Test system and evaluation method

Abstract

To provide a test system and an evaluation method with which it is possible to evaluate, similarity between the pseudo-propagation path characteristic of a channel model and the actual propagation path characteristic.SOLUTION: A test system 1 comprises: an actual propagation path estimate characteristic calculation unit 21 for calculating an estimate characteristic at a plurality of pieces of analysis object timing of the propagation path characteristics of one or more channels constituting an actual propagation path; a parameter calculation unit 22 for calculating a parameter that characterizes a statistical nature of the estimate characteristic; a pseudo-propagation path characteristic generation unit 30 for generating a plurality of pseudo-propagation path characteristics corresponding to the parameter; a pseudo-channel capacity calculation unit 24 for calculating a pseudo-channel capacity regarding each of the plurality of pseudo-propagation path characteristics; an actual propagation path channel capacity calculation unit 25 for calculating a channel capacity regarding each of estimate characteristics at at lease some of the analysis object timing among the plurality of pieces of analysis object timing; and a channel capacity evaluation unit 28 for calculating an evaluation index for evaluating a degree of similarity between the pseudo-channel capacity and the channel capacity.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a test system and an evaluation method for evaluating a channel model. [Background technology]

[0002] When testing a mobile phone terminal, the demodulation performance in a fading environment is evaluated by passing the downlink signal output from a base station simulator through a propagation path simulator and supplying the signal to the mobile radio terminal. The channel model used in the propagation path simulator is often one defined specifically for testing. However, there is also a demand for evaluating the demodulation performance of a mobile phone terminal using a channel model with propagation path characteristics closer to the actual propagation path environment.

[0003] Generally, as a method for simulating an actual propagation path environment, a method of reproducing the propagation path characteristics measured in the actual propagation path environment is known.

[0004] The ACE RNX Channel Emulator's "Field-to-Lab" (see, for example, Non-Patent Document 1) collects data on downlink signals transmitted by actual base stations as they travel through actual propagation paths, extracts the propagation path characteristics of the actual propagation paths by analyzing the data, and reproduces the instantaneous values ​​of the propagation path characteristics of the actual propagation paths as they are to test the demodulation units of mobile phone terminals. "Field-to-Lab" can faithfully reproduce the actual propagation path characteristics by reproducing them as they are.

[0005] However, the existing "Field-to-Lab" method disclosed in Non-Patent Document 1 reproduces the actual propagation path characteristics as they are, so the test time for the mobile phone terminal is determined by the data collection time. Also, since the antenna used for data collection is different from the antenna of the actual mobile phone terminal, there is no significant point in reproducing the instantaneous values ​​of the propagation path characteristics themselves. [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] "ACE RNX Channel Emulator" product catalog, March 1, 2018 Summary of the Invention [Problem to be solved by the invention]

[0007] On the other hand, as an alternative to the method disclosed in Non-Patent Document 1, there is a method in which the statistical properties of the measured propagation path characteristics are parameterized and converted into a channel model, and then the propagation path environment is simulated. In this method, it is desirable to be able to evaluate whether or not the channel model can simulate the propagation path characteristics in the actual propagation path environment with sufficient accuracy.

[0008] When evaluating the demodulation performance of mobile phone terminals, throughput is generally measured. The appropriateness of a channel model would be best understood by evaluating the "deviation" from the achieved throughput. However, factors that determine throughput include not only propagation path characteristics but also the amount of radio resources allocated to the communication being measured. Therefore, throughput is not an appropriate indicator for evaluating the similarity between the propagation path characteristics of a channel model that corresponds to the actual propagation path characteristics and the actual propagation path characteristics.

[0009] The present invention has been made to solve the above-mentioned conventional problems, and aims to provide a test system and evaluation method that can evaluate the similarity between the pseudo-propagation path characteristics of a channel model and the actual propagation path characteristics. [Means for solving the problem]

[0010] In order to solve the above problem, a test system according to the present invention includes: a real propagation path estimated characteristics calculation unit (21) that calculates estimated characteristics of propagation path characteristics of one or more channels constituting a real propagation path at a plurality of analysis target timings using IQ data of the downlink signal output from an antenna device (10) that receives the downlink signal transmitted from a transmission / reception device (100) on a network side in an environment of the real propagation path (110); a parameter calculation unit (22) that calculates parameters that characterize statistical properties of the estimated characteristics; a pseudo propagation path characteristics generation unit (30) that generates a plurality of pseudo propagation path characteristics in accordance with the parameters; a pseudo channel capacity calculation unit (24) that calculates pseudo channel capacities for each of the plurality of pseudo propagation path characteristics; a real propagation path channel capacity calculation unit (25) that calculates channel capacities for each of the estimated characteristics at at least some analysis target timings among the plurality of analysis target timings; and a channel capacity evaluation unit (28) that calculates an evaluation index for evaluating a similarity between the pseudo channel capacity and the channel capacity.

[0011] With this configuration, the test system according to the present invention can generate pseudo propagation path characteristics from parameters that characterize the statistical properties of the propagation path characteristics without being limited by the acquisition time of the downlink signal from the base station.

[0012] Furthermore, the test system according to the present invention can test the device under test by reproducing the statistical propagation path characteristics of an actual propagation path using the pseudo propagation path characteristics.

[0013] Furthermore, the test system according to the present invention can evaluate the similarity between the simulated channel characteristics of the channel model and the actual channel characteristics using the channel capacity, i.e., the test system according to the present invention can evaluate the validity of the process of calculating the parameters of the channel model using the channel capacity as an index.

[0014] Furthermore, the test system according to the present invention may be configured such that the channel capacity evaluation unit includes a frequency distribution calculation unit (26) that calculates a frequency distribution of the pseudo channel capacity and the frequency distribution of the channel capacity, and a similarity evaluation unit (27) that calculates a similarity between the frequency distribution of the pseudo channel capacity and the frequency distribution of the channel capacity as the evaluation index.

[0015] In addition, the test system according to the present invention may be configured such that the channel capacity evaluation unit calculates the average value and / or standard deviation of the pseudo channel capacity and the average value and / or standard deviation of the channel capacity as evaluation indexes.

[0016] In addition, the test system of the present invention may be configured so that the similarity evaluation unit calculates the evaluation index based on the difference between the average value of the frequency distribution of the pseudo channel capacity and the average value of the frequency distribution of the channel capacity, and the evaluation index based on the difference between the width of the frequency distribution of the pseudo channel capacity and the width of the frequency distribution of the channel capacity.

[0017] With these configurations, the test system according to the present invention can appropriately evaluate the degree of similarity between the simulated propagation path characteristics of the channel model and the actual propagation path characteristics.

[0018] Furthermore, the test system according to the present invention may be configured such that the width of the frequency distribution of the pseudo channel capacity is the difference between the maximum and minimum values ​​of a 95% confidence interval of the frequency distribution of the pseudo channel capacity, and the width of the frequency distribution of the channel capacity is the difference between the maximum and minimum values ​​of a 95% confidence interval of the frequency distribution of the channel capacity.

[0019] With this configuration, the test system according to the present invention can appropriately evaluate the degree of similarity between the simulated propagation path characteristics of the channel model and the actual propagation path characteristics.

[0020] Furthermore, the evaluation method according to the present invention includes a real propagation path estimated characteristics calculation step (S2) of calculating estimated characteristics of propagation path characteristics of one or more channels constituting the real propagation path at a plurality of analysis target timings using IQ data of the downlink signal output from an antenna device (10) that receives the downlink signal transmitted from a transmission / reception device (100) on a network side in an environment of the real propagation path (110); a parameter calculation step (S3) of calculating parameters that characterize statistical properties of the estimated characteristics; a pseudo propagation path characteristics generation step (S4) of generating a plurality of pseudo propagation path characteristics in accordance with the parameters; a pseudo channel capacity calculation step (S5) of calculating pseudo channel capacity for each of the plurality of pseudo propagation path characteristics; a real propagation path channel capacity calculation step (S6) of calculating channel capacity for each of the estimated characteristics at at least some analysis target timings among the plurality of analysis target timings; and a channel capacity evaluation step (S7, S8) of calculating an evaluation index for evaluating a similarity between the pseudo channel capacity and the channel capacity.

[0021] In addition, the evaluation method according to the present invention may be configured such that the channel capacity evaluation step includes a frequency distribution calculation step (S7) of calculating a frequency distribution of the pseudo channel capacity and the frequency distribution of the channel capacity, and a similarity evaluation step (S8) of calculating a similarity between the frequency distribution of the pseudo channel capacity and the frequency distribution of the channel capacity as the evaluation index.

[0022] In addition, the evaluation method of the present invention may be configured so that the channel capacity evaluation step calculates the average value and / or standard deviation of the pseudo channel capacity and the average value and / or standard deviation of the channel capacity as evaluation indexes.

[0023] In addition, the evaluation method of the present invention may be configured so that the similarity evaluation step calculates the evaluation index based on the difference between the average value of the frequency distribution of the pseudo channel capacity and the average value of the frequency distribution of the channel capacity, and the evaluation index based on the difference between the width of the frequency distribution of the pseudo channel capacity and the width of the frequency distribution of the channel capacity.

[0024] In addition, in the evaluation method of the present invention, the width of the frequency distribution of the pseudo channel capacity may be the difference between the maximum and minimum values ​​of a 95% confidence interval of the frequency distribution of the pseudo channel capacity, and the width of the frequency distribution of the channel capacity may be the difference between the maximum and minimum values ​​of a 95% confidence interval of the frequency distribution of the channel capacity. [Effects of the Invention]

[0025] The present invention provides a test system and evaluation method that can evaluate the degree of similarity between simulated propagation path characteristics of a channel model and actual propagation path characteristics. [Brief explanation of the drawings]

[0026] [Figure 1] FIG. 2 is a diagram schematically illustrating an environment of an actual propagation path between a base station and an antenna device. [Figure 2] 1 is a block diagram showing a configuration of a test system according to an embodiment of the present invention; [Figure 3] 10 is a graph schematically showing a frequency distribution of channel capacity. [Figure 4] 10 is a graph illustrating the relationship between the target throughput and the mean value and width of the frequency distribution of channel capacity. [Figure 5] 1 is a flowchart illustrating the process of an evaluation method using a test system according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, embodiments of a test system and an evaluation method according to the present invention will be described with reference to the drawings. The test system and evaluation method according to the present invention use channel capacity, which is the theoretical upper limit of throughput, as an index for evaluating the similarity between the simulated channel characteristics of a channel model and the actual channel characteristics.

[0028] Fig. 1 is a diagram schematically illustrating the environment of an actual propagation path 110 between a base station 100, which is an example of a network-side transmitting / receiving device, and an antenna device 10. In Fig. 1, data communication between the base station 100 and the antenna device 10 is performed using multiple subcarriers according to the Orthogonal Frequency Division Multiplexing (OFDM) modulation method.

[0029] The antenna device 10 receives downlink signals transmitted from T antennas Tx1 to TxT of the base station 100 in an environment of an actual propagation path 110 consisting of one or more channels. For example, the antenna device 10 is an air monitor or a mobile phone terminal. The antenna device 10 has R antennas Rx1 to RxR that receive the downlink signals transmitted from the antennas Tx1 to TxT of the base station 100 as received signals, and an IQ data output unit 11.

[0030] Here, the number T of antennas Tx1 to TxT of the base station 100 and the number R of antennas Rx1 to RxR of the antenna device 10 are each an integer of 1 or more, and the value of T×R is the number of channels of the actual propagation path 110.

[0031] The IQ data output unit 11 performs reception processing such as amplification, frequency conversion, and analog-to-digital conversion on the R reception signals received by the antennas Rx1 to RxR. Furthermore, the IQ data output unit 11 demodulates the R reception signals that have been subjected to reception processing to generate R sets of I-component baseband signals and Q-component baseband signals that are orthogonal to each other. In this specification, the I-component baseband signals and Q-component baseband signals are collectively referred to simply as "IQ data."

[0032] H in Figure 1 n 11 (k),H n 21 (k),···,H n R1 (k),H n 12 (k),H n 22 (k),···,H n R2 (k),···,H n 1T (k),H n 2T (k),···,H n RT (k) is an element of a channel matrix H(k,n) shown in equation (1) described later.

[0033] As shown in FIG. 2, the test system 1 of this embodiment includes a test device 15, a signal processing unit 20, a pseudo-path characteristics generating unit 30, and a display unit 41.

[0034] The test equipment 15 has the function of a pseudo base station device that generates downlink signals required for testing a device under test (DUT) 120, transmits the signals to the DUT 120 via a pseudo propagation path, receives uplink signals transmitted from the DUT 120, and performs processing required for the test. The test equipment 15 is configured to test, for example, the demodulation performance of the DUT 120. The pseudo propagation path between the test equipment 15 and the DUT 120 is formed by a pseudo propagation path characteristics generator 30, which will be described later. The DUT 120 is, for example, a mobile phone terminal capable of communication using a MIMO (Multiple Input Multiple Output) method.

[0035] The signal processing unit 20 includes an actual propagation path estimation characteristics calculation unit 21, a parameter calculation unit 22, a pseudo channel capacity calculation unit 24, an actual propagation path channel capacity calculation unit 25, and a channel capacity evaluation unit .

[0036] The actual propagation path estimation characteristic calculation unit 21 uses the IQ data output from the IQ data output unit 11 of the antenna device 10 to calculate the propagation path characteristic H of one or more channels that constitute the actual propagation path 110. n ij (k) Multiple analysis target timing t n Estimated characteristics H^ n ij (k) is calculated. Here, H n ij (k) represents each element of the channel matrix H(k,n) of the actual propagation path 110 in the following equation (1). i is the index of the R antennas Rx1 to RxR of the antenna device 10, and j is the index of the T antennas Tx1 to TxT of the base station 100.

[0037] That is, R=1 and T=1 represents the SISO (Single Input Single Output) method, R≧2 and T=1 represents the SIMO (Single Input Multiple Output) method, R=1 and T≧2 represents the MISO (Multiple Input Single Output) method, and R≧2 and T≧2 represents the MIMO method.

[0038]

number

[0039] In equation (1), k is an index in the frequency direction, for example, an index of the subcarrier number. Here, if Δf is the frequency interval of the subcarriers, then the frequency f of each subcarrier is k is k×Δf. Also, n is an index in the time direction, for example, an index of an OFDM symbol number. Here, k is an integer from 0 to K−1, and n is an integer from 0 to N−1.

[0040] A reference signal (RS) is included in the IQ data output from the IQ data output unit 11 of the antenna device 10. For example, in the 5G NR standard, reference signals such as a CSI-RS (Channel State Information Reference Signal), a DM-RS (Demodulation Reference Signal), a TRS (Tracking Reference Signal), and a PT-RS (Phase Tracking Reference Signal) are provided.

[0041] The actual propagation path estimation characteristic calculation unit 21 calculates the propagation path characteristic H from the known RS included in the downlink signals transmitted from the T antennas Tx1 to TxT of the base station 100 and the RS of each channel included in the R sets of IQ data output from the IQ data output unit 11. n ij (k) Estimated characteristic H^ n ij (k) is calculated. n ij (k) includes information on the amplitude fluctuation amount and phase fluctuation amount of the RS of the IQ data obtained from the received signal received by the i-th antenna Rxi for the known RS transmitted by the j-th antenna Txj. For example, in the 5G NR standard, the actual propagation path estimation characteristic calculation unit 21 calculates the estimated characteristic Ĥ n ij Used to calculate (k). Here, H^ n ij (k) represents each element of the matrix H^(k,n) of the estimated values ​​of the channel matrix H(k,n) of the actual channel 110 in equation (1), and is expressed as in equation (2).

[0042]

number

[0043] The parameter calculation unit 22 calculates the estimated characteristic H^ calculated by the actual propagation path estimation characteristic calculation unit 21. n ij That is, the parameter calculation unit 22 calculates a parameter that characterizes the statistical properties of the actual propagation path estimation characteristic Ĥ (k). n ij Among (k), the estimated characteristic H^ during the period in which the statistical properties can be considered unchanged n ij The parameters are calculated using (k). The parameters calculated by the parameter calculation unit 22 are input to the pseudo channel characteristics generation unit 30.

[0044] The pseudo channel characteristic generator 30 includes a known channel model such as a TDL model (Tapped Delay Line model) or a CDL model (Clustered Delay Line model). The pseudo channel characteristic generator 30 generates a plurality of pseudo channel characteristics P n1 ij (k1).

[0045] where P n1 ij (k1) represents each element of the channel matrix P(k1, n1) in the following equation (3). The indices i and j are the same as those in equation (1). k1 is an index in the frequency direction, and the frequency indicated by k1 does not necessarily have a one-to-one correspondence with the frequency indicated by index k in equation (1). Similarly, n1 is an index in the time direction, and the timing indicated by n1 corresponds to the analysis target timing t indicated by index n in equation (1). n There does not necessarily have to be a one-to-one correspondence.

[0046]

number

[0047] For example, the parameter calculation unit 22 calculates the "K factor," "PDP (Power Delay Profile)," "antenna correlation matrix," and the like as parameters of the TDL model.

[0048] Furthermore, the pseudo channel characteristic generating unit 30 generates the pseudo channel characteristic P n1 ij (k1) between the test equipment 15 and the DUT 120.

[0049] The pseudo channel capacity calculation unit 24 calculates the pseudo channel capacity P n1 ij (k1) for each pseudo channel capacity C p The following formula is calculated:

[0050]

number

[0051] The actual channel capacity calculation unit 25 calculates the actual channel capacity at a plurality of analysis target timings t n Estimated characteristics H^ at at least some of the timings to be analyzed n ij The channel capacity C0 for each of (k) is calculated.

[0052]

number

[0053] The channel capacity evaluation unit 28 evaluates the pseudo channel capacity C calculated by the pseudo channel capacity calculation unit 24. p and the channel capacity C0 calculated by the actual propagation path channel capacity calculation unit 25. The channel capacity evaluation unit 28 includes, for example, a frequency distribution calculation unit 26 and a similarity evaluation unit 27.

[0054] The frequency distribution calculation unit 26 calculates the pseudo channel capacity C p and the frequency distribution of the channel capacity C0 calculated by the actual propagation path channel capacity calculation unit 25.

[0055] The similarity evaluation unit 27 evaluates the pseudo channel capacity C calculated by the frequency distribution calculation unit 26. p The similarity evaluation unit 27 calculates, as an evaluation index, the degree of similarity between the frequency distribution of the pseudo channel capacity C p The similarity evaluation unit 27 calculates a value based on the difference between the average value of the frequency distribution of the pseudo channel capacity C p A value based on the difference between the width of the frequency distribution of the channel capacity C0 and the width of the frequency distribution of the channel capacity C1 is calculated.

[0056] Generally, the frequency distribution of channel capacity is as shown in the graph in Figure 3. The channel capacity takes various values ​​at each moment. In the graph in Figure 3, the average value C Ave is the average channel capacity. 95% is the difference between the maximum and minimum channel capacities in the 95% confidence interval of the frequency distribution of channel capacities.

[0057] Hereafter, we use the frequency distribution of the channel capacity C0 as Ave and W 95% C Ave(Org) and W 95%(Org) Also, the pseudo channel capacity C p Frequency distribution of C Ave and W 95% C Ave(Model) and W 95%(Model) In other words, the width W of the frequency distribution of the channel capacity C0 95%(Org) is the difference between the maximum and minimum values ​​of the 95% confidence interval of the frequency distribution of the channel capacity C0. Similarly, the pseudo channel capacity C pThe width of the frequency distribution W 95%(Model) is the pseudo channel capacity C p is the difference between the maximum and minimum values ​​of the 95% confidence interval of the frequency distribution.

[0058] The similarity evaluation unit 27 calculates C Ave(Org) and C Ave(Model) The absolute value of the difference between Ave(Org) The evaluation index is calculated by dividing the value by the number of users and displaying it as a percentage.

[0059]

number

[0060] Further, the similarity evaluation unit 27 calculates W 95%(Org) and W 95%(Model) The absolute value of the difference between 95%(Org) The evaluation index is calculated by dividing the value by the number of users and displaying it as a percentage.

[0061]

number

[0062] The width of the frequency distribution of channel capacities used by the similarity evaluation unit 27 is not limited to the width of the 95% confidence interval, but may be any other width.

[0063] Figure 4 is a graph illustrating the relationship between the target throughput and the mean value and width of the frequency distribution of channel capacity. Throughput is determined by the modulation method, error correction method, and amount of wireless resource allocation. Channel capacity is the theoretical upper limit of throughput and can be said to be an index that indicates how easily throughput can be achieved.

[0064] As shown in Figure 4, the mean value of the frequency distribution, C Ave Even if the width W 95%Depending on the magnitude of the frequency distribution, the channel capacity may fall below the target throughput. In such a case, CRC NG, which is information indicating a failure of the CRC (Cyclic Redundancy Check) used for error detection, occurs at a channel capacity below the target throughput. In other words, it can be seen that both the mean value and width of the frequency distribution of the channel capacity are important as evaluation indices for the similarity evaluation unit 27.

[0065] The channel capacity evaluation unit 28 is not limited to the configuration for calculating the frequency distribution described above, and may be configured to calculate the pseudo channel capacity C p The average value or / and standard deviation of the channel capacity C0 is calculated as an evaluation index, and the pseudo channel capacity C p and the channel capacity C0.

[0066] An example of a method for calculating the "K factor", "PDP", and "antenna correlation matrix" among the parameters of the TDL model by the parameter calculation unit 22 will be shown below.

[0067] Estimated property H^ n ij (k) is the frequency characteristic with k as the index in the frequency direction, but there are multiple delay taps τ corresponding to multiple paths. m The impulse response g consists of n ij First, the parameter calculation unit 22 calculates the estimated characteristic Ĥ in equation (2). n ij From (k), the impulse response g of the following equation (8) n ij (m) is calculated. Here, the generalized inverse matrix of matrix A is represented as A+. M represents the number of delay taps, and m is an integer between 0 and M-1. Matrix A is a kind of Fourier transform matrix that can calculate a column vector whose elements are frequency characteristics by multiplying it by a column vector whose elements are time-domain impulse responses.

[0068]

number

[0069] The K factor is a parameter that represents the ratio between the power of the direct wave (line-of-sight: LOS) and the power of the scattered wave (non-line-of-sight: NLOS). The K factor can be calculated using the method described in the reference document below, for example. The impulse response g of the first delay tap defined by equation (8) n ij By associating (0) with "V+v(t)" described in equation (1) in the reference document below, the K factor can be calculated from equation (9) in the reference document below.

[0070] Reference: LJ Greenstein, et al, "Moment-Method Estimation of the Ricean K-Factor," in IEEE Communications Letters, Vol. 3, No. 6, pp. 175-176, June 1999

[0071] PDP is a parameter that indicates the power versus delay characteristic of the averaged delay tap. PDP, normalized by the total power and expressed in dB units, is calculated as follows:

[0072]

number

[0073]

number

[0074] However, for the first delay tap, if the PDP is the NLOS component separated from the LOS component, then P tap (0) is the K factor K f It is calculated using the following formula (11):

[0075]

number

[0076] The antenna correlation matrix is ​​a function of the propagation path characteristics H n ij (k) is a matrix that represents how similar they are to each other. The antenna correlation matrix for the m-th delay tap can be calculated as follows, for example, in the case of 2x2 MIMO. (The antenna correlation matrix can be calculated in a similar way for other antenna configurations.)

[0077] First, the 2×2 MIMO channel matrix for the m-th delay tap is expressed as in the following equation (12).

[0078]

number

[0079] The column vector g generated by stacking the column vectors included in the propagation path matrix of equation (12) stack (m, n) is defined as in the following equation (13).

[0080]

number

[0081] The matrix representing the correlation between the elements of the vector in equation (13) is given by equation (14) below.

[0082]

number

[0083] Here, equation (14) is expressed in matrix notation as in equation (15) below. The diagonal elements of the matrix in equation (15) are always real numbers, but the off-diagonal elements are complex numbers.

[0084]

number

[0085] The antenna correlation matrix R is calculated by the following equation (16) so that all diagonal elements of the matrix in equation (15) are 1. corr (m) is calculated.

[0086]

number

[0087] The display unit 41 is configured with a display device such as an LCD (Liquid Crystal Display) or a CRT (Cathode Ray Tube), and displays a setting screen for setting the test contents of the test system 1, test results, and a pseudo channel capacity C p and a frequency distribution of the channel capacity C0. The display unit 41 may have an operation function such as a soft key on the display screen.

[0088] The signal processing unit 20 is configured by a control device such as a computer including, for example, a central processing unit (CPU), a graphics processing unit (GPU), a field programmable gate array (FPGA), a read only memory (ROM), a random access memory (RAM), a hard disk drive (HDD), etc. In addition, the signal processing unit 20 can configure at least a part of the actual propagation path estimation characteristics calculation unit 21, the parameter calculation unit 22, the pseudo channel capacity calculation unit 24, the actual propagation path channel capacity calculation unit 25, the frequency distribution calculation unit 26, and the similarity evaluation unit 27 in software form by executing a predetermined program by the CPU or the GPU.

[0089] The above program may be stored in advance in a ROM or HDD. Alternatively, the program may be provided or distributed in an installable or executable format recorded on a computer-readable recording medium such as a compact disc or DVD. Alternatively, the program may be stored in a computer connected to a network such as the Internet and provided or distributed by downloading via the network.

[0090] An example of the process of an evaluation method using the test system 1 of this embodiment will be described below with reference to the flowchart in Fig. 5. Note that descriptions that overlap with the description of the configuration of the test system 1 described above will be omitted as appropriate.

[0091] First, the IQ data of the downlink signal is input from the IQ data output unit 11 of the antenna device 10 to the signal processing unit 20 (step S1).

[0092] Next, the actual propagation path estimation characteristic calculation unit 21 calculates the propagation path characteristic H of one or more channels that constitute the actual propagation path 110 using the IQ data input in step S1. n ij (k) Multiple analysis target timing t n Estimated characteristics H^ n ij (k) is calculated (actual propagation path estimation characteristic calculation step S2).

[0093] Next, the parameter calculation unit 22 calculates the estimated characteristic H^ calculated in the actual propagation path estimation characteristic calculation step S2. n ij A parameter characterizing the statistical properties of (k) is calculated (parameter calculation step S3).

[0094] Next, the pseudo channel characteristic generating unit 30 generates a plurality of pseudo channel characteristics P n1 ij (k1) is generated (pseudo propagation path characteristic generation step S4).

[0095] Next, the pseudo channel capacity calculation unit 24 calculates a plurality of pseudo channel characteristics P n1 ij (k1) for each pseudo channel capacity C p is calculated (pseudo channel capacity calculation step S5).

[0096] Next, the actual propagation path channel capacity calculation unit 25 calculates the actual propagation path channel capacity at a plurality of analysis target timings t n Estimated characteristics H^ at at least some of the timings to be analyzed n ij The channel capacity C0 for each of (k) is calculated (actual propagation path channel capacity calculation step S6).

[0097] Next, the frequency distribution calculation unit 26 calculates the pseudo channel capacity C p and the frequency distribution of the channel capacity C0 calculated in the actual propagation path channel capacity calculation step S6 (frequency distribution calculation step S7).

[0098] Next, the similarity evaluation unit 27 calculates the pseudo channel capacity C p The similarity between the frequency distribution of the channel capacity C0 and the frequency distribution of the channel capacity C1 is calculated as an evaluation index (similarity evaluation step S8).

[0099] Next, the signal processing unit 20 causes the display unit 41 to display the evaluation index calculated in the similarity evaluation step S8 (step S9).

[0100] The actual channel capacity calculation step S6 and the frequency distribution calculation step S7 are carried out by using the pseudo channel capacity C p and the channel capacity C0.

[0101] As described above, the test system 1 according to this embodiment is capable of measuring the estimated characteristic Ĥ obtained in the environment of the actual propagation path 110. n ij(k) is calculated. As a result, the test system 1 according to this embodiment can calculate the estimated characteristic Ĥ n ij The pseudo propagation path characteristic P n1 ij (k1) can be generated.

[0102] Furthermore, the test system 1 according to this embodiment calculates the pseudo propagation path characteristic P n1 ij Using (k1), the statistical propagation path characteristics of the actual propagation path 110 can be reproduced, and the DUT 120 can be tested.

[0103] Furthermore, the test system 1 according to this embodiment uses the estimated characteristic H^ obtained in the environment of the actual propagation path 110. n ij Frequency distribution of channel capacity C0 of (k) and estimated characteristics H^ n ij The pseudo-path characteristic P obtained from the parameters characterizing the statistical properties of (k) n1 ij Pseudo channel capacity C of (k1) p Furthermore, the test system 1 according to this embodiment calculates the frequency distribution of the pseudo channel capacity C p The similarity between the frequency distribution of the channel capacity C0 and the frequency distribution of the channel capacity C1 is evaluated.

[0104] As a result, the test system 1 according to this embodiment calculates the pseudo propagation path characteristic P n1 ij (k1) and the actual estimated characteristic H^ n ij (k) can be evaluated using the channel capacity. In other words, the test system 1 according to this embodiment can evaluate the validity of the process of calculating the parameters of the channel model using the channel capacity as an index. However, the estimated characteristic Ĥ n ij(k) is calculated using a known RS included in the downlink signal, and its estimation accuracy is sufficiently high.

[0105] The test system 1 and evaluation method according to this embodiment can be applied mainly in the following two situations. Scene 1: Estimated characteristics H^ of the actual propagation path 110 n ij Evaluation when developing software to convert (k) into a channel model (measures to investigate whether there are any problems with the algorithm, etc.) Scene 2: Estimated characteristics H^ of the actual propagation path 110 n ij Evaluation as a means for users of software that converts (k) into a channel model to verify the reliability of that conversion.

[0106] When the test system 1 and the evaluation method according to this embodiment are used in Scene 2, the estimated characteristic H^ of the actual propagation path 110 is n ij As a function of the software that converts (k) into a channel model, the accuracy of the conversion can be evaluated using an evaluation index that indicates the deviation in channel capacity each time a channel model is generated. This allows the user of the software to evaluate a mobile phone terminal while checking the magnitude of the difference between the channel model and the actual propagation path 110.

[0107] Furthermore, the test system 1 according to this embodiment uses the average value C of the frequency distribution of the channel capacity C0. Ave(Org) and width W 95%(Org) and the pseudo channel capacity C p The mean value of the frequency distribution of Ave(Model) and width W 95%(Model) As a result, the test system 1 according to this embodiment calculates the pseudo propagation path characteristic P n1 ij (k1) and the actual estimated characteristic H^ n ij The similarity with (k) can be appropriately evaluated.

[0108] In the present embodiment described above, the base station 100 is the network-side transceiver that transmits the downlink signal toward the actual propagation path 110. However, instead of a base station, the network-side transceiver may be, for example, a Wi-Fi (registered trademark) access point. [Explanation of symbols]

[0109] 1 Test System 10 Antenna device 11 IQ data output section 15 Test equipment 20 Signal Processing Section 21 Actual propagation path estimation characteristic calculation unit 22 Parameter calculation section 24 Pseudo channel capacity calculation unit 25 Actual propagation path channel capacity calculation unit 26 Frequency distribution calculation section 27 Similarity evaluation section 28 Channel Capacity Evaluation Unit 30 Pseudo propagation path characteristic generator 41 Display section 100 Base station (network side transmitting / receiving device) 110 Actual propagation path 120 DUT Rx1~RxR antenna Tx1~TxT antenna

Claims

1. an actual propagation path estimation characteristic calculation unit (21) that calculates estimated characteristics of propagation path characteristics of one or more channels constituting the actual propagation path at a plurality of analysis target timings using IQ data of the downlink signal output from an antenna device (10) that receives the downlink signal transmitted from a transmission / reception device (100) on the network side in an actual propagation path (110) environment; a parameter calculation unit (22) that calculates parameters that characterize the statistical properties of the estimated characteristics; a pseudo propagation path characteristic generating unit (30) that generates a plurality of pseudo propagation path characteristics in accordance with the parameters; a pseudo channel capacity calculation unit (24) that calculates a pseudo channel capacity for each of the plurality of pseudo channel characteristics; an actual propagation path channel capacity calculation unit (25) that calculates a channel capacity for each of the estimated characteristics at at least some of the plurality of analysis target timings; a channel capacity evaluation unit (28) that calculates an evaluation index for evaluating the similarity between the pseudo channel capacity and the channel capacity.

2. The channel capacity evaluation unit a frequency distribution calculation unit (26) that calculates a frequency distribution of the pseudo channel capacity and a frequency distribution of the channel capacity; 2. The test system according to claim 1, further comprising a similarity evaluation unit (27) that calculates a similarity between the frequency distribution of the pseudo channel capacity and the frequency distribution of the channel capacity as the evaluation index.

3. The test system according to claim 2, characterized in that the similarity evaluation unit calculates the evaluation index based on the difference between the average value of the frequency distribution of the pseudo channel capacity and the average value of the frequency distribution of the channel capacity, and the evaluation index based on the difference between the width of the frequency distribution of the pseudo channel capacity and the width of the frequency distribution of the channel capacity.

4. the width of the frequency distribution of the pseudo channel capacity is the difference between the maximum and minimum values ​​of a 95% confidence interval of the frequency distribution of the pseudo channel capacity; 4. The test system of claim 3, wherein the width of the frequency distribution of the channel capacity is the difference between the maximum and minimum values ​​of a 95% confidence interval of the frequency distribution of the channel capacity.

5. an actual propagation path estimation characteristic calculation step (S2) of calculating estimated characteristics of propagation path characteristics of one or more channels constituting the actual propagation path at a plurality of analysis target timings using IQ data of the downlink signal output from an antenna device (10) that receives the downlink signal transmitted from a transmission / reception device (100) on the network side in an environment of the actual propagation path (110); a parameter calculation step (S3) of calculating parameters characterizing the statistical properties of the estimated characteristics; a pseudo channel characteristic generating step (S4) of generating a plurality of pseudo channel characteristics in accordance with the parameters; a pseudo channel capacity calculation step (S5) of calculating a pseudo channel capacity for each of the plurality of pseudo channel characteristics; an actual propagation path channel capacity calculation step (S6) of calculating a channel capacity for each of the estimated characteristics at at least some of the plurality of analysis target timings; a channel capacity evaluation step (S7, S8) of calculating an evaluation index for evaluating the similarity between the pseudo channel capacity and the channel capacity.

6. The channel capacity assessment step includes: a frequency distribution calculation step (S7) of calculating a frequency distribution of the pseudo channel capacity and a frequency distribution of the channel capacity; The evaluation method for a test system according to claim 5, further comprising a similarity evaluation step (S8) of calculating the similarity between the frequency distribution of the pseudo channel capacity and the frequency distribution of the channel capacity as the evaluation index.

7. 7. The evaluation method in a test system according to claim 6, wherein the similarity evaluation step calculates an evaluation index based on the difference between the average value of the frequency distribution of the pseudo channel capacity and the average value of the frequency distribution of the channel capacity, and an evaluation index based on the difference between the width of the frequency distribution of the pseudo channel capacity and the width of the frequency distribution of the channel capacity.

8. the width of the frequency distribution of the pseudo channel capacity is the difference between the maximum and minimum values ​​of a 95% confidence interval of the frequency distribution of the pseudo channel capacity; 8. The evaluation method for a test system according to claim 7, wherein the width of the frequency distribution of the channel capacity is the difference between the maximum value and the minimum value of a 95% confidence interval of the frequency distribution of the channel capacity.

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