KR20170103255A - Method, program and recoding medium for d2d-based content caching service - Google Patents

Abstract

The present invention relates to a wireless communication technique. More specifically, the present invention relates to a method for caching content in a user terminal device by using a gossiping technique, a computer program performing the same and recording media storing the program, based on device to device (D2D). To this end, according to an embodiment of the present invention, the method for caching content by a user terminal device comprises the following steps: collecting a content request generated from the user terminal device and a content request generated by another user terminal device capable of communicating with the user terminal device; storing a content request record with respect to the collected content requests; receiving the content; and performing caching of the received content based on the content request record.

Description

TECHNICAL FIELD [0001] The present invention relates to a content caching method based on a D2D, a computer program for performing the method, and a recording medium on which a program is recorded. [0002] METHOD, PROGRAM AND RECORDING MEDIUM FOR D2D- BASED CONTENT CACHING SERVICE [

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to a wireless communication technology, and more particularly, to a method of caching a content to a user terminal device using a gossiping technology based on direct communication between devices (device to device, D2D) A computer program for executing the program, and a recording medium storing the program.

The contents described in this section merely provide background information on the present embodiment and do not constitute the prior art.

With the recent advancement of smartphones and the development of content transmission technologies, there has been an increase in services for delivering large-volume content such as online video services such as video on demand (VOD) and live streaming, music streaming, file uploading and file downloading .

As the number of content providers and content users increases, the traffic of the mobile communication network is increasing. As the traffic increases, the transmission speed of the contents decreases, and the problem of degradation of the service quality due to the degradation of the contents transmission speed becomes an issue. Thus, there is a need to reduce unnecessary traffic in the mobile communication network.

Accordingly, efforts are being made to reduce gradually increasing traffic. As part of this effort, mobile network holders are providing CDN (Content Delivery Network) services. The CDN service is for delivering various contents including moving pictures such as movies and music videos to users in a stable manner. In general, contents are stored in a plurality of local caching devices distributed on a network, and GLB (Global Load Balance) An optimal cache server among a plurality of cache servers is selected through a load balancing device such as a server, and the requested content is transmitted to the user terminal device through the selected cache server. In addition, the CDN service is implemented to solve an unstable state such as data loss, bottleneck, transmission speed degradation, and data interruption on the Internet based on the Internet network.

Among the CDN services, the recently proposed mobile peer assisted CDN service includes a D2D link and a user terminal device that operate as a cache node and connect between user base stations and a plurality of user base stations connected to the base station, And may provide the cached content to the user terminal device or the base station via the BS link connecting the base stations.

As described above, in the case of the D2D-based CDN service, since the user terminal serves as a cache node, a part of the internal storage space must be allocated as a cache for providing contents. However, it is a reality that the cache capacity that can be provided by the user terminal device is relatively small as compared with the caching device connected to the base station. When the cache capacity is small, the capacity of the storable contents is limited. Accordingly, the case where the capacity of the cache is filled up frequently due to the user terminal receiving a large number of contents, cache replacement must be performed to delete contents stored in the cache and receive new contents .

However, when there is no predetermined rule for deleting the stored content at the time of caching replacement (for example, when the probability of deletion of the content is the same regardless of the frequency of the request in the cache of the user terminal device) There is a high possibility that the content is frequently deleted from the cache of a plurality of user terminal devices, and in this case, the cache hit rate may be significantly lowered.

As the cache hit rate is lowered, a plurality of user terminal apparatuses repeatedly receive, cache, and delete contents. This increases the congestion of content transmission, which causes performance degradation of the content service.

In addition, contents requested by other terminals may vary depending on the location or the surrounding environment of the user terminal device. However, in the existing caching management technique, it is difficult to adaptively manage the contents in consideration of this.

Accordingly, in a user terminal device having a limited cache capacity, there is a need for a scheme for controlling a cache hit rate by controlling so that a highly popular content is not deleted from the cache, depending on the location of the user terminal device or the surrounding environment.

Korean Patent Laid-Open Publication No. 10-2015-0109976, published on October 02, 2015 (name: Scheduling method and apparatus for inter-device communication)

The present invention provides a reactive method of caching using D2D-based content caching policies using an IP sharing technology.

More specifically, it is an object of the present invention to improve the service quality of a content transmission service by reducing caching of content having a high popularity and lowering the congestion of content transmission by performing caching based on a request record of the content.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, unless further departing from the spirit and scope of the invention as defined by the appended claims. It will be possible.

The present invention provides, as a means for solving the above-mentioned problems, a content caching method by a user terminal device, the content caching method comprising the steps of: receiving a content request generated by the user terminal device, ; Storing a content request record for the collected content request; Performing caching of the received content based on the content request record upon receiving the content; And a content caching method.

More specifically, the content request record may include at least one of a number of requests for each content, a request time, a content request subject, and a content capacity.

According to another aspect of the present invention, there is provided a method comprising: comparing a remaining capacity of a cache with a capacity of the received content; If the remaining capacity of the cache is smaller than the capacity of the content, deleting any one of the contents previously stored in the cache based on the content request record; And a content caching method.

The present invention further provides a computer readable recording medium on which a program for executing the content caching method as described above is recorded, and a computer program stored in the recording medium.

According to the present invention, a user terminal device based on D2D performs caching based on a request recording of contents by providing a reactive caching method using content provisioning technology in performing content provision and caching Thus, it is possible to reduce deletion of highly popular content and reduce the congestion of content transmission, thereby improving the service quality of the content transmission service.

The effects obtained in the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the following description .

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the technical features of the invention.
Figure 1 is a schematic representation of an existing content delivery system (CDN) that is not based on D2D.
2 is a block diagram schematically illustrating an existing content delivery system (CDN) based on D2D.
3 is a diagram schematically showing a network structure of a content transmission system based on D2D.
4 is a block diagram of a content transmission system based on D2D.
5 is a diagram for explaining a content transmission service according to an embodiment of the present invention
FIG. 6 is a diagram schematically illustrating a state in which a content request is collected by using a shuffling technique according to an embodiment of the present invention.
FIG. 7 is a table structure diagram in which a content request record according to an embodiment of the present invention is stored.
8 is a block diagram illustrating a user terminal device performing a content caching method according to an embodiment of the present invention.
9 is a flowchart illustrating a content caching method according to an embodiment of the present invention.
FIG. 10 is a flowchart illustrating a step of performing caching in a content caching method according to an exemplary embodiment of the present invention.
FIG. 11 is a flowchart illustrating a content caching method according to an exemplary embodiment of the present invention, more specifically illustrating a step of deleting content previously stored in a cache based on a content request record.

BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding of the nature and advantages of the present invention, reference should be made to the following detailed description taken in conjunction with the accompanying drawings, in which:

In the following description and the accompanying drawings, detailed description of well-known functions or constructions that may obscure the subject matter of the present invention will be omitted. It should be noted that the same constituent elements are denoted by the same reference numerals as possible throughout the drawings.

Also, terms including ordinal numbers such as first, second, etc. are used to describe various elements, and are used only for the purpose of distinguishing one element from another, Not used. For example, without departing from the scope of the present invention, the second component may be referred to as a first component, and similarly, the first component may also be referred to as a second component.

In addition, when referring to an element as being "connected" or "connected" to another element, it means that it can be connected or connected logically or physically. In other words, it is to be understood that although an element may be directly connected or connected to another element, there may be other elements in between, or indirectly connected or connected.

It will also be understood by those skilled in the art that in the context of describing the invention (particularly in the context of the following claims), the terms " a or an, ""Quot; or " include ", unless the context clearly dictates otherwise.

It is also to be understood that the terms such as " comprising "or" having ", as used herein, are intended to specify the presence of stated features, integers, It should be understood that the foregoing does not preclude the presence or addition of other features, numbers, steps, operations, elements, parts, or combinations thereof.

Also, the terms " part, "" module," and " module ", etc. in the specification mean a unit for processing at least one function or operation and may be implemented by hardware or software or a combination of hardware and software have.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of caching contents on a user terminal device using a gossiping technique based on direct communication between devices (device to device, D2D).

Hereinafter, a content caching method according to the present invention will be described with reference to FIGS. 1 to 11 based on a wireless communication environment.

In the following description, a user terminal device refers to a user device capable of connecting to a wireless communication network provided by the present invention and transmitting / receiving various data. Here, the user terminal may be a terminal, a user equipment (UE), a mobile station (MS), a mobile subscriber station (MSS), a subscriber station (SS), an advanced mobile station (AMS) (MTC), a machine-to-machine (M2M) device, a device-to-device (D2D) device, a station (STA), or the like. However, the present invention is not limited to this, and it may correspond to a user terminal device described in this specification as long as it is an apparatus connected to a wireless communication network provided by the present invention. A unit of the same level as the above-mentioned units may be used as the user terminal according to the present invention.

The user terminal device of the present invention can perform voice or data communication through the wireless communication network provided by the present invention. The user terminal device of the present invention includes a browser for transmitting and receiving information, a memory for storing a program and a protocol, And a microprocessor for calculating and controlling the microprocessor.

The user terminal device according to the embodiment of the present invention can be implemented in various forms. For example, the user terminal device described in this specification may be applied to a wireless communication technology such as a smart phone, a tablet PC, a PDA (personal digital assistant), a portable multimedia player (PMP) May be used.

In the present invention, a base station refers to a device connected to one or more user terminal devices via radio resources to transmit and receive data. For example, a base station (BS) includes a node B, An access point (AP), a radio access station (RAS), a base transceiver station (BTS), a mobile multihop relay (MMR) And may include all or some of the functions of Node B, eNodeB, AP, RAS, BTS, MMR-BS, and the like. It may also be implemented with a base station controller such as a base station controller (BSC) and a radio network controller (RNC). The base station may transmit a radio signal to the user terminal, and more specifically, may allocate and transmit one or more radio signals with different frequency or time resources, respectively.

1 is a diagram schematically illustrating a content transmission system not based on D2D.

As shown in FIG. 1, a conventional content transmission service is performed between a base station 400 and a user terminal device 100.

1 illustrates an example in which a base station 400 has communication coverage in an area such as a dotted line and a user terminal device 100 is located in a communication coverage and the uplink / Signal transmission / reception.

The portion indicated by the dashed line indicates the local communication area of each user terminal device 100, and indicates that each of the user terminal devices 100 is located in an area capable of short distance communication with each other.

In the conventional content caching method, the user terminal device 100 can only receive contents service from the base station 400 or use the contents stored in the internal memory of each user terminal device 100 itself, The contents are not provided between the terminal devices 100. [

2 is a block diagram illustrating an existing content transmission system not based on D2D.

The content transmission service not based on D2D is composed of a user terminal device 100, a local caching device 200, and a content providing device 300 which are connected through a communication network 500.

The user terminal device 100 is a terminal device of a user who is connected to the communication network 500 and utilizes the content provided through the communication network 500. The user terminal device 100 requests a specific content from the content providing device 300, And receives the content transmitted from the providing apparatus 300 or the local caching apparatus 200.

The local caching device 200 may be distributed to the communication network 500 to store the content provided by the content providing device 300 temporarily or for a predetermined period of time and if the content is requested from the user terminal device 100, Instead of the content providing apparatus 300, the content stored in the terminal apparatus 100 is provided. To this end, the local caching device 200 performs a caching operation of copying and storing a part or all of the content provided to the user terminal device 100 from the content providing device 300 using various caching techniques. 2, the local caching device 200 is shown as one, but the local caching devices 200 may be distributed in the communication network 500 or may be installed together with the base stations 400.

The content providing apparatus 300 is a service providing apparatus that provides various contents including a random content, for example, a moving picture file, an audio file, a web page, etc., through a communication network 500 in a streaming or downloading manner. Such a content providing apparatus 300 may be, for example, a video sharing site allowing uploading, viewing, or sharing of a paid or free video, an application store capable of freely trading mobile contents, And may be a server apparatus for providing IPTV or the like.

The communication network 500 refers to a network capable of transmitting and receiving data using an Internet protocol using various wired and wireless communication technologies such as an Internet network, an intranet network, a mobile communication network, and a satellite communication network.

In addition, the communication network 500 is combined with the content providing apparatus 300 or the local caching apparatus 200 to store computing resources such as hardware and software. The communication network 500 may be a closed network such as a LAN (Local Area Network) or a WAN (Wide Area Network), an open network such as the Internet, a Code Division Multiple Access (CDMA), a Wideband Code Division Multiple Access), Global System for Mobile Communications (GSM), Long Term Evolution (LTE), Evolved Packet Core (EPC), and next generation networks and computing networks to be implemented in the future.

In addition, the communication network 500 of the present invention includes, for example, a plurality of access networks (not shown) and a core network (not shown), and may include an external network such as an Internet network (not shown).

The present invention provides, in addition to the system as shown in FIG. 2, a content transmission system that allows a further provision of content services between user terminal devices 100. [

Hereinafter, a D2D-based content transmission system and a content caching method according to the present invention will be described with reference to FIG. 3 to FIG.

3 is a diagram schematically illustrating a content transmission system based on D2D.

As shown in FIG. 3, content transmission according to the present invention is performed between the base station 400, the user terminal device 100, and each user terminal device 100.

The dotted line and the one-dot chain line represent the communication coverage of the base station 400 and the user terminal device 100, respectively, as described with reference to FIG. Referring to FIG. 3, each user terminal 100 is located within the wireless communication coverage of each other, and can perform mutual D2D contents transmission service.

Various short-range communication technologies such as Bluetooth, Zigbee, Ultra-WideBand (UWB), ANT, Wi-Fi, and NFC may be used as the wireless communication method between the user terminal devices 100 for content transmission.

The content transmission service between the user terminal devices 100 does not go through the base station 400 and the user terminal device 100 operates as a server of the content delivery network.

4 is a block diagram illustrating a content transmission system based on D2D.

Referring to FIG. 4, a plurality of user terminal devices 100a, 100b, and 100c are located in communication coverage within one base station 400, and the base station 400 and the user terminal devices 100a, 100b, and 100c (BS connection, BS link), and connection (D2D connection, D2D link) between the user terminal devices 100a, 100b, and 100c may be performed. At this time, the BS connection and the D2D connection can be made by different communication protocols.

The content providing apparatus 300 is connected to the base station 400 as described with reference to FIG. 2, and serves as a source server for providing contents. The local caching device 200 may be connected to the base station 400 or may be included in the base station 400 to form a part of the base station 400.

The CDN (Content Delivery Network) control server 600 is a means for managing a plurality of local caching devices 200 distributed in a communication network 500 and controlling the process of delivering content by the plurality of local caching devices 200 The content providing apparatus 300 transmits the content request message of the user terminal apparatuses 100a, 100b and 100c to the content providing apparatus 300, receives the content data provided from the content providing apparatus 300, 100b and 100c at the local caching device 200. When it is confirmed that the content is cached in the specific local caching device 200, the content provision to the user terminal device 100a, 100b, As shown in Fig.

In addition, in the contents transmission system according to the present invention, it is also possible to provide contents among the respective user terminal devices 100a, 100b and 100c. Accordingly, the CDN control server 600 can perform request routing to determine a content providing path according to a content providing request message of the specific user terminal device 100a. In addition, it is possible to appropriately schedule the content providing order according to the content request of each of the user terminal devices 100a, 100b, and 100c in order to prevent the content traffic accumulation and effectively distribute the communication resources.

A content service procedure that can occur under such a system will be described with reference to FIG.

In Fig. 5, the dotted arrow is a message requesting content, and the solid arrow is content data providing content.

Hereinafter, the adjacency of two user terminal devices means that both user terminal devices are within a range where direct wireless communication is possible.

5A shows a case where a content requested by a specific user terminal device 100a is stored in an internal cache of the user terminal device 100a. This is called a local hit, and the user terminal device 100a requests and uses the content stored in its cache.

5B shows a case where a content requested by a specific user terminal device 100a can be received from an adjacent user terminal device 100b and is referred to as a D2D hit (D2D hit) The adjacent user terminal device 100b provides the content in accordance with the content request message of the user terminal device 100a.

In addition, when there is another user terminal device 100c capable of communicating with the adjacent user terminal device 100b, the content request message generated in the user terminal device 100a is transmitted to the other user terminal device 100c , It is also possible that the other user terminal device 100c provides the contents. The other user terminal device 100c transmits the content to the specific user terminal device 100a via the adjacent user terminal device 100b or transmits the content request to the specific user terminal device 100a.

5C shows a case where the content requested by the specific user terminal 100a exists in the local caching apparatus 200 located at the base station 400 and is called a BS hit, And receives content data from the base station 400 that has received the content request message of the user terminal device 100a.

As described above with reference to FIG. 4, the content request routing can be performed according to the determination of the CDN control server 600. [

In this content service procedure, a local hit or a D2D hit serves as a kind of cache server in which each of the user terminal devices 100a and 100b provides contents. To do so, a part of the storage space in the user terminal device 100 must be allocated as a cache for storing contents. At this time, the storage space of the user terminal device 100 is limited as compared with the local caching device 200 or the content providing device 300 that can be separately installed, and cache replacement is required to manage the storage space.

Each of the user terminal devices 100 performs caching of the content requested by itself or the content passed through it. In this case, the capacity of the cache may become insufficient. In this case, the caching replacement is performed according to a certain priority.

At this time, the reference information for determining the priority is the request record for each content. Hereinafter, the content of the request record and the collecting process will be described with reference to FIGS. 6 and 7. FIG.

FIG. 6 is a view schematically showing a step in which a user terminal device 100a collects content requests of different user terminal devices 100b, 100c and 100d using a gossiping technique according to the present invention.

The SHIP scheme is used to solve the problem that can be caused by not accurately grasping the content request information. In the user terminal apparatuses 100a, 100b, and 100c using the SHIP technique, If a data packet to be transmitted to another user terminal device is received, it is possible to transmit a unicast packet according to an arbitrary routing policy, the data is transmitted in a unicast format.

For example, if all of the user terminal devices are in a range capable of direct wireless communication, the specific user terminal device 100a may be a neighboring user terminal device 100b or 100c ) By directly receiving the content request message of the content request message.

The contents request message transmitted by the user terminal device 100d not located within one hop from the specific user terminal device 100a can be shipped by all the adjacent user terminal devices 100b and 100c, The content request message transmitted by the user terminal device 100d of the user terminal devices 100b and 100c is transmitted to the user terminal device that has sent the content request message and the specific user terminal device 100a located within one hop, The content server 100a may collect the content request from the user terminal device 100d that is not located within the one hop.

The request records for the collected content requests are accumulated and stored in the specific user terminal device 100a. The contents of the request record will be described with reference to FIG.

FIG. 7 is an exemplary diagram illustrating items that can be stored in a request record according to the present invention in the form of a table.

Referring to FIG. 7, since the request recording according to the present invention may include at least one of a request subject, a request count, a request time, and a content capacity of each content, the information stored in the request record at the time of caching replacement is utilized.

The content ID is for identification of each content and may be an arbitrary ID given by the content providing apparatus 300 or may be a prefix information of a predetermined length in the contents of the content, And may be one of a hash value calculated by a function or a metadata of the corresponding content.

The requesting entity is recorded in the user terminal device 100 requesting the corresponding content. The requesting entity can be briefly stored as the requesting entity itself and the other terminal device as shown in FIG. 7, or can be simply stored in the IP address or MAC MAC) address of the user terminal device.

The number of requests is the number of times a request for the content has occurred, and the latest request time is a record of the latest time when the request for the content occurred. The number of requests and the latest request time can be stored by distinguishing the request subject. The time shown in FIG. 7 is recorded as the concept of hour, minute, and second, but it is possible to further store the request date or the day of the week.

Capacity represents the amount of memory the content occupies in the cache.

If the remaining capacity of the cache is smaller than the capacity of the newly received content, the user terminal 100 can perform caching of the newly received content after deleting any of the previously stored contents based on the request record .

The criterion for deleting the content may be variously set by the service provider.

For example, the pre-stored content can be deleted based on the number of requests. At this time, it is possible to simply delete the content having the smallest total number of requests. In this case, content number 11003 with the smallest number of requests is deleted.

Alternatively, the number of requests can be utilized by identifying the subject of the content request. That is, by applying a different weight to each of the number of requests of the user terminal device performing the content caching and the number of requests of the other user terminal devices, the content having a high request rate of the user terminal device performing the content caching is deleted On the contrary, it is possible to delete a content having a high request rate of the other user terminal device.

As another example, it is possible to delete the content having the largest difference between the recent request time and the current time, based on the latest request time. In this case, content 11003, which is the oldest requested time, is deleted.

In this case, it is also possible to delete the content based on only the latest request time of the user terminal itself performing the content caching by distinguishing the content request subject, or delete the content based on only the latest request time of the other user terminal.

In addition, it is possible to calculate a result value by assigning different weights to the request frequency and the latest request time, and delete the content based on the result value. A more detailed description of weighting and calculation of result values will be given later.

The deletion of the pre-stored contents increases the remaining capacity of the cache. However, even if one of the pre-stored contents is deleted, the capacity of the content to be received may be larger than the remaining capacity of the cache. In this case, the content is deleted until the remaining capacity of the cache becomes equal to or greater than the capacity of the received content Can be repeatedly performed.

In another embodiment, it is possible to preferentially delete a content having a larger capacity than the content that generated the content request, among the pre-stored content, in order to prevent repeated deletion of the pre-stored content.

Thus, an example of a caching replacement method according to the present invention has been briefly described.

Hereinafter, a structure of a user terminal device 100 that performs a content caching method according to the present invention will be described.

FIG. 8 is a block diagram illustrating a user terminal device 100 that performs a content caching method according to the present invention.

Referring to FIG. 8, a user terminal 100 according to the present invention may include a communication unit 100, a storage unit 120, and a control unit 130.

The communication unit 110 is a means for receiving data from an external source and transmitting data to an external source, such as a network interface card and a corresponding Network Driver Interface Specification ("NDIS") stack May be represented by a logical combination of one or more software and / or hardware modules.

The communication unit 110 may support various communication protocols. For example, it can support various mobile communication standards such as AMPS, CDMA, GSM, W-CDMA, HSDPA, LTE and LTE-A and can also support short-range wireless network technologies such as BLE and Zigbee.

Particularly, in the present invention, the communication unit 110 can transmit / receive data to / from the base station 400 or another user terminal device via the communication network 500, and can access the communication network 500 according to a mobile communication standard, And a mobile communication module for performing the method. The data to be transmitted and received includes a content request message and content data transmitted in accordance with the content request message.

The storage unit 120 is a structure for storing data or programs executed or processed by the control unit 130. [ Basically, the storage unit 120 stores an operating system (OS) for operating each of the above-described configurations of the user terminal 100, various user functions such as a call of the user terminal 100 A user function for supporting functions, an MP3 user function for playing other sound sources, an image output function for playing back images such as photographs, and an application program for supporting a moving image playback function, respectively.

The storage unit 120 may be an optical storage medium such as a magnetic medium such as a hard disk, a floppy disk, and a magnetic tape, a compact disk read only memory (CD-ROM), and a digital video disk (DVD) A magneto-optical medium such as a floppy disk and a ROM, a random access memory (RAM), and a flash memory.

In particular, in the present invention, the storage unit 120 may store an application or a computer program for performing the content caching method according to the present invention.

In addition, the storage unit 120 according to the present invention includes a cache 121 for storing contents so that the user terminal device 100 operates as a cache server. In addition, the cache 121 includes a content request record 122 for performing efficient caching replacement. As described with reference to FIG. 7, the content request record 122 may store at least one of a content-based request subject, a request count, a recent request time, and a capacity.

The control unit 130 is configured to perform overall control of the user terminal device 100, and may be implemented with one or more processors. The processor may be a single-threaded processor, and in other embodiments, the processor may be a multithreaded processor.

Further, the control unit 130 can operate by processing the instructions stored in the storage unit 120 via the one or more processors. The instructions may include interpreted instructions or executable code such as, for example, JavaScript or ECMAScript commands, or other instructions stored in a computer-readable medium.

In particular, in the present invention, the control unit 130 controls the communication unit 110 to transmit and receive a data packet including a content request or a content itself to another user terminal device using a program stored in the storage unit 120 can do. That is, the control unit 130 operates according to the application logic stored in the storage unit 120 or the service logic of the computer program to perform the content caching method according to the present invention.

The control unit 130 includes a packet receiving module 131, a service processing module 132, and a cache processing module 133.

The packet receiving module 131 is connected to the communication unit 110 and is configured to receive a content request packet or a content packet from another user terminal. If the received packet includes a content request, the packet receiving module 131 may extract the content request and store it in the request record. If the received packet contains the content itself, the packet receiving module 131 may transmit the content to the cache processing module 133, Can be transmitted.

The cache processing module 133 receives the content transmitted by the packet receiving module 131 and performs caching. At this time, the cache processing module 133 may perform caching replacement using the request recording 122 in the storage unit 120. [

The service processing module 132 is configured to execute the received content and make it available to the user. The service processing module 132 executes the content received from the packet receiving module 131 and provides the content to the user.

The structure of the user terminal device 100 that performs the content caching method according to the present invention has been described above.

More specific operations of the user terminal device 100 will be more clearly understood through the flowcharts shown in FIGS. 9 to 11. FIG.

9 is a flowchart illustrating a content caching method according to the present invention.

Referring to FIG. 9, first, the user terminal 100 collects a content request generated by the user terminal 100 itself or a content request generated by another user terminal 100 capable of communicating with the user terminal 100 (S900), and stores the content request record of the collected content request in the storage unit 120 (S902).

Here, the other user terminal includes an adjacent user terminal located within a distance that enables wireless communication with the user terminal 100, or a user terminal capable of communicating through the adjacent user terminal.

Thereafter, or concurrently with this, when a content request is generated by the user terminal device 100 itself or when a content to be passed through the user terminal device 100 is received (S904) And performs caching of the received content based on the received content (S906).

FIG. 10 is a flowchart specifically showing a step of performing caching in the content caching method shown in FIG.

10, the user terminal 100 receives the content (S1000), compares the remaining cache capacity in the user terminal device 100 with the capacity of the content to be received (S1002), and updates the remaining cache capacity If the received content is equal to or larger than the content size to be received, the content is stored in the cache (S1004). On the other hand, if the remaining cache capacity is less than the content size to be received, the content stored in the cache is deleted based on the content request record (S1006).

After deleting the content, the user terminal device 100 again performs step S1002 of comparing the remaining cache capacity with the capacity of the content to be received, and repeats step S1004 or step S1006 according to the comparison result.

FIG. 11 is a flowchart illustrating an embodiment of a process of deleting content previously stored in the cache based on the content request record of FIG. 10.

Referring to FIG. 11, the user terminal 100 extracts a content request record of previously stored content (S1100), and determines the number of times requested by the user terminal 100 itself, The number of requests by the device is extracted (S1102). Here, the number of requests by the user terminal device 100 itself is a, and the number of requests by other user terminal devices is b.

Thereafter, the user terminal device 100 calculates a request-by-content ratio x (S1104). Here, if the weight of the number of requests by the user terminal device 100 itself is? And the weight of the number of requests by other user terminal devices is?

As shown in Fig. Here, the weights a and b may be arbitrary values according to the policy of the content provider. If? is large, the proportion of the content requested by the user terminal device 100 itself is reflected in the deletion of the requested content. If? is large, the proportion of the content requested by the other user terminal device is reflected to be high, Lt; / RTI >

Then, the user terminal device 100 deletes the content having the largest value of x or the smallest content (S1104). If the user terminal device 100 intends to establish a policy for not deleting a content having a large number of times requested by the user terminal device 100, the weight β may be given a relatively large value so that the proportion of b to the calculated number of requests x may be reflected to be high . In this case, the larger the x value is, the more content is requested by another user terminal device, so that the content having the largest request rate x can be deleted. On the other hand, when a policy is set to delete content having a large number of times requested by the other user, the content having the smallest request rate x can be preferentially deleted.

In addition, it is also possible to perform operations by assigning different weights to each item of the content request record, that is, the request subject, the request count, the request time and the capacity, and delete the content based on the result value (popularity). If the result is y,

And so on.

Where c is the number of times the content is requested, d is the difference between the current time of the content and the current time, and e is the capacity of the content. The number of times of requesting the content and the latest request time may be values reflecting the weight according to the request subject through the calculation process shown in FIG. γ, δ, and ε are weights arbitrarily assigned according to the caching policy.

The operation of the user terminal 100 according to the embodiment of the present invention has been described with reference to the flowcharts.

Although the present specification and drawings illustrate exemplary device configurations, implementations of the functional operations and the subject matter described herein may be embodied in other types of digital electronic circuitry or include structures and their structural equivalents disclosed herein Firmware, or hardware, or a combination of one or more of the foregoing. Implementations of the subject matter described herein may be embodied in one or more computer program products, that is, a computer program product encoded on a type of program storage medium for execution by, And can be implemented as a module as described above. The computer-readable medium can be a machine-readable storage device, a machine-readable storage substrate, a memory device, a composition of matter that affects the machine readable propagation type signal, or a combination of one or more of the foregoing.

While the specification contains a number of specific implementation details, it should be understood that they are not to be construed as limitations on the scope of any invention or claim, but rather on the description of features that may be specific to a particular embodiment of a particular invention Should be understood. Certain features described herein in the context of separate embodiments may be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented in multiple embodiments, either individually or in any suitable subcombination. Further, although the features may operate in a particular combination and may be initially described as so claimed, one or more features from the claimed combination may in some cases be excluded from the combination, Or a variant of a subcombination.

Likewise, although the operations are depicted in the drawings in a particular order, it should be understood that such operations must be performed in that particular order or sequential order shown to achieve the desired result, or that all illustrated operations should be performed. In certain cases, multitasking and parallel processing may be advantageous. Also, the separation of the various system components of the above-described embodiments should not be understood as requiring such separation in all embodiments, and the described program components and systems will generally be integrated together into a single software product or packaged into multiple software products It should be understood.

Thus, although the present invention has been described in detail with reference to the above examples, those skilled in the art will appreciate that various modifications, changes, and modifications can be made thereto without departing from the scope of the present invention.

Therefore, the scope of the present invention should not be limited by the described embodiments but should be defined by the claims.

INDUSTRIAL APPLICABILITY The present invention is applicable to a CDN for a wireless communication network and can be used industrially as a method for implementing content caching in various communication systems.

According to the present invention, in performing caching replacement at the time of content caching, the content request of the adjacent user terminal is collected by using the shuffling, caching based on the request record of the content is performed, and the deletion of the content with high popularity is reduced Congestion of content transmission can be lowered.

Through the reactive caching, the content caching service provider can improve the service quality of the content transmission service due to the congested content transmission, and can contribute to the development of the service industry soon. In addition, Is not only sufficient but also practically possible to be practically used.

100, 100a, 100b, 100c, 100d:
200: Local caching device
300: Content providing device
400: base station
500: Network
600: CDN control server

Claims (12)

A method of content caching by a user terminal device,
Collecting a content request generated by the user terminal and a content request generated by another user terminal capable of communicating with the user terminal;
Storing a content request record for each content based on the collected content request;
Performing caching of the received content based on the content request record upon receiving the content;
Lt; / RTI > The method according to claim 1,
The other user terminal device
A neighboring user terminal device located within a distance where wireless communication is possible or a user terminal device capable of communicating through the adjacent user terminal device. The method according to claim 1,
The content request record
A requesting time, a content requesting subject, and a content capacity of each content. The method of claim 3,
Wherein performing the caching comprises:
Comparing the remaining capacity of the cache with the capacity of the received content;
If the remaining capacity of the cache is smaller than the capacity of the content, deleting one of the contents stored in the cache based on the content request record; Wherein the content caching method comprises the steps of: The method according to claim 1,
The received content may be,
The content requested by the user terminal device or the content requested by the other user terminal device and passing through the user terminal device. 5. The method of claim 4,
Wherein the deleting comprises:
And deletes the content having the smallest number of requests from the pre-stored contents. 5. The method of claim 4,
Wherein the deleting comprises:
And deletes the content having the largest difference between the latest request time and the current time among the previously stored contents. 5. The method of claim 4,
Wherein the deleting comprises:
And the content having a larger capacity than the content that generated the content request is preferentially deleted from the stored content. 5. The method of claim 4,
Wherein the deleting comprises:
Wherein a content to be deleted is determined by applying different weights to the number of requests from the user terminal and the number of requests from the other user terminal from among the content request records. 5. The method of claim 4,
Wherein the deleting step is repeatedly performed until the remaining capacity of the cache becomes equal to or greater than the capacity of the received content. A computer-readable recording medium on which a program for executing the content caching method according to any one of claims 1 to 10 is recorded. A computer program embodied to execute the method of content caching recited in any one of claims 1 to 10 and stored in a computer-readable recording medium.

Images