JP5770655B2 - Communication quality measuring apparatus and method - Google Patents

Description

  The present invention relates to a communication quality measuring apparatus and method, and more particularly to a communication quality measuring apparatus and method considering characteristics of a wireless communication environment.

  There are basically the following two types of conventional communication quality measuring devices related to radio.

a. For end-to-end communication quality, a fixed line quality measuring device is also used in a wireless line:
b. Measuring radio access layer status and quality for radio access sections;
A. Basically, a loss rate, delay fluctuation, delay, throughput, and the like are measured for an end-to-end section including radio (for example, see Non-Patent Document 1).

  b. Measures the radio section state (for 3G wireless communication, measures the radio wave state between the base station and the terminal or confirms the reception state of the terminal) (for example, Non-Patent Document 2). reference).

IxChariot http://www.toyo.co.jp/it/ixhariot/ Anritsu MT8222b http://www.anritsu.com/en-us/products-solutions.products/mt8222b.aspx

  Conventional measuring instruments measure throughput, average delay, etc., assuming that the state is stable for a long time (general QoS index definitions are made in ITU-T recommendation Y. 1540).

  However, the quality state of wireless communication has quality state characteristics different from those of wired communication. The influence of the characteristics of the radio layer extends to the end-to-end section, and measuring them is necessary for end-to-end quality measurement in consideration of radio.

  Specifically, the communication quality (packet transfer delay) is distributed in a plurality of discrete values, and for each transfer delay value, it is not a statistically independent event, but from a good state to a bad state, In addition, there is a state transition from a bad state to a good state.

  On the other hand, in many QoS studies, each sample is often an independent event in terms of probability statistics (PASTA assumption), and the delay parameters are the average delay and delay fluctuation (ITU-T Y.1540 recommendation 99.9% value of transfer delay distribution-width of minimum value), minimum value, maximum value, median (median) of delay, etc. are used.

  Burst loss may be described by virtual state transitions in the Markov model / Gilbert Elliott model.

  In addition, as a consideration for the state change, there is a concept of evaluating each state since each transitioned state continues for a certain time.

  However, in the wireless communication environment, the following points may become a problem from the viewpoint of an actual user.

  It often happens that the round trip delay value is about 100 ms to about 200 ms to about 300 ms, and so on that the difference is so great as to affect the usability of the user application.

  In addition, the state transition frequently occurs even for several seconds to several tens of seconds, and there is a problem that the state itself changes in a time scale in which the application adjusts the buffer amount according to each state.

  Therefore, it is necessary to observe such state changes and collectively describe them in simple numerical information.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a communication quality measuring apparatus and method capable of observing transitions in the state of wireless communication and providing them in simple numerical information. To do.

In order to solve the above problems, the present invention (Claim 1) is a communication quality measuring device for measuring a quality state of wireless communication,
Parameter storage means for storing state transition determination time, state transition threshold rate, and starting state;
Packet data input / output means for inputting / outputting measurement probe packets to / from the measurement target device;
A delay calculation means for calculating a packet transfer delay time from the difference between the transmission time and the reception time of the acquired probe packet, and storing it in a delay result storage means;
Data is read in time series from the delay result storage means, flag = 1 is set for data in which the packet transfer delay time exceeds a predetermined value, flag = 0 is set for data in which the packet transfer delay time does not exceed, A deterioration state determination means for determining a better state or a deterioration state of a sequence of flags,
The deterioration state determining means includes
If all the data within the state transition determination time is extracted from the data with the flag set, the state at that time is in a good state, and the data of flag = 1 is included at a ratio equal to or higher than the state transition threshold rate A means for recording in the determination table as transitioning to a deteriorated state, and recording in the determination table as transitioning to a good state if data of flag = 0 is included at a ratio equal to or greater than the state transition threshold rate;
Referring to the determination table, the ratio of the good state in all the read data, the ratio of the deteriorated state in all the read data, the number of state transitions from the good state to the deteriorated state within the predetermined measurement time, and the good Means for calculating and outputting any one of a length in which the state continues, a length in which the deterioration state continues, and an average delay in the deterioration state .

  In the end-to-end quality measurement including the radio section, the present invention grasps the state due to the packet transfer delay and creates a state transition table from the feature amount, so that the good state, the deteriorated state, and those states can be obtained from the table. State transition data can be digitized and output.

It is a block diagram of the communication quality measuring device in one embodiment of this invention. It is a flowchart of the outline | summary operation | movement in one embodiment of this invention. It is an example of a setting parameter and an input parameter in an embodiment of the present invention. It is an example of the command of the probe packet transmission / reception interface in one embodiment of this invention. It is a storage example of delay result DB in one embodiment of this invention. It is an example of the threshold value excess data of the determination table in one embodiment of this invention. It is an example of the determination table in one embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  The present invention measures the “state” of packet transfer delay and extracts the feature amount in end-to-end quality measurement including a wireless section.

  This will be specifically described below.

  FIG. 1 shows a configuration of a communication quality measuring apparatus according to an embodiment of the present invention.

  The communication quality measuring apparatus 1 shown in FIG. 1 includes a parameter storage unit 10, a probe packet transmission / reception interface 20, a delay calculation unit 30, a clock 40, a delay result DB 50, and a degradation state determination unit 60.

  FIG. 2 is a flowchart of an outline operation in one embodiment of the present invention.

  Initial parameters are determined in advance and stored in the parameter storage unit 10 (step 1). In the probe packet transmission / reception interface 20, the address of the measurement partner server 2 specified in the parameter is accessed, and the probe packet is acquired (step 2). The delay calculation unit 30 obtains a delay for the acquired probe packet and stores the result in the delay result DB 50 (step 3). The degradation state determination unit 60 reads out the delay data from the delay result DB 50 and determines whether or not the state transition is made by comparing with the value specified by the parameter storage unit 10, and evaluates the degradation based on the determination state. (Step 4), and the evaluation result is output (step 5).

  Hereinafter, the operation of the communication quality measuring apparatus 1 will be described.

  The parameter storage unit 10 stores parameters as shown in FIG. As input parameters, an end-end quality measurement destination IP address, probe packet transmission interval, number of measurements, transfer delay value state threshold, state transition determination time, state transition threshold rate, and start state are set.

  The probe packet transmission / reception interface 20 is an interface for inputting / outputting measurement probe packets, obtains a transmission interval (t_g) and a destination IP address (remote_addr) of end-end quality measurement from the parameter storage unit 10, and probes The packet is output to the measurement partner server (remote_addr) at t_g, and the response packet is acquired.

  As an example of realizing the interface, it can be realized by a ping command that is often installed in a unix OS as shown in FIG. By collecting the data of the last “time =” field of the output result shown in FIG. 4 in the order of the “icmp_seq” field, it is possible to obtain data of time series change of the round-trip transfer delay described later. The same can be done for a one-way delay instead of a round trip delay.

  The data acquired as described above is output to the delay calculation unit 30.

The delay calculation unit 30 obtains the packet transfer time in time series. For the transfer time of each packet, the transmission side puts the sequence number and the timestamp of the transmission time acquired from the clock 40 on the packet payload, records the reception time acquired from the clock 40 on the reception side, and is recorded in the received packet. The transfer delay time can be measured for each packet from the difference with the transmission time. Specifically, it can be realized by the technology described in the document “One-way measuring machine: Yokogawa IQ2000 http://www.yokogawa.co.jp/rd/pdf/tr/rd-tr-r04902-007.pdf”. is there. The packet transfer delay times obtained as described above are stored in the delay result DB 50 in chronological order. For example, the parameter storage unit 10
Probe packet transmission interval (t_g) = 1 second Measurement count (n) = 100 times Transfer delay value state threshold (RTT_th) = 200 ms
State transition judgment time (t_s) = 3 seconds State transition threshold rate (r_s) = 60%
Is stored in the delay result DB 50, the delay calculation unit 30 obtains the difference between the transmission time and the reception time of the packet data measured 100 times per second with reference to the information. As shown in FIG. When data is lost due to packet loss, the delay transfer time is “NA (not available)”.

  The deterioration state determination unit 60 has a determination table 61 in the memory. The delay result DB 50 is read, and the quality state transition is evaluated based on the difference in transfer delay time. Specifically, the inter-state threshold value (RTT_th) of the transfer delay value is acquired from the parameter storage unit 10, and the data exceeding the threshold value (1 bit) is used for data exceeding RTT_th from the data read from the delay result DB50. Give. If RTT_th or less, the flag is set to “0”, and if it is RTT_th or more, the flag is set to “1”. For “NA” due to packet loss, the flag is set to “1”, and the data (sequence number, transfer delay time, threshold excess flag) to which the threshold value excess data as shown in FIG. Is stored in the determination table 61.

  Next, the deterioration state determination unit 60 calculates determination state data. First, the start state (Start_state) is determined as a parameter given in advance. Here, “good” (good state) is adopted as an example. Next, it is determined whether or not the state transitions to “poor” (degraded state). In the state determination, the time-series threshold value superdata in the determination table 61 shown in FIG. Do that.

  A specific calculation method is as follows.

Data for the state transition determination time (t_s) is extracted from the target data shown in FIG. That is, the first determination is made after data for t_s seconds is accumulated. For example, since the state transition determination time t_s of the parameter storage unit 10 in FIG. 3 is 3 seconds, three data after 0 to 2 seconds are targeted. In this example,
Data after 2 seconds (0, 0, 0)
It becomes.

  For this super-threshold data, when the current state is “good” and “1” is included at a ratio equal to or greater than the state transition threshold rate (r_s), the state becomes “poor” and a state transition occurs. Conversely, when the current state is “poor” and “0” is included at a ratio equal to or greater than the state transition threshold rate (r_s), the state becomes “good” and a state transition occurs.

  A specific example will be described with reference to FIG.

  If a determination state column is added to the determination table 61 of the memory shown in FIG. 65 in the deterioration state determination unit 60, the result is as shown in FIG.

  When the start state Start_state stored in the parameter storage unit 10 is “good”, the threshold value super-data in the determination table 61 is “0” at the start time (sequence number 0). The determination state remains good (good). Even in the sequence number 1, since the threshold value excess data is “0”, it remains in the initial state (good). In sequence number 2, since the threshold value super-data is “0” and the past three times are “0, 0, 0”, the state is similarly “good”.

  In sequence number 4, the threshold value excess data is “1”. The determination results for the past three times are “0, 0, 1”, and the ratio of “1” is the state transition threshold rate r_s = 60% in the parameter storage unit 10, which is less than 60% and the determination state is “ good ".

  In sequence number 6, the super-threshold data is “1”, and from the determination result of sequence number 5, the determination results for the past three times are “1, 0, 1”. Therefore, since the ratio of “1” is the state transition threshold rate r_s = 60%, it becomes 60% or more, and the determination state transitions to “poor”. Such repetition is repeated according to the specification of the parameter in the parameter storage unit 10.

  With the above processing, state determination data based on the threshold value of the transfer delay time is obtained.

  Next, the degradation state determination unit 60 reads the determination table 61 and calculates a quality parameter considering the state by the following method. The parameters to be calculated are the average “good” rate, the average “poor” rate, the number of occurrences of “poor” state within the period, the average “good” length, the average “poor” length, the average delay in the “poor” state, and the like. In the following calculation, since the state determination data cannot be calculated during the first t_s, there is no state data during the first t_s.

1) Average “good” rate:
(The number of good in all judgment status data / the number of all judgment status data)
2) Average “poor” rate:
(The number of poor in all judgment status data / the number of all judgment status data)
The average “poor” rate + the average “good” rate = 1.

3) Number of occurrences of “poor” status during period:
Number of transitions to the “poor” state that occurred within the measurement time t_s 4) Average “good” length:
The determination state data can be interpreted as one or more consecutive “good” determination data blocks separated by “poor” determination data in between. The duration of each “good” data chunk is calculated and the average value is calculated. In the above example, the length of the “good” judgment data chunks of sequences 2 to 5 is 4 seconds, and then the length of the “good” judgment data chunks of sequence 14 to (3 seconds or more), Thus, a data chunk length string of (4, 3,...) Can be obtained, and the average value is “good length”.

5) Average “poor” length:
The above calculation is performed by the same calculation method as in 4), replacing good and poor. That is, it is the average length of the “poor” determination data chunk.

6) Average delay in "poor" state:
Average value of transfer delay times for all judgment state data == poor data (NA data is excluded from the calculation of the average value).

  The results obtained in the above 1) to 6) are output as the results of the communication quality measuring device 1.

  The operation of each component of the communication quality measuring device 1 can be constructed as a program, installed in a computer used as the communication quality measuring device, executed, or distributed via a network. .

  The present invention is not limited to the above-described embodiments, and various modifications and applications are possible within the scope of the claims.

1 Communication Quality Measuring Device 10 Parameter Storage Unit 20 Probe Packet Transmission / Reception Interface 30 Delay Calculation Unit 40 Clock 50 Delay Result DB
60 Degradation State Determination Unit 61 Determination Table

Claims (3)

A communication quality measuring device for measuring a quality state of wireless communication,
Parameter storage means for storing state transition determination time, state transition threshold rate, and starting state;
Packet data input / output means for inputting / outputting measurement probe packets to / from the measurement target device;
A delay calculation means for calculating a packet transfer delay time from the difference between the transmission time and the reception time of the acquired probe packet, and storing it in a delay result storage means;
Data is read in time series from the delay result storage means, flag = 1 is set for data in which the packet transfer delay time exceeds a predetermined value, flag = 0 is set for data in which the packet transfer delay time does not exceed, A deterioration state determination means for determining a better state or a deterioration state of a sequence of flags,
The deterioration state determining means includes
If all the data within the state transition determination time is extracted from the data with the flag set, the state at that time is in a good state, and the data of flag = 1 is included at a ratio equal to or higher than the state transition threshold rate A means for recording in the determination table as transitioning to a deteriorated state, and recording in the determination table as transitioning to a good state if data of flag = 0 is included at a ratio equal to or greater than the state transition threshold rate;
Referring to the determination table, the ratio of the good state in all the read data, the ratio of the deteriorated state in all the read data, the number of state transitions from the good state to the deteriorated state within the predetermined measurement time, and the good Means for calculating and outputting any one of a length in which the state continues, a length in which the deteriorated state continues, and an average delay in the deteriorated state . A communication quality measuring method in which a communication quality measuring device having a packet data input / output unit, a delay calculating unit, and a degradation state determining unit measures the quality state of wireless communication,
Store the state transition judgment time, state transition threshold rate, start state in the parameter storage means,
The packet data input means, the packet data output step of inputting and outputting a probe packet for measuring with the communication quality measuring device and the measuring target apparatus,
The delay calculation means calculates a packet transfer delay time from the difference between the transmission time and the reception time of the acquired probe packet, and stores it in a delay result storage means;
The degradation state determination means reads data in time series from the delay result storage means, sets flag = 1 for data whose packet transfer delay time exceeds a predetermined value, and sets flag for data not exceeding A deterioration state determination step for setting = 0 and determining a better state or a deterioration state of a sequence of time-series flags , and
In the deterioration state determining step,
If all the data within the state transition determination time is extracted from the data with the flag set, the state at that time is in a good state, and the data of flag = 1 is included at a ratio equal to or higher than the state transition threshold rate , Recorded in the determination table as transitioning to a degraded state, and recorded in the determination table as transitioning to a good state if the data of flag = 0 is included at a ratio equal to or greater than the state transition threshold rate,
Referring to the determination table, the ratio of the good state in all the read data, the ratio of the deteriorated state in all the read data, the number of state transitions from the good state to the deteriorated state within the predetermined measurement time, and the good Calculate and output either the length of the continuous state, the length of the continuous deteriorated state, or the average delay in the deteriorated state.
A communication quality measuring method characterized by the above. Computer
The communication quality measurement program for functioning as each means of the communication quality measuring device of Claim 1.

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