the users in the built coding multicast group through the coding multicast link. A significant feature of the coded caching mechanism is that the coded caching mechanism can complete delivery of multiple user file requests within a coded multicast group by transmitting one coded multicast message even though the user file requests are different. When the encoded multicast message is received, the user may decode the encoded multicast message with the aid of the locally stored content to recover the file content that he requested. Compared with the traditional caching mechanism based on unicast, the coding caching mechanism can remarkably reduce the traffic load of a file delivery stage. However, in practical systems, the user request is asynchronous. The user asynchronous request may reduce the encoded multicast gain because in the case of an asynchronous request, the encoded multicast opportunities between multiple users are reduced. In order to increase the code multicast opportunity in the asynchronous request scene, the base station generally adopts a file request delay delivery method, namely, the base station delays the user file request for a certain time and then delivers the file request, thereby improving the code multicast opportunity between the first user and the second user, and further reducing the file delivery load of the asynchronous code cache. But the asynchronous coded caching mechanism based on the file request delay delivery method increases the user file request delivery delay, which reduces the user experience quality (Quality ofExperience, qoE, hereinafter referred to as user QoE). Disclosure of Invention In order to overcome the defects of the prior art, the invention provides a file distribution method, a system, a storage medium and a computer program product of asynchronous code cache, which realize the balance of file delivery profit and user QoE while guaranteeing the user QoE. The invention provides a file distribution method of asynchronous code cache, comprising the following steps: Establishing user QoE constraint about delivery delay and service preferential price, wherein the user QoE constraint comprises a first sub constraint based on the delivery delay and a second sub constraint based on the service preferential price, the second sub constraint considers price satisfaction degree of each user file request to the corresponding service preferential price when the delivery delay is given, base station profit is determined according to the difference value of service income of the base station and service cost of the base station, the service income of the base station is determined according to the service preferential price, the service cost of the base station is determined according to the delivery delay, the base station profit maximization problem is constructed by taking the maximized base station profit as an objective function based on the user QoE constraint, the base station profit maximization problem is solved, the optimal delivery delay and the corresponding optimal service preferential price of each user which enables the base station profit to