JP2011010236A - Network quality management threshold calculation device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To calculate a network quality management threshold taking jitters of packets into sufficient consideration.SOLUTION: An assumed threshold generation unit 20 generates, as assumed thresholds, a plurality of pairs of assumed unit times and assumed allowable numbers of received packets within predetermined verification ranges based upon a stationary unit time and the stationary number of received packets, and an evaluation correct answer rate calculation unit 21 verifies a packet transfer state included in each of pieces of packet information by conditions for each of the assumed thresholds based upon the assumed unit time and the assumed allowable number of received packets to estimate and evaluate whether video quality deteriorates under the communication condition. The assumed evaluation is compared with a quality evaluation result under the communication condition to calculate an evaluation correct answer rate associated with the assumed threshold. A network quality management threshold determination unit 22 determines, as a network quality threshold associated with the network, the assumed unit time and the assumed allowable number of received packets associated with the assumed threshold having the highest correct answer rate among evaluated correct answer rates of the respective assumed thresholds.

Description

  The present invention relates to a communication quality management technique, and more particularly to a technique for calculating an optimum value of a quality management threshold in a packet network that provides a video communication service.

In recent years, video-based IP services have begun to be provided in earnest throughout the world as IPTV services, and the market is expanding. On the other hand, since the quality of the packet network is not guaranteed, the quality management technology of the application that realizes the video communication service attracts attention, and the quality measuring instrument market is expanding.
In such quality management technology, it is becoming important to manage not only the quality of the packet network but also the quality of user experience (QoE: Quality of Experience) (see, for example, Non-Patent Document 1).

In order to manage user experience quality, conventionally, techniques for estimating user experience quality using various indexes that can be acquired from a network or a terminal have been studied.
Among these techniques, an approach using a video signal has been proposed as a user experience quality estimation technique for a video communication service (see, for example, Patent Document 1). However, since such an approach does not use information obtained from the network, it is impossible to specify an index to be managed by the network.
On the other hand, an approach using information that can be acquired on the network such as a packet transfer status has also been proposed (see, for example, Patent Document 2).

Japanese Patent No. 4257333 JP 2007-060475 A

ITU-T Recommendation P.10 / G.100, "Definition of Quality of Experience (QoE)," Jan., 2007.

  However, in such a conventional technique, when calculating a network quality management threshold value for obtaining a certain quality of user experience for a video played back at a receiving terminal, a fluctuation related to a packet for video communication that occurs in a packet network, that is, a user due to jitter. There is a problem in that the influence on the quality of experience is not sufficiently considered, and an effective network quality management threshold value that matches the actual quality of experience of the user cannot be calculated.

  For example, in the above-described approach using information that can be acquired on the network, packet loss and jitter are mainly used. However, with regard to the influence of jitter in the packet network, only the influence on the user experience quality due to the buffer underflow phenomenon in which the video communication packet arrives at the receiving terminal later than scheduled is considered, and the packet is earlier than the scheduled time. The influence on the user experience quality due to the buffer overrun phenomenon arriving at the receiving terminal is not considered. In practice, terminals and applications in which video quality deteriorates due to the effect that packets arrive at the terminal earlier are widely used.

  An object of the present invention is to provide a network quality management threshold value calculation technique capable of calculating a network quality management threshold value with sufficient consideration of packet jitter.

  In order to achieve such an object, the network quality control threshold value calculation apparatus according to the present invention is based on packet jitter in a packet network for video communication performed between a transmission terminal and a reception terminal via the packet network. A network quality management threshold value calculation device for calculating a network quality management threshold value for a measurement value indicating a transfer status of the video communication packet that has passed through the packet network, as an index for determining presence or absence of video quality degradation, Stores condition-specific packet information indicating packet transfer times measured for each video communication packet transferred from the packet network to the receiving terminal for each video communication performed under a plurality of communication conditions with different amounts of jitter in the network A packet information storage unit, a quality evaluation result storage unit for storing a quality evaluation result of a video reproduced by the receiving terminal for each communication condition, A steady-state value calculation unit that calculates the number of steady received packets received per preset steady-state unit time based on steady-state packet information during steady-state video communication in which the video quality at the receiving terminal is not degraded in the packet information And.

  In addition, the network quality control threshold value calculation apparatus according to the present invention assumes a set of an assumed unit time and an assumed allowable received packet number from a predetermined verification range based on the steady unit time and the steady received packet number. Assuming that a plurality of assumed threshold values are generated as threshold values, and for each assumed threshold value, verifying the packet transfer status included in each condition-specific packet information based on the assumed unit time and the assumed allowable number of received packets, the communication condition An evaluation accuracy rate calculation unit for calculating an evaluation accuracy rate for the assumed threshold value by estimating and evaluating the presence or absence of video quality degradation below, and comparing the estimated evaluation result with a quality evaluation result under the communication conditions, and each assumed threshold value The assumed unit time and the assumed allowable number of received packets for the assumed threshold with the highest accuracy rate are determined as the network quality control threshold for the network. And a network quality control threshold value determining unit for.

  At this time, when the steady-state value calculation unit calculates the number of steady received packets, it calculates the number of content-specific steady received packets received per steady unit time by the receiving terminal for each of a plurality of video communications with different contents. An average value of the number of other stationary reception packets may be calculated as the number of stationary reception packets.

  In addition, the steady value calculation unit may use a steady unit time consisting of a frame playback time for one frame at the receiving terminal.

  In addition, each assumption unit time may be generated by individually multiplying a plurality of integers specified in the verification range by the assumption threshold generation unit with respect to the steady unit time.

  Further, when the assumption threshold generation unit calculates the number of assumed allowable received packets corresponding to each assumed unit time, the number of steady received packets is multiplied by the integer used to calculate the assumed unit time, and the multiplication result is multiplied. A plurality of assumed unit times may be generated for each assumed unit time by individually multiplying a multiplication result obtained by multiplying a plurality of ratios specified in the verification range.

  Also, the network quality management threshold value calculation method according to the present invention determines the presence or absence of video quality degradation due to packet jitter in the packet network for video communication performed between the transmitting terminal and the receiving terminal via the packet network. As an index for this, a network quality management threshold value calculation method used in a network quality management threshold value calculation device for calculating a network quality management threshold value for a measurement value indicating a transfer state of the video communication packet that has passed through the packet network, The packet information storage unit calculates the packet transfer time measured for each video communication packet transferred from the packet network to the receiving terminal for each video communication performed under a plurality of communication conditions with different jitter amounts in the packet network. A packet information storage step for storing the packet information according to the condition to be indicated, and a quality evaluation result storage unit for reproduction by the receiving terminal for each communication condition. The quality evaluation result storage step for storing the quality evaluation result of the video, and the steady value calculation unit based on the steady packet information at the time of steady video communication in which the video quality at the receiving terminal is not deteriorated among the condition-specific packet information, A steady value calculating step for calculating the number of steady received packets received per steady unit time set in advance.

  In addition, in the network quality control threshold value calculation method according to the present invention, the assumed threshold value generator generates an assumed unit time and an assumed allowable received packet from a predetermined verification range based on the steady unit time and the number of steady received packets. An assumption threshold generation step for generating a plurality of sets of numbers as assumption thresholds and an evaluation accuracy rate calculation unit included in each condition-specific packet information for each assumption threshold based on the assumption unit time and the number of assumed allowable received packets. By evaluating the packet transfer status, the estimation accuracy of video quality degradation under the communication conditions is estimated, and the estimated accuracy rate for the hypothetical threshold is compared by comparing the estimation evaluation with the quality evaluation results under the communication conditions. The evaluation accuracy rate calculation step for calculating the threshold value and the network quality control threshold value determination unit determine whether the hypothetical threshold value with the highest accuracy rate among the evaluation accuracy rates for each assumption threshold value is Assumptions allowable number of received packets as the unit time, and a network quality control threshold determination step of determining the network quality control threshold relating to the network.

  At this time, when calculating the number of steady received packets in the steady value calculating step, the number of steady received packets for each content received per steady unit time at the receiving terminal is calculated for each of a plurality of video communications with different contents, and these contents are calculated. An average value of the number of other stationary reception packets may be calculated as the number of stationary reception packets.

  Further, in the steady value calculation step, a steady unit time consisting of a frame playback time for one frame at the receiving terminal may be used.

  Further, in the assumed threshold value generation step, each assumed unit time may be generated by individually multiplying the steady unit time by a plurality of integers specified in the verification range.

  Further, when calculating the number of assumed allowable received packets corresponding to each assumed unit time in the assumed threshold value generation step, the number of stationary received packets is multiplied by the integer used for calculating the assumed unit time, and this multiplication result is multiplied. A plurality of assumed unit times may be generated for each assumed unit time by individually multiplying a multiplication result obtained by multiplying a plurality of ratios specified in the verification range.

  According to the present invention, since the unit time and the allowable number of received packets are used as the network quality management threshold value, whether or not the video communication packet transferred in actual video communication is transferred within the allowable number of received packets. By verifying this, it is determined whether or not quality degradation has occurred for the video communication. As a result, it is possible to calculate a network quality management threshold considering the influence on the user experience quality due to the buffer overrun phenomenon in which the packet arrives at the receiving terminal 3 earlier than the scheduled time.

It is a block diagram which shows the structure of the network quality control threshold value apparatus concerning this Embodiment. It is an example of a structure of packet information classified by conditions. It is a structural example of terminal information. It is a structural example of a quality evaluation result. It is a flowchart which shows the information acquisition process in the network quality management threshold value calculation apparatus concerning this Embodiment. It is a structural example of a steady value. It is a flowchart which shows the network quality management threshold value determination process in the network quality management threshold value calculation apparatus concerning this Embodiment. It is a structural example of an assumption threshold value. It is a flowchart which shows the evaluation correct rate calculation process in the network quality management threshold value calculation apparatus concerning this Embodiment. It is an example of a calculation result of an evaluation correct answer rate. It is a graph which shows the calculation result of an evaluation correct answer rate.

Next, an embodiment of the present invention will be described with reference to the drawings.
[Network quality control threshold value calculation device]
First, a network quality control threshold value calculation apparatus according to this embodiment will be described with reference to FIG. FIG. 1 is a block diagram showing a configuration of a network quality management threshold device according to the present embodiment.

  The network quality control threshold value calculation device 10 as a whole is composed of an information processing communication terminal such as a general server device or workstation, and packet information obtained by video communication performed in advance on a trial basis and a receiving terminal at that time 3 has a function of calculating a network quality management threshold value for the packet network 2 used in the test.

The video distribution apparatus 1 as a whole is composed of an information processing communication terminal such as a general server apparatus or workstation, and has a function of distributing video data in packets by operating as a transmission terminal in video communication. .
The receiving terminal 3 is composed of a communication terminal such as an STB (Set-Top-Box) which connects a television receiver to a data communication network and enables use of various communication services. It has a function of receiving video data in packets by performing video communication with the connected video distribution device 1 and reproducing and outputting the video data on a video display device 4 including a television receiver.

The network quality control device 5 is composed of a test device that gives an arbitrary amount of jitter to an input packet and outputs it. The network quality control device 5 is installed on the communication network between the packet network 2 and the receiving terminal 3, and the packet network 2 Has a function of giving a jitter amount corresponding to a designated communication condition to a video communication packet transferred from the terminal to the receiving terminal 3.
The branching device 6 is composed of a communication device such as a tap or a hub, and is installed on a communication path between the network quality control device 5 and the receiving terminal 3, and is sent from the packet network 2 to the receiving terminal 3. It has a function of capturing the transferred video communication packet.

In the present embodiment, as a network quality management threshold, a set of a unit time which is a frame reproduction required time for one frame at the receiving terminal 3 and an allowable number of received packets at the receiving terminal 3 in the unit time is used. It is determined whether or not quality degradation has occurred in the video communication by verifying whether or not the video communication packet transferred in actual video communication is transferred within the allowable number of received packets.
As a result, it is possible to calculate a network quality management threshold considering the influence on the user experience quality due to a buffer overrun phenomenon in which the packet arrives at the receiving terminal 3 earlier than the scheduled time.

  As a network quality control threshold value calculation method, video communication is experimentally performed in advance under a plurality of communication conditions with different amounts of jitter in the packet network 2 and transferred from the packet network to the receiving terminal for each video transmission. In addition to preparing packet information by condition indicating the packet transfer time measured for each video communication packet, a quality evaluation result of a video reproduced by the receiving terminal 3 under these communication conditions is prepared.

  Then, in the network quality management threshold value calculation device 10, a plurality of network quality management threshold values each composed of a set of a unit time that is a frame reproduction required time for one frame at the receiving terminal 3 and the allowable number of received packets in the unit time are assumed. For each of these hypothetical network quality control thresholds, the presence or absence of quality degradation in video communication under the communication conditions is evaluated by verifying the packet information for each condition. Assumed network quality management threshold is determined as the assumed network quality management threshold value that provides the closest evaluation to the actual quality evaluation result at the receiving terminal 3 for video communication.

[Configuration of the embodiment]
Next, the configuration of the network quality control threshold value calculation apparatus according to the present embodiment will be described in detail with reference to FIG.
As shown in FIG. 1, the network quality management threshold value calculation device 10 includes, as main functional units, a packet information acquisition unit 11, a packet information storage unit 12, a terminal information acquisition unit 13, a steady value calculation unit 14, a steady value storage. A unit 15, a quality evaluation result acquisition unit 16, a quality evaluation result storage unit 17, an assumption threshold generation unit 20, an evaluation accuracy rate calculation unit 21, a network quality management threshold determination unit 22, and a screen display unit 23 are provided.

  The packet information acquisition unit 11 branches the video communication that is generated by the network quality control device 5 and is performed on a trial basis between the video distribution device 1 and the receiving terminal 3 under a plurality of communication conditions with different jitter amounts. A function for acquiring condition-specific packet information related to video communication packets related to the video communication captured by the device 6, and a function for storing the acquired condition-specific packet information in the packet information storage unit 12.

FIG. 2 is a configuration example of condition-specific packet information. This condition-specific packet information includes, for each video communication packet transferred from the packet network 2 to the receiving terminal 3 through at least the branching device 6, the transfer time with the packet number (sequence number) of the packet. ing.
At this time, the network quality control device 5 may vary the jitter amount, detect in advance the jitter amount at which the video quality starts to deteriorate, select several jitter amounts before and after that, and set the communication conditions. In the example of FIG. 2, the jitter amount at which the video quality starts to deteriorate is 90 ms, and the communication conditions are 60 ms to 120 ms before and after that in 1 ms increments.

The packet transfer time of the condition-specific packet information is described by relative time information from the first video communication packet that starts measurement, but may be absolute time information.
As for the packet transfer time, the reception time of each video communication packet captured by the branching device 6 and received by the packet information acquisition unit 11 may be used. Each of the video communication packets measured by the branching device 6 may be used. The packet information acquisition unit 11 may acquire the transfer time from the branching device 6.

  As for the packet transfer time used as the condition-specific packet information, the most accurate network quality control threshold can be calculated by using the packet reception time at the receiving terminal 3. However, since the jitter generated in the communication path from the branching device 6 to the receiving terminal 3 is negligible as compared with the jitter generated in the packet network 2, the network quality is determined at the point where the branching device 6 is installed. If it is on the communication path between the control device 5 and the receiving terminal 3, for example, it is calculated even if it is installed adjacent to the network quality control device 5 at the connection point between the packet network 2 and the access line of the receiving terminal 3. The impact on the network quality control threshold is negligible.

  When managing the packet network 2 in an in-service environment where a video communication service is provided using a network quality control threshold during network management operation, a branching device 6 is provided in the same manner as the experimental video communication described above. Thus, it is necessary to obtain packet information from actual video communication packets. Therefore, it is desirable to provide the branching device 6 at the edge node of the packet network 2 that is easy for the communication service provider to manage. The error from the management operation can be suppressed.

  The same applies to the jitter that occurs in the communication path from the branching device 6 to the network quality control threshold value calculation device 10, and the packet transfer time is measured by the packet information acquisition unit 11 even if it is measured by the branching device 6. The influence on the calculated network quality control threshold is negligible.

The terminal information acquisition unit 13 has a function of acquiring various terminal information used for video communication at the receiving terminal 3.
FIG. 3 is a configuration example of terminal information. As the terminal information acquired by the terminal information acquisition unit 13, there is a video frame display rate indicating the number of frames to be reproduced per second by the receiving terminal 3, as shown in FIG.
For the video frame display rate, a value measured at the time of video reproduction at the receiving terminal 3 may be used, or a value set as a specification of the receiving terminal 3 may be used.

  As a method for acquiring the terminal information, the terminal information acquiring unit 13 acquires the terminal information from the data communication between the terminal information acquiring unit 13 and the receiving terminal 3 or the recording medium on which the terminal information is recorded. Alternatively, the terminal information acquisition unit 13 may acquire terminal information input by an operator using a keyboard provided in the network quality management threshold value calculation apparatus 10.

  The steady value calculation unit 14 calculates a frame reproduction required time required to reproduce one frame of video at the receiving terminal 3 from the video frame display rate acquired by the terminal information acquisition unit 13 as a steady unit time, Received by the receiving terminal 3 per steady unit time based on the steady packet information during steady video communication in which the video quality at the receiving terminal is not deteriorated among the packet information classified by conditions stored in the packet information storage unit 12 And a function of saving the steady unit time and the number of steady received packets in the steady value storage unit 15 as steady values.

The quality evaluation result acquisition unit 16 determines, for each communication condition, the user experience quality of the video reproduced by the receiving terminal 3 for the trial video communication when the packet information classified by conditions acquired by the packet information acquisition unit 11 is obtained. A function of acquiring the quality evaluation result to be shown, and a function of storing the acquired quality evaluation result in the quality evaluation result storage unit 17.
FIG. 4 is a configuration example of the quality evaluation result. The quality evaluation result may be information in which presence / absence of video quality deterioration is detected, or information quantified by 5-step evaluation or the like (for example, MOS: Mean Opinion Score defined in ITU-T recommendation P800) ).

  The assumption threshold generation unit 20 uses, as an assumption threshold, a set of an assumption unit time and an assumed allowable received packet number within a predetermined verification range based on the steady unit time and the number of steady reception packets read from the steady value storage unit 15. It has a function to generate multiple.

  The evaluation accuracy rate calculation unit 21 is included in each condition-specific packet information read from the packet information storage unit 12 based on the assumed unit time and the number of assumed allowable received packets for each assumption threshold generated by the assumption threshold generation unit 20. A function for estimating the presence / absence of video quality degradation under the communication conditions by verifying the packet transfer status, and comparing these estimation evaluations with the quality evaluation results under the communication conditions read from the quality evaluation result storage unit 17 By doing so, it has a function of calculating an evaluation accuracy rate regarding the assumed threshold.

At this time, the evaluation accuracy rate calculation unit 21 compares the presence / absence of video quality degradation obtained for each of these assumption thresholds with the quality evaluation result under the communication conditions read from the quality evaluation result storage unit 17, and both evaluations are performed. When both indicate deterioration or no deterioration, that is, when both evaluations match, it is determined that the estimated evaluation based on the assumed threshold is correct. In addition, when one of the two evaluations shows deterioration and the other shows no deterioration, that is, when the two evaluations do not coincide with each other, it is determined that the estimated evaluation based on the assumed threshold is correct.
Thereafter, the evaluation correct answer rate calculation unit 21 calculates the correct answer rate for each hypothetical threshold number by dividing the correct answer number by the number of condition-specific packet information.

  The network quality management threshold value determination unit 22 compares the correct answer rate for each assumed threshold number obtained by the evaluation correct answer rate calculating unit 21, and calculates the assumed unit time of the assumed threshold number with the highest correct answer rate and the assumed allowable received packet number. It has a function of determining the unit quality and the allowable number of received packets indicating the network quality control threshold value, and a function of displaying the unit time and the allowable number of received packets on the screen display unit 23.

  The network quality control threshold value calculation device 10 has a general configuration provided in a normal information processing device, in addition to a screen display unit 23, an arithmetic processing unit, a storage unit, a data communication interface unit, a data entrance Tsutsu interface. Functional units such as a unit and an operation input unit are provided, and each functional unit described above performs a processing operation using these functional units.

Among the functional units of the network quality management threshold calculation device 10 described above, the packet information acquisition unit 11, the terminal information acquisition unit 13, the steady value calculation unit 14, the quality evaluation result acquisition unit 16, the assumed threshold generation unit 20, and the evaluation accuracy rate The calculation unit 21 and the network quality management threshold value determination unit 22 may be realized by an arithmetic processing unit.
The arithmetic processing unit includes a microprocessor such as a CPU and its peripheral circuits, and implements various functional units by reading and executing a program stored in advance in the storage unit.

  Among the functional units of the network quality management threshold value calculation device 10, the packet information storage unit 12, the steady value storage unit 15, and the quality evaluation result storage unit 17 may be realized by a storage device such as a hard disk or a semiconductor memory. . Each of these storage units may be realized by separate storage devices, or any one or a plurality of storage units may be realized by one storage device.

[Operation of this embodiment]
Next, the operation of the network quality management threshold value calculation apparatus 10 according to the present embodiment will be described.
Main processing operations in the network quality management threshold value calculation apparatus 10 include an information acquisition process, a network quality management threshold value determination process, and an evaluation accuracy rate calculation process.

[Information acquisition processing]
First, the information acquisition process in the network quality management threshold value calculation apparatus 10 according to the present embodiment will be described with reference to FIG. FIG. 5 is a flowchart showing information acquisition processing in the network quality management threshold value calculation apparatus according to this embodiment.

  This information acquisition process is executed when video communication is experimentally performed between the video distribution device 1 and the receiving terminal 3 under a plurality of communication conditions with different amounts of jitter. At this time, the network quality control device 5 may vary the jitter amount, detect in advance the jitter amount at which the video quality starts to deteriorate, select several jitter amounts before and after that, and set the communication conditions.

  In the information acquisition process of FIG. 5, the network quality management threshold value calculation device 10 first performs a test between the video distribution device 1 and the receiving terminal 3 under a plurality of communication conditions with different jitter amounts by the packet information acquisition unit 11. For the video communication to be performed, the condition-specific packet information regarding the video communication packet related to the video communication captured by the branching unit 6 is acquired, and the acquired condition-specific packet information is stored in the packet information storage unit 12 (step 100). ).

  Next, the network quality management threshold value calculation device 10 uses the quality evaluation result acquisition unit 16 for the experimental video communication when the packet information by condition acquired by the packet information acquisition unit 11 is obtained for each communication condition. The quality evaluation result of the video reproduced by the receiving terminal 3 is acquired, and the acquired quality evaluation result is stored in the quality evaluation result storage unit 17 (step 101).

Moreover, the network quality management threshold value calculation apparatus 10 acquires various terminal information used for video communication at the receiving terminal 3 by the terminal information acquisition unit 13 (step 102).
Subsequently, the network quality management threshold value calculation device 10 uses the steady value calculation unit 14 to calculate the steady unit time and the number of steady received packets as steady values during steady video communication in which the video quality at the receiving terminal 3 is not degraded. And it preserve | saves to the steady value memory | storage part 15 (step 103).

  At this time, the steady value calculation unit 14 calculates a frame reproduction required time required to reproduce one frame of video at the receiving terminal 3 from the video frame display rate acquired by the terminal information acquisition unit 13 as a normal unit time. . Further, out of the condition-specific packet information stored in the packet information storage unit 12, the receiving terminal per steady unit time based on steady packet information at the time of steady video communication in which the video quality at the receiving terminal 3 is not degraded. In step 3, the number of stationary reception packets received is calculated.

FIG. 6 is a configuration example of steady values. Among the steady values, the steady unit time can be calculated by the reciprocal of the video frame display rate acquired by the terminal information acquisition unit 13. Regarding the number of steady received packets, among each packet included in the steady packet information, a time interval of a steady unit time length is provided in order from the transfer time of the first packet, and the transfer time is included in the time interval for each of these time intervals. The number of received packets may be calculated by counting the number of packets received and averaging the number of packets in each time interval.
Thereby, the network quality management threshold value calculation apparatus 10 ends a series of information acquisition processing.

[Network quality control threshold determination processing]
Next, with reference to FIG. 7, the network quality management threshold value determination process in the network quality management threshold value calculation apparatus 10 according to the present embodiment will be described. FIG. 7 is a flowchart showing network quality management threshold value determination processing in the network quality management threshold value calculation apparatus according to this embodiment.

  In the network quality management threshold value determination process of FIG. 7, the network quality management threshold value calculation device 10 first determines in advance based on the steady unit time and the number of steady received packets read from the steady value storage unit 15 by the assumed threshold value generation unit 20. A plurality of sets of the assumed unit time and the assumed allowable number of received packets are generated as assumption thresholds from the determined verification range (step 110).

  FIG. 8 is a configuration example of an assumed threshold value. Here, as the assumed unit time, the verification range is up to nine times the steady unit time, and nine types of values obtained by the steady unit time × n (n is an integer of 1 to 9) are used. Further, regarding the assumed allowable number of received packets, the verification range is increased from 80% of the number of steady received packets to 100% in increments of 5%, and the steady unit time × (n + x) (x is 80%, 85%, 90%) , 95%, or 100%) are used. As a result, the assumed threshold value is 45 (= 9 × 5).

Next, the network quality management threshold value calculation device 10 starts an assumption threshold loop in which the evaluation accuracy rate calculation unit 21 repeatedly executes steps 112 and 113 described later for each assumption threshold value generated by the assumption threshold value generation unit 20 ( Step 111).
In this assumption threshold loop, the evaluation accuracy rate calculation unit 21 first acquires the assumption threshold selected at the head of the assumption threshold loop from the assumption threshold generation unit 20 (step 112), and the evaluation accuracy rate based on this assumption threshold In order to calculate the correct answer sequence described later (step 113).

Thus, after calculating the evaluation accuracy rate by the evaluation accuracy rate calculation unit 21 for all the assumption thresholds generated by the assumption threshold generation unit 20, the network quality management threshold value calculation device 10 performs the network quality management threshold value determination unit 22 Thus, the correct answer rates of these assumed threshold numbers are compared (step 114).
Then, the network quality management threshold value determination unit 22 determines the assumed unit time of the assumed threshold number having the highest accuracy rate and the assumed allowable received packet number as the unit time indicating the network quality management threshold and the allowable received packet number (step 115). ).

  Thereafter, the network quality management threshold value determination unit 22 displays the unit time and the number of allowable received packets on the screen display unit 23 (step 116), and ends a series of network quality management threshold value determination processing.

[Evaluation accuracy rate calculation processing]
Next, an evaluation accuracy rate calculation process in the network quality management threshold value calculation apparatus 10 according to the present embodiment will be described. FIG. 9 is a flowchart showing an evaluation accuracy rate calculation process in the network quality management threshold value calculation apparatus according to this embodiment.

  In the evaluation accuracy rate calculation process of FIG. 9, the network quality management threshold value calculation device 10 first executes a communication condition loop in which the evaluation accuracy rate calculation unit 21 repeatedly executes steps 121 to 128 described later for each communication condition. (Step 120).

  In this hypothetical threshold loop, the evaluation accuracy rate calculation unit 21 first reads out the condition-specific packet information corresponding to the communication condition selected at the head of the communication condition loop from the packet information storage unit 12 (step 121), and the evaluation The number of packets is counted for each virtual unit time selected at the start of the accuracy rate calculation process (step 122).

  At this time, the evaluation accuracy rate calculation unit 21 sets time intervals in order for each virtual unit time from the first packet described in the packet information according to the condition, and packets transferred within the time interval for each time interval. The number may be counted. In addition, for each packet described in the condition-specific packet information, a time interval may be set using the transfer time of the packet as a start time.

  Thereafter, the evaluation accuracy rate calculation unit 21 verifies whether or not there is a time interval in which the counted packets exceed the number of assumed allowable received packets selected at the time of starting the evaluation accuracy rate calculation process. (Step 123).

  As a result of the verification, if there is a time interval exceeding the number of assumed allowable received packets (step 123: YES), the evaluation accuracy rate calculating unit 21 estimates and evaluates that the video quality is deteriorated (step 124), and assumes the allowable allowable received packets. If there is no time interval exceeding the number (step 123: NO), the evaluation accuracy rate calculation unit 21 estimates and evaluates that there is no deterioration in video quality (step 125).

After estimating the presence or absence of video quality degradation in this way, the evaluation accuracy rate calculation unit 21 reads the quality evaluation result corresponding to the communication condition selected in the loop processing from the quality evaluation result storage unit 17 (step 126). ) Compare this quality evaluation result with the estimated evaluation result (step 127).
Here, when both evaluation results indicate that there is deterioration or no deterioration and both evaluation results match (step 127: YES), the evaluation accuracy rate calculation unit 21 performs the estimation evaluation based on the assumed threshold value. Is the correct answer, the number of correct answers of the estimated evaluation related to the virtual threshold selected at the time of starting the evaluation correct rate calculation process is counted by 1 (step 128).

  On the other hand, when one of the two evaluations shows deterioration and the other shows no deterioration, and the evaluation results of the two do not match (step 127: NO), the evaluation accuracy rate calculation unit 21 estimates the evaluation based on the assumed threshold. Because the answer is incorrect, the number of correct answers is not counted.

In this way, after performing the process of counting the number of correct answers in accordance with the correct / incorrect answer of the estimated evaluation, the evaluation correct rate calculating unit 21 ends the loop process related to the communication condition selected in Step 120 and proceeds to Step 120. Returning to the next loop processing for the next communication condition.
Further, when the loop processing regarding all communication conditions is completed, the evaluation accuracy rate calculation unit 21 ends the series of evaluation accuracy rate calculation processing.

  FIG. 10 is an example of the calculation result of the evaluation accuracy rate. FIG. 11 is a graph showing the calculation result of the evaluation accuracy rate. Here, when the assumed unit time is 33 ms and the assumed allowable received packet rate is 85%, the evaluation accuracy rate is 100%, which is the largest. Therefore, in this example, unit time = 33 ms and assumed allowable number of received packets = 94 are selected as the network quality management threshold.

[Effects of the present embodiment]
As described above, in the present embodiment, the steady-state value calculation unit 14 uses the steady-state packet information based on the steady-state packet information at the time of steady-state video communication in which the video quality at the receiving terminal 3 is not deteriorated among the condition-specific packet information. The number of stationary received packets received per stationary unit time, which is the frame reproduction required time for one frame, is calculated, and the assumption threshold generation unit 20 performs a predetermined verification based on the stationary unit time and the number of stationary received packets. A plurality of sets of assumed unit time and assumed allowable number of received packets are generated as assumption threshold values from within the range.

  Then, the evaluation accuracy rate calculation unit 21 verifies the packet transfer status included in each condition-specific packet information based on the assumed unit time and the assumed allowable number of received packets for each assumed threshold, thereby obtaining the communication condition. By estimating and evaluating the presence / absence of video quality degradation in the network, and comparing the estimated evaluation with the quality evaluation result under the communication conditions, an evaluation accuracy rate for the hypothetical threshold is calculated, and the network quality management threshold determining unit 22 Of the estimated correct answer rates of the assumed threshold value, the assumed unit time and the assumed allowable number of received packets for the assumed threshold value with the highest correct answer rate are determined as the network quality control threshold value for the network.

Therefore, since unit time and the number of allowable received packets are used as the network quality control threshold, it is verified whether or not the video communication packet transferred in actual video communication is transferred within the allowable number of received packets. Thus, it is determined whether or not quality degradation has occurred for the video communication.
As a result, it is possible to calculate a network quality management threshold considering the influence on the user experience quality due to a buffer overrun phenomenon in which the packet arrives at the receiving terminal 3 earlier than the scheduled time.

  In the present embodiment, the steady value calculation unit 14 calculates the number of steady received packets for each content received by the receiving terminal 3 per steady unit time for each of a plurality of video communications with different contents. An average value of the number of received packets may be calculated as the number of stationary received packets, and a network quality control threshold from which dependency on content is eliminated can be calculated.

Further, in the present embodiment, the steady value calculation unit 14 uses a steady unit time consisting of a frame playback time for one frame at the receiving terminal 3, so that when verifying each frame and packet transfer status The packet delimiter can be almost synchronized.
Therefore, the evaluation accuracy rate calculation unit 21 can estimate and evaluate the presence / absence of video quality degradation under the same conditions as the video quality evaluation at the receiving terminal 3, and can improve the calculation accuracy of the network quality management threshold value. .

In the present embodiment, the assumed threshold value generation unit 20 generates each assumed unit time by individually multiplying the steady unit time by a plurality of integers specified in the verification range, When calculating the number of assumed allowable received packets corresponding to each assumed unit time, the number of stationary received packets is multiplied by the integer used to calculate the assumed unit time, and this multiplication result is multiplied by a plurality of values specified in the verification range. A plurality of assumed unit times are generated for each assumed unit time by individually multiplying the respective multiplication results by the respective ratios, so that each frame and packet for verifying the packet transfer status The break can be almost synchronized.
Therefore, the evaluation accuracy rate calculation unit 21 can estimate and evaluate the presence / absence of video quality degradation under the same conditions as the video quality evaluation at the receiving terminal 3, and can improve the calculation accuracy of the network quality management threshold value. .

[Extended embodiment]
The present invention has been described above with reference to the embodiments, but the present invention is not limited to the above embodiments. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.

  In the above description, the steady value calculating unit 14 calculates the number of steady received packets, and the case where the steady received packet number is calculated from the video communication for which the condition-specific packet information is measured has been described as an example. It is not limited to.

  For example, for each of a plurality of video communications with different contents, the number of steady received packets for each content received by the receiving terminal 3 per steady unit time is calculated, and the average value of the steady received packets for each content is calculated as the number of steady received packets. Alternatively, it is possible to calculate a network quality control threshold from which the dependency on the content is excluded.

  Further, depending on the service provided, instead of the average value, the minimum value of the number of steady received packets for each content may be selected as the number of steady received packets based on the service policy.

  DESCRIPTION OF SYMBOLS 1 ... Video distribution apparatus (transmission terminal), 2 ... Packet network, 3 ... Reception terminal, 4 ... Video display apparatus, 5 ... Network quality control apparatus, 6 ... Branch device, 10 ... Network quality management threshold value calculation apparatus, 11 ... Packet Information acquisition unit, 12 ... packet information storage unit, 13 ... terminal information acquisition unit, 14 ... steady value calculation unit, 15 ... steady value storage unit, 16 ... quality evaluation result acquisition unit, 17 ... quality evaluation result storage unit, 20 ... Assumption threshold value generation unit, 21... Evaluation correct answer rate calculation unit, 22... Network quality control threshold value determination unit, 23.

Claims (10)

For video communication performed between a transmission terminal and a reception terminal via a packet network, the video communication that has passed through the packet network as an index for determining the presence or absence of video quality degradation due to packet jitter in the packet network A network quality control threshold value calculation device for calculating a network quality control threshold value for a measurement value indicating a transfer state of a packet for communication,
By condition indicating the packet transfer time measured for each video communication packet transferred from the packet network to the receiving terminal for each of the video communications performed under a plurality of communication conditions with different amounts of jitter in the packet network A packet information storage unit for storing packet information;
For each of the communication conditions, a quality evaluation result storage unit that stores a quality evaluation result of the video reproduced by the receiving terminal;
Based on the steady packet information during steady video communication in which the video quality at the receiving terminal is not deteriorated among the packet information by condition, the number of steady received packets received per steady unit time set in advance is calculated. A steady value calculation unit;
Based on the stationary unit time and the stationary received packet number, an assumed threshold generation unit that generates a plurality of sets of assumed unit time and assumed allowable received packet number as a hypothetical threshold from within a predetermined verification range;
For each hypothetical threshold, based on the hypothetical unit time and the hypothetical allowable number of received packets, by verifying the packet transfer status included in each condition-specific packet information, the presence or absence of video quality degradation under the communication conditions An evaluation accuracy rate calculation unit that calculates an evaluation accuracy rate related to the assumed threshold value by performing estimation estimation and comparing the estimation evaluation with the quality evaluation result in the communication condition;
A network quality management threshold value determining unit that determines the assumed unit time and the assumed allowable number of received packets as the network quality management threshold value for the network among the estimated correct answer rates of the respective assumed threshold values. A network quality control threshold value calculation device characterized by the above. In the network quality control threshold value calculation device according to claim 1,
When calculating the number of steady received packets, the steady value calculating unit calculates the number of steady received packets for each content received by the receiving terminal per unit unit time for each of a plurality of video communications having different contents. An apparatus for calculating a network quality control threshold value, characterized in that an average value of the number of different stationary reception packets is calculated as the number of regular reception packets. In the network quality control threshold value calculation device according to claim 1,
The network quality management threshold value calculation device according to claim 1, wherein the steady value calculation unit uses the steady unit time including a frame reproduction time for one frame at the receiving terminal. In the network quality control threshold value calculation device according to claim 1,
The assumption threshold generation unit generates each of the assumption unit times by individually multiplying the steady unit time by a plurality of integers specified in the verification range. Calculation device. In the network quality control threshold value calculation device according to claim 4,
The hypothesis threshold generation unit, when calculating the number of assumed allowable received packets corresponding to each assumed unit time, multiply the number of stationary received packets by the integer used to calculate the assumed unit time, A plurality of assumption unit times are generated for each assumption unit time by individually multiplying the multiplication result by multiplying each of the multiplication results by a plurality of ratios specified in the verification range. A network quality control threshold value calculation device. For video communication performed between a transmission terminal and a reception terminal via a packet network, the video communication that has passed through the packet network as an index for determining the presence or absence of video quality degradation due to packet jitter in the packet network A network quality management threshold value calculation method used in a network quality management threshold value calculation device for calculating a network quality management threshold value for a measurement value indicating a transfer state of a packet for use,
Packets measured by the packet information storage unit for each video communication packet transferred from the packet network to the receiving terminal for each video communication performed under a plurality of communication conditions with different jitter amounts in the packet network A packet information storage step for storing condition-specific packet information indicating a transfer time;
A quality evaluation result storing step for storing a quality evaluation result of a video reproduced by the receiving terminal for each communication condition;
The stationary value calculation unit receives the stationary unit per preset stationary unit time based on the stationary packet information at the time of stationary video communication in which the video quality at the receiving terminal is not deteriorated among the packet information by condition. A steady value calculating step for calculating the number of received packets;
Assumed threshold generation unit generates a plurality of sets of assumed unit time and assumed allowable received packet number as assumption thresholds from a predetermined verification range based on the steady unit time and the number of stationary received packets. Steps,
The evaluation accuracy rate calculation unit verifies the packet transfer status included in each condition-specific packet information based on the assumed unit time and the assumed allowable number of received packets for each of the assumed thresholds. An evaluation accuracy rate calculation step for calculating an evaluation accuracy rate for the hypothetical threshold by estimating and evaluating the presence or absence of video quality degradation of the image, and comparing the estimation evaluation with the quality evaluation result in the communication conditions;
A network quality management threshold value determining unit determines an assumed unit time and an assumed allowable number of received packets as the network quality management threshold value for the network, with respect to the assumed threshold value with the highest accuracy rate among the evaluation correct answer rates of the respective assumed threshold values. A network quality management threshold value calculation method comprising: a management threshold value determination step. In the network quality control threshold value calculation method according to claim 6,
The steady value calculating step calculates the number of steady received packets for each content received by the receiving terminal per steady unit time for each of a plurality of video communications having different contents when calculating the number of steady received packets. A network quality management threshold value calculation method, wherein an average value of the number of other steady received packets is calculated as the number of steady received packets. In the network quality control threshold value calculation method according to claim 6,
The network quality management threshold value calculation method according to claim 1, wherein the steady value calculation step uses the steady unit time including a frame reproduction time for one frame at the receiving terminal. In the network quality control threshold value calculation method according to claim 6,
The hypothetical threshold generation step generates the hypothetical unit time by individually multiplying the stationary unit time by a plurality of integers specified in the verification range, respectively. Calculation method. The network quality control threshold value calculation method according to claim 9,
In the assumption threshold generation step, when calculating the number of assumed allowable received packets corresponding to each assumption unit time, the number of stationary reception packets is multiplied by the integer used to calculate the assumption unit time, A plurality of assumption unit times are generated for each assumption unit time by individually multiplying the multiplication result by multiplying each of the multiplication results by a plurality of ratios specified in the verification range. A network quality control threshold value calculation method.

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