Centralized coding caching method and device based on partial cooperation D2D communication

Abstract

The invention discloses a centralized coding caching method and device based on partial cooperation D2D communication, and the method comprises the steps: segmenting an initial file according to a preset parameter, and obtaining initial sub-file blocks; caching the initial sub-file block to obtain a pre-cached file; establishing a D2D communication system to obtain an access terminal set; according to the D2D communication system, requesting to obtain a target request file; in response to a request for obtaining a target request file, constructing a coded data packet according to the access terminal set; and according to the pre-cached file, decoding the coded data packet to obtain the target request file. The method can improve the overall performance of the communication network, and can be widely applied to the technical field of network communication.

Description

Technical Field

[0001] The present invention relates to the field of network communication technology, and in particular to a centralized coding cache method and device based on partial collaborative D2D communication. Background Art

[0002] The widespread use of mobile Internet and smart devices and the rise of AR / VR devices have enabled the Internet to provide users with richer service content. However, while supporting various application service users, the growing number of terminals has given rise to massive data transmission needs. In the mobile communication network architecture, the data traffic generated by the interaction between different terminals or servers often needs to be relayed through base stations or core networks, which in turn places a huge load on base stations and core networks. In extreme cases, network congestion will affect the service quality of the communication system and reduce the overall performance of the communication network. Summary of the invention

[0003] In view of this, the main purpose of the embodiments of the present invention is to provide a centralized code caching method and device based on partially cooperative D2D communication to improve the overall performance of the communication network.

[0004] To achieve the above object, an embodiment of the present invention provides a centralized coding caching method based on partially cooperative D2D communication, comprising the following steps:

[0005] According to preset parameters, the initial file is divided to obtain initial sub-file blocks;

[0006] caching the initial sub-file block to obtain a pre-cached file;

[0007] Establish a D2D communication system and obtain an access terminal set;

[0008] According to the D2D communication system, requesting to obtain a target request file;

[0009] In response to the request to obtain the target request file, construct an encoded data packet according to the set of access terminals;

[0010] The encoded data packet is decoded according to the pre-cached file to obtain the target requested file.

[0011] In some embodiments, before the step of dividing the initial file according to preset parameters to obtain initial sub-file blocks, the following steps are also included:

[0012] According to the preset parameters, the initial selfless terminals are divided into default selfless terminals and non-default selfless terminals;

[0013] According to the preset parameters, selfish terminals are divided into several categories.

[0014] In some embodiments, caching the initial sub-file block to obtain a pre-cached file includes the following steps:

[0015] Placing the corresponding initial sub-file block into the default selfless terminal to obtain a first cache file;

[0016] The corresponding initial sub-file block is placed into the selfish terminal to obtain a second cache file.

[0017] In some embodiments, the step of establishing a D2D communication system and obtaining a set of access terminals includes the following steps:

[0018] Broadcast connection establishment signal and obtain connection request;

[0019] According to the connection request and the preset parameters, a plurality of the initial selfless terminals are connected to the D2D communication system to obtain a first access terminal;

[0020] According to the connection request and the category, a plurality of the selfish terminals are connected to the D2D communication system to obtain a second access terminal;

[0021] The access terminal set includes the first access terminal and the second access terminal.

[0022] In some embodiments, after the step of establishing the D2D communication system and obtaining the access terminal set, the following steps are further included:

[0023] Acquire a third cache file corresponding to the default selfless terminal that is not connected to the D2D communication system;

[0024] It is determined whether the initial selfless terminal in the access terminal set is the non-default selfless terminal, and if the initial selfless terminal in the access terminal set is the non-default selfless terminal, the third cache file is placed in the non-default selfless terminal in the access terminal set.

[0025] In some embodiments, the step of constructing a coded data packet according to the set of access terminals in response to the request to obtain the target request file comprises the following steps:

[0026] Selecting a plurality of the first access terminals and a plurality of the second access terminals from the access terminal set to form a plurality of multicast groups;

[0027] Acquire a plurality of pre-cached sub-file blocks corresponding to each pre-cached file of each of the first access terminals and each of the second access terminals in the multicast group;

[0028] Construct an encoded data packet according to the pre-cached sub-file block.

[0029] In some embodiments, constructing the encoded data packet according to the pre-cached sub-file block comprises the following steps:

[0030] Acquire the number of the first access terminals that cache the pre-cached sub-file blocks;

[0031] According to the number, the corresponding pre-cached sub-file blocks are divided to obtain target sub-file blocks;

[0032] Construct an encoded data packet according to the target sub-file block.

[0033] To achieve the above object, another aspect of an embodiment of the present invention provides a centralized coding cache device based on partially cooperative D2D communication, the device comprising:

[0034] The first module is used to divide the initial file according to preset parameters to obtain initial sub-file blocks;

[0035] The second module is used to cache the initial sub-file block to obtain a pre-cache file;

[0036] The third module is used to establish a D2D communication system and obtain an access terminal set;

[0037] A fourth module is used to request to obtain a target request file according to the D2D communication system;

[0038] A fifth module is used to obtain the target request file in response to the request, and construct a coded data packet according to the access terminal set;

[0039] The sixth module is used to decode the encoded data packet according to the pre-cached file to obtain the target requested file.

[0040] To achieve the above-mentioned purpose, another aspect of an embodiment of the present invention provides an electronic device, which includes a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, it implements the aforementioned centralized coding caching method based on partially collaborative D2D communication.

[0041] To achieve the above-mentioned purpose, another aspect of an embodiment of the present invention provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, it implements the aforementioned centralized coding caching method based on partially collaborative D2D communication.

[0042] To achieve the above object, another aspect of an embodiment of the present invention provides a computer program product or a computer program, the computer program product or the computer program includes computer instructions, and the computer instructions are stored in a computer-readable storage medium. A processor of a computer device can read the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the computer device performs the aforementioned centralized coding cache method based on partially cooperative D2D communication.

[0043] The embodiments of the present invention include at least the following beneficial effects: The present invention provides a centralized coding cache method and device based on partially collaborative D2D communication, which divides the initial file according to preset parameters to obtain initial sub-file blocks; caches the initial sub-file blocks to obtain pre-cached files; establishes a D2D communication system to obtain an access terminal set; requests to obtain a target request file according to the D2D communication system; in response to the request to obtain the target request file, constructs a coded data packet according to the access terminal set; decodes the coded data packet according to the pre-cached file to obtain the target request file. The present invention can improve the overall performance of the communication network. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0045] Figure 1 It is a flowchart of a centralized coding caching method based on partial cooperative D2D communication provided by an embodiment of the present invention;

[0046] Figure 2 is a schematic diagram of a partially cooperative D2D communication system architecture provided by an embodiment of the present invention;

[0047] Figure 3 is a flowchart of the steps in the pre-caching phase provided by an embodiment of the present invention;

[0048] Figure 4 is a flowchart of the steps in the communication establishment phase provided by an embodiment of the present invention;

[0049] Figure 5 This is a D2D communication system architecture provided by an embodiment of the present invention when K=4, S=1, M=2.4, and N=4;

[0050] Figure 6It is a schematic diagram of file segmentation in the pre-caching stage and the data transmission stage under the condition of K=4, S=1, M=2.4, N=4 provided by an embodiment of the present invention;

[0051] Figure 7 It is a schematic diagram of each selfless terminal broadcasting coded data packets and the terminal decoding to obtain data packets in the data transmission stage under the condition of K=4, S=1, M=2.4, N=4 provided by an embodiment of the present invention;

[0052] Figure 8 It is a schematic diagram of the overall step flow provided by an embodiment of the present invention;

[0053] Fig. 9 It is a schematic diagram of the hardware structure of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the embodiments of the present invention, and they are only examples of devices and methods consistent with some aspects of the embodiments of the present invention as detailed in the attached claims.

[0055] It should be noted that, although the functional modules are divided in the system schematic diagram and the logical order is shown in the flow chart, in some cases, the steps shown or described may be performed in a different order than the module division in the system or the flow chart. The terms "first / S100" and "second / S200" in the specification and claims and the above-mentioned drawings may be used to describe various concepts in this article, but unless otherwise specified, these concepts are not limited by these terms. These terms are only used to distinguish one concept from another. For example, without departing from the scope of the embodiment of the present invention, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the words "if" and "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determination".

[0056] The terms "at least one", "multiple", "each", "any", etc. used in the present invention, at least one includes one, two or more, multiple includes two or more, each refers to each of the corresponding multiple, and any refers to any one of the multiple.

[0057] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein are only for the purpose of describing the embodiments of the present invention and are not intended to limit the present invention.

[0058] Before describing the embodiments of the present invention in detail, some nouns and terms involved in the embodiments of the present invention are first described. The nouns and terms involved in the embodiments of the present invention are subject to the following explanations.

[0059] Selfless Terminals,Existing D2D code cache technology requires all terminals in the system to have the,ability to receive and send data at the same time. These terminals are,called selfless terminals.

[0060] Selfish terminals,In real systems, there are some terminals that turn off the sending function for the purpose of privacy protection or energy saving. Such terminals are called selfish terminals.

[0061] Cooperative D2D communication,D2D communication in which selfish terminals exist in the system is called,partially cooperative D2D communication.

[0062] In the mobile communication network architecture, the data traffic generated by the interaction between different terminals or servers often needs to be relayed through the base station or core network, which in turn causes a huge load on the base station and the core network. In extreme cases, network congestion will affect the service quality of the communication system and reduce the overall performance of the communication network. D2D code cache combines D2D communication and code cache technology to bring gains in both spatial and temporal dimensions to the communication system. However, when selfish terminals cannot send data, the code cache solution for fully collaborative D2D communication scenarios cannot be directly applied.

[0063] In view of this, if Figure 1 As shown, an embodiment of the present invention provides a centralized coding cache method based on partial cooperative D2D communication, which may include but is not limited to steps S100 to S600:

[0064] Step S100, dividing the initial file according to preset parameters to obtain initial sub-file blocks;

[0065] Step S200, caching the initial sub-file block to obtain a pre-cached file;

[0066] Step S300, establishing a D2D communication system and obtaining an access terminal set;

[0067] Step S400, requesting to obtain a target request file according to the D2D communication system;

[0068] Step S500, in response to the request to obtain the target request file, construct an encoded data packet according to the access terminal set;

[0069] Step S600: decoding the encoded data packet according to the pre-cached file to obtain the target requested file.

[0070] Before step S100 in some embodiments, KS initial selfless terminals in the service area are arbitrarily selected as default selfless terminals, S initial selfless terminals are selected as non-default selfless terminals, and the selfish terminals are evenly divided into S classes. The selfish terminals in each class will cache the same file content, wherein K and S are both integers, and their values ​​are related to system parameters.

[0071] In step S100 of some embodiments, the central server determines a file cache scheme to divide each initial file in the database into a certain number of initial sub-file blocks of equal or unequal size.

[0072] In some embodiments, step S200 may include but is not limited to steps S210 to S220:

[0073] Step S210, placing the corresponding initial sub-file block into the default selfless terminal to obtain a first cache file;

[0074] Step S220: placing the corresponding initial sub-file block into the selfish terminal to obtain a second cache file.

[0075] In step S200 of some embodiments, a cache scheme of the terminal device into which each initial sub-file block is to be placed is determined, so that the central server broadcasts each initial sub-file block according to the determined cache scheme. By default, the selfless terminal selects the initial sub-file block to be placed in its own cache for storage, and obtains a first cache file; all selfish terminals select the initial sub-file block to be placed in their own cache for storage, and obtain a second cache file.

[0076] In some embodiments, step S300 may include but is not limited to steps S310 to S330:

[0077] Step S310, broadcasting a connection establishment signal to obtain a connection request;

[0078] Step S320: according to the connection request and the preset parameters, a plurality of the initial selfless terminals are connected to the D2D communication system to obtain a first access terminal;

[0079] Step S330, according to the connection request and the category, connecting a plurality of the selfish terminals to the D2D communication system to obtain a second access terminal;

[0080] The access terminal set includes the first access terminal and the second access terminal.

[0081] In step S300 of some embodiments, the central server broadcasts a connection establishment signal to the terminal devices in its service area to detect the terminal devices to be connected that wish to request files. After receiving the connection establishment signal, the terminal devices to be connected reply to the central server with a connection establishment request. After receiving the connection request in the statistical service area, the central server broadcasts a terminal connection control signal and allocates corresponding communication resources for the newly established D2D communication system, wherein the communication resources include but are not limited to communication frequency and time slot resources. When the number of the initial selfless terminal and selfish terminal to be connected exceeds the threshold of the service area, or when the communication establishment time reaches the preset maximum time threshold, the central server determines the initial selfless terminal and selfish terminal to access the system, and stops broadcasting the connection establishment signal at the same time.

[0082] In some embodiments, after step S300, it is also necessary to determine whether the initial selfless terminal in the access terminal set is a non-default selfless terminal. If the initial selfless terminal in the access system is not the default selfless terminal, it is necessary to obtain a pre-cached file, that is, a third cache file, from the default selfless terminal that has not been accessed, and place the third cache file in the non-default selfless terminal in the access terminal set, so that the file contents cached by each initial selfless terminal in the access system are different.

[0083] In step S400 of some embodiments, in the D2D communication system in which a connection is established, each terminal broadcasts the requested file number information to request the missing file content from other selfless terminals, that is, to request to obtain the target requested file.

[0084] In some embodiments, step S500 may include but is not limited to steps S510 to S530:

[0085] Step S510, selecting a plurality of the first access terminals and a plurality of the second access terminals in the access terminal set to form a plurality of multicast groups;

[0086] Step S520, obtaining a plurality of pre-cached sub-file blocks corresponding to each pre-cached file of each of the first access terminals and each of the second access terminals in the multicast group;

[0087] Step S530: construct an encoded data packet according to the pre-cached sub-file block.

[0088] In some embodiments, step S530 may include but is not limited to steps S531 to S533:

[0089] Step S531, obtaining the number of the first access terminals that have cached the pre-cached sub-file blocks;

[0090] Step S532, dividing the corresponding pre-cached sub-file blocks according to the quantity to obtain target sub-file blocks;

[0091] Step S533: construct an encoded data packet according to the target sub-file block.

[0092] In step S500 of some embodiments, several access terminals are randomly selected from the access terminal set to form several multicast groups. Then, a coded data packet is designed for each multicast group, that is, in response to a request signal for obtaining a target request file, the corresponding pre-cached sub-file block is obtained, and then the pre-cached sub-file block is divided, and the coded data packet can be constructed by the selfless terminal. Each selfless terminal receives the request file information of other terminals, determines according to the centralized coding cache scheme, and broadcasts the coded data packet to other terminals. The multicast gain used in the broadcast transmission process can significantly reduce the amount of data that the selfless terminal needs to send, thereby reducing the communication load of the system.

[0093] In step S600 of some embodiments, each terminal receives an encoded data packet from another terminal, and uses cached data to decode the file content it needs from the encoded data packet, thereby obtaining the target requested file.

[0094] Exemplarily, assume that the terminal set accessing the system is {U4, U2, U3, U6, U8}, and the set arrangement corresponds to the set arrangement {K1, K2, K3, K4, K5} in the pre-caching stage, that is, U4 pre-caches the file content of K1, U2 pre-caches the file content of K2, and so on. At the same time, assume that the file set requested by {U4, U2, U3, U6, U8} is {A, B, C, D, E}, that is, U4 requests file A, U2 requests file B, and so on. After knowing the files requested by all terminals, the selfless terminals U4, U2, and U3 calculate the encoded data packets that they need to send. First, 4 terminals are randomly selected from the access terminal set {U4, U2, U3, U6, U8} to form a multicast group (the number of selected terminals is related to the initially set K value, the terminal cache size M and the number of files N, and its value is equal to KM / N), then 5 multicast groups can be obtained. For example, {U4, U2, U3, U6} is the first multicast group, and {U4, U2, U6, U8} is the second multicast group. Therefore, there are 5 possible multicast groups. Encoded data packets are designed for each multicast group. In the multicast group {U4, U2, U3, U6}, taking U4 as an example, in the cache of U4, the pre-cached sub-file blocks of the pre-cached file A are (A 123 ,A 124 ,A 125 ,A134 ,A 135 ,A 145 ), other pre-cached files B, C, D, E are also cached by U4 in the same way, and the other terminals also have corresponding cache contents. Observe that U4 lacks the pre-cached sub-file block A 234 Cached by U2, U3, and U6, pre-cached sub-file block B missing from U2 134 Pre-cached sub-file block C cached by U4, U3, and U6, but missing by U3 124 Pre-cached sub-file block D that is cached by U4, U2, and U6 but is missing from U6 123 The pre-cached sub-file blocks missing by each terminal in the multicast group are cached by other terminals in the multicast group. Based on this property, a broadcast coded data packet can be designed for each terminal so that multiple terminals can decode the files they need from the same coded data packet. Next, each pre-cached sub-file block involved in the above example is further divided into two target sub-file blocks (the pre-cached sub-file block is divided into two equal parts according to the number of selfless terminals that have cached the pre-cached sub-file block). For example, A 234 Cached by U2, U3, and U6, where U2 and U3 are selfless terminals, i.e., pre-caching sub-file block A 234 The number of caches cached by the selfless terminal is 2, then A 234 Divide into 2 target sub-file blocks, respectively The superscript number corresponds to the terminal that sends the pre-cached sub-file block. 134 Divide into C 124 Divide into D 123 Divide into Selfless terminal U4 broadcasts and sends coded data packets U2 broadcast sends coded data packets U3 broadcast sends coded data packets At this time, the selfless terminal U4 is missing subfiles You can use the cache Decoded from X2, You can use the cache Decoded from X3, and so on, each terminal in the multicast group can decode the sub-file missing in the cache. At the same time, the above data transmission scheme is used for all multicast groups, and the files requested by each terminal accessing the system can be satisfied. In the terminal set accessing the system, it may happen that the number of selfish terminals does not reach the upper limit of access. During the data transmission phase, a selfish terminal of each type can be selected from the selfish terminal types that are not connected in the system to create a virtual request to access the system, which is convenient for the subsequent calculation of the corresponding broadcast coded data packet, and then the sub-file corresponding to the virtual request can be eliminated from the coded data packet.

[0095] In some embodiments, the partially cooperative D2D communication system applied in the embodiments of the present invention includes a central server with sending and receiving functions and equipped with a file database. A certain number of terminals with sending and receiving functions, caching functions, and computing decoding functions are distributed in the service area of ​​the central server, wherein the selfless terminal also has a computing coding function and is responsible for broadcasting coded data packets to meet the file requests of other terminals, and the selfish terminal does not have the functions of computing coding and broadcasting coded data packets. All terminals receive the pre-cached sub-files from the central server through a shared link. After the terminal requests the file, the selfless terminal broadcasts the coded data packet to other terminals, and each terminal uses the file information in the cache to decode the received coded data packet to obtain the requested file information. The embodiments of the present invention can significantly reduce the total amount of data sent by the selfless terminals in the partially cooperative D2D communication system and improve the overall performance of the communication network.

[0096] In the embodiment of the present invention, the architecture of the overall system is as follows: Figure 2 As shown, it mainly includes a central server and terminal devices of the edge network. Figure 2 In the example, there are 9 terminals in the service area, among which U1~U5 are selfless terminals and U6~U9 are selfish terminals. In the pre-caching stage, the value of S depends on K, cache size M and the number of files N. S≤KM / N-1 is the prerequisite that the system needs to meet. Assuming K=5, the terminal cache size is M=3, and the number of files N=5, the value of S satisfies S≤2, so S=2 can be taken. U1, U2, and U3 are selected as the default selfless terminals. Here, they are selected arbitrarily. U2, U3, and U4 can also be selected as the default selfless terminals. At the same time, the 4 selfish terminals are evenly divided into 2 categories. For example, {U6, U7} are the first category and {U8, U9} are the second category. The division of selfish terminals is also arbitrary. The same type of selfish terminals will pre-cache the same file content later. Correspondingly, in the communication establishment stage, the upper limit of the number of selfless terminals that can be accessed in the service area KS is set to 3, and the upper limit of the number of selfish terminals S is set to 2.

[0097] like Figure 2As shown in the figure, suppose there are 5 files of size 1 in the database, that is, N = 5, and the five files are A, B, C, D, and E. The cache size of each terminal is M = 3. Define a terminal set accessing the system as {K1, K2, K3, K4, K5}, {K1, K2, K3} represents selfless terminals, and {K4, K5} represents selfish terminals. Then Figure 2 Taking the system shown in FIG. 1 as an example, a centralized coding cache method based on partially cooperative D2D communication according to an embodiment of the present invention includes the following steps:

[0098] In the pre-caching stage, such as Figure 3 As shown, each file is equally divided into 10 sub-files. For example, file A is divided into (A 123 ,A 124 ,A 125 ,A 134 ,A 135 ,A 234 ,A 235 ,A 145 ,A 245 ,A 345 ). The subscript of each subfile indicates the terminal cache into which the subfile will be placed. For example, A 123 will be pre-cached by selfless terminals K1, K2, K3, A 124 It will be pre-cached by selfless terminals K1, K2 and selfish terminal K4, and so on. The same file segmentation scheme is adopted for other files B, C, D, E. In the pre-caching stage, the default selfless terminals U1, U2, U3 store the cache contents corresponding to selfless terminals K1, K2, K3 respectively, the first type of selfish terminals U6, U7 store the cache contents corresponding to selfish terminal K4, and the second type of selfish terminals U8, U9 store the cache contents corresponding to selfish terminal K5. At this time, the default selfless terminal and all selfish terminals obtain the pre-cached sub-files, and the non-default selfless terminals do not need to pre-cache files, and the pre-caching stage ends.

[0099] Next, we enter the communication establishment phase, such as Figure 4As shown, the central server first broadcasts a connection establishment signal to the terminal devices in its service area to detect the terminal devices to be connected that want to request files. After the terminal device to be connected receives the connection establishment signal, if it needs to request a file, it replies to the central server with a connection establishment request. The central server continues to receive terminal requests until the number of selfless terminals and selfish terminals to be connected exceeds the upper limit of their respective access numbers, or reaches the preset maximum communication establishment time threshold. After the central server finishes receiving requests, if the selfless terminals to be connected exceed the upper limit of the access number, KS terminals are selected to access the system. If the upper limit is not reached, the default selfless terminals that have not been connected to the system are activated to make the number of selfless terminals connected to the system KS. At the same time, there are no more than S categories of selfish terminals to be connected in the system, and one selfish terminal is selected from each category to access the D2D communication system. Other terminals to be connected that have not been connected in this cycle enter the waiting queue and wait for the establishment of communication in the next cycle. The above communication establishment process is explained by taking several cases as examples: In the first case, assuming that the waiting queue is empty, the selfless terminals to be connected are U2, U3, U4, and U5, and the selfish terminals are U6, U7, and U8. At this time, the number of selfless terminals to be connected exceeds 3, and the number of selfish terminals to be connected exceeds 2, and the central server stops broadcasting the connection establishment signal. Among the selfless terminals to be connected, U2, U3, and U4 are selected to access the system. Among the selfish terminals to be connected, the first type of selfish terminal U6 and the second type of selfish terminal U8 are selected to access the system, so U5 and U7 wait for the next cycle to establish communication. Therefore, the terminal set accessing the D2D communication system is {U2, U3, U4, U6, and U8}, and the waiting queue is {U5, U7}. In the second case, assuming that the waiting queue is empty, after reaching the maximum communication establishment time, assuming that the selfless terminals to be connected are U3 and U4, and the selfish terminal is U6, the number of selfless terminals and selfish terminals to be connected does not exceed the given threshold. Activate the default selfless terminal U1 that has not been connected to the system. At this time, the terminal set connected to the D2D communication system is {U1, U3, U4, U6}, and the waiting queue is

[0100] After determining the terminal accessing the system, if all the selfless terminals accessing the system are default selfless terminals, there is no need to transfer the pre-cached content to each other. If there are non-default selfless terminals, they need to obtain the pre-cached files from the default selfless terminals that have not been connected. For example, the terminal set accessing the system is {U2, U3, U4, U6, U8}, U2 and U3 are default selfless terminals, and U4 is a non-default selfless terminal. Since U4 did not obtain the cached content in the pre-caching stage, to ensure the subsequent normal data transmission, U4 will obtain the pre-cached sub-files from the default selfless terminal U1 that has not been connected. If the terminal set accessing the system is {U3, U4, U5, U6, U8}, U3 is the default selfless terminal, and U4 and U5 are non-default selfless terminals, then U4 and U5 need to obtain the pre-cached sub-files from the two default selfless terminals U1 and U2. No matter U4 obtains U1 and U5 obtains U2, or U4 obtains U2 and U5 obtains U1, subsequent normal data transmission can be guaranteed as long as the file contents cached by each selfless terminal accessing the system are different.

[0101] After all the selfless terminals connected to the system obtain the pre-cached files, they enter the data transmission stage. The data distribution in this stage does not require the participation of the central server. The terminals connected to the system broadcast the requested file number information, and each selfless terminal can obtain the requested file information of all terminals. The selfless terminal determines the broadcast coded data packet based on the known file request and the centralized coding cache scheme. Each terminal can use the cached data to decode the coded data packet to obtain the file content it needs, thereby reconstructing the requested file.

[0102] In some embodiments, when K=4, S=1, M=2.4, N=4, Figure 5 The D2D communication system architecture shown in Figure 6 The schematic diagram of file segmentation in the pre-caching stage and the data transmission stage is shown in FIG. Figure 7 The diagram shows a schematic diagram of each selfless terminal broadcasting coded data packets and the terminal decoding to obtain data packets during the data transmission stage.

[0103] like Figure 8 As shown, a centralized coding cache method based on partial cooperative D2D communication in an embodiment of the present invention includes a pre-caching stage, a communication establishment stage and a data transmission stage, wherein the pre-caching stage occurs during the communication trough period. Figure 8 An optional implementation process of the embodiment of the present invention includes the following steps:

[0104] Step 1: In the pre-caching stage, the central server arbitrarily selects KS selfless terminals in the service area as the default selfless terminals, and evenly divides the selfish terminals into S categories. The centralized coding cache scheme is determined according to the system parameters K, S values, the cache space size of the terminal, and the number of files in the database, and each initial file in the database is divided into a certain number of initial sub-file blocks of equal or different sizes. Each initial sub-file block is broadcast and sent, and the default selfless terminal and all selfish terminals select the initial sub-file block that should be placed in their own cache area for storage, and the pre-caching stage ends.

[0105] Step 2: The central server broadcasts a connection establishment signal to the terminal devices within its service area to detect the terminal devices to be connected that wish to request files.

[0106] Step 3: After receiving the connection establishment signal, the terminal device to be connected replies to the central server with a connection establishment request. When the number of selfless terminals and selfish terminals to be connected exceeds the threshold of the service area, or when the communication establishment time reaches the preset maximum time threshold, the central server determines the selfless terminals and selfish terminals that have accessed the system, and stops broadcasting the connection establishment signal. The central server allocates corresponding communication resources for the newly established D2D communication system, and the communication resources include but are not limited to communication frequency and time slot resources.

[0107] Step 4: If the selfless terminal connected to the system is not the default selfless terminal, it is necessary to obtain the pre-cached file from the default selfless terminal that has not been connected, so that the file content cached by each selfless terminal connected to the system is different, and the communication establishment phase ends.

[0108] Step 5: The data transmission phase begins. In the D2D communication system where a connection is established, each terminal broadcasts the requested file number information to request the missing file content from other selfless terminals.

[0109] Step 6: Each selfless terminal receives the requested file information from other terminals, determines and broadcasts the encoded data packet to other terminals according to the centralized encoding cache solution;

[0110] Step 7: Each terminal receives the coded data packet from other terminals and decodes the file content it needs from the coded data packet using the cached data. When each terminal reconstructs the requested file, the data transmission phase ends and it is ready to enter the next communication cycle.

[0111] The embodiment of the present invention further provides a centralized coding cache device based on partial cooperative D2D communication, which can implement the above-mentioned centralized coding cache method based on partial cooperative D2D communication, and the device includes:

[0112] The first module is used to divide the initial file according to preset parameters to obtain initial sub-file blocks;

[0113] The second module is used to cache the initial sub-file block to obtain a pre-cache file;

[0114] The third module is used to establish a D2D communication system and obtain an access terminal set;

[0115] A fourth module is used to request to obtain a target request file according to the D2D communication system;

[0116] A fifth module is used to obtain the target request file in response to the request, and construct a coded data packet according to the access terminal set;

[0117] The sixth module is used to decode the encoded data packet according to the pre-cached file to obtain the target requested file.

[0118] It can be understood that the contents of the above method embodiments are all applicable to the present device embodiments, the functions specifically implemented by the present device embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0119] The embodiment of the present invention further provides an electronic device, which includes a processor and a memory, wherein the memory stores a computer program, and when the processor executes the computer program, the centralized coding cache method based on partially cooperative D2D communication is implemented. The electronic device can be any intelligent terminal including a tablet computer, a car computer, etc.

[0120] It can be understood that the contents of the above method embodiments are all applicable to the present device embodiments, the functions specifically implemented by the present device embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0121] refer to Fig. 9 , Fig. 9 The hardware structure of an electronic device of another embodiment is illustrated, and the electronic device includes:

[0122] The processor 701 may be implemented by a general-purpose CPU (Central Processing Unit), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits, and is used to execute relevant programs to implement the technical solutions provided in the embodiments of the present invention;

[0123] The memory 702 can be implemented in the form of a read-only memory (ROM), a static storage device, a dynamic storage device, or a random access memory (RAM). The memory 702 can store an operating system and other applications. When the technical solution provided in the embodiment of this specification is implemented by software or firmware, the relevant program code is stored in the memory 702, and the processor 701 calls and executes a centralized coding cache method based on partially cooperative D2D communication according to an embodiment of the present invention;

[0124] Input / output interface 703, used to implement information input and output;

[0125] Communication interface 704, used to realize communication interaction between the device and other devices, which can be realized by wired mode (such as USB, network cable, etc.) or wireless mode (such as mobile network, WIFI, Bluetooth, etc.);

[0126] A bus 705 that transmits information between the various components of the device (e.g., the processor 701, the memory 702, the input / output interface 703, and the communication interface 704);

[0127] The processor 701 , the memory 702 , the input / output interface 703 and the communication interface 704 are connected to each other in communication within the device via a bus 705 .

[0128] An embodiment of the present invention further provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, the centralized coding caching method based on partially cooperative D2D communication is implemented.

[0129] It can be understood that the contents of the above method embodiments are all applicable to the present storage medium embodiments, the functions specifically implemented by the present storage medium embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0130] The embodiment of the present invention further provides a computer program product or a computer program, which includes computer instructions stored in a computer-readable storage medium. A processor of a computer device can read the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the computer device performs the aforementioned centralized coding cache method based on partially cooperative D2D communication.

[0131] In summary, a centralized coding cache method and device based on partially cooperative D2D communication according to an embodiment of the present invention has the following advantages:

[0132] 1. In the data transmission stage, the embodiment of the present invention can provide consistent communication service quality for selfless terminals and selfish terminals by optimizing the transmission process of the joint selfless terminals and effectively utilizing the cache information of the selfish terminals, thereby improving the transmission performance of the entire system.

[0133] 2. The embodiment of the present invention adopts a centralized coding cache algorithm and optimizes the file segmentation in the data transmission stage for the access of selfish terminals. It combines the coding cache technology to fully and efficiently utilize the cache information of selfless terminals and selfish terminals, effectively reducing the transmission rate required by the system. In addition, the addition of selfish terminals creates more multicast opportunities for the communication system, brings significant multicast gain, and thus greatly reduces the traffic load of the system, thereby improving the overall performance of the communication network.

[0134] 3. The traditional cellular communication system adopts a centralized network architecture. All data interacting with the terminal or server needs to be processed by the central node and then forwarded to the destination node. The distributed network architecture adopted by the embodiment of the present invention through D2D communication provides a path for data transmission to directly reach the destination node without passing through the central node. This communication method can avoid massive data from pouring into the core network, unload part of the traffic of the core network to the edge of the network, and realize load balancing of the communication system in the spatial dimension. At the same time, the short-distance transmission of adjacent devices can effectively reduce the transmission delay and improve the quality of communication services.

[0135] 4. The embodiment of the present invention combines D2D communication and coding cache technology through D2D coding cache, thereby bringing gains in both spatial and temporal dimensions to the communication system.

[0136] 5. Under the premise of considering the partial collaborative D2D communication system, the embodiment of the present invention designs the terminal to cache content to obtain multicast opportunities, and the selfless terminal calculates the broadcast coded signal. Through the joint design of caching and multicast, the bandwidth required by the system to meet the requests of each terminal is reduced, thereby reducing the communication load of the core network.

[0137] In some selectable embodiments, the function / operation mentioned in the block diagram may not occur in the order mentioned in the operation diagram. For example, depending on the function / operation involved, the two boxes shown in succession can actually be executed substantially simultaneously or the boxes can sometimes be executed in reverse order. In addition, the embodiment presented and described in the flow chart of the present invention is provided by way of example, for the purpose of providing a more comprehensive understanding of technology. The disclosed method is not limited to the operation and logic flow presented herein. Selectable embodiments are expected, wherein the order of various operations is changed and the sub-operation of a part for which is described as a larger operation is performed independently.

[0138] In addition, although the present invention is described in the context of functional modules, it should be understood that, unless otherwise specified, one or more of the functions and / or features described may be integrated into a single physical device and / or software module, or one or more functions and / or features may be implemented in separate physical devices or software modules. It is also understood that a detailed discussion of the actual implementation of each module is unnecessary for understanding the present invention. More specifically, in view of the properties, functions, and internal relationships of the various functional modules in the device disclosed herein, the actual implementation of the module will be understood within the conventional skills of the engineer. Therefore, those skilled in the art can implement the present invention set forth in the claims without excessive experimentation using ordinary techniques. It is also understood that the specific concepts disclosed are merely illustrative and are not intended to limit the scope of the present invention, which is determined by the full scope of the appended claims and their equivalents.

[0139] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc., which can store program codes.

[0140] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in conjunction with such instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in conjunction with such instruction execution systems, devices or apparatuses.

[0141] More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering or, if necessary, processing in another suitable manner, and then stored in a computer memory.

[0142] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0143] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0144] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

[0145] The above is a specific description of the preferred implementation of the present invention, but the present invention is not limited to the described embodiments. Those skilled in the art may make various equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of the present invention.

Claims

1. A centralized coding cache method based on partially cooperative D2D communication, characterized in that: The following steps are involved: According to preset parameters, the initial file is divided to obtain initial sub-file blocks; caching the initial sub-file block to obtain a pre-cached file; Establish a D2D communication system and obtain an access terminal set; According to the D2D communication system, requesting to obtain a target request file; In response to the request to obtain the target request file, construct an encoded data packet according to the set of access terminals; The encoded data packet is decoded according to the pre-cached file to obtain the target requested file.

2. According to claim 1, a centralized coding cache method based on partially cooperative D2D communication is characterized in that: Before the step of dividing the initial file according to the preset parameters to obtain the initial sub-file blocks, the following steps are also included: According to the preset parameters, the initial selfless terminals are divided into default selfless terminals and non-default selfless terminals; According to the preset parameters, selfish terminals are divided into several categories.

3. According to claim 2, a centralized coding cache method based on partially cooperative D2D communication is characterized in that: The step of caching the initial sub-file block to obtain a pre-cached file comprises the following steps: Placing the corresponding initial sub-file block into the default selfless terminal to obtain a first cache file; The corresponding initial sub-file block is placed into the selfish terminal to obtain a second cache file.

4. According to claim 2, a centralized coding cache method based on partially cooperative D2D communication is characterized in that: The step of establishing a D2D communication system and obtaining a set of access terminals comprises the following steps: Broadcast connection establishment signal and obtain connection request; According to the connection request and the preset parameters, a plurality of the initial selfless terminals are connected to the D2D communication system to obtain a first access terminal; According to the connection request and the category, a plurality of the selfish terminals are connected to the D2D communication system to obtain a second access terminal; The access terminal set includes the first access terminal and the second access terminal.

5. According to claim 2, a centralized coding cache method based on partially cooperative D2D communication is characterized in that: After the step of establishing the D2D communication system and obtaining the access terminal set, the following steps are also included: Acquire a third cache file corresponding to the default selfless terminal that is not connected to the D2D communication system; It is determined whether the initial selfless terminal in the access terminal set is the non-default selfless terminal, and if the initial selfless terminal in the access terminal set is the non-default selfless terminal, the third cache file is placed in the non-default selfless terminal in the access terminal set.

6. A centralized coding cache method based on partially cooperative D2D communication according to claim 4, characterized in that: The step of obtaining the target request file in response to the request and constructing a coded data packet according to the access terminal set includes the following steps: Selecting a plurality of the first access terminals and a plurality of the second access terminals from the access terminal set to form a plurality of multicast groups; Acquire a plurality of pre-cached sub-file blocks corresponding to each pre-cached file of each of the first access terminals and each of the second access terminals in the multicast group; Construct an encoded data packet according to the pre-cached sub-file block.

7. A centralized coding cache method based on partially cooperative D2D communication according to claim 6, characterized in that: The step of constructing a coded data packet according to the pre-cached sub-file block comprises the following steps: Acquire the number of the first access terminals that cache the pre-cached sub-file blocks; According to the number, the corresponding pre-cached sub-file blocks are divided to obtain target sub-file blocks; Construct an encoded data packet according to the target sub-file block.

8. A centralized coding cache device based on partial cooperative D2D communication, characterized in that: include: The first module is used to divide the initial file according to preset parameters to obtain initial sub-file blocks; The second module is used to cache the initial sub-file block to obtain a pre-cache file; The third module is used to establish a D2D communication system and obtain an access terminal set; A fourth module is used to request to obtain a target request file according to the D2D communication system; A fifth module is used to obtain the target request file in response to the request, and construct a coded data packet according to the access terminal set; The sixth module is used to decode the encoded data packet according to the pre-cached file to obtain the target requested file.

9. An electronic device, characterized in that: including a processor and a memory; The memory is used to store programs; The processor executes the program to implement the method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: The storage medium stores a program, and the program is executed by a processor to implement the method according to any one of claims 1 to 7.

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