Measuring device and measuring method

Abstract

This enables the measurement of a highly accurate delay profile of the system under test without transmitting a specific signal from the measuring device. [Solution] The system comprises a signal converter 1 connected to a first receiving antenna 4 located near the transmitter 2 of the wireless communication system 200 and a second receiving antenna 3 located at the receiver position of the delay profile measurement point of the wireless communication system 200, which converts analog signals from the first receiving antenna 4 and the second receiving antenna 3 into digital signals, and a signal processing device 5 that receives the input of the digital signal from the signal converter 1 and calculates the delay profile PDP(t) at time t based on the transfer function Hi(ω) of the input signal to the first receiving antenna 4, the transfer function Ho(ω) of the input signal to the second receiving antenna 3, and Hoi(ω)=Ho(ω) / Hi(ω) in a frequency band that includes a band in which leakage spectrum leaking outside the frequency of the main signal band of the system under measurement exists, at least.

Description

[Technical Field]

[0001] The technologies described herein relate to measuring devices and measuring methods. [Background technology]

[0002] The measurement of power delay profiles (PDPs) for wireless communication systems is used in channel design for wireless systems, including multi-channel or multi-input multiple-output (MIMO) designs (see, for example, Non-Patent Document 1).

[0003] Figure 1 is a block diagram schematically showing an example configuration of the wireless communication system 600 in the first conventional example.

[0004] The wireless communication system 600 comprises a PDP measuring device 6, a transmitter (Tx) 7, and a receiver (Rx) 8. The PDP measuring device 6, which may also be called a sounder, inputs a Tx signal to Tx 7. Based on the input Tx signal, Tx 7 transmits a signal to Rx via a multi-channel transmission path. Rx 8 inputs the Rx signal received from Tx 7 to the PDP measuring device 6. The PDP measuring device 6 then calculates a delay profile.

[0005] The delay profile PDP(t) may be calculated based on the following formula, where So(t) is the received signal (Rx signal) and Sr(t) is a special reference signal (for example, in the case of a modulated wave of a PN code such as the longest code sequence, the Tx signal is also a modulated wave of the same PN code).

number

[0006] Furthermore, when a Vector Network Analyzer (VNA) is used as the PDP measuring device 6, the Tx signal and Rx signal may be frequency-swept continuous signals (CW). In this case, the delay profile PDP(t) may be calculated based on the following equation, where Hs(ω) is the transfer function of the wireless communication system 600. Note that IFFT represents the inverse Fourier transform.

number

[0007] Figure 2 is a block diagram schematically showing an example configuration of the wireless communication system 600a in the second conventional example.

[0008] The wireless communication system 600a comprises a signal converter 6a, a transmitter (Tx (L5G RU; Local 5th Generation Radio Unit)) 7a, a receiver (Rx; receiving antenna) 8a, and a transmitting receiving antenna 9a.

[0009] Tx7a transmits an arbitrary signal to Rx8a via a multi-channel transmission line. Rx8a inputs the signal (CH2) received from Tx7a to the signal converter (oscilloscope) 6a.

[0010] Furthermore, Tx7a also transmits an arbitrary signal to the transmitting receiving antenna 9a. The transmitting receiving antenna 9a inputs the signal (CH1) received from Tx7a to the signal converter 6a. The signal input to the signal converter 6a is sent as digital data to a signal processing device (PC) not shown.

[0011] The signal converter 6a may be an oscilloscope, an ADC (analog to digital converter), or a spectrum monitor using either. A signal processing device (PC), not shown, calculates a delay profile using the signal input from the digitized transmitting receiving antenna 9a (CH1) and the signal input from Rx8a (CH2).

[0012] The delay profile PDP(t) may be calculated based on the following equation using the inverse Fourier transform (IFFT) when S CH1 is the input signal (reference signal) of CH1 and S CH2 is the input signal (received signal) of CH2 (see Non-Patent Document 2).

Equation

[0013] Also, the delay profile PDPmusic(t) may be calculated based on the following equation using the MUSIC method when S CH1 is the input signal (reference signal) of CH1 and S CH2 is the input signal (received signal) of CH2 (see Non-Patent Document 3). Here, p represents the maximum dimension number of the signal, M represents the total dimension number, V represents the eigenvector of the signal correlation matrix, and e(t) represents the complex sine wave vector.

Equation

Prior Art Documents

Patent Documents

[0014]

Patent Document 1

Patent Document 2

Non-Patent Documents

[0015]

Non-Patent Document 1

[0016] However, in the PDP measurement device 6 in the first conventional example, there is a problem that a specific transmission signal output from the PDP measurement device 6 must be output from the Tx7 of the wireless communication system 600.

[0017] On the other hand, in the signal converter 6a in the second conventional example, although the output of a transmission signal determined from the Tx7a of the wireless communication system 600a becomes unnecessary, there is a problem that the time side lobe becomes relatively large and is determined by the time resolution ΔT = 1 / B and the system bandwidth B.

[0018] Figure 3 shows an example of the output of PDP characteristics using the inverse Fourier transform (IFFT) in the second conventional example. Figure 3(a) shows the spectrum at the transmitting station (CH1), and Figure 3(b) shows the spectrum at the terminal (CH2). When a predetermined filter is applied to these spectra, the spectrum of the main signal band at the transmitting station (CH1) (transfer function H1) shown in Figure 3(c) and the spectrum of the main signal band at the terminal (CH2) (transfer function H2) shown in Figure 3(d) are output. Next, the transfer function ratio H2 / H1 shown in Figure 3(e) is calculated based on the transfer functions H1 and H2. Then, by applying the inverse Fourier transform (IFFT) to the transfer function ratio H2 / H1, the PDP characteristics shown in Figure 3(f) are output.

[0019] Figure 4 shows an example of the output of PDP characteristics using the MUSIC method in the second conventional example. Figure 4(a) shows the spectrum at the transmitting station (CH1), and Figure 4(b) shows the spectrum at the terminal (CH2). When a predetermined filter is applied to these spectra, the spectrum of the main signal band at the transmitting station (CH1) (transfer function H1) shown in Figure 4(c) and the spectrum of the main signal band at the terminal (CH2) (transfer function H2) shown in Figure 4(d) are output. Next, based on the transfer functions H1 and H2, the transfer function ratio H2 / H1 shown in Figure 4(e) is calculated. Then, by applying the MUSIC method to the transfer function ratio H2 / H1, the PDP characteristics shown in Figure 4(f) are output.

[0020] In factories where wireless communication system 600a is used, the bandwidth of the output from Tx7a may be set to, for example, 20MHz. Similarly, when LTE (Long Term Evolution) equipment is used as Tx7a, the bandwidth of the output from Tx7a is also limited to, for example, 20MHz.

[0021] Thus, when the output bandwidth from Tx7a is narrow, sharp (in other words, high-precision) PDP characteristics may not be obtained, as shown in Figure 3(f) and Figure 4(f).

[0022] In one aspect, the technology described herein aims to enable the measurement of a highly accurate delay profile between the transmitter and receiver of a system under test without transmitting a specific signal from the measuring device. [Means for solving the problem]

[0023] In one aspect, the measuring device is a measuring device for measuring the delay profile of an incoming signal of a wireless communication system which is a system under measurement, and comprises a signal converter connected to a first receiving antenna located near the transmitter of the wireless communication system and a second receiving antenna located at a receiver position at a delay profile measurement point of the wireless communication system, which converts analog signals from the first receiving antenna and the second receiving antenna into digital signals, and a signal processing device that receives the input of the digital signal from the signal converter and calculates the delay profile PDP(t) at time t based on the transfer function Hi(ω) of the input signal to the first receiving antenna (CH1), the transfer function Ho(ω) of the input signal to the second receiving antenna (CH2), and the ratio Hoi(ω)=Ho(ω) / Hi(ω) of the transfer function Ho(ω) and the transfer function Hi(ω), in a frequency band that includes at least a band in which there is a leakage spectrum that leaks out outside the frequency of the main signal band of the system under measurement. [Effects of the Invention]

[0024] One aspect of this is that it is possible to measure a highly accurate delay profile between the transmitter and receiver of the system under test without sending a specific signal from the measuring device. [Brief explanation of the drawing]

[0025] [Figure 1] This is a block diagram schematically showing an example of the configuration of a wireless communication system in the first conventional example. [Figure 2] This is a block diagram schematically showing an example of the configuration of a wireless communication system in the second conventional example. [Figure 3] The second example shows an example of the output of PDP characteristics using the inverse Fourier transform (IFFT) in a conventional example, where (a) is a graph showing an example of the spectrum at the transmitting station, (b) is a graph showing an example of the spectrum at the terminal, (c) is a graph showing an example of the spectrum of the main signal band at the transmitting station, (d) is a graph showing an example of the spectrum of the main signal band at the terminal, (e) is a graph showing the transfer function ratio between the transmitting station and the terminal, and (f) is a graph showing the PDP characteristics. [Figure 4] The second figure shows an example of the output of PDP characteristics using the MUSIC method in a conventional example, where (a) is a graph showing an example of the spectrum at the transmitting station, (b) is a graph showing an example of the spectrum at the terminal, (c) is a graph showing an example of the spectrum of the main signal band at the transmitting station, (d) is a graph showing an example of the spectrum of the main signal band at the terminal, (e) is a graph showing the transfer function ratio between the transmitting station and the terminal, and (f) is a graph showing the PDP characteristics. [Figure 5] This is a schematic block diagram showing an example of the configuration of the measuring device in the embodiment. [Figure 6] This figure shows a first output example of PDP characteristics using the inverse Fourier transform (IFFT) in the embodiment, where (a) is a graph showing an example of the spectrum at the transmitting station, (b) is a graph showing an example of the spectrum at the terminal, (c) is a graph showing the transfer function ratio between the transmitting station and the terminal, and (d) is a graph showing the PDP characteristics. [Figure 7] This figure shows a second output example of the PDP characteristics using the inverse Fourier transform (IFFT) in the embodiment, where (a) is a graph showing an example of the spectrum at the transmitting station, (b) is a graph showing an example of the spectrum at the terminal, (c) is a graph showing the transfer function ratio between the transmitting station and the terminal, and (d) is a graph showing the PDP characteristics. [Figure 8] This graph illustrates the sidelobe suppression and temporal resolution of the signal processing device in the embodiment. [Figure 9]This figure shows a first example of the output of the PDP characteristics using the MUSIC method in the modified example, where (a) is a graph showing an example of the spectrum at the transmitting station, (b) is a graph showing an example of the spectrum at the terminal, (c) is a graph showing the transfer function ratio between the transmitting station and the terminal, and (d) is a graph showing the PDP characteristics. [Figure 10] This figure shows a second example of the output of the PDP characteristics using the MUSIC method in the modified example, where (a) is a graph showing an example of the spectrum at the transmitting station, (b) is a graph showing an example of the spectrum at the terminal, (c) is a graph showing the transfer function ratio between the transmitting station and the terminal, and (d) is a graph showing the PDP characteristics. [Figure 11] This is a schematic block diagram showing an example of the hardware configuration of the signal converter, antenna, and signal processing device in the embodiment. [Modes for carrying out the invention]

[0026] The embodiments will now be described with reference to the drawings. However, the embodiments shown below are merely illustrative, and there is no intention to exclude various modifications or applications of techniques not explicitly shown in the embodiments. In other words, these embodiments can be implemented with various modifications without departing from their spirit.

[0027] Furthermore, each figure is not intended to represent only the components shown in the figure, but may include other components. In the following figures, parts denoted by the same reference numerals indicate the same or similar parts unless otherwise specified.

[0028] [Example of an embodiment] Figure 5 is a schematic block diagram showing an example configuration of the measuring device 100 in the embodiment. Here, a Local 5G system will be used as the system under measurement (in other words, the wireless communication system 200) in the explanation.

[0029] The measuring device 100 comprises a signal converter 1, a transmitter (L5G RU; Local 5th Generation Radio Unit) 2, a receiver (Rx; receiving antenna) 3 and a transmitting receiving antenna 4, and a signal processing device 5. In this embodiment, a PC was used for the signal processing device 5. In this embodiment, an oscilloscope was used for the signal converter 1.

[0030] Tx2 transmits an arbitrary signal to Rx3 via a multi-channel transmission line. Rx3 inputs the signal (CH2) received from Tx2 to the signal converter (oscilloscope) 1.

[0031] Furthermore, Tx2 also transmits an arbitrary signal to the transmitting / receiving antenna 4. The transmitting / receiving antenna 4 inputs the signal (CH1) received from Tx2 to the signal converter (oscilloscope) 1. The signal input to the signal converter (oscilloscope) 1 is sent as digital data to the signal processing unit (PC) 5.

[0032] The signal converter (oscilloscope) 1 is an example of the measuring device 100, and may use only an ADC (Analog to Digital Converter) circuit. Alternatively, a spectrum monitor using a direct RF undersampling type ADC (analog to digital converter) may be used. The signal processing device (PC) 5 calculates a delay profile using the signal input from the digitized transmitting receiving antenna 4 (CH1) and the signal input from Rx3 (CH2).

[0033] The delay profile PDP(t) is S CH1 This is the input signal (reference signal) for CH1, S CH2 When this is the input signal (received signal) of CH2, it may be calculated based on the following formula.

number

[0034] Figure 6 shows a first example of the PDP characteristics in the embodiment. Figure 6(a) shows the spectrum at the transmitting station (CH1), and Figure 6(b) shows the spectrum at the terminal (CH2).

[0035] In this embodiment, in addition to the main signal bandwidths of CH1 and CH2, the leakage spectra of CH1 and CH2 (see codes A11, A12 for CH1 and A21, A22 for CH2) are used as transfer functions H1 and H2, and the transfer function ratio H2 / H1 shown in Figure 6(c) is calculated. Then, by applying the inverse Fourier transform (IFFT) to the transfer function ratio H2 / H1, the PDP characteristics shown in Figure 6(d) are output. In other words, the PDP characteristics are calculated over a frequency bandwidth wider than the main signal bandwidth of the system under test. Note that the leakage spectrum is the spectrum that leaks out outside the frequency range of the instantaneous signal bandwidth (in other words, the main signal bandwidth) defined by the communication. The leakage spectrum can be acquired in any range as long as the leakage spectrum is within a range where the influence of noise is small.

[0036] This makes it possible to obtain sharper (in other words, higher precision) PDP characteristics than the second conventional example described above.

[0037] Figure 7 shows a second example of the PDP characteristics in the embodiment. Figure 7(a) shows the spectrum at the transmitting station (CH1), and Figure 7(b) shows the spectrum at the terminal (CH2).

[0038] In the first output example shown in Figure 6, the PDP characteristics were output using both sides of the instantaneous signal bandwidth (high-bandwidth and low-bandwidth). On the other hand, as in the second example shown in Figure 7, the PDP characteristics may be output using only the high-bandwidth side of the instantaneous signal bandwidth.

[0039] In the example shown in Figure 7, in addition to the main signal bandwidths of CH1 and CH2, the leakage spectra of CH1 and CH2 (see code B1 for CH1 and code B2 for CH2) are used as transfer functions H1 and H2, and the transfer function ratio H2 / H1 shown in Figure 7(c) is calculated. Then, by applying the inverse Fourier transform (IFFT) to the transfer function ratio H2 / H1, the PDP characteristics shown in Figure 7(d) are output.

[0040] The leakage spectrum may exist on both sides of the instantaneous signal band, as shown in Figure 6; it may exist only on the high-bandwidth side of the instantaneous signal band, as shown in Figure 7; or, although not shown in the illustration, it may exist only on the low-bandwidth side of the instantaneous signal band.

[0041] Generally, in the instantaneous signal bandwidth (in other words, the main signal bandwidth), the spectrum level is relatively high compared to the noise. Therefore, in this embodiment, both the spectrum of the instantaneous signal bandwidth and the leakage spectrum are used. However, if the effects of the above-mentioned noise do not need to be considered (for example, if the noise level is sufficiently low), the PDP characteristics may be output using only the leakage spectrum without using the instantaneous signal bandwidth.

[0042] Figure 8 is a graph illustrating the sidelobe suppression and time resolution by the signal processing device 5 in the embodiment.

[0043] In Figure 8, at symbol C1, the PDP characteristics calculated by the signal processing device 5 are illustrated. The side lobes shown at symbol C11 are caused by errors due to zero padding. Zero padding represents the calculation of Ho(ω) / Hi(ω) by converting the waveform shown at symbol C22 to the waveform shown at symbol C23, based on the transfer function Hi(ω) shown at symbol C21. Specifically, zero padding is applied when the absolute value of Hi(ω) is extremely small compared to the values ​​of other frequencies (for example, 10 times the peak). -4 If the value is smaller than the given value, the value of Ho(ω) / Hi(ω) becomes extremely large, as shown in Figure 8, and other important information gets buried. Therefore, the process of setting the value of Ho(ω) / Hi(ω) to 0 is performed.

[0044] Also, if the system transmission signal bandwidth of the transmitter 2 is B, the time resolution ΔT = 1 / B. For example, in the case of the Local 5G system, B≒100Hz and ΔT≒10ns.

[0045] According to the measuring device 100 in the embodiment, without sending a specific signal from the wireless communication system 200 which is the system to be measured (without changing the circuit and signal processing method of the transmitter), it is possible to measure the high-precision delay profile between the transmitter and the receiver of the wireless communication system 200 which is the system to be measured.

[0046] [Modification of the Embodiment] According to an example of the above-described embodiment, a PDP can be obtained. However, the side lobes due to the above zero-padding processing become relatively large, and the time resolution is determined by the system transmission signal bandwidth B. Therefore, in the modification, the MUSIC method is applied to the measurement of the PDP.

[0047] Hereinafter, the MUSIC method will be described as an example, but it is not limited thereto. The advantages in the following embodiments can be obtained similarly by using a method using eigenvectors of other signal correlation matrices such as the ESPRIT method. The delay profile PDPmusic(t) by the MUSIC method is S CH1 is the input signal (reference signal) of CH1, and S CH2 is the input signal (received signal) of CH2, p is the maximum dimension number of the signal, M is the total dimension number, V is the eigenvector of the signal correlation matrix obtained from the correlation matrix of Hoi(ω), e(t) is the complex sine wave vector, and V H is the conjugate transpose matrix of V, and it may be calculated based on the following formula.

Equation

[0048] In the MUSIC method, since the desired PDP characteristics are obtained from the eigenvectors of the correlation matrix, basically, the time resolution is not limited by the system bandwidth B, so higher time resolution characteristics can be obtained.

[0049] In the MUSIC method, processing is often performed on multiple data points called snapshots. Here, for example, 1ms of data was divided into 10 parts in the time direction, and a correlation matrix was calculated for each as a snapshot. The MUSIC method can also be applied to a single data point (e.g., 10 snapshots). When the MUSIC method is applied to the same data, the suppression of side lobes is approximately 15dB at most, which is equivalent to the embodiment, but the time resolution is approximately 10 times greater than that of the original embodiment, allowing observation of multipath signals that could not be observed in the original embodiment.

[0050] Furthermore, multiple data points may be measured to increase the number of snapshots. That is, the MUSIC method may be applied to multiple (e.g., 46) data points (460 (10 × 46) snapshots) under the same conditions. In this case, the side lobes caused by the zero-padding process described above can be considered as noise that does not appear at a fixed position, and if the number of data points can be increased, the side lobes can be suppressed. When the MUSIC method is applied to 46 data points, the degree of side lobe suppression is improved to a maximum of about 20 dB compared to the original embodiment, and the temporal resolution is about 10 times that of the embodiment.

[0051] Figure 9 shows a first example of the PDP characteristics in a modified example. Figure 9(a) shows the spectrum at the transmitting station (CH1), and (b) shows the spectrum at the terminal (CH2).

[0052] In this modified example, similar to the embodiment described above, in addition to the main signal bandwidths of CH1 and CH2, the leakage spectra of CH1 and CH2 (see symbols D11, D12 for CH1 and D21, D22 for CH2) are used as transfer functions H1 and H2, and the transfer function ratio H2 / H1 shown in Figure 9(c) is calculated. Then, by applying the MUSIC method to the transfer function ratio H2 / H1, the PDP characteristics shown in Figure 9(d) are output. In other words, the PDP characteristics are calculated over a frequency bandwidth wider than the main signal bandwidth of the system under test.

[0053] This makes it possible to obtain PDP characteristics that are sharper (in other words, more accurate) than the second conventional example described above, as well as improving temporal resolution (in other words, clarifying multipath effects) and obtaining PDP characteristics with suppressed sidelobes.

[0054] Figure 10 shows a second example of the PDP characteristics in the embodiment. Figure 10(a) shows the spectrum at the transmitting station (CH1), and (b) shows the spectrum at the terminal (CH2).

[0055] In the first output example shown in Figure 9, the PDP characteristics were output using both sides of the instantaneous signal bandwidth (high-bandwidth and low-bandwidth). On the other hand, as in the second example shown in Figure 10, the PDP characteristics may be output using only the high-bandwidth side of the instantaneous signal bandwidth.

[0056] In the example shown in Figure 10, in addition to the main signal bandwidths of CH1 and CH2, the leakage spectra of CH1 and CH2 (see code E1 for CH1 and code E2 for CH2) are used as transfer functions H1 and H2, and the transfer function ratio H2 / H1 shown in Figure 10(c) is calculated. Then, by applying the MUSIC method to the transfer function ratio H2 / H1, the PDP characteristics shown in Figure 10(d) are output.

[0057] The leakage spectrum may exist on both sides of the instantaneous signal band, as shown in Figure 9; it may exist only on the high-bandwidth side of the instantaneous signal band, as shown in Figure 10; or, although not shown in the illustration, it may exist only on the low-bandwidth side of the instantaneous signal band.

[0058] Furthermore, similar to the embodiments described above, if the effects of noise do not need to be considered (for example, if the noise level is sufficiently low), the PDP characteristics may be output based only on the leakage spectrum without using the instantaneous signal bandwidth.

[0059] In other words, by using a modified embodiment, the output time resolution can be set to be smaller than the time resolution determined by the bandwidth B of the wireless communication system 200, which is the system under measurement, and the side lobes due to zero padding can also be made smaller.

[0060] [Example Hardware Configuration] Figure 11 is a schematic block diagram showing an example of the hardware configuration of the signal converter (oscilloscope) 1, antennas 3 and 4, and signal processing device 5 in the embodiment.

[0061] Antenna 4 (transmitting receiving antenna) is positioned near the transmitter 2 of the system under test, as shown in Figure 5. Antenna 3 (receiving receiving antenna) is positioned at the delay profile measurement point of the system under test and corresponds to the receiver 3 of the system under test. The signals from antennas 3 and 4 are input to the signal converter 1.

[0062] Figure 11 shows a case where an oscilloscope is used as the signal converter 1. The signal converter 1 comprises a CPU 11, main memory 12, display control unit 13, storage device 14, input IF 15, external recording medium processing unit 16, communication IF 17, and ADC circuit 18. Similarly, the signal processing device 5 may comprise a CPU 11, main memory 12, display control unit 13, storage device 14, input IF 15, external recording medium processing unit 16, and communication IF 17.

[0063] Main memory 12 is an example of a storage unit, and exemplifies it as Read Only Memory (ROM) and Random Access Memory (RAM). The ROM of main memory 12 may contain programs such as a Basic Input / Output System (BIOS). Software programs in main memory 12 may be read and executed by the CPU 11 as appropriate. The RAM of main memory 12 may be used as temporary storage memory or working memory.

[0064] The display control unit 13 is connected to the display device 131 and controls the display device 131. The display device 131 is a liquid crystal display, an organic light-emitting diode (OLED) display, a cathode ray tube (CRT), an electronic paper display, etc., and displays various information to the operator, etc. The display device 131 may be combined with an input device, for example, a touch panel. The display device 131 displays various information to the user of the signal converter (oscilloscope) 1.

[0065] The storage device 14 is a storage device with high I / O performance, and may include, for example, Dynamic Random Access Memory (DRAM), SSD (Solid State Drive), Storage Class Memory (SCM), or HDD (Hard Disk Drive).

[0066] Input IF15 is connected to an input device such as a mouse 151 or a keyboard 152, and may control such an input device. The mouse 151 and keyboard 152 are examples of input devices, and the operator performs various input operations through these input devices.

[0067] The external recording medium processing unit 16 is configured to accommodate the recording medium 160. The external recording medium processing unit 16 is configured to read the information recorded on the recording medium 160 when the recording medium 160 is mounted. In this example, the recording medium 160 is portable. For example, the recording medium 160 is a flexible disk, optical disk, magnetic disk, magneto-optical disk, or semiconductor memory. Specifically, the signal data of CH1 and CH2, which have been converted to digital values ​​by the ADC circuit 18 described below, may be sent to the signal processing unit (PC) 5 via this recording medium 160.

[0068] The communication IF17 is an interface that enables communication with an external device. As described above, CH1 and CH2 signal data may be sent to the signal processing device (PC) 5 via the recording medium 160, or data may be sent to the signal processing device (PC) 5 via this communication IF17.

[0069] The ADC circuit 18 has the function of converting signals input from a terminal (CH1) that receives signals from a receiving antenna 4 for receiving transmission signals, which is located near the transmitter 2 of the system under test, and a terminal (CH2) that receives signals from a receiving antenna for the delay profile measurement point of the system under test (where the receiver 3 of the system under test is installed), into digital signals and transmitting them to a common bus.

[0070] The CPU 11 is an example of a processor, and is a processing unit that performs various control and calculations. The CPU 11 realizes various functions by executing the Operating System (OS) and programs loaded into the main memory 12. The CPU 11 may be a multiprocessor containing multiple CPUs, a multicore processor having multiple CPU cores, or a configuration having multiple multicore processors. In this embodiment, CH1 and CH2 signal data were sent to the signal processing unit (PC) 5 via the recording medium 160 or the communication IF 17, but it is also possible to perform the processing of the present invention using the CPU 11 and main memory 12 within the oscilloscope and obtain a PDP without using the external signal processing unit (PC) 5.

[0071] The signal processing device 5 uses the aforementioned CH1 signal and CH2 signal sent from the signal converter (oscilloscope) 1 to determine the PDP using the signal processing method of the present invention.

[0072] The measurement device and measurement method of this embodiment enable the measurement of the delay profile between the transmitter and receiver without sending a specific signal from the measurement device of the system under test. This eliminates the need to modify the circuit or signal processing of the transmitter of the system under test. Furthermore, it enables PDP measurement of the signal itself of the system under test, resulting in more accurate and precise PDP measurements. This is particularly effective when the frequency bandwidth of the transmitted signal of the system under test cannot be changed due to transmitter specifications or regulations. The measured PDP characteristics are effective in determining the communication capacity in multipath communication.

[0073] Furthermore, by applying the MUSIC method, the measurement apparatus and measurement method of this embodiment can achieve improved temporal resolution and suppression of side lobes, similar to conventional PDP measurements.

[0074] [others] The disclosed technology is not limited to the embodiments described above, and can be implemented in various ways without departing from the spirit of each embodiment. Each configuration and each process of each embodiment can be selected or combined as needed.

[0075] In the embodiments described above, the wireless communication system 200, which is the system under test, is assumed to perform Local 5G communication, but it is not limited to this. The wireless communication system 200, which is the system under test, may also perform 4G communication or 3G communication.

[0076] The communication system 200 may use OFDM (Orthogonal Frequency-Division Multiplexing), which is a common multi-carrier method, or it may also use a single-carrier method such as QAM (Quadrature Amplitude Modulation; 64QAM, 128QAM, etc.). [Explanation of Symbols]

[0077] 1, 6a: Signal converter 2, 7, 7a:Tx 3, 8, 8a:Rx 4, 9a: Transmitting receiving antenna 5: Signal Processing Device 6: PDP measuring device 11: CPU 12: Main memory 13: Display Control Unit 14:Storage device 15: Input IF 16: External recording medium processing unit 17: Communication Interface 18:ADC circuit 100: Measuring device 131:Display device 151: Mouse 152: Keyboard 160: Recording media 200, 600, 600a: Wireless communication systems

Claims

1. A measuring device for measuring the delay profile of the incoming signal of a wireless communication system, which is the system under measurement, A signal converter is connected to a first receiving antenna located near the transmitter of the wireless communication system and a second receiving antenna located at the receiver position of the delay profile measurement point of the wireless communication system, and converts analog signals from the first receiving antenna and the second receiving antenna into digital signals. A signal processing device that receives the input of the digital signal from the signal converter and calculates the delay profile PDP(t) at time t based on the transfer function Hi(ω) of the input signal to the first receiving antenna (CH1), the transfer function Ho(ω) of the input signal to the second receiving antenna (CH2), and the ratio of the transfer function Ho(ω) to the transfer function Hi(ω), which is Hoi(ω) = Ho(ω) / Hi(ω), in a frequency band that includes at least a band in which there is a leakage spectrum that leaks outside the frequency of the main signal band of the system under measurement. A measuring device characterized by comprising the following features.

2. The frequency band used includes the band in which the leakage spectrum exists, as well as the band in which the main signal band exists. The measuring device according to claim 1.

3. The bandwidth using the leakage spectrum is both a bandwidth higher than the main signal bandwidth and a bandwidth lower than the main signal bandwidth. The measuring device according to claim 1 or 2.

4. The signal processing device is If the absolute value of Hi(ω) is extremely small compared to the values ​​of other frequencies, zero-padding is performed to set the value of Hoi(ω) to 0. A measuring device according to claim 1 or 2, characterized in that...

5. The signal processing device is When FFT represents the Fourier transform and IFFT represents the inverse Fourier transform, and Hi(ω) = FFT(CH1) and Ho(ω) = FFT(CH2), the delay profile at time t is calculated using the formula PDP(t) = IFFT(Hoi(ω)). A measuring device according to claim 1 or 2, characterized in that...

6. Using a method that utilizes eigenvectors of the signal correlation matrix, the delay profile PDP(t) is calculated from the Hoi(ω). A measuring device according to claim 1 or 2, characterized in that...

7. The signal processing device is Using the Multiple Signal Classification (MUSIC) method, the above Hoi(ω) and [Math 1] (p is the maximum number of dimensions of the signal, M is the total number of dimensions, V is the eigenvector of the signal correlation matrix obtained from the correlation matrix of Hoi(ω), e(t) is the complex sinusoidal vector, V Ｈ The delay profile PDP(t) is calculated based on the formula (where represents the conjugate transpose matrix of V). The measuring device according to claim 6, characterized in that

8. The signal processing device is The output time resolution is set to be smaller than the time resolution determined by the bandwidth of the system under measurement. The measuring device according to claim 6, characterized in that...

9. The signal processing device is The delay profile PDP(t) is calculated based on at least one snapshot, which is either a snapshot obtained by dividing the data over time or a snapshot obtained from multiple data under the same conditions. The measuring device according to claim 6, characterized in that...

10. A measuring device that measures the delay profile of the incoming signal of a wireless communication system under test, and includes a signal converter and a signal processing device, The signal converter is connected to a first receiving antenna located near the transmitter of the wireless communication system and a second receiving antenna located at the receiver position of the delay profile measurement point of the wireless communication system, and converts analog signals from the first receiving antenna and the second receiving antenna into digital signals. The signal processing device calculates the delay profile PDP(t) at time t based on the transfer function Hi(ω) of the input signal to the first receiving antenna (CH1), the transfer function Ho(ω) of the input signal to the second receiving antenna (CH2), and the ratio Hoi(ω) = Ho(ω) / Hi(ω) of the transfer function Ho(ω) to the transfer function Hi(ω), in a frequency band that includes at least a band in which there is a leakage spectrum that leaks outside the frequency of the main signal band of the system under measurement. A measurement method characterized by the following features.

11. The frequency band includes the main signal band in addition to the band in which the leakage spectrum exists. The measurement method according to claim 10.

12. The bandwidth using the leakage spectrum is both a bandwidth higher than the main signal bandwidth and a bandwidth lower than the main signal bandwidth. The measurement method according to claim 10 or 11.

13. The signal processing device is If the absolute value of Hi(ω) is extremely small compared to the values ​​of other frequencies, zero-padding is performed to set the value of Hoi(ω) to 0. The measurement method according to claim 10 or 11, characterized in that

14. The signal processing device is When FFT represents the Fourier transform and IFFT represents the inverse Fourier transform, and Hi(ω) = FFT(CH1) and Ho(ω) = FFT(CH2), the delay profile at time t is calculated using the formula PDP(t) = IFFT(Hoi(ω)). The measurement method according to claim 10 or 11, characterized in that

15. Using a method that utilizes eigenvectors of the signal correlation matrix, the delay profile PDP(t) is calculated from the Hoi(ω). The measurement method according to claim 10 or 11, characterized in that

16. The signal processing device is Using the Multiple Signal Classification (MUSIC) method, the above Hoi(ω) and [Math 2] (p is the maximum number of dimensions of the signal, M is the total number of dimensions, V is the eigenvector of the signal correlation matrix obtained from the correlation matrix of Hoi(ω), e(t) is the complex sinusoidal vector, V Ｈ The delay profile PDP(t) is calculated based on the formula (where represents the conjugate transpose matrix of V). The measurement method according to claim 15, characterized in that

17. The signal processing device is The output time resolution is set to be smaller than the time resolution determined by the bandwidth of the system under measurement. The measurement method according to claim 15, characterized in that

18. The signal processing device is The delay profile PDP(t) is calculated based on at least one snapshot, which is either a snapshot obtained by dividing the data over time or a snapshot obtained from multiple data under the same conditions. The measurement method according to claim 15, characterized in that

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