JP2011019068A - Quality control device, quality control system, quality control method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a quality control system capable of specifying a terminal to be degraded in QoE (Quality of Experience) in the case of improving user's QoE in a certain terminal, and then appropriately degrading the QoE of the terminal.SOLUTION: The quality control system includes: a storing means for storing a rule obtained by associating a distribution condition of the terminal with the quality value of QoE under the distribution condition; a quality control method selecting means for reading a predetermined rule from the storing means and calculating a variation of bandwidth needed for quality control on the basis of a difference between a distribution condition of the read rule and the distribution condition of the terminal for each read rule; a control method determining means for respectively selecting an improvement rule and an reduction rule which satisfy a condition on which an increment does not exceed a decrement; and a distribution control means for changing the distribution condition of the terminal to that of the improvement rule or the reduction rule.

Description

  The present invention relates to a quality control apparatus that performs distribution control in consideration of the user experience quality of the entire service.

  In a content distribution service via an IP (Internet Protocol) network, if the network quality deteriorates due to the occurrence of packet loss or the like, for example, media data received by a receiving terminal receiving the service may be lost. At this time, the quality of the received content is reduced at the receiving terminal. Then, in this receiving terminal, the user experience quality (hereinafter sometimes referred to as QoE (Quality of Experience)), which is the subjective quality experienced by the user, decreases.

  In the content distribution service, in order for the quality control device that performs distribution control to ensure QoE in the receiving terminal, the quality control device controls to ensure the network quality between the content distributing device and the receiving terminal. May be effective.

  Techniques for improving QoE in the receiving terminal are described in, for example, Patent Document 1, Patent Document 2, and Patent Document 3.

  The quality control system of the bidirectional video communication service disclosed in Patent Document 1 includes a communication terminal, a quality management device, and a quality control device, and operates as follows.

  The quality control system obtains a predicted QoE quality value (user experience quality value) for each connected communication terminal in a state where there is no quality deterioration between the communication terminals. And a quality control system makes the control object the communication terminal in which QoE more than a certain threshold value is anticipated. Next, the quality control system collects user experience quality values of individual communication terminals, and calculates a user experience quality value of the entire service from the collected quality values. The quality control system compares the user experience quality value of the entire service with a certain threshold value, and executes quality control when the user experience quality value of the entire service is equal to or less than the threshold value.

  In the technique described in Patent Document 1 having such characteristics, the quality control system brings the user experience quality value on the receiving terminal side having a low QoE closer to the maximum value of QoE predicted by communication using the network. Control can be performed.

  The network measurement control system of Patent Document 2 includes a storage device and a control unit, and operates as follows.

  The control unit receives measurement value data such as a delay for each flow to be measured in the network. Then, when the measured value exceeds a predetermined upper limit value stored in the storage unit, the control unit increases the bandwidth allocated to the measurement target flow. On the other hand, when the measured value falls below a predetermined lower limit value stored in the storage unit, the control unit reduces the bandwidth allocated to the measurement target flow. When the control unit increases the bandwidth allocated to the measurement target flow, the control unit decreases the bandwidth allocated to the non-measurement target flow by the increased bandwidth.

  With the technique described in Patent Document 2 having such characteristics, it is possible to perform an optimal bandwidth allocation according to the network status.

  The resource amount allocating device disclosed in Patent Document 3 includes a receiving unit, a dissatisfaction calculating unit, and a bandwidth determining unit, and operates as follows.

  When the receiving unit receives the subjective quality value for each user from the terminal used by each user, the receiving unit passes the received subjective quality value to the dissatisfaction degree calculating unit. The dissatisfaction degree calculation unit calculates the dissatisfaction degree of the user based on the received subjective quality value. The bandwidth determination unit determines a resource amount to be allocated based on the user's dissatisfaction level calculated by the dissatisfaction level calculation unit and a fee determined according to the allocated bandwidth.

  In the technique described in Patent Document 3 having such a feature, the resource allocation amount can be determined based on the subjective quality requirement of the user and the fee determined according to the allocated bandwidth. Allocate resources with good performance.

JP 2007-221318 A JP 2002-16599 A JP-A-11-68840 JP 2007-135040 A

ITU-T Recommendation J.246, “Perceptual visual quality measurement techniques for multimedia services over digital cable television networks in the presence of a reduced bandwidth reference”, 2008 ITU-T Recommendation G.1070, “Opinion model for video-telephony applications”, 2007

However, any of the above-mentioned patent documents has a problem that when QoE is improved with respect to a certain terminal, a terminal that lowers QoE is specified and the QoE of the terminal cannot be lowered appropriately. This is because the quality control system does not consider the influence on other terminals when improving QoE for a certain terminal.
[Object of invention]
An object of the present invention is to provide a quality control system that identifies a terminal that lowers QoE when improving QoE for a certain terminal, and can appropriately lower the QoE of the terminal.

  The first quality control apparatus according to the present invention provides a rule that associates a distribution condition including an attribute indicating characteristics when distributing content to a terminal with an estimated quality value of a user experience quality obtained under the distribution condition. Control information storage means for storing and a first rule whose estimated quality value is a rule higher than the user experience quality value of the first terminal is selected and read from the control information storage means, and for each first rule Bandwidth increment for raising the user experience quality value of the first terminal to the estimated quality value of the first rule based on the difference between the delivery condition of the first rule and the delivery condition of the first terminal The second rule, which is a rule whose estimated quality value is lower than the user experience quality value of the second terminal, is selected and read from the control information storage means, and the second rule is read for each second rule. Delivery conditions and A quality control method for calculating a bandwidth decrement when the user experience quality value of the second terminal is lowered to the estimated quality value of the second rule based on a difference from the delivery condition of the second terminal Control method determination for selecting selection means and one or more improvement rules from the first rule and one or more reduction rules from the second rule satisfying a condition that the calculated increment does not exceed the calculated decrement And a delivery control means for changing the delivery condition of the first terminal to the delivery condition of the improvement rule and changing the delivery condition of the second terminal to the delivery condition of the reduction rule.

  The first quality control system of the present invention provides a rule that associates a delivery condition including an attribute indicating characteristics when delivering content to a terminal and an estimated quality value of a user experience quality obtained under the delivery condition. Control information storage means for storing and a first rule whose estimated quality value is a rule higher than the user experience quality value of the first terminal is selected and read from the control information storage means, and for each first rule Bandwidth increment for raising the user experience quality value of the first terminal to the estimated quality value of the first rule based on the difference between the delivery condition of the first rule and the delivery condition of the first terminal The second rule, which is a rule whose estimated quality value is lower than the user experience quality value of the second terminal, is selected and read from the control information storage means, and the second rule is read for each second rule. Delivery terms Control that calculates a decrement of bandwidth when the user experience quality value of the second terminal is lowered to the estimated quality value of the second rule based on the difference between the distribution condition of the second terminal and the second terminal Method selection means and a control method for selecting one or more improvement rules from the first rule and one or more reduction rules from the second rule that satisfy a condition that the calculated increment does not exceed the calculated decrement Quality control comprising: a determining unit; and a distribution control unit that changes the distribution condition of the first terminal to the distribution condition of the improvement rule and changes the distribution condition of the second terminal to the distribution condition of the reduction rule. And a terminal that transmits to the quality control device a distribution condition for receiving content distribution and an estimated quality value of user experience quality obtained under the distribution condition.

  In the first quality control method of the present invention, a rule that associates a delivery condition including an attribute indicating characteristics when delivering content to a terminal with an estimated quality value of a user experience quality obtained under the delivery condition is provided. A rule storage step to store in the control information storage means, and a first rule whose estimated quality value is higher than the user experience quality value of the first terminal is selected and read from the control information storage means, and the first For increasing the user experience quality value of the first terminal to the estimated quality value of the first rule based on the difference between the distribution condition of the first rule and the distribution condition of the first terminal for each rule The bandwidth increment is calculated, and the second rule which is a rule whose estimated quality value is lower than the user experience quality value of the second terminal is selected and read from the control information storage means, and the second rule is determined for each second rule. second Based on the difference between the rule delivery condition and the second terminal delivery condition, the bandwidth decrement when the user experience quality value of the second terminal is lowered to the estimated quality value of the second rule is A quality control method selection step to calculate, and one or more improvement rules from the first rule and one or more reduction rules from the second rule satisfying a condition that the calculated increment does not exceed the calculated decrement. A control method determining step to select, a distribution control step of changing the distribution condition of the first terminal to the distribution condition of the improvement rule, and changing the distribution condition of the second terminal to the distribution condition of the reduction rule; Is provided.

  The first program of the present invention is a rule in which a distribution condition including an attribute indicating characteristics when content is distributed to a terminal and an estimated quality value of a user experience quality obtained under the distribution condition are associated with a computer. Is stored in the control information storage means, and the first rule whose estimated quality value is higher than the user experience quality value of the first terminal is selected and read from the control information storage means, and the first To raise the user experience quality value of the first terminal to the estimated quality value of the first rule based on the difference between the delivery condition of the first rule and the delivery condition of the first terminal for each rule The second rule, which is a rule whose estimated quality value is lower than the user experience quality value of the second terminal, is selected and read from the control information storage means, and each second rule is calculated. Bandwidth when the user experience quality value of the second terminal is lowered to the estimated quality value of the second rule based on the difference between the delivery condition of the second rule and the delivery condition of the second terminal A quality control method selection process for calculating a decrement of the first rule, an improvement rule that is one of the first rules that satisfy a condition that the calculated increment does not exceed the calculated decrement, and one of the second rule Control method determination processing for selecting a reduction rule, and the distribution condition of the first terminal is changed to the distribution condition of the improvement rule, and the distribution condition of the second terminal is changed to the distribution condition of the reduction rule Distribution control processing to be executed.

  The first effect of the present invention is that an appropriate terminal can be specified when QoE is improved for a certain terminal, and the QoE of the terminal can be appropriately reduced.

FIG. 1 is a schematic diagram showing a configuration of a quality control system according to the first embodiment of the present invention. FIG. 2 is a block diagram showing the configuration of the quality control system according to the first embodiment of the present invention. FIG. 3 shows an example of terminal information stored in the terminal information storage means. FIG. 4 is a block diagram showing a configuration of the quality control apparatus 2 according to the first embodiment of the present invention. FIG. 5 shows an example of rules stored in the control information storage unit 24 when a plurality of attributes are included as attributes of the distribution condition. FIG. 6 shows an example of terminal information of the control target terminal a. FIG. 7 shows an example of the rules stored in the control information storage unit 24 when the content bit rate is included as an attribute of the distribution condition. FIG. 8 shows an example of the terminal information of the control target terminal b. FIG. 9 shows the variation of the bandwidth calculated by the quality control method selection means 21 for each rule. FIG. 10 is a flowchart showing an operation example of the first exemplary embodiment of the present invention. FIG. 11 is a block diagram showing a configuration example of the quality control apparatus 2 in the sixth modification example of the first embodiment of the present invention. FIG. 12 is a block diagram showing a configuration example of the quality control system according to the second embodiment of the present invention. FIG. 13 shows an example of control information stored in the control information storage means 64. FIG. 14 shows (1) terminal information of the control target terminal a, (2) rules stored in the control information storage unit 64, and (3) control information when the packet loss rate is included as an attribute of the distribution condition. One example of control information stored in the storage means 64 is shown. FIG. 15 shows (1) terminal information of the control target terminal a, (2) rules stored in the control information storage means 64, and (3) control when the frame rate of the content is included as an attribute of the distribution condition. One example of control information stored in the information storage means 64 is shown. FIG. 16 shows (1) terminal information of the control target terminal a, (2) rules stored in the control information storage means 64, and (3) control when content resolution information is included as an attribute of distribution conditions. One example of control information stored in the information storage means 64 is shown. FIG. 17 shows (1) terminal information of the control target terminal a, (2) rules stored in the control information storage means 64, and (3) control information when content hierarchy information is included as an attribute of distribution conditions. The control information stored in the storage means 64 and (4) an example of the hierarchical structure of hierarchically encoded content are respectively shown. FIG. 18 is a flowchart showing an operation example of the second exemplary embodiment of the present invention. FIG. 19 is a block diagram showing a configuration example in the first modification of the second embodiment of the present invention. FIG. 20 shows an example of a control policy including a plurality of types of situation information stored in the policy storage unit 66. FIG. 21 shows an example of a control policy in which content identification information stored in the policy storage unit 66 is included as status information. FIG. 22 shows an example of a control policy in which the information amount per frame stored in the policy storage unit 66 is included as status information. FIG. 23 shows an example of control policies stored in the policy storage means 66 that are different between when quality is improved and when it is lowered.

  The following is a detailed description of the best mode for carrying out the invention. In each drawing and each embodiment described in this specification, the same reference numerals are given to components having similar functions.

[First Embodiment]
[Description of configuration]
FIG. 1 is a schematic diagram showing a configuration example of a quality control system according to the first embodiment of the present invention. FIG. 2 is a block diagram showing a configuration example of the quality control system according to the first embodiment of the present invention. The quality control system includes a terminal 1, a quality control device 2, a bandwidth management device 3, and a content distribution device 4, which are connected via a network 5.

  The following is a description of each component included in the quality control system.

=== Terminal 1 ===
As shown in FIG. 2, the terminal 1 includes a sensation quality estimation unit 10, a network quality information collection unit 11, and a terminal information transmission unit 12. The sensation quality estimation means 10 is connected to the terminal information transmission means 12, and the network quality information collection means 11 is connected to the terminal information transmission means 12.

  The terminal 1 may be a communicable device such as a personal computer (PC (Personal Computer)) or a set top box (STB). The terminal 1 may be a communication terminal such as a mobile phone or a personal digital assistant (PDA).

  The following is a description of each component included in the terminal 1.

<Experience quality estimation means 10>
The bodily sensation quality estimation means 10 estimates the QoE of the user who is viewing this content for the content being played back by the display means (not shown) provided in the terminal 1. In the present specification, the content may be data including sound and moving image, or may be data including only sound or only moving image. The content may include any information such as images and character information.

  In this specification, QoE refers to a subjective quality value experienced by a user receiving a content distribution service. Also, the content distribution service refers to a service that receives content distribution from the content distribution device 4.

  Examples of methods for estimating the QoE by the sensation quality estimation means 10 include the following methods.

  For example, as a method described above, there is a media layer model that estimates QoE by using a media signal of content as an input. Specifically, there are the following models as media layer models. The first is a FR (Full-Reference) method for estimating QoE by comparing the media signal (original signal) of the content distributed by the content distribution device 4 with the media signal (degraded signal) of the content received by the terminal 1. It is. The second is an NR (No-Reference) method that estimates QoE using only degraded signals. The third is an RR (Reduced Reference) method for estimating QoE using a part of information of an original signal and a degraded signal.

  As a specific example of the above-described NR method, for example, there is the following method. The content distribution apparatus 4 stores at least the type or location of each picture of content data included in each packet at the time of content distribution. For example, it is assumed that the content is encoded by H.264. The types of pictures of the content data are, for example, an I picture (Intra Picture), a B picture (Bi-directional Predictive Picture), and a P picture (Predictive Picture). The location of each picture of the content data indicates information such as “a packet includes the first half 5/7 of the I picture”. When the terminal 1 receives the content, the terminal 1 detects which packet of the content is lost. Then, the terminal 1 estimates the user experience quality value based on the detected lost packet and the terminal specifications (eg, screen size) of the terminal 1.

  As a specific example of the above-mentioned RR method, there is a method of Non-Patent Document 1, which is a technology approved by an international standardization organization ITU-T (International Telecommunication Union Telecommunication Standardization Sector).

  Further, there are the following methods for estimating QoE other than the media layer model. The first is a packet layer model that uses only the header information included in the packet header of the content received by the terminal 1 without directly using the content degradation signal. The second is a bit stream model that estimates QoE using the header information described above and a bit string before decryption of content distributed by the content distribution device 4. The third is a planning model. This method is as follows. The system administrator prepares specific content in advance and obtains an average user experience quality value for each content. The system administrator designs encoding parameters and the like at the time of content distribution based on the average user experience quality value.

  As a specific example of the packet layer model, there is a method described in Patent Document 4. Patent Document 4 describes the following method. The sensation quality estimation device collects header information of media packets transmitted by the transmission side terminal and media packets received by the reception side terminal. Then, the sensible quality estimation device calculates the proportion of invalid frames (invalid frame rate) affected by packet loss among the above-described media packets based on the header information. Then, the sensation quality estimation device estimates QoE from the above-described invalid frame rate.

  As a specific example of the planning model, there is a method described in Non-Patent Document 2. The technique described in Non-Patent Document 2 is a method well known as E-model in bidirectional video / audio communication.

  Further, the sensation quality estimation unit 10 may receive a user sensation quality value from the user and use the input value as the user sensation quality value output by the sensation quality estimation unit 10. Assume that the user inputs a user experience quality value using, for example, MOS (Mean Opinion Score) as a scale. In this case, the user senses what the user feels most applicable from five levels of 1 (very bad), 2 (bad), 3 (normal), 4 (good), and 5 (very good). 10 will be input.

  The methods listed above are examples, and the method by which the sensation quality estimation means 10 estimates QoE is not limited to the above method. Moreover, it is also possible to implement | achieve combining the method mentioned above as a method with which the bodily sensation quality estimation means 10 estimates QoE.

  In this specification, it is assumed that the user inputs a user experience quality value to the experience quality estimation means 10 using MOS as a scale. The advantage of using MOS as the user experience quality value is that even when the network quality is the same, it is possible to grasp the case where QoE is different. For example, it is assumed that the terminal 1 capable of reproducing HD resolution content is receiving SD resolution content due to bandwidth limitations or the like. In this case, it may happen that the network quality at the terminal 1 is good but the QoE is not sufficient. Further, it is assumed that the terminal 1 receives content at a resolution suitable for the terminal. In this case, QoE may be different depending on which portion of the data when the packet lost due to packet loss is the content displayed on the terminal 1. Therefore, in the method in which the value input by the user is used as the user experience quality value, it is possible to determine a difference in QoE that cannot be determined only by network quality.

<Network quality information collecting means 11>
The network quality information collecting unit 11 collects information (hereinafter, also referred to as distribution conditions) related to reception quality for content packets received by the terminal 1. For example, the distribution condition may include information on the network such as a packet loss rate, a burst loss rate, and the presence / absence of a priority flag / non-priority flag for each packet. In addition, the distribution conditions may include information on content such as FEC (Forward Error Correction) strength, reception bit rate (reception band), content encoding method, bit rate, resolution, and frame rate. These are merely examples, and it is only necessary that the distribution conditions include at least one piece of information indicating the reception quality of the content packet received by the terminal 1.

  The distribution condition may also be defined as information including an attribute indicating characteristics when the content distribution device 4 distributes content. In this case, the attribute refers to information about each network and information about each content.

  Here, the packet loss rate is the ratio of the number of missing packets to the total number of packets of content. The burst loss rate indicates the ratio of the number of packets lost due to burst loss among the lost packets. Burst loss means that two or more packets are continuously lost.

  FEC is a technology shown below. First, a content distribution apparatus divides content into blocks of a certain size. The distribution apparatus adds a redundant code for error correction to each divided block, and transmits each block to the content reproduction apparatus. If the playback device fails to receive all of the blocks transmitted from the distribution device, the playback device restores a part of the content using the redundant code added to the received block. With the FEC, as the distribution device increases the amount of redundant code for error correction added to each block of content, the playback device can restore more blocks.

  The network quality information collecting unit 11 may collect information on the type of access network used by the terminal 1 to connect to the Internet, the current location of the terminal 1, and the date and time of data collection.

<Terminal information transmitting means 12>
The terminal information transmission unit 12 transmits terminal information that is information including the user experience quality value estimated by the experience quality estimation unit 10 and the distribution conditions collected by the network quality information collection unit 11. The terminal information transmitting unit 12 may transmit the terminal information described above using a protocol capable of transmitting the distribution conditions of the terminal 1. An example of the protocol is RTCP XR (RTP (Real-time Transport Protocol) control protocol extended reports). The terminal information transmission unit 12 may transmit the terminal information to the quality control device 2. The terminal information transmitting unit 12 may transmit terminal information to a terminal information management device (not shown), and the terminal information management device may transmit the above-described terminal information to the quality control device 2.

  Each of the information transmitted to the quality control device 2 may be stored in a terminal information storage unit (not shown) provided in the quality control device 2. An example of terminal information stored in the terminal information storage means is shown in FIG. As shown in FIG. 3, the terminal information includes, for example, content distribution conditions such as content coding scheme, resolution, frame rate, content bit rate, and FEC intensity. In addition, the terminal information includes, for example, distribution conditions related to the network such as a packet loss rate and the presence / absence of a priority / non-priority flag of a packet (TOS (Type of Service) presence / absence). The terminal information includes, for example, a user experience quality value, an IP address of the terminal 1, a data acquisition date, a data acquisition time, a type of access network, and the like.

=== Quality Control Device 2 ===
FIG. 4 is a block diagram showing a configuration example of the quality control apparatus 2 according to the first embodiment of the present invention.

  As shown in FIG. 4, the quality control apparatus 2 includes a quality control method selection unit 21, a control method determination unit 22, a distribution control unit 23, and a control information storage unit 24. The quality control method selection means 21 is a control method determination means 22 and a control information storage means 24, the control method determination means 22 is a quality control method selection means 21, a distribution control means 23, and the distribution control means 23 is a control method determination means. 22 respectively.

  The following is a description of each component included in the quality control device 2.

<Control information storage means 24>
As shown in FIG. 5, the control information storage unit 24 includes a distribution condition, and a user experience quality value estimated when it is assumed that there is no transmission deterioration on the network when content is distributed under the distribution condition. Is stored. In the present specification, the user experience quality value estimated as described above may be referred to as an estimated quality value.

  Referring to the example of FIG. 5, “encoding method”, “content bit rate”, “resolution”, and “frame rate” are distribution conditions. “Estimated MOS” is an estimated quality value under the above-described distribution conditions. For example, the rule A distribution conditions include an encoding method “H.264 / AVC”, a content bit rate “10 [Mbps]”, a resolution “HD”, and a frame rate “30 [fps]”. ing. The estimated quality value under the distribution conditions of rule A is “4.2”. In the present specification and drawings, “HD” in the resolution item refers to a resolution of 1920 pixels * 1080 pixels, and “SD” refers to a resolution of 720 pixels * 480 pixels. However, the present invention is not limited to this. Not what you want.

  The rules stored in the control information storage unit 24 may be input to the control information storage unit 24 by an administrator of the system based on actual measurement data obtained in advance through experiments or the like. Alternatively, as shown in Patent Document 1, for example, the quality control device 2 calculates how much improvement in the user experience quality value can be expected based on distribution conditions (for example, invalid frame rate of content packet) (not shown). An information generation unit may be provided. As for the experiment, there is a method of creating a simulated environment, but an experiment using a real network is desirable.

<Quality control method selection means 21>
The quality control method selection means 21 receives terminal information including at least the QoE quality value (user experience quality value) of each terminal 1 and the distribution conditions of the terminal 1.

  Referring to the example of FIG. 6, the terminal information of the terminal 1 indicates that “reception bit rate” is “8 [Mbps]” and the user experience quality value is “3.2” as distribution conditions.

  The quality control method selection means 21 may receive the terminal information of each terminal 1 from each of the terminals 1. Further, the quality control method selection means 21 may receive terminal information from all terminals 1 that are receiving services from the content distribution device 4 or may receive terminal information from some terminals 1. Alternatively, the following configuration may be used. For example, this quality control system newly includes a terminal information management device (not shown) that manages terminal information of each terminal 1. And the quality control method selection means 21 may receive terminal information from the above-mentioned terminal information management device. Further, for example, the quality control device 2 of this quality control system may be configured to newly include terminal information measuring means (not shown). In this case, the above-described terminal information measuring unit measures the user experience quality value of each terminal 1 and the distribution condition of the terminal 1. Then, the terminal information measurement unit may pass the measured user experience quality value and distribution condition to the quality control method selection unit 21. Further, the terminal information of each terminal 1 may include terminal identification information that can identify each terminal 1.

  The quality control method selection means 21 determines a rule from the control information storage means 24 based on the user experience quality value included in the terminal information related to one terminal 1 (hereinafter referred to as a control target terminal a) among the terminal information of each terminal 1. read out. Specifically, a rule in which the estimated quality value of each rule stored in the control information storage unit 24 is higher than the user experience quality value included in the terminal information of the control target terminal a (hereinafter, referred to as a first rule). read out.

  Here, the quality control method selection unit 21 may read a rule having an estimated quality value higher than a predetermined threshold value as the first rule. According to this method, the quality control apparatus 2 can ensure that the user experience quality value of the control target terminal a is at least equal to or greater than the above-described threshold value.

  The description in this specification is based on the premise that the QoE is high when the user experience quality value is large, and the QoE is low when the user experience quality value is small. Of course, implementation is possible that indicates that QoE is low when the user experience quality value is large, and that QoE is high when the user experience quality value is small.

  The quality control method selection means 21 calculates the increment of the bandwidth for raising the user experience quality value of the control target terminal a to the estimated quality value of the first rule for each read first rule. Specifically, the quality control method selection unit 21 calculates an increase in bandwidth based on the difference between the delivery condition of the first rule and the user experience quality value included in the terminal information of the control target terminal a.

  For example, it is assumed that the rule A, the rule B, and the rule C as shown in FIG. Here, the rule A indicates that “reception bit rate” is “8 [Mbps]” and the estimated quality value is “2.8” as distribution conditions. Rule B indicates that “reception bit rate” is “10 [Mbps]” and the estimated quality value is “3.3” as distribution conditions. Further, the rule C indicates that “reception bit rate” is “12 [Mbps]” and the estimated quality value is “3.8” as distribution conditions. Further, it is assumed that the terminal information of the control target terminal a is as shown in FIG.

  The quality control method selection means 21 selects a rule corresponding to an estimated quality value higher than the user experience quality value “3.2” of the control target terminal “a” as the first rule. For example, the quality control method selection means 21 selects rule B having the estimated quality value “3.3” and rule C having the estimated quality value “3.8” as the first rule.

  At this time, the quality control method selection unit 21 increases the bandwidth for each selected rule based on the difference between the distribution condition of the terminal information of the terminal a to be controlled and the distribution condition of each rule described above. calculate.

  Now, the distribution condition of the terminal information of the control target terminal “a” is ““ Reception bit rate ”is“ 8 [Mbps] ””. On the other hand, the distribution condition of rule B is ““ reception bit rate ”is“ 10 [Mbps] ””. Therefore, the quality control method selection means 21 calculates the bandwidth increment for raising the user experience quality value of the terminal a to be controlled to the estimated quality value of the rule B as 10−8 = 2 [Mbps].

  The terminal information distribution condition of the control target terminal “a” is ““ Reception bit rate ”is“ 8 [Mbps] ””. On the other hand, the distribution condition of rule C is ““ reception bit rate ”is“ 12 [Mbps] ””. Therefore, the quality control method selection unit 21 calculates the bandwidth increment for raising the user experience quality value of the control target terminal a to the estimated quality value of the rule C as 12−8 = 4 [Mbps].

  Here, the bandwidth refers to the bandwidth in the path from the content distribution device 4 to each terminal 1.

  The quality control method selection means 21 determines a rule from the control information storage means 24 based on the user experience quality value included in the terminal information of one terminal 1 (hereinafter referred to as a control target terminal b) among the terminal information of each terminal 1. read out. Specifically, a rule in which the estimated quality value of each rule stored in the control information storage unit 24 is lower than the user experience quality value included in the terminal information of the control target terminal b (hereinafter, referred to as a second rule). read out.

  The quality control method selection means 21 calculates a decrease in bandwidth when the user experience quality value of the control target terminal b is lowered to the estimated quality value of the second rule for each read second rule. Specifically, the quality control method selection unit 21 calculates the bandwidth decrement based on the difference between the delivery condition of the second rule and the user experience quality value included in the terminal information of the control target terminal b.

  For example, it is assumed that rules A, B and C as shown in FIG. 7 are stored in the control information storage unit 24, and the terminal information of the control target terminal b is as shown in FIG.

  The quality control method selection means 21 selects a rule corresponding to the estimated quality value lower than the user experience quality value “3.8” of the control target terminal b as the second rule. For example, the quality control method selecting means 21 selects rule A having an estimated quality value “2.8” and rule B having an estimated quality value “3.3” as the second rule.

  At this time, the quality control method selection means 21 reduces the bandwidth based on the difference between the distribution condition of the terminal information of the terminal b to be controlled and the distribution condition of each rule described above for each selected rule. Is calculated.

  Now, the distribution condition of the terminal information of the control target terminal b is ““ Reception bit rate ”is“ 12 [Mbps] ””. On the other hand, the distribution condition of rule A is ““ reception bit rate ”is“ 8 [Mbps] ””. Therefore, the quality control method selection means 21 calculates the bandwidth decrement when the user experience quality value of the control target terminal b is lowered to the estimated quality value of the rule A as 12−8 = 4 [Mbps].

  The terminal information distribution condition of the control target terminal b is ““ Reception bit rate ”is“ 12 [Mbps] ””. On the other hand, the distribution condition of rule B is ““ reception bit rate ”is“ 10 [Mbps] ””. Therefore, the quality control method selection unit 21 calculates the bandwidth decrement when the user experience quality value of the control target terminal b is reduced to the estimated quality value of the rule B as 12-10 = 2 [Mbps].

  The quality control method selection unit 21 associates each first rule with the bandwidth increment calculated from the rule and passes it to the control method determination unit 22. Further, the quality control method selection means 21 associates each second rule with the bandwidth decrement calculated from the rule and passes it to the control method determination means 22. For example, the quality control method selection unit 21 associates the rule B shown in FIG. 9 with the bandwidth increment “2 [Mbps]” and passes it to the control method determination unit 22. Further, for example, the quality control method selection means 21 associates the rule A shown in FIG. 9 with the bandwidth decrement “4 [Mbps]” and passes it to the control method determination means 22.

<Control method determining means 22>
The control method determination unit 22 selects, for example, one rule as an improvement rule from the first rules received from the quality control method selection unit 21. Further, the control method determination unit 22 selects, for example, one rule from the second rules received from the quality control method selection unit 21 as a reduction rule. At this time, the control method determination means 22 selects the improvement rule and the reduction rule so that the increment of the bandwidth associated with the improvement rule does not exceed the decrement of the bandwidth associated with the reduction rule. . Then, the control method determination unit 22 passes the selected improvement rule and reduction rule to the distribution control unit 23.

  The specific operation of the control method determining means 22 is as follows. Assume that the control method determining means 22 receives the rule B and the rule C shown in FIG. 7 as the first rule. Further, it is assumed that the control method determining means 22 receives the rule A and the rule B shown in FIG. 7 as the second rule. Further, as shown in FIG. 9, it is assumed that the increment or decrement of the bandwidth for each rule is calculated by the quality control method selection means 21 described above.

  At this time, for example, the control method determination means 22 may select the improvement rule in preference to the rule having a small increment as the improvement rule. In this case, the control method determination means 22 selects the rule B, for example. When the content is distributed to the control target terminal a under the distribution condition of the rule B, the bandwidth increment is “2 [Mbps]”. In this case, the control method determining means 22 selects one of the rules associated with a decrement equal to or greater than the bandwidth increment (2 [Mbps]) as the reduction rule. At this time, the control method determining means 22 can select the rule A and the rule B. The control method determination unit 22 may select the rule with a larger decrement as a reduction rule with priority. In this case, for example, the control method determination unit 22 selects the rule A as the reduction rule. At this time, the control method determination unit 22 passes the rule B as the improvement rule and the rule A as the reduction rule to the distribution control unit 23.

  The control method determination means 22 may select the improvement rule in preference to the rule with a small increment. Alternatively, the control method determining unit 22 may select the improvement rule in preference to the rule having an increment equal to or greater than a predetermined threshold.

  The control method determination means 22 may select the rule as the reduction rule in preference to the rule having the smallest difference between the increment and the decrement. Alternatively, the control method determining means 22 may select the reduction rule in preference to the rule with the decrement less than or equal to a predetermined threshold.

<Distribution control means 23>
The distribution control unit 23 changes the distribution condition of the control target terminal a to the distribution condition of the improvement rule received from the control method determination unit 22. Further, the distribution control unit 23 changes the distribution condition of the control target terminal b to the distribution condition of the reduction rule received from the control method determination unit 22.

For example, it is assumed that the distribution control unit 23 receives the rule B as the improvement rule. At this time, the distribution control means 23 increases the bandwidth allocated to the control target terminal a from 8 [Mbps] to 10 [Mbps] by increasing the number of transmission packets per unit time.
Further, it is assumed that the distribution control unit 23 receives the rule A as a reduction rule. At this time, the distribution control means 23 reduces the bandwidth allocated to the control target terminal b from 10 [Mbps] to 8 [Mbps] by reducing the number of transmission packets per unit time.

  The distribution control unit 23 may transmit information instructing the bandwidth management device 3 to change the distribution condition of the control target terminal a to the distribution condition of the improvement rule received from the control method determination unit 22. Further, the distribution control unit 23 may transmit information instructing the bandwidth management device 3 to change the distribution condition of the control target terminal b to the distribution condition of the reduction rule received from the control method determining unit 22.

  Alternatively, the distribution control unit 23 may transmit information instructing the content distribution apparatus 4 to change the distribution condition of the control target terminal a to the distribution condition of the improvement rule received from the control method determination unit 22. Further, the distribution control unit 23 may transmit information instructing the content distribution apparatus 4 to change the distribution condition of the control target terminal b to the distribution condition of the reduction rule received from the control method determination unit 22.

=== Bandwidth management device 3 ===
When the bandwidth management device 3 receives information from the quality control device 2 that instructs to change the distribution condition of the control target terminal a to the distribution condition of the improvement rule, the distribution condition of the control target terminal a is set to the distribution condition of the improvement rule. change. In addition, when the bandwidth management device 3 receives information from the quality control device 2 that instructs to change the distribution condition of the control target terminal b to the distribution condition of the reduction rule, the distribution management condition of the control target terminal b is distributed to the reduction rule. Change to conditions.

=== Content Distribution Device 4 ===
As shown in FIG. 2, the content distribution device 4 includes at least content holding means 41 that stores content, and content distribution means 42 that distributes content. The content holding unit 41 is connected to the content distribution unit 42.

  The following is a detailed description of the components included in the content distribution device 4.

<Content holding means 41>
The content holding unit 41 stores content to be distributed to the terminal 1. The content holding unit 41 may store the content and content identification information that can identify the content in association with each other.

<Content distribution means 42>
When the content distribution unit 42 receives a content request from the terminal 1 via the network 5, the content distribution unit 42 reads the content corresponding to the request received from the content holding unit 41. Then, the content distribution unit 42 distributes the read content to the terminal 1 via the network 5. The content request may include content identification information of the content, terminal identification information that can identify the terminal 1, and the like.

  When the content distribution unit 42 receives information from the quality control device 2 to instruct to change the distribution condition of the control target terminal a to the improvement rule distribution condition, the content distribution unit 42 sets the distribution condition of the control target terminal a to the improvement rule distribution condition. change. Further, when the content distribution unit 42 receives information from the quality control device 2 that instructs to change the distribution condition of the control target terminal b to the distribution condition of the reduction rule, the content distribution unit 42 distributes the distribution condition of the control target terminal b to the reduction rule. Change to conditions.

[Description of operation]
FIG. 10 is a sequence diagram showing an outline of the operation of the first exemplary embodiment of the present invention.

  The quality control method selection means 21 receives terminal information including at least the user experience quality value of each terminal 1 and the distribution condition of the terminal 1 (step S1). The quality control method selection means 21 is a rule (first rule) that includes an estimated quality value higher than the user experience quality value included in the terminal information of one terminal 1 (control target terminal a) among the terminal information of each terminal 1 ) Is read from the control information storage means 24 (step S2). The quality control method selection means 21 calculates the bandwidth increment for raising the user experience quality value of the control target terminal a to the estimated quality value of the first rule for each read first rule (step S3). .

  The quality control method selection means 21 is a rule (second rule) including an estimated quality value lower than the user experience quality value included in the terminal information of one terminal 1 (control target terminal b) among the terminal information of each terminal 1 ) Is read from the control information storage means 24 (step S4). The quality control method selection means 21 calculates the bandwidth decrement when the user experience quality value of the control target terminal b is lowered to the estimated quality value of the second rule for each read second rule (step S5). The quality control method selection unit 21 associates each first rule with the bandwidth increment calculated from the rule and passes it to the control method determination unit 22. Further, the quality control method selection means 21 associates each second rule with the bandwidth decrement calculated from the rule and passes it to the control method determination means 22.

  The control method determination unit 22 selects one rule from the first rules received from the quality control method selection unit 21 as an improvement rule. Further, the control method determining means 22 selects one rule that satisfies a predetermined requirement from the second rules received from the quality control method selecting means 21 as a reduction rule (step S6). The predetermined requirement is that the increment of the bandwidth associated with the improvement rule does not exceed the decrement of the bandwidth associated with the reduction rule. The control method determination unit 22 passes the selected improvement rule and reduction rule to the distribution control unit 23.

  The distribution control unit 23 changes the distribution condition of the control target terminal a to the distribution condition of the improvement rule received from the control method determination unit 22. In addition, the distribution control unit 23 changes the distribution condition of the control target terminal b to the distribution condition of the reduction rule received from the control method determination unit 22 (step S7).

  In the first embodiment, the quality control method selection unit 21 selects a first rule that satisfies a predetermined condition and increases the bandwidth used by the control target terminal a. Further, the quality control method selection means 21 selects a second rule that satisfies a predetermined condition and reduces the bandwidth used by the control target terminal b. Then, the control method determining means 22 selects one improvement rule from the first rule and one reduction rule from the second rule. The distribution control unit 23 changes the distribution condition of the control target terminal a based on the above-described improvement rule. And the delivery control means 23 changes the delivery conditions of the control object terminal b based on the above-mentioned reduction rule.

  Therefore, when the quality control apparatus 2 increases the user experience quality value of the control target terminal a by a value that can be specified by the improvement rule, the quality control apparatus 2 decreases the user experience quality value of the control target terminal b by a value that can be specified by the reduction rule. Can do. That is, when the quality control device 2 improves the user experience quality value with respect to the control target terminal a, the quality control apparatus 2 specifies the control target terminal b that decreases the user experience quality value, and appropriately sets the user experience quality value of the control target terminal b. Can be lowered.

  Further, the control method determination unit 22 selects the improvement rule and the reduction rule so that the increment of the bandwidth associated with the improvement rule does not exceed the decrement of the bandwidth associated with the reduction rule. Therefore, the total amount of bandwidth used by this quality control system does not increase before and after the distribution control performed by the distribution control means 23. Then, there is no possibility that resources allocated to the terminals 1 other than the control target terminal b are reduced by the distribution control performed by the distribution control unit 23. That is, the quality control apparatus 2 does not decrease the user experience quality values other than the control target terminal b when improving the user experience quality value with respect to the control target terminal a.

  In the first embodiment, the quality control method selection means 21 is a control target terminal from among the terminals 1 that have sent a user experience quality value that is less than or equal to a preset threshold value γ (eg, γ = 2.5, γ: MOS). It is good also as a structure which selects a. Alternatively, the quality control method selection means 21 ranks all the terminals 1 in descending order of the user experience quality value of the terminal information of each terminal. Then, the quality control method selection means 21 may select the control target terminal a from among the terminals 1 of the lower rank N% (N is an arbitrary number from 0 to 100) in the above-described order (first modification). Example).

  According to such a configuration, the quality control method selection means 21 preferentially selects the control target terminal a from the terminal 1 having a low user experience quality value. Therefore, the quality control system can reduce the variation in the user experience quality value between the terminals 1. The quality control system can also improve the user experience quality value of the entire service.

  In the first embodiment, the quality control method selection means 21 controls the control target from the terminals 1 that have sent a user experience quality value equal to or higher than a preset threshold value δ (for example, δ = 3.8, δ: MOS). The terminal b may be selected. Alternatively, the quality control method selection means 21 ranks the terminal 1 in descending order of the user experience quality value of the terminal information of each terminal. Then, the quality control method selection means 21 may select the control target terminal b from the terminals M of the upper M% (M is an arbitrary number from 0 to 100) in the above-described order (second modification). Example).

  According to such a configuration, the quality control method selection means 21 preferentially selects the control target terminal b from the terminal 1 having a high user experience quality value. Therefore, the quality control system can reduce the variation in the user experience quality value between the terminals 1.

  In the first embodiment, the quality control method selection unit 21 may be configured to select a plurality of control target terminals b. Moreover, the control method determination means 22 may select a plurality of improvement rules or reduction rules. In this case, if the control method determination means 22 selects each such that the sum of the bandwidth increments of the one or more improvement rules is smaller than the sum of the bandwidth reductions of the one or more reduction rules. Good (third modification).

  According to such a configuration, the quality control device 2 can distribute the decrease in the user experience quality value to each control target terminal b. Moreover, the quality control apparatus 2 can implement | achieve the cancellation of unfairness in the user who is providing service.

  In the first embodiment, the quality control method selection unit 21 may be configured to select a plurality of control target terminals a. Moreover, the control method determination means 22 may select a plurality of improvement rules or reduction rules. In this case, if the control method determination means 22 selects each such that the sum of the bandwidth increments of the one or more improvement rules is smaller than the sum of the bandwidth reductions of the one or more reduction rules. Good (fourth modification).

  According to such a configuration, the quality control device 2 can reduce the number of times of distribution control. Therefore, the quality control apparatus 2 can reduce the load of distribution control. Moreover, the quality control apparatus 2 can reduce the opportunity of distribution control. Therefore, the distribution conditions of the content viewed by the user are not frequently changed.

  In the case of the third modification or the fourth modification described above, the quality control apparatus 2 sets the number of units to be distributed at a time as X% (for example, 1 to 5%) of the entire service. In addition, distribution control can be realized without greatly changing the network configuration. Thereby, the quality control system can provide a stable service.

  In the first embodiment, the quality control device 2 may include a quality calculation unit 25 that estimates an average quality value of QoE of the entire service. FIG. 11 is a configuration example of the quality control apparatus 2 in this modification. The quality calculation means 25 is connected to the quality control method selection means 21 (fifth modification).

<Quality calculation means 25>
The quality calculation means 25 calculates the average quality value of QoE of the entire service based on the user experience quality value included in the terminal information of each terminal 1. Specifically, the quality calculation unit 25 may calculate the average quality value by a calculation method such as an arithmetic average or a geometric average of the user experience quality values included in each terminal information.

  Further, the quality calculation means 25 may calculate the mode value of the user experience quality value included in the terminal information of each terminal 1 as the average quality value.

  The quality calculation unit 25 may be configured to control the quality control method selection unit 21 to select a rule when the calculated average quality value is equal to or less than a certain value.

  According to such a configuration, the quality control device 2 can perform distribution control only when QoE of the entire service is low. Thereby, the quality control apparatus 2 can reduce the opportunity of distribution control. Therefore, the quality control apparatus 2 can reduce the load of distribution control. In addition, the distribution conditions of the content viewed by the user are not frequently changed.

  Further, the quality calculation unit 25 may calculate the variance of QoE of the entire service based on the user experience quality value included in the terminal information of the terminal 1. In this case, the quality calculating unit 25 may be configured to control the quality control method selecting unit 21 to select a rule when the calculated variance is a certain value or more.

  According to such a configuration, the quality control device 2 can perform distribution control only when there is a large variation in QoE between the terminals 1 receiving the service. Therefore, the quality control apparatus 2 can reduce the load of distribution control. Moreover, the quality control apparatus 2 can implement | achieve the cancellation of unfairness in the user who is providing service.

  Moreover, the quality calculation means 25 calculates the QoE average quality value and variance of the entire service based on the user experience quality value included in the terminal information of each terminal 1. The quality calculating means 25 is configured to control the quality control method selecting means 21 to select a rule when the calculated average quality value is not more than a certain value and the calculated variance is not less than a certain value. May be.

  According to such a configuration, the quality control apparatus 2 can perform distribution control only when the average quality value and variance of the QoE of the entire service are predetermined values. As a result, the quality control device 2 can reduce the number of times of distribution control. Therefore, the quality control apparatus 2 can reduce the load of distribution control.

  If the terminal information includes information indicating the time at which the terminal information is collected, information such as the type of access network, usage location, usage time zone, etc., the quality calculation means 25 determines the content of each piece of information. An average quality value or variance may be calculated.

  According to such a configuration, the quality control apparatus 2 can determine the necessity of distribution control based on more detailed conditions such as conditions such as the usage environment of the terminal 1.

  In addition, it is possible to realize an embodiment in which various modifications in the first embodiment are combined with each other.

[Second Embodiment]
[Description of configuration]
FIG. 12 is a block diagram showing a configuration example of the quality control system according to the second embodiment of the present invention. The quality control system includes a terminal 1, a quality control device 6, a bandwidth management device 3, and a content distribution device 4, which are connected via a network 5. Here, only the differences of the second embodiment from the first embodiment will be described, and the same components are denoted by the same reference numerals and the description thereof is omitted.

  The following is a description of each component included in the quality control system.

<Control information storage means 64>
As shown in FIG. 13, the control information storage means 64 has a value before the change of one attribute of the distribution condition, a value after the change of the one attribute, a variation value of the bandwidth due to the change, Is different from the control information storage means 24 in that the control information associated with each other is further stored.

  Referring to the example of FIG. 13, “packet loss rate before change” is a value before the change of one attribute of the distribution condition, “packet loss rate after change” is a value after the change of the above one attribute, “Bandwidth variation” corresponds to the variation value of the bandwidth according to the change.

  One attribute of the distribution condition is, for example, packet loss rate, burst loss rate, reception bit rate, presence / absence of priority flag / non-priority flag of each packet, FEC strength, encoding method, content bit rate, content resolution, content Frame rate, etc.

  The control information stored in the control information storage unit 64 may be input to the control information storage unit 64 by a system administrator or the like based on actual measurement data obtained in advance through experiments or the like.

  In the present embodiment, the configuration in which the rule and the control information are stored in one storage unit is shown, but the present invention is not limited to this. In other words, the rule and control information may be stored in different storage means.

<Quality control method selection means 61>
The quality control method selection means 61 differs from the quality control method selection means 21 in the following points.

  The quality control method selection means 61 is characterized in that, for each read first rule, the control information is read from the control information storage means 64 based on the distribution conditions of the rule and the distribution conditions of the control target terminal a. 21 and different. Specifically, the quality control method selecting unit 61 corresponds to the value of one attribute of the distribution condition of the control target terminal a corresponding to the value of the attribute before the change, and the distribution condition included in each of the first rules described above. The control information corresponding to the attribute value after the change is read out.

  For example, the control information stored in the control information storage unit 64 in FIG. 14 (1) and the rule stored in the control information storage unit 64 in FIG. Are respectively shown in FIG. 14 (3). In this example, as shown in FIG. 14, one attribute of the distribution condition is “packet loss rate”. In this case, the quality control method selection unit 61 stores the control information storage unit 64 based on the packet loss rate “0.3” of the distribution condition of the control target terminal “a” and the packet loss rate “0.1” of the distribution condition of the rule A. The control information 1 being read is read out. Next, the quality control method selection means 61 stores the control information storage means 64 based on the packet loss rate “0.3” of the delivery condition of the control target terminal a and the packet loss rate “0.05” of the delivery condition of the rule B. The control information 2 being read is read out.

  The quality control method selection means 61 selects the quality control method in that the variation value of the bandwidth included in the control information read for each first rule is used as the bandwidth increment calculated by the quality control method selection means 61. Different from means 21.

  The quality control method selection unit 61 reads the control information from the control information storage unit 64 based on the distribution conditions of the rule and the distribution conditions of the control target terminal b for each read second rule. 21 and different. Specifically, the quality control method selection unit 61 corresponds to the value of one attribute of the distribution condition of the control target terminal b corresponding to the value of the attribute before the change, and the distribution condition included in each of the above-described second rules. The control information corresponding to the attribute value after the change is read out.

  The quality control method selection means 61 is a quality control method in that the variation value of the bandwidth included in the control information read for each second rule is used as a decrement of the bandwidth calculated by the quality control method selection means 61. Different from the selection means 21.

<Delivery control means 63>
The distribution control unit 63 may operate as follows when changing the distribution condition of the control target terminal a to the distribution condition of the improvement rule received from the control method determination unit 22. The distribution control unit 63 may perform distribution control based on the control information used when the quality control method selection unit 61 reads the improvement rule. That is, the distribution control unit 63 changes the value of one attribute of the distribution condition of the control target terminal “a” to the changed value of one attribute included in the control information.

  As a result of this change, the distribution control means 63 performs distribution control for further allocating the bandwidth to the control target terminal a by the bandwidth increment included in the control information.

  The distribution control unit 63 may operate as follows when changing the distribution condition of the control target terminal b to the distribution condition of the reduction rule received from the control method determination unit 22. The distribution control unit 63 may perform distribution control based on the control information used when the quality control method selection unit 61 reads the reduction rule. That is, the distribution control unit 63 changes the value of one attribute of the distribution condition of the control target terminal b to a value after changing one attribute included in the control information.

  With this change, the distribution control means 63 performs distribution control for reducing the bandwidth allocated to the control target terminal b by the reduction of the bandwidth included in the control information.

  For example, assume that the improvement rule is control information 1 shown in FIG. In this case, the distribution control means 63 adds a redundant code to the content by 2 [Mbps] which is a variation of the bandwidth. For example, when the above-described FEC is applied to the content, the distribution control means 63 specifies the amount of data to be added to each block based on the size of each block of the content and the variation 2 [Mbps] of the bandwidth. Then, the distribution control unit 63 adds a redundant code having a specified data amount to each block.

  The following examples are cases where the distribution conditions are different. For example, it is assumed that the terminal information of the control target terminal a is as shown in (1) of FIG. The improvement rule is rule C shown in FIG. Further, it is assumed that the control information used when the quality control method selecting unit 61 reads the rule C is the control information 4 shown in FIG. One attribute of the rule C distribution condition is “content frame rate”. In this case, the distribution control means 63 changes the content frame rate to the value after change (60 [fps]). For example, a desired change can be realized by transcoding the content by the distribution control means 63 or the content distribution device 4. The content transcoding includes, for example, an operation of thinning out a frame of content or interpolating data of a new frame from data of a predetermined frame of content.

  For example, it is assumed that the terminal information of the control target terminal a is as shown in (1) of FIG. The improvement rule is rule F shown in FIG. Further, it is assumed that the control information used when the quality control method selection unit 61 reads the rule F is the control information 5 shown in FIG. One attribute of the distribution condition of rule F is “content resolution information”. In this case, the distribution control means 63 changes the resolution of the content to the value after change (HD). Similarly to the above, a desired change can be realized, for example, when the distribution control unit 63 or the content distribution device 4 transcodes the content.

  For example, assume that the terminal information of the control target terminal a is as shown in (1) of FIG. The improvement rule is rule I shown in FIG. One attribute of the distribution condition of Rule I is “information indicating which level of content is distributed (hierarchy information)”. Further, it is assumed that the control information used when the quality control method selecting unit 61 reads the rule I is the control information 8 shown in FIG. Furthermore, it is assumed that the content is hierarchically encoded as shown in (4) of FIG. Hierarchical coding refers to compressing content data according to a standard such as H.264 / SVC (Scalable Video Coding) when the content data is a moving image, for example. When the content data is an image, the content data is compressed according to a standard such as JPEG2000 (Joint Photographic Experts Group 2000). In this example, the standard used for hierarchical encoding is not limited to H.264 or JPEG2000, and any standard may be used. In this case, the distribution control means 23 distributes content from the basic layer to the layer indicated by the layer information based on the layer information “Enhanced-3” of the distribution condition of rule I in FIG. In this example, the distribution control means 23 distributes contents from Base to Enhanced-3 (Base, Enhanced-1, Enhanced-2, Enhanced-3) based on the hierarchical information “Enhanced-3”.

[Description of operation]
FIG. 18 is a sequence diagram showing an outline of the operation of the second exemplary embodiment of the present invention.

  The quality control method selection means 61 receives terminal information including at least the user experience quality value of each terminal 1 and the distribution condition of the terminal 1 (step S1). The quality control method selection means 61 is a rule (first rule) including an estimated quality value higher than the user experience quality value included in the terminal information of one terminal 1 (control target terminal a) among the terminal information of each terminal 1 ) Is read from the control information storage means 64 (step S2).

  The quality control method selection unit 61 reads out control information from the control information storage unit 64 for each read first rule based on the distribution conditions of the rule and the distribution conditions of the control target terminal a (step S11). The quality control method selection means 61 uses the bandwidth variation value included in the control information read for each first rule as the bandwidth increment calculated by the quality control method selection means 61 (step S12).

  The quality control method selection means 61 includes a rule (second rule) including an estimated quality value lower than the user experience quality value included in the terminal information of one terminal 1 (control target terminal b) among the terminal information of each terminal 1 ) Is read from the control information storage means 64 (step S4).

  The quality control method selection unit 61 reads out the control information from the control information storage unit 64 for each read second rule based on the distribution condition of the rule and the distribution condition of the control target terminal b (step S13). The quality control method selection unit 61 sets the variation value of the bandwidth included in the control information read for each second rule as a reduction of the bandwidth calculated by the quality control method selection unit 61 (step S14). The quality control method selection means 61 associates each first rule with the bandwidth increment calculated from the rule and passes it to the control method determination means 22. Further, the quality control method selection means 61 associates each second rule with the bandwidth decrement calculated from the rule and passes it to the control method determination means 22.

  The control method determination unit 22 selects one rule from the first rules received from the quality control method selection unit 61 as an improvement rule. Further, the control method determining means 22 selects one rule satisfying a predetermined requirement from the second rules received from the quality control method selecting means 61 as a reduction rule (step S6). The predetermined requirement is that the increment of the bandwidth associated with the improvement rule does not exceed the bandwidth decrement associated with the reduction rule. The control method determination unit 22 passes the selected improvement rule and reduction rule to the distribution control unit 63.

  The distribution control means 63 performs distribution control based on the control information used when the quality control method selection means 61 reads the improvement rule. Further, the distribution control unit 63 performs distribution control based on the control information used when the quality control method selection unit 61 reads the reduction rule (step S15).

  In the second embodiment, when the distribution control unit 63 changes the distribution condition of the control target terminal a based on the improvement rule, it is based on the control information used when the quality control method selection unit 61 reads the improvement rule. To perform distribution control. Specifically, the distribution control unit 63 changes the value of the attribute included in the control information so as to increase the bandwidth allocated to the control target terminal a by the increment of the bandwidth included in the control information. When the distribution control unit 63 changes the distribution condition of the control target terminal b based on the reduction rule, the distribution control is performed based on the control information used when the quality control method selection unit 61 reads the reduction rule. . Specifically, the distribution control means 63 changes the value of the attribute included in the control information so as to reduce the bandwidth allocated to the control target terminal b by the reduction of the bandwidth included in the control information.

  The control information associates distribution conditions with bandwidth variations. Therefore, the quality control device 6 replaces the resource change by the distribution control for changing the value of those attributes with the variation of the bandwidth, regardless of the attribute parameters included in the distribution condition. In other words, the quality control device 6 can select a delivery control method based on the variation of the bandwidth regardless of any attribute parameter as a delivery condition. Therefore, the quality control apparatus 6 can employ various parameters as distribution conditions.

  Further, the distribution control means 63 can realize distribution control only by referring to the variation of bandwidth and the value of one attribute after the change included in the control information.

  In the second embodiment, the quality control device 6 stores a control policy in which the change priority of each attribute included in the distribution condition is associated with information indicating a predetermined condition (hereinafter referred to as status information). It is good also as a structure provided with the memory | storage means 66. FIG.

  In this modification, the quality control method selection means 61 receives at least the terminal information including the QoE quality value (user experience quality value) of each terminal 1 and the distribution condition of the terminal 1, and the above-described situation information. This status information may be included in the distribution condition, the distribution condition, or the terminal information, or may be information different from the terminal information.

  FIG. 19 is a block diagram showing a configuration example of the quality control device 6 in this modification. The policy storage unit 66 is connected to the control method determination unit 62 (first modification).

<Policy storage means 66>
As shown in FIG. 20, the policy storage unit 66 stores a control policy that associates the change priority of each attribute included in the distribution condition with the status information in association with each other.

  Referring to the example of FIG. 20, “content identification information”, “information amount per frame”, “age”, “use plan”, and “access network type” correspond to the status information. The situation information is not limited to the above-mentioned items, and may include various profile information related to the user who uses each terminal 1.

  Referring to the example of FIG. 20, “packet loss rate”, “frame rate”, “resolution”, and “hierarchy information” correspond to the change priority of each attribute.

  The control information stored in the policy storage unit 66 may be input to the policy storage unit 66 by a system administrator or the like based on actually measured data obtained in advance through experiments or the like.

<Control method determining means 62>
In this modification, the control method determining unit 62 reads out a policy corresponding to the status information of the control target terminal a from the policy storage unit 66. Then, the control method determination unit 62 identifies an attribute with a high change priority included in the read policy. The control method determination means 62 preferentially selects an improvement rule having different specified attribute values for the distribution condition of the control target terminal a and the distribution condition of the improvement rule.

  Further, the control method determining unit 62 reads out a policy corresponding to the status information of the control target terminal b from the policy storage unit 66. Then, the control method determination unit 62 identifies an attribute with a high change priority included in the read policy. The control method determination means 62 preferentially selects a reduction rule having different specified attribute values for the distribution condition of the control target terminal b and the distribution condition of the reduction rule.

  For example, it is assumed that the control method determination unit 62 reads out from the policy storage unit 66 a policy including the content identification information of “movie B” among the policies shown in FIG. In this case, the control method determining means 62 selects an improvement rule having a different packet loss rate, which is an attribute having the highest change priority, for the distribution condition of the control target terminal a and the distribution condition of the improvement rule.

  According to this configuration, the administrator of the quality control system can easily set which attribute of the delivery condition should be preferentially changed according to the characteristics of the situation information.

  For example, it is assumed that the control method determination unit 62 reads a policy from the policy storage unit 66 according to “content identification information” in the situation information. Assume that the policy storage unit 66 stores a policy as shown in FIG. When the content is “movie B”, it is presumed that there is a strong movement in the display of the content. Therefore, as shown in FIG. 21, priority is given to lowering the packet loss rate. This is because, when the content is moving rapidly, it is likely that a small number of frames will be dropped, which is thought to have a significant impact on QoE.

  In addition, when the content is “education television D”, since it is considered that the movement of the content is slow, priority is given to increasing the resolution instead of decreasing the packet loss rate. This is because, when the content is displayed slowly, it is difficult to be afraid of dropping a few frames, and it is considered that QoE is not greatly affected.

  As described above, the control method determination unit 62 reads out the policy from the policy storage unit 66 according to the “content identification information”, so that it is possible to realize distribution control according to the content.

  Further, for example, it is assumed that the control method determining unit 62 reads out a policy from the policy storage unit 66 according to “information amount per frame” in the situation information. Assume that the policy storage means 66 stores a policy as shown in FIG.

  Here, for example, it is assumed that the content is encoded in H.264 / AVC (Advanced Video Coding) format. If there is a lot of movement in content display, the difference in data between frames also increases and the amount of information for P pictures and B pictures increases, so if the amount of information per frame of content is large, Is estimated to be intense.

  Therefore, as shown in FIG. 22, when the amount of information per frame of content is large, it is presumed that there is a strong movement in the display of the content, so priority is given to lowering the packet loss rate. This is because if there is a lot of movement in the content display, a few frames are likely to be dropped, which has a great impact on QoE.

  In contrast to the above, when the amount of information per frame of content is small, it is considered that the movement of the content is slow, so increase the resolution instead of decreasing the packet loss rate. Prioritize. This is because, when the movement of content is slow, it is hard to be afraid to drop a few frames, and QoE is not greatly affected.

  As described above, the control method determining unit 62 reads the policy from the policy storage unit 66 in accordance with the “information amount per frame”. According to this configuration, for example, the control method determination unit 62 realizes different distribution control in a time zone in which the amount of information per frame is large and a time zone in which the amount of information per frame is small even in the distribution of the same content. It becomes possible.

  Further, for example, it is assumed that the control method determining unit 62 reads a policy from the policy storage unit 66 according to the “use plan” in the situation information. For example, it is assumed that the policy storage unit 66 stores a policy as shown in FIG. In FIG. 23A, the change priority of “0” means that the change of the attribute value is not permitted. As shown in FIG. 23 (1), when the usage plan is free, only distribution control for reducing the packet loss rate is performed.

  As shown in FIG. 23A, when the usage plan is premium, any of the attributes of the packet loss rate, the frame rate, the resolution, and the content hierarchy can be changed.

  The above shows an example of quality improvement. When the quality is lowered, the quality control device 6 stores a policy different from the policy used at the time of quality improvement in the control policy storage means 66 as shown in FIG. 23 (2), for example. And the quality control apparatus 6 may perform delivery control based on the policy shown in FIG.

  As described above, the control method determination unit 62 reads out the policy from the policy storage unit 66 in accordance with the “use plan”. According to this configuration, the control method determining means 62 can realize different distribution control depending on the usage plan that the user contracts with the service provider.

  The first modification of the second embodiment is suitable for a service in which the contents of content distributed to each terminal 1 can be confirmed in advance by an administrator of the quality control system. Further, the first modification of the second embodiment is particularly suitable for a VoD (Video on Demand) service that is assumed that channel switching by the terminal 1 does not occur much.

  In the first modification of the second embodiment, the quality control method selection unit 61 may select the control target terminal b based on the status information of the terminal 1. In general, in the distribution control for the terminal 1 viewing the video content, the variation in the user experience quality value varies depending on the content viewed on each terminal 1. For example, even when the quality control device 6 performs the same distribution control on each terminal 1, the user experience quality value tends to decrease for a terminal that is viewing content such as a sports broadcast where the movement of a subject is intense. On the other hand, when the quality control device 6 performs distribution control to the terminal 1 that is viewing a content whose subject is moving slowly, such as a round-table discussion or a news program studio, the user experience quality value is unlikely to decrease. Using this, the quality control method selection means 61 is based on the status information of each terminal 1 (for example, the content identification information or the amount of information per frame). The control target terminal b is selected from the list. Then, it is possible to reduce the decrease in the user experience quality value as compared with the case where the quality control method selection unit 61 selects the terminal 1 that is viewing content that is moving rapidly as the control target terminal b.

  Moreover, the following delivery control method is realizable in the 1st modification of 2nd Embodiment. That is, this is a method in which the quality control device 6 controls the user experience quality value according to an SLA (Service Level Agreement) that is an agreement regarding a service level that the user of the terminal 1 ties with the content distribution service provider. In general, when a user pays a high amount of money, an SLA indicating a high service level is connected between the user and the content distribution service provider. On the other hand, when the user pays only a cheap amount, an SLA indicating a low service level is connected between the user and the content distribution service provider.

  In this case, the quality control method selection means 61 selects the control target terminal a from the terminals 1 of the SLA indicating a high service level based on the status information (SLA) of each terminal 1. Further, the quality control method selection means 61 selects the control target terminal b from the SLA terminals 1 indicating a low service level.

  With the above configuration, the administrator of the quality control system can realize an operation in which the distribution control by the quality control device 6 varies depending on the amount paid by the user.

  Further, in the first modification of the second embodiment, the quality control method selection unit 61 may read a rule having an estimated quality value higher than a predetermined threshold value as the first rule. Furthermore, the quality management device 6 may determine the predetermined threshold according to the SLA. According to this method, the quality control device 6 can guarantee that the user experience quality value of the control target terminal a is at least equal to or greater than the above-described threshold value. Furthermore, the quality control apparatus 6 can set the minimum value of the user experience quality value guaranteed for the control target terminal a by the SLA. Since the administrator of the quality control system can set the bandwidth allocated to each user according to the amount paid by the user, the amount received from the user per used bandwidth can be maximized.

  Each embodiment described so far is a preferred embodiment of the present invention, and the scope of the present invention is not limited only to the above-described embodiment, and various modifications are possible without departing from the gist of the present invention. It is possible to implement in a form that has been modified.

  In addition, each component in each embodiment of the present invention can be realized by a computer and a program as well as its function in hardware. The program is provided by being recorded on a computer-readable recording medium such as a magnetic disk or a semiconductor memory, and is read by the computer when the computer is started up. The read program causes the computer to function as a component in each of the embodiments described above by controlling the operation of the computer.

The present invention can be utilized for service quality control in a content distribution service.

DESCRIPTION OF SYMBOLS 1 Terminal 2 Quality control apparatus 3 Band management apparatus 4 Content distribution apparatus 5 Network 6 Quality control apparatus 10 Experience quality estimation means 11 Network quality information collection means 12 Terminal information transmission means 21 Quality control method selection means 22 Control method determination means 23 Distribution control Means 24 Control information storage means 25 Quality calculation means 41 Content holding means 42 Content distribution means 61 Quality control method selection means 62 Control method determination means 63 Distribution control means 64 Control information storage means 66 Policy storage means

Claims (25)

Control information storage means for storing a rule associating a distribution condition including an attribute indicating characteristics when distributing content to a terminal and an estimated quality value of a user experience quality obtained under the distribution condition;
The first rule which is a rule whose estimated quality value is higher than the user experience quality value of the first terminal is selected and read out from the control information storage means, and the distribution condition of the first rule for each of the first rules, Calculating a bandwidth increment for raising the user experience quality value of the first terminal to the estimated quality value of the first rule based on a difference with the delivery condition of the first terminal;
The second rule which is a rule whose estimated quality value is lower than the user experience quality value of the second terminal is selected and read from the control information storage means, and the distribution condition of the second rule for each second rule, A quality control method for calculating a bandwidth decrement when the user experience quality value of the second terminal is lowered to the estimated quality value of the second rule based on a difference from the delivery condition of the second terminal Selection means,
Control method determining means for selecting one or more improvement rules from the first rule and one or more reduction rules from the second rule that satisfy a condition that the calculated increment does not exceed the calculated decrement;
A quality control apparatus comprising: a delivery control unit that changes the delivery condition of the first terminal to the delivery condition of the improvement rule and changes the delivery condition of the second terminal to the delivery condition of the reduction rule. The delivery condition includes a packet loss rate as the attribute,
The control information storage means stores control information in which a packet loss rate before change, a packet loss rate after change, and an increment value of bandwidth are associated with each other,
The quality control method selecting means is a control in which the packet loss rate of the first terminal is associated with the packet loss rate before change, and the packet loss rate included in the first rule is associated with the packet loss rate after change. Calculating a bandwidth increment for raising the user experience quality value of the first terminal to the estimated quality value of the first rule based on the bandwidth increment included in the information;
The quality control apparatus according to claim 1, wherein the distribution control unit adds a redundant code for the content to the content distributed to the first terminal by an increment of the bandwidth. The distribution condition includes content frame rate information as the attribute,
The control information storage means stores control information in which pre-change frame rate information, post-change frame rate information, and bandwidth increment values are associated with each other,
The quality control method selection means is a control in which the frame rate information of the first terminal is associated with pre-change frame rate information, and the frame rate information included in the first rule is associated with post-change frame rate information. Calculating a bandwidth increment for raising the user experience quality value of the first terminal to the estimated quality value of the first rule based on the bandwidth increment included in the information;
The quality control apparatus according to claim 1, wherein the distribution control unit changes a frame rate of content distributed to the first terminal to the changed frame rate. The distribution condition includes content resolution information as the attribute,
The control information storage means stores control information in which pre-change resolution information, post-change resolution information, and an increment value of a bandwidth are associated with each other,
In the quality control method selection means, the resolution information of the first terminal is included in the pre-change resolution information, and the resolution information included in the first rule is included in the control information associated with the post-change resolution information. Calculating a bandwidth increment for raising the user experience quality value of the first terminal to the estimated quality value of the first rule based on the bandwidth increment;
The quality control apparatus according to claim 1, wherein the distribution control unit changes a resolution of content to be distributed to the first terminal to the changed resolution. The content delivered to the device is hierarchically encoded,
The distribution condition includes hierarchical information indicating which level of content that is hierarchically encoded as the attribute is distributed,
The control information storage means stores control information in which pre-change hierarchical information, post-change hierarchical information, and bandwidth increment values are associated with each other,
The quality control method selection means includes the hierarchical information of the first terminal in the control information associated with the pre-change hierarchical information and the hierarchical information included in the first rule, respectively. Calculating a bandwidth increment for raising the user experience quality value of the first terminal to the estimated quality value of the first rule based on the bandwidth increment;
5. The distribution control unit according to any one of claims 1 to 4, wherein the distribution control unit changes the content to be distributed to the first terminal so as to distribute up to the hierarchy indicated in the changed hierarchy information among the content. The quality control device described. The distribution condition includes a plurality of the attributes and content identification information capable of identifying the content to be distributed,
Policy storage means for storing a control policy in which content identification information and change priority of each attribute included in the distribution condition are associated with each other.
The control method determining unit reads a control policy corresponding to content identification information of content distributed to the first terminal from the policy storage unit, and includes an attribute value of an attribute having a high change priority included in the control policy The quality control apparatus according to claim 1, wherein a rule that is different between the delivery condition of the first terminal and the delivery condition of the first rule is selected as the improvement rule. The distribution condition includes a plurality of the attributes and a frame information amount indicating an information amount per frame of the content to be distributed,
Policy storage means for storing a control policy that associates the amount of frame information with the change priority of each attribute included in the distribution condition,
The control method determination unit reads a control policy including the amount of frame information of the content distributed to the first terminal from the policy storage unit, and an attribute value of an attribute having a high change priority included in the control policy is obtained. The quality control apparatus according to claim 1, wherein a rule that is different between the delivery condition of the first terminal and the delivery condition of the first rule is selected as the improvement rule. The delivery condition includes a plurality of the attributes,
Policy storage means for storing a control policy in which a user profile, which is information related to a user of each terminal, and a change priority of each attribute included in the distribution condition are associated with each other,
The control method determination unit reads a control policy including a user profile of the first terminal from the policy storage unit, and an attribute value of an attribute having a high change priority included in the control policy is distributed by the first terminal. The quality control apparatus according to any one of claims 1 to 7, wherein a rule that differs between a condition and a delivery condition of the first rule is selected as the improvement rule. A quality control device according to any one of claims 1 to 8,
A terminal that transmits a distribution condition when receiving distribution of content and an estimated quality value of the user experience quality obtained under the distribution condition to the quality control device;
With a quality control system. A rule storage step for storing in the control information storage means a rule in which a distribution condition including an attribute indicating characteristics when distributing content to a terminal and an estimated quality value of user experience quality obtained under the distribution condition are associated with each other; ,
The first rule which is a rule whose estimated quality value is higher than the user experience quality value of the first terminal is selected and read out from the control information storage means, and the distribution condition of the first rule for each of the first rules, Calculating a bandwidth increment for raising the user experience quality value of the first terminal to the estimated quality value of the first rule based on a difference with the delivery condition of the first terminal;
The second rule which is a rule whose estimated quality value is lower than the user experience quality value of the second terminal is selected and read from the control information storage means, and the distribution condition of the second rule for each second rule, A quality control method for calculating a bandwidth decrement when the user experience quality value of the second terminal is lowered to the estimated quality value of the second rule based on a difference from the delivery condition of the second terminal A selection step;
A control method determining step of selecting one or more improvement rules from the first rule and one or more reduction rules from the second rule that satisfy a condition that the calculated increment does not exceed the calculated decrement;
A quality control method comprising: a distribution control step of changing the distribution condition of the first terminal to the distribution condition of the improvement rule and changing the distribution condition of the second terminal to the distribution condition of the reduction rule. The delivery condition includes a packet loss rate as the attribute,
A control information storage step of storing control information in which the packet loss rate before change, the packet loss rate after change and the increment value of the bandwidth are associated with each other in the control information storage unit;
Increase in bandwidth included in the control information in which the packet loss rate of the first terminal is associated with the packet loss rate before change, and the packet loss rate included in the first rule is associated with the packet loss rate after change, respectively. The quality control method selection step of calculating the bandwidth increment for raising the user experience quality value of the first terminal to the estimated quality value of the first rule based on
The quality control method according to claim 10, further comprising: a distribution control step of adding a redundant code for the content to the content distributed to the first terminal by an increment of the bandwidth. The distribution condition includes content frame rate information as the attribute,
A control information storage step of storing control information in which the pre-change frame rate information, the post-change frame rate information, and the bandwidth increment value are associated with each other in the control information storage unit;
Increase in bandwidth included in control information in which the frame rate information of the first terminal is associated with pre-change frame rate information and the frame rate information included in the first rule is associated with post-change frame rate information, respectively. The quality control method selection step of calculating the bandwidth increment for raising the user experience quality value of the first terminal to the estimated quality value of the first rule based on
The quality control method according to claim 10 or 11, further comprising: the distribution control step of changing a frame rate of content to be distributed to the first terminal to the changed frame rate. The distribution condition includes content resolution information as the attribute,
A control information storage step of storing control information in which the pre-change resolution information, the post-change resolution information, and the bandwidth increment value are associated with each other in the control information storage unit;
The resolution information of the first terminal is based on the increment of bandwidth included in the control information associated with the pre-change resolution information and the resolution information included in the first rule is associated with the post-change resolution information, respectively. The quality control method selection step of calculating a bandwidth increment for raising the user experience quality value of the first terminal to the estimated quality value of the first rule;
The quality control method according to any one of claims 10 to 12, further comprising: the distribution control step of changing a resolution of content distributed to the first terminal to the changed resolution. The content delivered to the device is hierarchically encoded,
The distribution condition includes hierarchical information indicating which level of content that is hierarchically encoded as the attribute is distributed,
A control information storage step of storing control information in which the hierarchical information before change, the hierarchical information after change, and the increment value of the bandwidth are associated with each other in the control information storage unit;
Based on the increase in bandwidth included in the control information associated with the hierarchical information of the first terminal in the pre-change hierarchical information and the hierarchical information included in the first rule in the post-change hierarchical information, respectively. The quality control method selection step of calculating a bandwidth increment for raising the user experience quality value of the first terminal to the estimated quality value of the first rule;
The distribution control step of changing the content to be distributed to the first terminal so as to distribute up to the hierarchy indicated in the post-change hierarchy information among the content. The quality control method described in 1. The distribution condition includes a plurality of the attributes and content identification information capable of identifying the content to be distributed,
A policy storage step of storing in the policy storage means a control policy in which content identification information is associated with a change priority of each attribute included in the distribution condition;
The control policy corresponding to the content identification information of the content distributed to the first terminal is read from the policy storage means, and the attribute value of the attribute having a high change priority included in the control policy is the value of the first terminal. The quality control method according to any one of claims 10 to 14, further comprising: the control method determination step of selecting, as the improvement rule, a rule that is different between a delivery condition and a delivery condition of the first rule. The distribution condition includes a plurality of the attributes and a frame information amount indicating an information amount per frame of the content to be distributed,
A policy storage step of storing in the policy storage means a control policy in which the amount of frame information and the change priority of each attribute included in the distribution condition are associated with each other;
A control policy including the amount of frame information of content distributed to the first terminal is read from the policy storage means, and an attribute value of a high change priority attribute included in the control policy is distributed by the first terminal. The quality control method according to any one of claims 10 to 15, further comprising: a control method determination step of selecting, as the improvement rule, a rule that is different between a condition and a delivery condition of the first rule. The delivery condition includes a plurality of the attributes,
A policy storage step of storing in the policy storage means a control policy in which a user profile, which is information relating to the user of each terminal, is associated with a change priority of each attribute included in the distribution condition;
A control policy including a user profile of the first terminal is read out from the policy storage unit, and an attribute value of an attribute having a high change priority included in the control policy is the distribution condition of the first terminal and the first rule The quality control method according to any one of claims 10 to 16, further comprising: a control method determination step of selecting a rule that differs depending on the delivery condition as the improvement rule. On the computer,
A rule storage process for storing, in the control information storage means, a rule in which a distribution condition including an attribute indicating characteristics when distributing content to a terminal and an estimated quality value of a user experience quality obtained under the distribution condition are associated with each other ,
The first rule which is a rule whose estimated quality value is higher than the user experience quality value of the first terminal is selected and read out from the control information storage means, and the distribution condition of the first rule for each of the first rules, Calculating a bandwidth increment for raising the user experience quality value of the first terminal to the estimated quality value of the first rule based on a difference with the delivery condition of the first terminal;
The second rule which is a rule whose estimated quality value is lower than the user experience quality value of the second terminal is selected and read from the control information storage means, and the distribution condition of the second rule for each second rule, A quality control method for calculating a bandwidth decrement when the user experience quality value of the second terminal is lowered to the estimated quality value of the second rule based on a difference from the delivery condition of the second terminal Selection process,
A control method determination process for selecting an improvement rule that is one of the first rules and a reduction rule that is one of the second rules that satisfy a condition that the calculated increment does not exceed the calculated decrement; ,
A program for executing distribution control processing for changing the distribution condition of the first terminal to the distribution condition of the improvement rule and changing the distribution condition of the second terminal to the distribution condition of the reduction rule. The delivery condition includes a packet loss rate as the attribute,
In the computer,
A control information storage process for storing control information in which the packet loss rate before change, the packet loss rate after change and the increment value of the bandwidth are associated with each other in the control information storage unit;
Increase in bandwidth included in the control information in which the packet loss rate of the first terminal is associated with the packet loss rate before change, and the packet loss rate included in the first rule is associated with the packet loss rate after change, respectively. The quality control method selection process for calculating the bandwidth increment for raising the user experience quality value of the first terminal to the estimated quality value of the first rule based on
The program according to claim 18, wherein the distribution control process of adding a redundant code for the content by an increment of the bandwidth is performed on the content distributed to the first terminal. The distribution condition includes content frame rate information as the attribute,
In the computer,
Control information storage processing for storing control information in which the pre-change frame rate information, post-change frame rate information, and bandwidth increment values are associated with each other in the control information storage unit;
Increase in bandwidth included in control information in which the frame rate information of the first terminal is associated with pre-change frame rate information and the frame rate information included in the first rule is associated with post-change frame rate information, respectively. The quality control method selection process for calculating the bandwidth increment for raising the user experience quality value of the first terminal to the estimated quality value of the first rule based on
The program according to claim 18 or 19, wherein the distribution control process for changing a frame rate of content to be distributed to the first terminal to the changed frame rate is executed. The distribution condition includes content resolution information as the attribute,
In the computer,
Control information storage processing for storing control information in which the pre-change resolution information, the post-change resolution information, and the bandwidth increment value are associated with each other in the control information storage unit;
The resolution information of the first terminal is based on the increment of bandwidth included in the control information associated with the pre-change resolution information and the resolution information included in the first rule is associated with the post-change resolution information, respectively. The quality control method selection process for calculating a bandwidth increment for raising the user experience quality value of the first terminal to the estimated quality value of the first rule;
The program according to any one of claims 18 to 20, wherein the distribution control process for changing a resolution of content to be distributed to the first terminal to the post-change resolution is executed. The content delivered to the device is hierarchically encoded,
The distribution condition includes hierarchical information indicating which level of content that is hierarchically encoded as the attribute is distributed,
In the computer,
Control information storage processing for storing control information in which the hierarchy information before change, the hierarchy information after change, and the increment value of the bandwidth are associated with each other in the control information storage unit;
Based on the increase in bandwidth included in the control information associated with the hierarchical information of the first terminal in the pre-change hierarchical information and the hierarchical information included in the first rule in the post-change hierarchical information, respectively. The quality control method selection process for calculating a bandwidth increment for raising the user experience quality value of the first terminal to the estimated quality value of the first rule;
The distribution control process for changing the content to be distributed to the first terminal so as to distribute up to the hierarchy indicated in the post-change hierarchy information among the content. The program described in the section. The distribution condition includes a plurality of the attributes and content identification information capable of identifying the content to be distributed,
In the computer,
A policy storage process for storing, in the policy storage unit, a control policy in which content identification information and a change priority of each attribute included in the distribution condition are associated with each other;
The control policy corresponding to the content identification information of the content distributed to the first terminal is read from the policy storage means, and the attribute value of the attribute having a high change priority included in the control policy is the value of the first terminal. The program according to any one of claims 18 to 22, wherein the control method determination process of selecting a rule that is different between a delivery condition and a delivery condition of the first rule as the improvement rule is executed. The distribution condition includes a plurality of the attributes and a frame information amount indicating an information amount per frame of the content to be distributed,
In the computer,
A policy storage process for storing a control policy in which the amount of frame information is associated with a change priority of each attribute included in the distribution condition in a policy storage unit;
A control policy including the amount of frame information of content distributed to the first terminal is read from the policy storage means, and an attribute value of a high change priority attribute included in the control policy is distributed by the first terminal. The program according to any one of claims 18 to 23, wherein the control method determination process for selecting, as the improvement rule, a rule that is different between a condition and a delivery condition of the first rule is executed. The delivery condition includes a plurality of the attributes,
In the computer,
A policy storage process for storing, in the policy storage unit, a control policy in which a user profile, which is information relating to a user of each terminal, and a change priority of each attribute included in the distribution condition are associated with each other;
A control policy including a user profile of the first terminal is read out from the policy storage unit, and an attribute value of an attribute having a high change priority included in the control policy is the distribution condition of the first terminal and the first rule The program according to any one of claims 18 to 24, wherein the control method determining process of selecting a rule that differs depending on a delivery condition of the control method as the improvement rule is executed.

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