Secure video transmission method and device based on scalable video coding

Abstract

The present invention provides a secure video transmission method and device based on scalable video coding, relating to the field of video transmission technology. The video transmission method includes: according to a preset caching strategy, layered caching of the base layer file and multiple enhancement layer files of at least a portion of the video files in a content server in a target macro base station and a target micro base station in a preset cellular network; determining whether the target video file is included in at least a portion of the video files based on a video acquisition request sent by a target user; if the target video file is included in at least a portion of the video files, sending the base layer file of the target video file to the target user via the target macro base station, and superimposing at least one enhancement layer file of the target video file using a non-orthogonal transmission method via the target micro base station before sending the superimposed file to the target user. This application can improve video transmission efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of video transmission, and in particular to a secure video transmission method and device based on scalable video coding. Background Art

[0002] With the rapid development of wireless networks and the widespread adoption of mobile devices such as smartphones, tablets, and laptops, mobile data traffic will enter a new phase of rapid growth. Video data traffic will account for the majority of mobile data traffic consumption. The primary driver of video traffic growth is user demand for social media push notifications and high-quality videos. Ensuring and improving the Quality of Service (QoS) of video received by users is crucial for increasing operator revenue, and has therefore received significant attention from both the industry and academia.

[0003] However, with massive amounts of video traffic, a large number of duplicate video files are repeatedly transmitted over the backhaul links between the core network and base stations. Over a period of time, 80% of data traffic was comprised of repeated requests for the 20% most popular video files. This repetitive video data traffic puts enormous pressure on the network. Furthermore, the potential for unauthorized users on wireless networks, coupled with the open nature of wireless channels and the broadcast nature of wireless signals, creates security risks during transmission.

[0004] Therefore, how to ensure the efficient and secure delivery of requested video files has become a challenging and necessary problem. Summary of the Invention

[0005] The object of the present invention is to provide a secure video transmission method and apparatus based on scalable video coding to address the above-mentioned deficiencies in the prior art.

[0006] To achieve the above objectives, the technical solutions adopted in the embodiments of the present invention are as follows:

[0007] In a first aspect, an embodiment of the present invention provides a secure video transmission method based on scalable video coding, the method comprising:

[0008] According to a preset caching strategy, hierarchically cache the base layer file and multiple enhancement layer files of at least part of the video file in the content server in a target macro base station and a target micro base station of a preset cellular network respectively;

[0009] Determining, based on a video acquisition request sent by a target user, whether the at least part of the video files includes a target video file;

[0010] If the at least part of the video file contains the target video file, the base layer file of the target video file is sent to the target user through the target macro base station, and at least one enhancement layer file of the target video file is superimposed on the target video file using a non-orthogonal transmission method through the target micro base station and then sent to the target user.

[0011] Optionally, superimposing at least one enhancement layer file of the target video file by the target micro base station in a non-orthogonal transmission manner and then sending the superimposed file to the target user includes:

[0012] Determining the number of layers of the enhancement layer file according to the video quality information in the video acquisition request;

[0013] According to the number of layers of the enhancement layer file, the target micro base station uses the non-orthogonal transmission method to superimpose the enhancement layer files of the corresponding number of layers of the target video file and then sends them to the target user.

[0014] Optionally, the method further includes:

[0015] If the at least part of the video files does not include the target video file, obtaining the base layer file and multiple enhancement layer files of the target video file from the content server through the target macro base station and the target micro base station based on a backhaul link respectively;

[0016] The target macro base station uses the allocated first orthogonal channel resources to send the base layer file of the target video file to the target user, and the target micro base station uses the allocated second orthogonal channel resources to send at least one enhancement layer file of the target video file to the target user.

[0017] Optionally, the method further includes:

[0018] Modeling the preset cellular network, wherein the preset cellular network includes: at least one macro base station, at least one micro base station, the target user, and at least one eavesdropper;

[0019] determining a first confidentiality cache assistance data rate for the base layer file based on a first request probability for the base layer file of the at least portion of the video file, a first cache probability, a first successful transmission probability of sending the base layer file of the at least portion of the video file, a confidentiality interruption probability, and a first minimum cache assistance data rate;

[0020] determining a second secure cache assistance data rate for the enhancement layer files based on a second request probability of the plurality of enhancement layer files of the at least portion of the video file, a second cache probability, a second successful transmission probability of sending the enhancement layer files of the at least portion of the video file, and a second minimum cache assistance data rate;

[0021] Based on the first confidential cache auxiliary data rate and the second confidential cache auxiliary data rate, a target confidential cache data rate of the preset cellular network is determined, and the target confidential cache data rate is used to indicate the performance of caching and transmitting video files in the preset cellular network when the eavesdropper exists.

[0022] Optionally, the method further includes:

[0023] Calculating a first received signal-to-interference ratio for receiving the base layer file by the target user based on small-scale channel fading and distance between the target user and the target macro base station, and small-scale channel fading and distance between the target user and other macro base stations;

[0024] Determining a first probability density function of a distance between the target macro base station and the target user based on the density of the at least one macro base station;

[0025] A first successful transmission probability of sending each base layer file is calculated according to the first received signal-to-interference ratio and the first probability density function.

[0026] Optionally, the method further includes:

[0027] Calculating a second received signal-to-interference ratio for receiving the enhancement layer file by the target user based on small-scale channel fading and distance between the target user and the target micro base station, and small-scale channel fading and distance between the target user and other micro base stations;

[0028] Determining a second probability density function of a distance between the target micro base station and the target user based on a density of the at least one micro base station;

[0029] A second successful transmission probability of sending each enhancement layer file is calculated according to the second received signal-to-interference ratio and the second probability density function.

[0030] Optionally, the method further includes:

[0031] Determining a third received signal-to-interference ratio of each eavesdropper based on the channel fading and distance between each eavesdropper and the eavesdropped macro base station, and the channel fading and distance between each eavesdropper and the non-eavesdropped macro base station;

[0032] The privacy interruption probability is calculated according to the density of the at least one eavesdropper, the density of the at least one macro base station and the third received signal-to-interference ratio.

[0033] Optionally, the method further includes:

[0034] The first minimum cache assistance data rate is calculated according to the transmission bandwidth of the target macro base station and the minimum reception threshold of the base layer file.

[0035] Optionally, the method further includes:

[0036] The second minimum cache assistance data rate is calculated based on the transmission bandwidth of the target micro base station and the minimum reception threshold of the enhancement layer file.

[0037] In a second aspect, an embodiment of the present invention provides a secure video transmission device based on scalable video coding, the device comprising:

[0038] a caching module, configured to cache, in a predetermined caching strategy, a base layer file and a plurality of enhancement layer files of at least part of the video files in the content server in a predetermined target macro base station and a predetermined target micro base station of the cellular network;

[0039] a determination module, configured to determine whether the at least part of the video files includes a target video file according to a video acquisition request sent by a target user;

[0040] A sending module is used to send the base layer file of the target video file to the target user through the target macro base station if the target video file is included in at least part of the video file, and to superimpose at least one enhanced layer file of the target video file through the target micro base station using a non-orthogonal transmission method and then send it to the target user.

[0041] Optionally, the sending module is also used to determine the number of layers of the enhancement layer file based on the video quality information in the video acquisition request; based on the number of layers of the enhancement layer file, the target micro base station adopts the non-orthogonal transmission method to superimpose the enhancement layer files of the corresponding number of layers of the target video file and then send them to the target user.

[0042] Optionally, the device further comprises:

[0043] an acquisition module, configured to acquire, if the at least part of the video files does not include the target video file, a base layer file and multiple enhancement layer files of the target video file from the content server via the target macro base station and the target micro base station based on a backhaul link;

[0044] The sending module is also used to send the base layer file of the target video file to the target user through the target macro base station using the allocated first orthogonal channel resources, and to send at least one enhanced layer file of the target video file to the target user through the target micro base station using the allocated second orthogonal channel resources.

[0045] Optionally, the device further comprises:

[0046] A modeling module, configured to model the preset cellular network, wherein the preset cellular network includes: at least one macro base station, at least one micro base station, the target user, and at least one eavesdropper;

[0047] a calculation module, configured to determine a first confidentiality cache assistance data rate for the base layer file based on a first request probability for the base layer file of the at least portion of the video file, a first cache probability, a first successful transmission probability of sending the base layer file of the at least portion of the video file, a confidentiality interruption probability, and a first minimum cache assistance data rate;

[0048] The calculation module is further configured to determine a second confidential cache assistance data rate for the enhancement layer file based on a second request probability of the plurality of enhancement layer files of the at least portion of the video file, a second cache probability, a second successful transmission probability of sending the enhancement layer file of the at least portion of the video file, and a second minimum cache assistance data rate;

[0049] The calculation module is also used to determine the target confidential cache data rate of the preset cellular network based on the first confidential cache auxiliary data rate and the second confidential cache auxiliary data rate, and the target confidential cache data rate is used to indicate the performance of caching and transmitting video files in the preset cellular network when the eavesdropper exists.

[0050] Optionally, the calculation module is also used to calculate the first received signal-to-interference ratio of the target user receiving the base layer file based on the small-scale channel and distance between the target user and the target macro base station, and the small-scale channel fading and distance between the target user and other macro base stations; determine the first probability density function of the distance between the target macro base station and the target user based on the density of the at least one macro base station; and calculate the first successful transmission probability of sending each base layer file based on the first received signal-to-interference ratio and the first probability density function.

[0051] Optionally, the calculation module is also used to calculate the second received signal-to-interference ratio of the target user receiving the enhanced layer file based on the small-scale channel fading and distance between the target user and the target micro base station, and the small-scale channel fading and distance between the target user and other micro base stations; determine the second probability density function of the distance between the target micro base station and the target user based on the density of the at least one micro base station; and calculate the second successful transmission probability of sending each enhanced layer file based on the second received signal-to-interference ratio and the second probability density function.

[0052] Optionally, the calculation module is also used to determine the third received signal-to-interference ratio of each eavesdropper based on the channel fading and distance between each eavesdropper and the eavesdropped macro base station, and the channel fading and distance between each eavesdropper and the non-eavesdropped macro base station; and calculate the confidentiality interruption probability based on the density of the at least one eavesdropper, the density of the at least one macro base station and the third received signal-to-interference ratio.

[0053] Optionally, the calculation module is further used to calculate the first minimum cache auxiliary data rate according to the transmission bandwidth of the target macro base station and the minimum reception threshold of the base layer file.

[0054] Optionally, the calculation module is further used to calculate the second minimum cache auxiliary data rate based on the transmission bandwidth of the target micro base station and the minimum reception threshold of the enhancement layer file.

[0055] The beneficial effects of the present invention are:

[0056] The secure video transmission method and apparatus based on scalable video coding, provided in this application, employs scalable video coding technology to cache video files in layers, sending base layer files and enhancement layer files to users via macro and micro base stations, respectively, effectively improving video transmission efficiency. Furthermore, the enhancement layer files are divided into multiple layers, each with different numbers of layers, providing varying video quality to meet diverse user viewing needs. This method and apparatus can flexibly adapt to dynamically changing network conditions, improving the user experience quality and alleviating network congestion. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0058] Figure 1 Schematic diagram of an application scenario of an embodiment of the present invention;

[0059] Figure 2 The process of the secure video transmission method provided by the embodiment of the present invention Figure 1 ;

[0060] Figure 3 The process of the secure video transmission method provided by the embodiment of the present invention Figure 2 ;

[0061] Figure 4 The process of the secure video transmission method provided by the embodiment of the present invention Figure 3 ;

[0062] Figure 5 The process of the secure video transmission method provided by the embodiment of the present invention Figure 4 ;

[0063] Figure 6 A simulation diagram of the first successful transmission probability of the base layer file provided in an embodiment of the present application;

[0064] FIG7( a ) is a simulation diagram of the second successful transmission probability of the first enhancement layer file provided by an embodiment of the present application;

[0065] FIG7( b ) is a simulation diagram of the second successful transmission probability of the second enhancement layer file provided by an embodiment of the present application;

[0066] Figure 8 A simulation diagram of the confidentiality interruption probability of the base layer file provided in an embodiment of the present application;

[0067] Figure 9 A simulation diagram of the target confidentiality cache data rate provided in an embodiment of the present application;

[0068] Figure 10 A schematic diagram of a secure video transmission device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0069] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0070] The following describes the embodiments of the present invention by means of specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0071] The accompanying drawings are for illustrative purposes only and are schematic diagrams rather than actual drawings, and should not be construed as limiting the present invention. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the accompanying drawings.

[0072] In order to better understand the solution of the present invention, the application scenario of the secure video transmission method of the present invention is first introduced below.

[0073] Figure 1 Schematic diagram of an application scenario of an embodiment of the present invention, such as Figure 1 As shown, in a cellular network that supports caching and has eavesdropping risks, there are macro base stations (MBS), small base stations (SBS), legitimate users, and passive eavesdroppers (Eve).

[0074] Based on the above application scenarios, the specific implementation of the secure video transmission method based on scalable video coding provided by the present invention is described below in combination with embodiments.

[0075] Figure 2 The process of the secure video transmission method provided by the embodiment of the present invention Figure 1 ,like Figure 2 As shown, the secure video transmission method may include:

[0076] Step 101: hierarchically cache base layer files and multiple enhancement layer files of at least part of the video files in the content server in a target macro base station and a target micro base station of a preset cellular network according to a preset cache strategy.

[0077] Specifically, the macro base station and micro base station of the preset cellular network communicate with the content server respectively to obtain video files from the content server, where multiple video files are stored in the content server. The popularity of each video file can be determined based on the number of times legitimate users within the coverage area of ​​the preset cellular network request each video file.

[0078] The content server uses Scalable Video Coding (SVC) technology to encode each video file into L layers, including a base layer (BL) file and L-1 enhancement layer (EL) files.

[0079] Based on the preset caching strategy and the cache capacity of the macro and micro base stations, at least some video files are cached from multiple video files. If the preset caching strategy is equal probability caching, multiple video files are randomly cached until the cache capacity of each base station is fully utilized. The caching probability of equal probability caching is the cache capacity divided by the total size of the video files. For example, if the total cache capacity of the macro and micro base stations accommodates 10 layers of files, each video file contains 3 layers, and the content server contains 10 video files, for a total of 30 layers of files, only 10 layers of files can be cached from the content server, resulting in a caching probability of approximately 33%. During the caching of video files, both the base layer and enhancement layer files need to be cached simultaneously.

[0080] If the preset caching strategy is to cache by popularity, the multiple video files are sorted according to their popularity, and each video file is cached in order from high to low. After all L layers of each video file are cached, the next video file is cached until there is no cache capacity left. The cache probability of the cached video file is 1, and the cache probability of the uncacheable video file is 0.

[0081] During the caching process, the BL layer files are cached in each macro base station of the preset cellular network, and the EL layer files are cached in each micro base station of the preset cellular network.

[0082] Step 102: Determine whether at least some of the video files include the target video file according to the video acquisition request sent by the target user.

[0083] Specifically, the target user sends a video acquisition request to the preset cellular network. The video acquisition request includes the file identifier of the target video file. The radius of the target user is determined according to the location of the target user. The nearest micro base station within the range is the target micro base station, and the nearest macro base station is determined as the target macro base station. It is determined from the target macro base station whether there is a base layer file of the target video file, and it is determined from the target micro base station whether there is an enhancement layer file of the target video file.

[0084] Step 103: If at least part of the video files contain the target video file, the base layer file of the target video file is sent to the target user through the target macro base station, and at least one enhancement layer file of the target video file is superimposed on the target video file using a non-orthogonal transmission method through the target micro base station and then sent to the target user.

[0085] Specifically, if the base layer file of the target video file exists in the target macro base station, the base layer file of the target video file is sent to the target user through the target macro base station; if the enhancement layer file of the target video file exists in the target micro base station, the enhancement layer file of the target video file is sent to the target user through the target micro base station.

[0086] Among them, the target micro base station uses non-orthogonal transmission to send the enhanced layer file of the target video file to the target user. Non-orthogonal transmission is to superimpose the enhanced layer file of the target video file, and the target user uses decoding technology to decode the superimposed signal to obtain the enhanced layer file of the target video file.

[0087] The secure video transmission method based on scalable video coding provided in the above embodiment uses scalable video coding technology to cache video files in layers, and sends base layer files and enhancement layer files to users through macro base stations and micro base stations respectively, thereby improving video transmission efficiency.

[0088] In some possible implementations, Figure 3 The process of the secure video transmission method provided by the embodiment of the present invention Figure 2 ,like Figure 3 As shown, the process of superimposing at least one enhancement layer file of the target video file by the target micro base station in a non-orthogonal transmission manner and then sending the superimposed file to the target user in step 103 may include:

[0089] Step 201: Determine the number of layers of the enhancement layer file according to the video quality information in the video acquisition request.

[0090] Step 202: Based on the number of layers of the enhancement layer file, the target micro base station uses a non-orthogonal transmission method to superimpose the enhancement layer files of the corresponding number of layers of the target video file and then sends them to the target user.

[0091] Specifically, the base layer file contains basic and necessary information of the video file, the enhancement layer file contains enhanced information and improves the received video quality, and the video quality levels are divided according to the number of layers of the enhancement layer file, and the correspondence between the video quality and the number of layers of the enhancement layer file is determined. It is determined that the more layers the enhancement layer file has, the higher the video quality level, and the fewer layers the enhancement layer file has, the lower the video quality level.

[0092] The video quality information in the video acquisition request sent by the target user to the preset cellular network is the requested video quality level. According to the video quality level, the number of layers of the enhancement layer file is determined, and the target micro base station sends the enhancement layer file of the corresponding number of layers to the target user.

[0093] Furthermore, the target micro base station superimposes the enhanced layer files of the corresponding number of layers and sends them to the target user. The target user decodes the enhanced layer files of the corresponding number of layers from the superimposed signal, combines them with the basic layer files, and displays the content of the target video file on the target user's terminal device.

[0094] In some embodiments, the video quality level may be a video quality level selected by the target user through a video software program of the terminal device, or may be a video quality level automatically matched according to the network status of the terminal device, which is not limited in this embodiment.

[0095] The secure video transmission method based on scalable video coding provided in the above embodiment divides the enhancement layer files into multiple layers. Enhancement layer files of different numbers can provide different video quality to meet the diverse viewing needs of users. At the same time, it can flexibly adapt to dynamically changing network conditions, thereby improving the user content experience quality and alleviating network congestion problems.

[0096] In some possible implementations, Figure 4 The process of the secure video transmission method provided by the embodiment of the present invention Figure 3 ,like Figure 4 As shown, the secure video transmission method may further include:

[0097] Step 301: If at least some video files do not contain the target video file, obtain the base layer file and multiple enhancement layer files of the target video file from the content server via the target macro base station and the target micro base station based on the backhaul link.

[0098] Specifically, if the target macro base station does not contain the base layer file of the target video file and the target micro base station does not contain the enhancement layer file of the target video file, it is determined that the target video file is not cached and needs to be obtained from the content server.

[0099] The target macro base station sends a request to obtain the base layer file of the target video file to the content server via the backhaul link. The content server sends the base layer file of the target video file to the target macro base station via the backhaul link. The target micro base station sends a request to obtain the enhancement layer file of the target video file to the content server via the backhaul link. The content server sends the enhancement layer file of the target video file to the target micro base station via the backhaul link. The number of layers of the obtained enhancement layer file can be determined according to the method of step 201 above.

[0100] Step 302: Send the base layer file of the target video file to the target user through the target macro base station using the allocated first orthogonal channel resources, and send at least one enhancement layer file of the target video file to the target user through the target micro base station using the allocated second orthogonal channel resources.

[0101] Specifically, in order to avoid decoding interference caused by the target macro base station and the target micro base station sending the basic layer file and the enhanced layer file to the target user respectively, it is necessary to allocate orthogonal channel resources to the target macro base station and the target micro base station. Part of the orthogonal channel resources allocated to the target macro base station are the first orthogonal channel resources, and the other part of the orthogonal signal resources allocated to the target micro base station are the second orthogonal channel resources. The target macro base station sends the basic layer file of the target video file to the target user based on the first orthogonal channel resources, and the target micro base station sends the enhanced layer file of the target video file to the target user based on the second orthogonal channel resources.

[0102] The secure video transmission method based on scalable video coding provided in the above embodiment obtains the base layer file and enhancement layer file of the target video file from the content server through the backhaul link when the target video file is not cached, and sends the base layer file and enhancement layer file of the target video file to the user respectively based on the allocated orthogonal channel resources, thereby avoiding decoding interference between the base layer file and the enhancement layer file and ensuring correct decoding.

[0103] In some possible implementations, Figure 5 The process of the secure video transmission method provided by the embodiment of the present invention Figure 4 ,like Figure 5 As shown, the method may further include:

[0104] Step 401: Model a preset cellular network, where the preset cellular network includes: at least one macro base station, at least one micro base station, a target user, and at least one eavesdropper.

[0105] Step 402: Determine a first confidential cache auxiliary data rate for the base layer file based on a first request probability for the base layer file of at least a portion of the video file, a first cache probability, a first successful transmission probability for sending the base layer file of at least a portion of the video file, a confidentiality interruption probability, and a first minimum cache auxiliary data rate.

[0106] Step 403: Determine a second confidential cache auxiliary data rate for the enhancement layer files based on the second request probability of multiple enhancement layer files of at least a portion of the video file, the second cache probability, the second successful transmission probability of sending the enhancement layer files of at least a portion of the video file, and the second minimum cache auxiliary data rate.

[0107] Step 404: Determine a target confidential cache data rate of the preset cellular network based on the first confidential cache auxiliary data rate and the second confidential cache auxiliary data rate. The target confidential cache data rate is used to indicate the performance of caching and transmitting video files when an eavesdropper exists in the preset cellular network.

[0108] Specifically, in order to evaluate the performance of video transmission using the secure video transmission method provided by the present invention on a preset cellular network, a model is constructed for the preset cellular network, wherein the positions of MBS, SBS, and Eve are respectively modeled as Poisson point processes that follow independent and identical distributions. , , , and their density parameters are , , .

[0109] Among the legitimate users who have video viewing needs, one person is randomly selected as the target user, denoted as , the SBS with caching capability can send the requested content to its coverage radius Assuming that each node in the network is equipped with a single antenna, the invention denotes the target MBS and target SBS provided by the service as and .

[0110] The number of at least some video files is F, and the first request probability For the f The probability that the base layer file of a video file is requested by the user, the second request probability For the f The probability that each layer of the enhanced layer file of a video file is requested by the user can be obtained according to the f The popularity of video files is used to calculate the first request probability and the second request probability .

[0111] For example, the formula for calculating the first request probability and the second request probability can be expressed as:

[0112]

[0113] in, p(f) For the f The popularity of a video file, according to the Mandelbrot-Zipf law, ,in, is the skewness parameter, which reflects the degree of concentration of requests. A larger value means that less video content is sufficient to satisfy most user requests. q is the flatness factor, q The larger it is, the smaller the difference between the request probabilities of the most popular files.

[0114] First cache probability is the probability that the base layer file of the f-th video file is cached by the target macro base station, and the second cache probability is the probability that each enhancement layer file of the f-th video file is cached by the target micro base station, and the cache probability can be determined according to the aforementioned cache strategy.

[0115] First successful transmission probability Used to represent the probability of a macro base station successfully transmitting the base layer file of a video file requested by a user to a user. In this scheme, the first successful transmission probability of a target macro base station transmitting the base layer file of a target video file to a target user represents the probability of each macro base station successfully transmitting the base layer file of a video file requested by a user to its service user.

[0116] Second successful transmission probability Used to represent the probability of a micro base station successfully transmitting the enhanced layer file of a video file requested by a user to a user. In this scheme, the first successful transmission probability of a target micro base station transmitting the enhanced layer file of a target video file to a target user represents the probability of each micro base station successfully transmitting the enhanced layer file of a video file requested by a user to its service user.

[0117] Confidentiality interruption probability It is the probability of being eavesdropped by an eavesdropper when the macro base station sends the base layer file of the video file to the user.

[0118] First minimum buffer assist data rate Used to indicate the minimum data rate at which the macro base station sends the base layer file based on the allocated system bandwidth, the second minimum buffered auxiliary data rate Used to indicate the minimum data rate at which the micro base station sends the enhancement layer file based on the allocated system bandwidth.

[0119] The target secret cache data rate (Secrecy Cache-aided Data Rate, SCADR) can be calculated as follows:

[0120]

[0121] In some embodiments, the process of calculating the first successful transmission probability may include:

[0122] Based on the small-scale channel fading and distance between the target user and the target macro base station, and the small-scale channel fading and distance between the target user and other macro base stations, the first received signal-to-interference ratio of the target user receiving the base layer file is calculated; based on the density of at least one macro base station, the first probability density function of the distance between the target macro base station and the target user is determined; based on the first received signal-to-interference ratio and the first probability density function, the first successful transmission probability of sending each base layer file is calculated.

[0123] Specifically, the calculation formula of the first received signal-to-interference ratio can be expressed as:

[0124]

[0125] in, and Target users With the target MBS The small-scale channel fading between the MBS and other non-serving MBS follows a complex Gaussian distribution with a mean of 0 and a variance of 1, which is denoted as ; yes With target users the distance between them; Non-service MBS and target users the distance between them; is the path loss coefficient.

[0126] The target MBS is determined as follows: The distance between the users it serves r The first probability density function of:

[0127]

[0128] in is the density of MBS.

[0129] The success rate of BL transmission is determined as follows:

[0130]

[0131] Where Pr represents the probability calculation, It is the minimum reception threshold to ensure that the signal transmitted by MBS can be correctly decoded.

[0132] The first successful transmission probability in this case is obtained by the above formula:

[0133]

[0134] in, , , x is the integration variable.

[0135] For example, Figure 6 The simulation diagram of the first successful transmission probability of the base layer file provided in the embodiment of the present application is as follows: Figure 6 As shown in Figure 2, over 50,000 Monte Carlo simulations were performed for each QoS point. The simulation results show that the performance gap between the analytical results and the Monte Carlo simulation results is negligible. It is clear that the lower the QoS requirement, the higher the probability of first successful transmission.

[0136] In some embodiments, the process of calculating the second successful transmission probability may include:

[0137] Based on the small-scale channel fading and distance between the target user and the target micro base station, and the small-scale channel fading and distance between the target user and other micro base stations, the second received signal-to-interference ratio of the target user receiving the enhancement layer file is calculated; based on the density of at least one micro base station, the second probability density function of the distance between the target micro base station and the target user is determined; based on the second received signal-to-interference ratio and the second probability density function, the second successful transmission probability of sending each enhancement layer file is calculated.

[0138] Specifically, determine the The second received signal-to-interference ratio at the user when the enhancement layer file is transmitted is:

[0139]

[0140] Among them, from the target SBS and other non-serving SBS small-scale channel fading is denoted as and , they obey ; Target SBS With target users the distance between them; Non-service SBS and target users the distance between them; is the path loss coefficient.

[0141] Determine the distance between the nearest SBS and the users it serves by the following formula: r The second probability density function is:

[0142]

[0143] in is the density of SBS.

[0144] Press the formula to determine The probability of successful transmission of an enhancement layer file is:

[0145]

[0146] in, It is the minimum reception threshold to ensure that the SBS transmitted signal can be correctly decoded.

[0147] Through the above formula, we can get The probability of successful transmission of an EL is:

[0148]

[0149] in, , , is the power transmission factor. Since the enhancement layer file needs to be superimposed and transmitted in the power domain, a power allocation factor is applied to each enhancement layer file.

[0150] For example, Figure 7(a) shows a simulation diagram of the second successful transmission probability of a first-layer enhancement layer file provided by an embodiment of the present application, and Figure 7(b) shows a simulation diagram of the second successful transmission probability of a second-layer enhancement layer file provided by an embodiment of the present application. As shown in Figures 7(a) and 7(b), the number of enhancement layer files is 2. The correctness of the successful transmission probabilities of EL1 and EL2 was verified, respectively. Over 50,000 Monte Carlo simulations were performed for each QoS point. The simulation results show that the performance gap between the analytical results and the Monte Carlo simulation results is negligible. It can be seen that the lower the quality of service (QoS) requirement, the higher the second successful transmission probability.

[0151] In some embodiments, the process of calculating the probability of a privacy outage may include:

[0152] The third received signal-to-interference ratio of each eavesdropper is determined based on the channel fading and distance between each eavesdropper and the eavesdropped macro base station, as well as the channel fading and distance between each eavesdropper and the non-eavesdropped macro base station; the confidentiality interruption probability is calculated based on the density of at least one eavesdropper, the density of at least one macro base station and the third received signal-to-interference ratio.

[0153] Specifically, the following formula is used to determine the The third received signal-to-interference ratio of Eve is:

[0154]

[0155] in, and Respectively The channel fading between Eve and the eavesdropped MBS and other MBSs that are not eavesdropped obeys ; MBS and the first The distance between Eves; MBS and the first The distance between Eves; is the path loss coefficient.

[0156] The confidentiality interruption probability of BL is determined as follows:

[0157]

[0158] in, is the predetermined threshold used by Eve to receive the signal.

[0159] Using random geometry tools, we can obtain the probability of confidentiality interruption when transmitting base layer files:

[0160]

[0161] in, is the density of Eve, for The lower limit of the integral is 0, which is the integral result of .

[0162] For example, Figure 8 The simulation diagram of the confidentiality interruption probability of the base layer file provided in the embodiment of the present application is as follows: Figure 8 As shown in Figure 2, more than 50,000 Monte Carlo simulations were performed for each QoS point. The simulation results show that the performance gap between the analytical results and the Monte Carlo simulation results is negligible. It can be seen that the lower the QoS requirement, the higher the probability of confidentiality interruption.

[0163] In some embodiments, the process of calculating the first minimum buffer assistance data rate may include:

[0164] A first minimum buffered assistance data rate is calculated according to the transmission bandwidth of the target macro base station and the minimum reception threshold of the base layer file.

[0165] Specifically, the first minimum buffer auxiliary data rate , is the system bandwidth allocated for MBS transmission.

[0166] In some embodiments, the process of calculating the second minimum buffer assistance data rate may include:

[0167] The second minimum buffered auxiliary data rate is calculated based on the transmission bandwidth of the target micro base station and the minimum reception threshold of the enhancement layer file.

[0168] Specifically, the second minimum buffer auxiliary data rate , Indicates the system bandwidth allocated for SBS transmission.

[0169] Based on the above formula, the calculation formula of the target confidential cache data rate SCADR can be expressed as:

[0170]

[0171] For example, Figure 9 This is a simulation diagram of the target confidentiality cache data rate provided by the embodiment of the present application, such as Figure 9As shown in Figure 3, comparing the two schemes of equal probability caching and popularity caching, it can be seen that the SCADR of popularity caching is better than the SCADR of equal probability caching. This is because equal probability caching ignores the content popularity and viewing quality preferences of different videos and layers.

[0172] Based on the above method embodiment, an embodiment of the present invention provides a secure video transmission device based on scalable video coding. Figure 10 A schematic diagram of a secure video transmission device provided in an embodiment of the present application is shown in FIG. Figure 10 As shown, the device may include:

[0173] a caching module, configured to cache, in a predetermined caching strategy, a base layer file and a plurality of enhancement layer files of at least part of the video files in the content server in a predetermined target macro base station and a predetermined target micro base station of the cellular network;

[0174] a determination module, configured to determine whether at least part of the video files contain a target video file based on a video acquisition request sent by a target user;

[0175] A sending module is used to send the base layer file of the target video file to the target user through the target macro base station if at least part of the video file contains the target video file, and to superimpose at least one enhanced layer file of the target video file using a non-orthogonal transmission method through the target micro base station and then send it to the target user.

[0176] Optionally, the sending module is also used to determine the number of layers of the enhancement layer file based on the video quality information in the video acquisition request; based on the number of layers of the enhancement layer file, the enhancement layer files of the corresponding number of layers of the target video file are superimposed by the target micro base station using a non-orthogonal transmission method and then sent to the target user.

[0177] Optionally, the device further comprises:

[0178] an acquisition module, configured to acquire, if at least some of the video files do not contain the target video file, a base layer file and multiple enhancement layer files of the target video file from a content server via a target macro base station and a target micro base station based on a backhaul link;

[0179] The sending module is also used to send the base layer file of the target video file to the target user through the target macro base station using the allocated first orthogonal channel resources, and to send at least one enhanced layer file of the target video file to the target user through the target micro base station using the allocated second orthogonal channel resources.

[0180] Optionally, the device further comprises:

[0181] A modeling module, configured to model a preset cellular network, wherein the preset cellular network includes: at least one macro base station, at least one micro base station, a target user, and at least one eavesdropper;

[0182] a calculation module configured to determine a first confidentiality cache assistance data rate for the base layer file based on a first request probability for the base layer file of at least a portion of the video file, a first cache probability, a first successful transmission probability of sending the base layer file of at least a portion of the video file, a confidentiality interruption probability, and a first minimum cache assistance data rate;

[0183] The calculation module is further configured to determine a second confidential cache assistance data rate for the enhancement layer files based on the second request probability of the plurality of enhancement layer files of the at least portion of the video file, the second cache probability, the second successful transmission probability of sending the enhancement layer files of the at least portion of the video file, and the second minimum cache assistance data rate;

[0184] The calculation module is also used to determine the target confidential cache data rate of the preset cellular network based on the first confidential cache auxiliary data rate and the second confidential cache auxiliary data rate. The target confidential cache data rate is used to indicate the performance of caching and transmitting video files when there is an eavesdropper in the preset cellular network.

[0185] Optionally, the calculation module is also used to calculate the first received signal-to-interference ratio of the target user receiving the base layer file based on the small-scale channel fading and distance between the target user and the target macro base station, and the small-scale channel fading and distance between the target user and other macro base stations; determine the first probability density function of the distance between the target macro base station and the target user based on the density of at least one macro base station; and calculate the first successful transmission probability of sending each base layer file based on the first received signal-to-interference ratio and the first probability density function.

[0186] Optionally, the calculation module is also used to calculate the second received signal-to-interference ratio of the target user receiving the enhanced layer file based on the small-scale channel fading and distance between the target user and the target micro base station, and the small-scale channel fading and distance between the target user and other micro base stations; determine the second probability density function of the distance between the target micro base station and the target user based on the density of at least one micro base station; and calculate the second successful transmission probability of sending each enhanced layer file based on the second received signal-to-interference ratio and the second probability density function.

[0187] Optionally, the calculation module is also used to determine the third received signal-to-interference ratio of each eavesdropper based on the channel fading and distance between each eavesdropper and the eavesdropped macro base station, and the channel fading and distance between each eavesdropper and the non-eavesdropped macro base station; and calculate the confidentiality interruption probability based on the density of at least one eavesdropper, the density of at least one macro base station and the third received signal-to-interference ratio.

[0188] Optionally, the calculation module is further configured to calculate a first minimum cache auxiliary data rate according to a transmission bandwidth of the target macro base station and a minimum receiving threshold of the base layer file.

[0189] Optionally, the calculation module is further used to calculate a second minimum cache auxiliary data rate based on the transmission bandwidth of the target micro base station and the minimum reception threshold of the enhancement layer file.

[0190] The above-mentioned device is used to execute the method provided in the above-mentioned embodiment. Its implementation principle and technical effect are similar and will not be repeated here.

[0191] The above modules can be one or more integrated circuits configured to implement the above methods, such as one or more application-specific integrated circuits (ASICs), one or more microprocessors, or one or more field programmable gate arrays (FPGAs). For example, when a module is implemented by scheduling program code through a processing element, the processing element can be a general-purpose processor, such as a central processing unit (CPU) or other processor that can call program code. For another example, these modules can be integrated together and implemented in the form of a system-on-a-chip (SOC).

[0192] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A secure video transmission method based on scalable video coding, characterized in that: The method comprises: According to a preset caching strategy, hierarchically cache the base layer file and multiple enhancement layer files of at least part of the video file in the content server in a target macro base station and a target micro base station of a preset cellular network respectively; Determining, based on a video acquisition request sent by a target user, whether the at least part of the video files includes a target video file; If the at least part of the video files includes the target video file, sending the base layer file of the target video file to the target user through the target macro base station, and superimposing at least one enhancement layer file of the target video file by using a non-orthogonal transmission method through the target micro base station and then sending the superimposed file to the target user; The method further comprises: Modeling the preset cellular network, wherein the preset cellular network includes: at least one macro base station, at least one micro base station, the target user, and at least one eavesdropper; determining a first confidentiality cache assistance data rate for the base layer file based on a first request probability for the base layer file of the at least portion of the video file, a first cache probability, a first successful transmission probability of sending the base layer file of the at least portion of the video file, a confidentiality interruption probability, and a first minimum cache assistance data rate; determining a second secure cache assistance data rate for the enhancement layer files based on a second request probability of the plurality of enhancement layer files of the at least portion of the video file, a second cache probability, a second successful transmission probability of sending the enhancement layer files of the at least portion of the video file, and a second minimum cache assistance data rate; determining a target confidential cache data rate of the preset cellular network according to the first confidential cache auxiliary data rate and the second confidential cache auxiliary data rate, wherein the target confidential cache data rate indicates a performance of caching and transmitting video files in the preset cellular network when the eavesdropper exists; The method further comprises: Determining a third received signal-to-interference ratio of each eavesdropper based on the channel fading and distance between each eavesdropper and the eavesdropped macro base station, and the channel fading and distance between each eavesdropper and the non-eavesdropped macro base station; The privacy interruption probability is calculated according to the density of the at least one eavesdropper, the density of the at least one macro base station and the third received signal-to-interference ratio.

2. The method according to claim 1, wherein The superimposing at least one enhancement layer file of the target video file by the target micro base station in a non-orthogonal transmission manner and then sending the superimposed file to the target user includes: Determining the number of layers of the enhancement layer file according to the video quality information in the video acquisition request; According to the number of layers of the enhancement layer file, the target micro base station uses the non-orthogonal transmission method to superimpose the enhancement layer files of the corresponding number of layers of the target video file and then sends them to the target user.

3. The method according to claim 1, wherein The method further comprises: If the at least part of the video files does not include the target video file, obtaining the base layer file and multiple enhancement layer files of the target video file from the content server through the target macro base station and the target micro base station based on a backhaul link respectively; The target macro base station uses the allocated first orthogonal channel resources to send the base layer file of the target video file to the target user, and the target micro base station uses the allocated second orthogonal channel resources to send at least one enhancement layer file of the target video file to the target user.

4. The method according to claim 1, wherein The method further comprises: Calculating a first received signal-to-interference ratio for receiving the base layer file by the target user based on small-scale channel fading and distance between the target user and the target macro base station, and small-scale channel fading and distance between the target user and other macro base stations; Determining a first probability density function of a distance between the target macro base station and the target user based on the density of the at least one macro base station; A first successful transmission probability of sending each of the base layer files is calculated according to the first received signal-to-interference ratio and the first probability density function.

5. The method according to claim 1, wherein The method further comprises: Calculating a second received signal-to-interference ratio for receiving the enhancement layer file by the target user based on small-scale channel fading and distance between the target user and the target micro base station, and small-scale channel fading and distance between the target user and other micro base stations; Determining a second probability density function of a distance between the target micro base station and the target user based on a density of the at least one micro base station; A second successful transmission probability of sending each of the enhancement layer files is calculated according to the second received signal-to-interference ratio and the second probability density function.

6. The method according to claim 1, wherein The method further comprises: The first minimum cache assistance data rate is calculated according to the transmission bandwidth of the target macro base station and the minimum reception threshold of the base layer file.

7. The method according to claim 1, wherein The method further comprises: The second minimum cache assistance data rate is calculated based on the transmission bandwidth of the target micro base station and the minimum reception threshold of the enhancement layer file.

8. A secure video transmission device based on scalable video coding, characterized in that: The device comprises: a caching module, configured to cache, in a predetermined caching strategy, a base layer file and a plurality of enhancement layer files of at least part of the video files in the content server in a predetermined target macro base station and a predetermined target micro base station of the cellular network; a determination module, configured to determine whether the at least part of the video files includes a target video file according to a video acquisition request sent by a target user; a sending module, configured to, if the at least part of the video files includes the target video file, send a base layer file of the target video file to the target user via the target macro base station, and superimpose at least one enhancement layer file of the target video file on the target video file using a non-orthogonal transmission method via the target micro base station and then send the superimposed file to the target user; The device further comprises: A modeling module, configured to model the preset cellular network, wherein the preset cellular network includes: at least one macro base station, at least one micro base station, the target user, and at least one eavesdropper; a calculation module, configured to determine a first confidentiality cache assistance data rate for the base layer file based on a first request probability for the base layer file of the at least portion of the video file, a first cache probability, a first successful transmission probability of sending the base layer file of the at least portion of the video file, a confidentiality interruption probability, and a first minimum cache assistance data rate; The calculation module is further configured to determine a second confidential cache assistance data rate for the enhancement layer file based on a second request probability of the plurality of enhancement layer files of the at least partial video file, a second cache probability, a second successful transmission probability of sending the enhancement layer file of the at least partial video file, and a second minimum cache assistance data rate; The calculation module is further configured to determine a target confidential cache data rate of the preset cellular network based on the first confidential cache auxiliary data rate and the second confidential cache auxiliary data rate, wherein the target confidential cache data rate indicates a performance of caching and transmitting video files in the preset cellular network when the eavesdropper exists; The calculation module is also used to determine the third received signal-to-interference ratio of each eavesdropper based on the channel fading and distance between each eavesdropper and the eavesdropped macro base station, as well as the channel fading and distance between each eavesdropper and the non-eavesdropped macro base station; and calculate the confidentiality interruption probability based on the density of the at least one eavesdropper, the density of the at least one macro base station and the third received signal-to-interference ratio.

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