JP5753605B1 - Interference wave power measuring apparatus, interference wave power measuring method, SIR measuring apparatus and SIR measuring method - Google Patents

Abstract

An interference wave power measuring apparatus capable of measuring interference wave power with higher accuracy than conventional in a high-speed moving environment in addition to a multipath environment. An interference wave power measuring apparatus (20) includes a correlation value calculation unit (22) that calculates a correlation value between a received reference signal component and a complex conjugate of the known signal component, and multipath characteristics based on correlation result data. The differential correlation value calculation unit 25 that calculates the differential correlation value based on the consideration method and each differential correlation value based on the high-speed movement characteristic consideration method, and a predetermined number of differential correlation values based on the multipath characteristic consideration method or the high-speed mobility characteristic consideration method are integrated. Then, an interference wave power calculation unit 26 that calculates the average interference wave power for each method, and a selection unit 28 that selects a smaller value of the average interference wave power for each method are provided. [Selection] Figure 1

Description

  The present invention relates to an interference wave power measuring apparatus, an interference wave power measuring method, an SIR measuring apparatus, and an SIR measurement for measuring the power of an interference wave signal in a mobile communication system using an OFDM (Orthogonal Frequency Division Multiplexing) signal. Regarding the method.

  In recent years, an orthogonal frequency modulation method has been adopted as a communication method for mobile communication network systems such as mobile phones. For example, in the LTE (Long Term Evolution) standard of 3GPP (3rd Generation Partnership Project), OFDMA (Orthogonal Frequency Division Multiplexing Access) using an OFDM signal as a communication method in a downlink direction, that is, a direction from a base station to a mobile station. The division multiple access method is adopted.

  In a mobile communication network system, a large number of base stations are installed close to each other in a telephone service area. Measuring the radio waves from each base station at each point in the telephone service area and evaluating the radio wave condition at that point is to install a new base station or maintain an installed base station. It is very important to do. Specifically, since the mobile communication network system is susceptible to multipath failures and fading, radio waves actually emitted from the base station are received by, for example, an in-vehicle measuring device, and SIR (Signal to Interference Ratio) is received. : The ratio of the desired wave power to the interference wave power) is measured, and the service area is identified and confirmed.

  Generally, in a mobile communication network system using an OFDM signal, a method of estimating SIR using reference signal components discretely arranged in the time axis direction and the frequency axis direction is used. However, in a multipath environment in which a delayed wave exists, there is a problem that the SIR cannot be accurately measured because the complex amplitude correlation between the reference signal components existing at different frequencies becomes low.

  As a method for solving this problem, for example, the SIR measurement method disclosed in Non-Patent Document 1 is known. However, since this SIR measurement method is configured to perform a relatively complicated calculation, the calculation is performed. There was a problem that the amount would be enormous. Therefore, the applicant pays attention to the amount of change between the correlation values of the reference signal components on the time axis and the frequency axis, and can obtain the interference wave power with a relatively small amount of calculation in a multipath environment. A power measuring device has been proposed (see Patent Document 1).

Suzuki Motoaki et al., “Examination of high-accuracy SIR measurement method in multipath environment in OFDM system”, IEICE, IEICE Technical Report, A.P. 91-96

JP 2011-193221 A

  However, according to the study of the present applicant, in the technique described in Patent Document 1, when the measurement is performed while the interference wave power measuring device is moved on the vehicle, moving at a high speed is more than when moving at a low speed. However, it was found that the measurement error of the interference wave power becomes large and there is room for further improvement.

  The present invention has been made in view of the circumstances as described above, and is capable of measuring interference wave power with higher accuracy than ever in a high-speed moving environment in addition to a multipath environment. It is an object to provide an apparatus, an interference wave power measuring method, an SIR measuring apparatus, and an SIR measuring method.

  An interference wave power measuring apparatus according to claim 1 of the present invention receives a signal including a desired wave signal component including a known reference signal component and an interference wave signal component that interferes with the desired wave signal component. An interference wave power measuring device (20) for measuring the power of the interference wave signal component, the Fourier transform means (21) for converting the received wave signal received from a time domain signal to a frequency domain signal; Correlation value calculation means (22) for calculating the correlation value between the signal value of the received reference signal component included in the received wave signal and the signal value of the known reference signal component, and the calculation result calculated by the correlation value calculation means Differential correlation value calculating means (25) for calculating a first and second differential correlation value indicating a difference between predetermined correlation values based on the absolute value of each of the first and second differential correlation values; Multiply square An interference wave power calculating means (26) for calculating the power of the first and second interference wave signal components based on the result, and an error relative to a true value of the powers of the first and second interference wave signal components. Selecting means (28) for selecting the smaller one of the interference wave signal components as the power of the interference wave signal component, and the differential correlation value calculating means includes a correlation value at the first time at the first frequency and a delay time that is later than the first time. A first difference that is a difference from a correlation value at two times; a correlation value at a third time between the first time and the second time at a second frequency; and a correlation at a fourth time that is later than the second time. A third difference that is a difference between the correlation value at the first time and the correlation value at the second time at a third frequency is obtained as the first difference correlation value. And the correlation value at the first time at the fourth frequency and the second time The difference between the first difference and the fourth difference is obtained as the second difference correlation value, and the frequency difference between the first frequency and the second frequency is calculated as follows: The configuration is smaller than the frequency difference with the fourth frequency.

  With this configuration, the interference power measuring apparatus according to claim 1 of the present invention has the power of the first interference wave signal component considering the multipath characteristics and the second interference wave signal component considering the high-speed movement characteristics. Since it is possible to select the power with the smaller error with respect to the true value, it is possible to measure the interference wave power with higher accuracy than in the conventional case in the high-speed moving environment in addition to the multipath environment.

Interference signal power measuring apparatus according to claim 2 of the present invention, the interference power calculating means, calculated on the basis of the average value P _I of the power of the first interference signal component to [6] below , preferably calculated based on the second power average value P _I of the interference signal component below Equation 7].

In the interference wave power measuring apparatus according to claim 3 of the present invention, the reception wave signal includes reception reference signal components received from two transmission antennas, and the interference wave power calculation means includes the first interference wave signal. below the average value P _I of the components of the power is calculated based on the formula [10], that is calculated based on the second power average value P _I of the interference signal component below Equation 11] preferable.

  In the interference wave power measuring apparatus according to claim 4 of the present invention, the selection unit selects a power having a smaller value from the powers of the first and second interference wave signal components as the power of the interference wave signal component. It is preferable that

  In the interference wave power measuring apparatus according to claim 5 of the present invention, the selection means includes the power of the desired wave signal component and the interference wave signal component of the power of the first and second interference wave signal components. It is preferable to select the one that obtains a large SIR value indicating the ratio to the power of the interference wave signal component as the power of the interference wave signal component.

  The SIR measuring apparatus according to claim 6 of the present invention is an interference wave power measuring apparatus (20) and SIR calculating means (14) for calculating a ratio between the power of the desired wave signal component and the power of the interference wave signal component. And a configuration provided with.

  With this configuration, since the SIR measuring apparatus according to claim 6 of the present invention includes the interference wave power measuring apparatus, it is possible to measure SIR with higher accuracy than in the past in a high-speed moving environment in addition to a multipath environment. Can do.

  An interference wave power measuring method according to claim 7 of the present invention receives a signal including a desired wave signal component including a known reference signal component and an interference wave signal component interfering with the desired wave signal component. An interference wave power measurement method for measuring the power of the interference wave signal component, wherein the received wave signal is converted from a time domain signal into a frequency domain signal (S12), and the received wave signal A correlation value calculation step (S13) for calculating a correlation value between the signal value of the received reference signal component and the signal value of the known reference signal component included in the signal, and a predetermined value based on the calculation result calculated in the correlation value calculation step Calculating first and second differential correlation values indicating a difference between the correlation values of the first and second differential correlation values; and calculating absolute values of the first and second differential correlation values An interference wave power calculating step (S16, S18) for calculating the power of the first and second interference wave signal components based on the result of integrating the power, and the power of the first and second interference wave signal components; A selection step (S19) for selecting the one having a smaller error from the true value as the power of the interference wave signal component, and in the differential correlation value calculation step, the correlation value at the first time at the first frequency and the first time A first difference that is a difference from a correlation value at a second time later than the time, a correlation value at a third time between the first time and the second time at a second frequency, and a second later than the second time. A difference from the second difference, which is a difference from the correlation value at four times, is obtained as the first difference correlation value, and the difference between the correlation value at the first time and the correlation value at the second time at a third frequency is obtained. A third difference and a fourth frequency. The difference between the correlation value at the first time and the fourth difference that is the difference between the correlation value at the second time is obtained as the second difference correlation value, and the frequency between the first frequency and the second frequency The difference is smaller than the frequency difference between the third frequency and the fourth frequency.

  With this configuration, the interference wave power measurement method according to claim 7 of the present invention has the power of the first interference wave signal component considering the multipath characteristics and the second interference wave signal component considering the high-speed movement characteristics. Since it is possible to select the power with the smaller error with respect to the true value, it is possible to measure the interference wave power with higher accuracy than in the past in a high-speed moving environment in addition to a multipath environment.

  The SIR measurement method according to claim 8 of the present invention calculates each ratio of the power of the desired wave signal component and the power of the interference wave signal component, and each step of the interference wave power measurement method according to claim 7. SIR calculation step (S20).

  With this configuration, the SIR measurement method according to claim 8 of the present invention includes the steps of the interference wave power measurement method, so that SIR can be performed with higher accuracy than in the past in a high-speed moving environment in addition to a multipath environment. Can be measured.

  INDUSTRIAL APPLICABILITY The present invention provides an interference wave power measuring apparatus, interference wave power measuring method, and SIR measurement having an effect that interference wave power can be measured with higher accuracy than in the past in a high-speed moving environment in addition to a multipath environment. An apparatus and an SIR measurement method can be provided.

It is a block block diagram in 1st Embodiment of the SIR measuring apparatus which concerns on this invention. It is a figure which shows arrangement | positioning of the reference signal component in case the base station is transmitting the radio wave of an OFDM signal with two transmission antennas. It is a figure which shows the data of the correlation result which the correlation value calculation part calculated in the 1st Embodiment of the SIR measuring apparatus which concerns on this invention, when the base station is transmitting the radio wave of an OFDM signal with one transmission antenna. It is explanatory drawing of the multipath characteristic consideration system in 1st Embodiment of the SIR measuring apparatus which concerns on this invention. It is explanatory drawing of the high-speed movement characteristic consideration system in 1st Embodiment of the SIR measuring apparatus which concerns on this invention. It is explanatory drawing about the characteristic of the multipath characteristic consideration system in 1st Embodiment of the SIR measuring apparatus which concerns on this invention. It is explanatory drawing about the characteristic of the high-speed movement characteristic consideration system in 1st Embodiment of the SIR measuring apparatus which concerns on this invention. It is a flowchart in 1st Embodiment of the SIR measuring apparatus which concerns on this invention. It is a figure which shows the data of the correlation result which a correlation value calculation part calculates, when the base station is transmitting the radio wave of an OFDM signal with two transmission antennas in 1st Embodiment of the SIR measuring apparatus which concerns on this invention. It is a block block diagram in 2nd Embodiment of the SIR measuring apparatus which concerns on this invention. It is a flowchart in 2nd Embodiment of the SIR measuring apparatus which concerns on this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the interference wave power measuring apparatus of the present invention is an SIR measuring apparatus that receives an electric wave from a base station that transmits an RF (radio frequency) signal including an OFDM signal component according to the LTE standard and measures the SIR. An applied example will be described.

(First embodiment)
First, the structure in 1st Embodiment of the SIR measuring apparatus which concerns on this invention is demonstrated.

  As shown in FIG. 1, the SIR measurement device 10 in this embodiment includes a reception antenna 11, a reception unit 12, an interference wave power measurement device 20, an average received power calculation unit 13, a SIR calculation unit 14, and a display unit 15. Yes.

  The interference wave power measuring apparatus 20 includes an FFT calculation unit 21, a correlation value calculation unit 22, a correlation result storage unit 23, a method application control unit 24, a differential correlation value calculation unit 25, an interference wave power calculation unit 26, and a method-specific result storage unit. 27, a selection unit 28 is provided.

  The receiving antenna 11 receives radio waves of an RF signal (hereinafter simply referred to as “OFDM signal”) including OFDM signal components transmitted from a base station (not shown), and outputs the received radio signals to the receiving unit 12. It has become.

  The receiving unit 12 converts the OFDM signal received by the receiving antenna 11 into an IF (intermediate frequency) signal having a predetermined frequency, converts the IF signal from an analog value to a digital value, and outputs the converted signal to the FFT operation unit 21. It is like that.

  The FFT calculation unit 21 converts the time domain signal output from the reception unit 12 into a frequency domain signal and outputs the signal to the correlation value calculation unit 22. The FFT operation unit 21 constitutes a Fourier transform unit according to the present invention. The signal output from the FFT operation unit 21 includes a signal component of a data symbol and a reference signal component. The reference signal component may be called a reference signal component, a reference signal symbol, a reference symbol, a pilot signal component, a pilot symbol, a scattered pilot, or the like.

  When the base station transmits the radio wave of the OFDM signal with two transmission antennas, for example, as shown in FIG. 2, the reference signal component (RS) is TX = 0 (transmission antenna 0) and TX = 1 ( It is arranged at the position indicated by the transmitting antenna 1). In the following description, it is assumed that the base station transmits the radio wave of the OFDM signal with one transmission antenna 0, and only the reference signal component indicated by TX = 0 in FIG.

Further, as shown in FIG. 2, the signal value of the received reference signal component is represented by S _nm . Here, n is an integer indicating the position of the reference signal component in the time axis direction, and the larger n is, the later the reception time is. M is an integer indicating the position of the reference signal component on the frequency axis, and indicates that the larger m is, the higher the frequency is. Here, n = 0 to N-1 (where N is 4 or more), m = 0 to M-1 (where M is 2 or more).

The correlation value calculation unit 22 stores in advance a pattern in which C _nm , which is a known signal component of the reference signal component S _nm shown in FIG. 2, is associated with S _nm , at a position on the time axis n and the frequency axis m. The correlation value R _nm between the reference signal component S _nm and the complex conjugate of the known signal component C _nm is calculated by [Equation 1]. Here, the symbol “*” indicates a complex conjugate. The correlation value calculation unit 22 constitutes a correlation value calculation unit according to the present invention.

The correlation result data calculated by the correlation value calculation unit 22 is shown in FIG. For example, in one slot (seven symbols) shown at the left end, a symbol including R ₀₀ , R ₀₂ ,..., R _0M-2 , R ₁₁ , R _{13 ,.} 2 symbols including ₁ are included. In a slot adjacent to the right side of this slot, a symbol including R ₂₀ , R ₂₂ ,..., R _2M-2 and a symbol including R ₃₁ , R _{33 ,.} Two symbols are included.

  The correlation result storage unit 23 stores the correlation result data calculated by the correlation value calculation unit 22 (see FIG. 3).

  The method application control unit 24 applies a multipath characteristic consideration method for obtaining the power of the interference wave signal component in consideration of the multipath characteristic for the correlation result data calculated by the correlation value calculation unit 22, Control for switching the application of the high-speed movement characteristic consideration method for obtaining the power of the interference wave signal component in consideration of the movement characteristic is executed on the differential correlation value calculation unit 25. The multipath characteristic consideration method and the high-speed movement characteristic consideration method will be described later.

  Based on the correlation result data stored in the correlation result storage unit 23, the differential correlation value calculation unit 25 converts the differential correlation value indicating a difference between predetermined correlation values into a multipath characteristic under the control of the method application control unit 24. It is calculated by a consideration method and a high-speed movement characteristic consideration method. Each calculated differential correlation value is output to the interference wave power calculation unit 26. The differential correlation value calculation unit 25 constitutes differential correlation value calculation means according to the present invention.

The interference wave power calculation unit 26 integrates a predetermined number of differential correlation values calculated by the multipath characteristic consideration method or the high-speed movement characteristic consideration method calculated by the difference correlation value calculation unit 25, and averages the average power of the interference wave signal component. the interference signal power P _I and calculates for each method. Data of the average interference signal power P _I of each calculated manner is output to the system by result storage unit 27. The interference wave power calculation unit 26 constitutes interference wave power calculation means according to the present invention.

Method-specific result storage unit 27, for each multipath characteristics considered system and high-speed transfer characteristics considered method, interference wave power calculation unit 26 is adapted to store the average interference signal power P _I calculated by scheme.

Selecting unit 28, out of the system by result storage unit 27 is stored in that manner by the average interference signal power P _I, select a value towards low power, SIR calculator average interference signal power P _I selected 14 is output. This selection part 28 comprises the selection means which concerns on this invention.

Average received power calculating unit 13, the correlation result from the storage unit 23 inputs the data of the predetermined correlation result, and calculates the average reception power P _R in accordance with the multipath characteristic considering system and high-speed transfer characteristics considered scheme SIR calculator 14 is output.

Specifically, the average received power calculation unit 13 calculates the average by [Equation 2] when the multipath characteristic consideration method is applied and by [Equation 3] when the high-speed mobility characteristic consideration method is applied. It calculates the reception power P _R and outputs to the SIR calculation section 14. The basic concept for deriving [Equation 2] and [Equation 3] is described in Japanese Patent Application Laid-Open No. 2011-193221, which is an earlier application, and will not be described here (average interference wave power described later). each calculation formula P _I also).

  Here, TX is a variable indicating the transmission antenna 0 or 1 of the base station. In this embodiment, only transmission antenna 0 is used, so TX = 0. For example, (n + m + TX) mod 2 indicates a remainder obtained by dividing (n + m + TX) by 2.

SIR calculation unit 14, in response to the multi-path characteristics considered system and high-speed transfer characteristics considered method, and data of the average interference signal power P _I of the selector 28 is selected, the average received average received power calculating unit 13 calculates power P inputs the _R data, and calculates the average desired wave reception power P _S by Equation 4].

Further, SIR calculation unit 14, and calculates the SIR by [Expression 5] from the average desired wave reception power _{P S} and the average interference signal power _{P I.} The calculated SIR data is output to the display unit 15. The SIR calculation unit 14 constitutes SIR calculation means according to the present invention.

The display unit 15 includes a liquid crystal display, for example, and displays the SIR calculated by the SIR calculation unit 14. Incidentally, the display unit 15, the average interference signal power P _I, the average received power P _R, may be configured to display the average desired wave reception power P _S and the like.

Next, the function of the interference wave power calculation unit 26 will be specifically described. As described above, the interference wave power calculation unit 26, and calculates the average interference signal power P _I in accordance with the multipath characteristic considering system and high-speed transfer characteristics considered scheme.

First, the case where the multipath characteristic consideration method is applied will be described. In this case, the interference wave power calculation unit 26 integrates the differential correlation values based on [Equation 6] to calculate the average interference wave power P _I (the power of the first interference wave signal component). .

  The first to fourth terms in Σ in [Equation 6] will be specifically described with reference to FIG. Here, the difference between the first term and the second term in Σ and the difference between the third term and the fourth term are calculated by the differential correlation value calculation unit 25.

The left side of FIG. 4A shows the first to fourth terms in Σ of [Equation 6] when n = 0, and m = 0, 1, 2, and 3 are changed. Each correlation value (see FIG. 3) is displayed. For example, if n = 0 and m = 0 are substituted into [Equation 6], R ₀₀ is obtained for the first term, R _{20 for} the second term, R _{11 for} the third term, and R _{31 for} the fourth term.

On the left side of FIG. 4B, when n = 0 and m = 0, the respective correlation values indicated by the first to fourth terms in Σ in [Equation 6] in FIG. Is a time axis, and a vertical axis is a frequency axis). From this figure, R ₀₀ of the first term and R _{20 of} the second term are the same frequency (same subcarrier), and R _{11 of} the third term and R _{31 of} the fourth term are the same frequency ( The same subcarrier). For example, the first frequency according to the present invention corresponds to the frequency of R _{00 of} the first term and the frequency of R ₂₀ of the second term, and the second frequency is the frequency of R _{11 of} the third term and the frequency of R ₃₁ of the fourth term. Corresponding to

Also, R ₀₀ in the first term, R _{20 in} the second term, R _{11 in} the third term, and R _{31 in} the fourth term are at different time positions. For example, the first time according to the present invention is the time of R ₀₀ of the first term, the second time is the time of R ₁₁ of the third term, the third time is the time of R ₂₀ of the second term, the fourth time Corresponds to the time of R _{31 in} the fourth term.

In addition, referring to FIG. 3, R ₀₀ of the first term and R _{11 of} the third term are in the same slot, and R _{20 of} the second term and R _{31 of} the fourth term are in the same slot. Is shown. Here, R ₀₀ of the first term and R _{20 of} the second term are in different slots.

  Similar to the left side of FIG. 4B, when n = 0 and m = 1 on the left side of FIG. 4C, and when n = 0 and m = 2 on the left side of FIG. Each position in FIG. 3 of each correlation value indicated by the first term to the fourth term in Σ in [Equation 6] is schematically represented by hatching. These figures show that the position of each correlation value indicated by the first term to the fourth term in Σ of [Equation 6] changes as m increases.

  In the right side of FIGS. 4A to 4D, the same configuration as the left side diagrams is shown. When n = 1, when m = 0, 1, 2, and 3 are changed, [Equation 6] Each correlation value (see FIG. 3) indicated by the first term to the fourth term in Σ is displayed. In these figures, the correlation values indicated by the first term to the fourth term in Σ of [Equation 6] are in the direction in which the time advances with respect to the diagrams on the left side of FIGS. It shows that one is moving.

Next, a case where the high-speed movement characteristic consideration method is applied will be described. In this case, the interference wave power calculation unit 26 integrates the differential correlation values based on [Equation 7] to calculate the average interference wave power P _I (the power of the second interference wave signal component). .

  The first to fourth terms in Σ of [Equation 7] will be specifically described with reference to FIG. Here, the difference between the first term and the second term in Σ and the difference between the third term and the fourth term are calculated by the differential correlation value calculation unit 25.

On the left side of FIG. 5A, when n = 0, when m = 0, 1, 2, and 3 are changed, the first to fourth terms in Σ in [Expression 7] are shown. Each correlation value (see FIG. 3) is displayed. For example, if n = 0 and m = 0 are substituted into [Equation 7], R ₀₀ is obtained for the first term, R _{20 for} the second term, R _{02 for} the third term, and R _{22 for} the fourth term.

On the left side of FIG. 5B, when n = 0 and m = 0, each correlation value (horizontal direction) of each correlation value indicated by the first to fourth terms in Σ of [Equation 7] is shown. Is a time axis, and a vertical axis is a frequency axis). From this figure, R ₀₀ of the first term and R _{20 of} the second term are the same frequency (same subcarrier), and R _{02 of} the third term and R _{22 of} the fourth term are the same frequency ( The same subcarrier). For example, the third frequency according to the present invention corresponds to the frequency of R _{00 of} the first term and the frequency of R ₂₀ of the second term, and the fourth frequency is the frequency of R _{02 of} the third term and the frequency of R ₂₂ of the fourth term. Corresponding to

In addition, R _{00 in} the first term and R _{02 in} the third term are the same time, and R _{20 in} the second term and R _{22 in} the fourth term are the same time. Here, for example, the first time according to the present invention corresponds to the time of R _{00 of} the first term and the time of R ₀₂ of the third term, and the second time corresponds to the time of R ₂₀ of the second term and R ₂₂ of the fourth term. It corresponds to the time.

Also, referring to FIG. 3, R _{00 in} the first term and R _{02 in} the third term are in the same slot, and R _{20 in} the second term and R _{22 in} the fourth term are in the same slot. Is shown. Here, R ₀₀ of the first term and R _{20 of} the second term are in different slots.

  Similar to the left side of FIG. 5B, when n = 0 and m = 1 on the left side of FIG. 5C, and when n = 0 and m = 2 on the left side of FIG. 5D, Each position in FIG. 3 of each correlation value indicated by the first term to the fourth term in Σ in [Expression 7] is schematically represented by hatching. These figures show that the position of each correlation value indicated by the first term to the fourth term in Σ of [Equation 7] changes as m increases.

  In the right side of FIGS. 5A to 5D, the same configuration as the left side diagrams is shown. When n = 1, when m = 0, 1, 2, and 3 are changed, [Equation 7] Each correlation value (see FIG. 3) indicated by the first term to the fourth term in Σ is displayed. In these figures, the correlation values indicated by the first term to the fourth term in Σ of [Equation 7] are in the direction in which the time advances with respect to the diagrams on the left side of FIGS. It shows that one is moving.

  Next, the features of the multipath characteristic consideration method and the high-speed movement characteristic consideration method will be described by comparing the two.

  First, the characteristics of the multipath characteristic consideration method will be described with reference to FIG.

  FIG. 6A shows a combination 31 that takes the difference between the first term and the second term in Σ, and the third and fourth terms in Σ when n = 0 and m = 0 in [Equation 6]. A combination 32 that takes a difference from a term is surrounded by a solid line. Further, a combination 33 that takes a difference in absolute value symbols in Σ is surrounded by a broken line.

  Here, when [Formula 6] is transformed, [Formula 8] is obtained.

  FIG. 6B is a representation of what is shown in FIG. 6A re-expressed using [Equation 8]. When n = 0 and m = 0 in [Equation 8], A combination 34 that takes the sum of the first term and the second term and a combination 35 that takes the sum of the third term and the fourth term in Σ are surrounded by a solid line. Further, a combination 33 that takes a difference in absolute value symbols in Σ is surrounded by a broken line.

As shown in FIG. 6B, the multipath characteristic considering method has a frequency difference of 3 subcarriers, and thus is more resistant to fluctuation for each frequency in the multipath environment than the high-speed moving characteristic considering method described later. It has been shown. On the other hand, as shown in FIG. 6B, the multipath characteristic consideration method occurs in a high-speed moving environment because the combination 34 of R ₀₀ and R ₃₁ has a larger time difference than the combination 35 of R ₁₁ and R _20. It is shown that the characteristics deteriorate when the time fluctuation is large.

  Next, features of the high-speed movement characteristic consideration method will be described with reference to FIG.

  FIG. 7A shows a combination 41 that takes the difference between the first term and the second term in Σ, and the third and fourth terms in Σ when n = 0 and m = 0 in [Equation 7]. A combination 42 that takes a difference from a term is surrounded by a solid line. A combination 43 that takes a difference in the absolute value symbol in Σ is surrounded by a broken line.

  Here, [Equation 9] is obtained by transforming [Equation 7].

  FIG. 7 (b) is a representation of what is shown in FIG. 7 (a) by using [Equation 9]. In [Equation 9], when n = 0 and m = 0, A combination 44 that takes the sum of the first term and the second term and a combination 45 that takes the sum of the third term and the fourth term in Σ are surrounded by a solid line. A combination 43 that takes a difference in the absolute value symbol in Σ is surrounded by a broken line.

As shown in FIG. 7B, the high-speed movement characteristic consideration method is the same as that of the combination 44 of R ₀₀ and R ₂₂ and the time difference of the combination 45 of R ₀₂ and R _20, and the time variation that occurs in a high-speed movement environment. On the other hand, it is shown that it is more resistant than the above-mentioned multipath characteristic consideration method. On the other hand, since the frequency difference is 6 subcarriers in the high-speed mobility characteristic consideration method, it is shown that the characteristic deteriorates when the variation for each frequency in a multipath environment is large.

  As described above, the multipath characteristic consideration method is resistant to fluctuations for each frequency in a multipath environment, so that it is possible to measure the interference wave power with high accuracy in a multipath environment and to move at high speed. It can be seen that the characteristic consideration method is resistant to temporal fluctuations that occur in a high-speed moving environment, so that interference wave power can be measured with high accuracy in a high-speed moving environment.

Therefore, if the average interference wave power P _I is calculated separately by the multipath characteristic consideration method and the high-speed movement characteristic consideration method and the smaller average interference wave power P _I is selected, the selected average interference wave power P _I is true. It becomes equivalent to small average interference signal power P _I of error for the values.

That is, the selection unit 28, by selecting a value towards small power of system-specific result storage unit 27 is stored in that manner by the average interference signal power P _I, the true value of the average interference signal power P _I The one with the smaller error with respect to is selected.

  Next, the operation of the SIR measurement apparatus 10 in the present embodiment will be described with a focus on the flowchart shown in FIG.

  The receiving unit 12 receives the OFDM signal via the receiving antenna 11 (step S11), converts the signal into an IF signal having a predetermined frequency, converts the IF signal from an analog value to a digital value, and outputs the converted signal to the FFT operation unit 21. .

  The FFT calculation unit 21 converts the time domain signal output from the reception unit 12 into a frequency domain signal (step S <b> 12), and outputs the signal to the correlation value calculation unit 22.

Correlation value calculation unit 22, the time axis n, calculates a reference signal component _{S nm} at the position of the frequency axis m, the correlation value _{R nm} of the complex conjugate of the known signal component _{C nm} by [Expression 1] (step S13) .

  The correlation result storage unit 23 stores the correlation result data calculated by the correlation value calculation unit 22 (step S14).

  The difference correlation value calculation unit 25 is based on the correlation result data stored in the correlation result storage unit 23 and performs the difference based on the multipath characteristic consideration method according to the control of the method application control unit 24 (instructing the multipath characteristic consideration method). A correlation value is calculated (step S15). Specifically, the difference (first difference) between the first term and the second term in Σ in [Equation 6], and the difference (second difference) between the third term and the fourth term are calculated.

Interference wave power calculation unit 26, the average interference signal power P _I in multipath characteristics considered scheme calculated by Equation 6], the data of the calculated average interference signal power P _I is a method-specific result storage unit 27 stores ( Step S16).

  The difference correlation value calculation unit 25 is based on the correlation result data stored in the correlation result storage unit 23, and the difference based on the high-speed movement characteristic consideration method according to the control of the method application control unit 24 (instructing the high-speed movement characteristic consideration method). A correlation value is calculated (step S17). Specifically, the difference (third difference) between the first term and the second term in Σ in [Equation 7] and the difference (fourth difference) between the third term and the fourth term are calculated.

Interference wave power calculation unit 26, the average interference signal power P _I fast transfer characteristics considered scheme calculated by [Equation 7], the data of the calculated average interference signal power P _I is a method-specific result storage unit 27 stores ( Step S18).

Selecting unit 28, out of the system by result storage unit 27 is stored in that manner by the average interference signal power P _I, select a value towards the power is small (step S19), the average interference signal power P _I selected Are output to the SIR calculation unit 14.

SIR calculation unit 14, an average desired wave reception power _{P S} from the average received power calculating unit 13 calculates the SIR by [Expression 5] from the average interference power _{P I} from the selector 28 (step S20).

  The display unit 15 displays the SIR calculated by the SIR calculation unit 14 (step S21).

  Although FIG. 8 shows an example in which the calculation of the multipath characteristic consideration method is performed first and the calculation of the high speed movement characteristic consideration method is performed later, this order may be changed. That is, the order of steps S17, S18, S15, S16, S19,.

As described above, the interference signal power measuring device 20 of this embodiment, respectively calculates the average interference signal power P _I in multipath characteristics considered system and high-speed transfer characteristics considered method, these two average interference signal power P _I because of which the smaller value selecting section 28 of the configured to select, multipath average interference signal power in the multipath characteristics considered scheme in environments P _I, in high-speed transfer characteristics considered system under high-speed moving environment It will select the average interference signal power P _I.

  Therefore, the interference wave power measuring apparatus 20 according to the present embodiment can measure the interference wave power with higher accuracy than in the past in a high-speed moving environment in addition to a multipath environment.

  Moreover, since the SIR measurement apparatus 10 in the present embodiment includes the interference wave power measurement apparatus 20 that can measure the interference wave power with higher accuracy than in the past in a high-speed moving environment in addition to a multipath environment, In addition to the multipath environment, the SIR can be measured with higher accuracy than in the prior art in a high-speed moving environment.

(Other aspects)
In the above-described embodiment, the base station transmits an OFDM signal radio wave with one transmission antenna 0. However, even when the base station transmits an OFDM signal radio wave with two transmission antennas, the above-described embodiment and it is possible to determine the average interference signal power P _I and SIR in a similar idea.

FIG. 9 shows correlation result data for the reference signal components arranged at the positions indicated by TX = 0 (transmitting antenna 0) and TX = 1 (transmitting antenna 1) in FIG. In this case, Equation 2, by substituting the TX = 0, TX = 1 in [Numerical equation 3], the average received power _{P R} of the transmitting antenna 0 and 1 are obtained for each method.

Also, the mathematical expressions corresponding to [Equation 6] to [Equation 9] are represented by the following mathematical expressions, respectively. [Expression 10], by substituting TX = 0, TX = 1 in Equation 11], in the multipath characteristics considered system and high-speed transfer characteristics considered scheme average interference power _{P I} of the transmitting antenna 0 and 1 obtained.

  The mathematical formula corresponding to [Formula 6] is represented by [Formula 10].

  An equation corresponding to [Equation 7] is represented by [Equation 11].

  An equation corresponding to [Equation 8] is represented by [Equation 12].

  An equation corresponding to [Equation 9] is represented by [Equation 13].

  By applying [Equation 10] and [Equation 11], the SIR measurement apparatus 10 can be used in a high-speed moving environment in addition to the multipath environment even when the base station transmits the radio wave of the OFDM signal using two transmission antennas. Even underneath, the interference wave power can be measured with higher accuracy than before.

(Second Embodiment)
As shown in FIG. 10, the SIR measurement device 50 in the present embodiment includes an interference wave power measurement device 60 instead of the interference wave power measurement device 20 (see FIG. 1) of the first embodiment, and the SIR calculation unit 14 includes The difference is that it has been abolished. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  The interference wave power measurement device 60 includes an SIR calculation unit 61, a method-specific result storage unit 62, and a selection unit 63 instead of the interference wave power calculation unit 26, the method-specific result storage unit 27, and the selection unit 28 in the first embodiment. I have.

The SIR calculation unit 61 has the functions of the interference wave power calculation unit 26 and the SIR calculation unit 14 in the first embodiment. That is, the SIR calculation unit 61 integrates a predetermined number of differential correlation values calculated by the multipath characteristic consideration method or the high-speed movement characteristic consideration method calculated by the differential correlation value calculation unit 25, and averages the average power of the interference wave signal component. the interference signal power P _I and calculates for each method.

Further, SIR calculation unit 61, and the average interference signal power P _I of calculated by the average reception power P _R of the average received power calculating unit 13 is calculated, the specific method based on the formula [4] and [Equation 5] SIR is calculated.

  The method-specific result storage unit 62 stores the SIR data calculated by the SIR calculation unit 61 for each of the multipath characteristic consideration method and the high-speed movement characteristic consideration method.

  The selection unit 63 selects a value having a larger SIR among the SIRs for each method stored in the result storage unit 27 for each method. That is, the selection unit 63 selects the one having a smaller error with respect to the true value of SIR. The selected SIR data is output to the display unit 15. Note that when the interference wave power measuring device 60 outputs average interference wave power data as in the first embodiment, the selection unit 63 selects and outputs an interference wave signal component that provides a large SIR value. What is necessary is just composition.

  Next, the operation of the SIR measurement apparatus 10 in the present embodiment will be described with a focus on the flowchart shown in FIG. In addition, since only the steps S31 to S33 are different in the present embodiment from the flowchart (see FIG. 8) in the first embodiment, description of other steps is omitted.

  After the differential correlation value calculation unit 25 calculates the differential correlation value by the multipath characteristic consideration method in step S15, the SIR calculation unit 61 performs the SIR by the multipath characteristic consideration method based on [Equation 4] and [Equation 5]. The method-specific result storage unit 62 stores the calculated SIR data (step S31).

  Similarly, after the differential correlation value calculation unit 25 calculates the differential correlation value by the high-speed movement characteristic consideration method, the SIR calculation unit 61 calculates the SIR by the high-speed movement characteristic consideration method based on [Equation 4] and [Equation 5]. The calculated result storage unit 62 stores the calculated SIR data (step S32).

  The selection unit 63 selects a value having a larger SIR among the SIRs for each method stored in the result storage unit 27 for each method (step S33), and outputs the selected SIR data to the display unit 15.

  Although FIG. 11 shows an example in which the multipath characteristic considering method is calculated first and the high speed moving characteristic considering method is calculated later, this order may be changed. That is, the order of steps S17, S32, S15, S31, S33,.

  As described above, the interference wave power measuring apparatus 60 according to the present embodiment calculates the SIR using the multipath characteristic consideration method and the high-speed movement characteristic consideration method, and the selector 63 selects the larger SIR of these two SIRs. Since the selected configuration is adopted, it is possible to measure the interference wave power with higher accuracy than in the past in a high-speed moving environment in addition to a multipath environment.

  In addition, the SIR measurement device 50 in the present embodiment includes the interference wave power measurement device 60 that can measure the interference wave power with higher accuracy than in the past in a high-speed moving environment in addition to a multipath environment. In addition to the multipath environment, the SIR can be measured with higher accuracy than in the prior art in a high-speed moving environment.

  As described above, the interference wave power measuring apparatus, the interference wave power measuring method, the SIR measuring apparatus, and the SIR measuring method according to the present invention can reduce the interference wave power in the high-speed moving environment in addition to the conventional multipath environment. Interference wave power measurement apparatus, interference wave power measurement method, SIR measurement apparatus and SIR measurement method for measuring the power of an interference wave signal in a mobile communication system using an OFDM signal, having the effect of being able to measure with high accuracy Useful as.

DESCRIPTION OF SYMBOLS 10, 50 SIR measuring device 11 Reception antenna 12 Reception part 13 Average received power calculation part 14 SIR calculation part (SIR calculation means)
15 Display unit 20, 60 Interference wave power measurement device 21 FFT calculation unit (Fourier transform means)
22 Correlation value calculation unit (correlation value calculation means)
23 correlation result storage unit 24 method application control unit 25 differential correlation value calculation unit (differential correlation value calculation means)
26 Interference wave power calculation unit (interference wave power calculation means)
27, 62 Result storage unit by method 28, 63 Selection unit (selection means)
61 SIR calculation section

Claims (8)

Interference wave power measurement for receiving a signal including a desired wave signal component including a known reference signal component and an interference wave signal component interfering with the desired wave signal component and measuring the power of the interference wave signal component A device (20) comprising:
Fourier transform means (21) for converting a received wave signal received from a time domain signal to a frequency domain signal;
Correlation value calculating means (22) for calculating a correlation value between the signal value of the received reference signal component included in the received wave signal and the signal value of the known reference signal component;
Differential correlation value calculation means (25) for calculating first and second differential correlation values indicating differences between predetermined correlation values based on the calculation result calculated by the correlation value calculation means;
Interference wave power calculating means (26) for calculating the power of the first and second interference wave signal components based on the result of integrating the squares of the absolute values of the first and second differential correlation values;
Selecting means (28) for selecting, as the power of the interference wave signal component, the one having the smaller error from the true value among the powers of the first and second interference wave signal components;
With
The differential correlation value calculating means includes
Between the first difference that is the difference between the correlation value at the first time at the first frequency and the correlation value at the second time later than the first time, and between the first time and the second time at the second frequency A difference between a correlation value at a third time and a second difference that is a difference between a correlation value at a fourth time later than the second time is obtained as the first difference correlation value;
A third difference that is a difference between the correlation value at the first time and the correlation value at the second time at a third frequency, and the correlation value at the first frequency and the correlation value at the second time at a fourth frequency. A difference with a fourth difference which is a difference is obtained as the second difference correlation value;
The interference wave power measuring device, wherein a frequency difference between the first frequency and the second frequency is smaller than a frequency difference between the third frequency and the fourth frequency. The interference wave power calculation means calculates an average power value P _I of the first interference wave signal component based on [Equation 1], and calculates an average power value P _I of the second interference wave signal component. 2. The interference wave power measuring apparatus according to claim 1, wherein the interference wave power measuring apparatus is calculated based on [Equation 2].

Where N (an integer of 4 or more) is the position of the received reference signal component in the time axis direction, M (an integer of 1 or more) is the position of the received reference signal component in the frequency axis direction, and R _nm is n (n = 0) ˜N−3) and m (m = 0 to M−1), the correlation value of the received reference signal components, and (n + m) mod 2 represents the remainder of dividing (n + m) by 2.

However, R _nm is the correlation value of the received reference signal component represented by n (n = 0 to N-2) and m (m = 0 to M / 2-1), and (n) mod 2 is (n) 2 Indicates the remainder when divided by. The received wave signal includes received reference signal components received from two transmitting antennas,
The interference wave power calculation means calculates an average power value P _I of the first interference wave signal component based on [Equation 3], and calculates an average power value P _I of the second interference wave signal component. The interference wave power measuring apparatus according to claim 1, wherein the interference wave power measuring apparatus is calculated based on [Equation 4].

Where N (an integer of 4 or more) is the position of the received reference signal component in the time axis direction, M (an integer of 2 or more) is the position of the received reference signal component in the frequency axis direction, and R _nm is n (n = 0) ~ N-3) and m (m = 0 to M-1), the correlation value of the received reference signal component, TX (0 or 1) is the transmission antenna 0 or 1, and (n + m + TX) mod 2 is (n + m + TX). The remainder after dividing by 2.

However, R _nm is a correlation value of received reference signal components represented by n (n = 0 to N−2) and m (m = 0 to M / 2-1), and (n + TX) mod 2 is 2 (n + TX). Indicates the remainder when divided by.   The said selection means selects the electric power of a small value among the electric power of the said 1st and said 2nd interference wave signal component as the electric power of the said interference wave signal component, The Claim 1 characterized by the above-mentioned. 4. The interference wave power measuring apparatus according to any one of up to 3.   The selection means can obtain a large SIR value indicating a ratio between the power of the desired wave signal component and the power of the interference wave signal component, among the powers of the first and second interference wave signal components. The interference wave power measuring device according to any one of claims 1 to 3, wherein the interference wave signal component is selected as power of the interference wave signal component. The interference wave power measuring device (20) according to any one of claims 1 to 5,
SIR calculating means (14) for calculating a ratio between the power of the desired wave signal component and the power of the interference wave signal component;
An SIR measuring apparatus comprising: Interference wave power measurement for receiving a signal including a desired wave signal component including a known reference signal component and an interference wave signal component interfering with the desired wave signal component and measuring the power of the interference wave signal component A method,
A Fourier transform step (S12) for converting the received received wave signal from a time domain signal to a frequency domain signal;
A correlation value calculating step (S13) for calculating a correlation value between the signal value of the received reference signal component included in the received wave signal and the signal value of the known reference signal component;
Calculating first and second differential correlation values indicating differences between predetermined correlation values based on the calculation result calculated in the correlation value calculating step (S15, S17);
Interference wave power calculating step (S16, S18) for calculating the power of the first and second interference wave signal components based on the result of integrating the squares of the absolute values of the first and second differential correlation values. When,
A selection step (S19) of selecting, as the power of the interference wave signal component, the smaller one of the errors of the first and second interference wave signal components with respect to the true value,
Including
In the differential correlation value calculating step,
Between the first difference that is the difference between the correlation value at the first time at the first frequency and the correlation value at the second time later than the first time, and between the first time and the second time at the second frequency A difference between a correlation value at a third time and a second difference that is a difference between a correlation value at a fourth time later than the second time is obtained as the first difference correlation value;
A third difference that is a difference between the correlation value at the first time and the correlation value at the second time at a third frequency, and the correlation value at the first frequency and the correlation value at the second time at a fourth frequency. The difference from the fourth difference which is a difference is obtained as the second difference correlation value,
An interference wave power measuring method, wherein a frequency difference between the first frequency and the second frequency is smaller than a frequency difference between the third frequency and the fourth frequency. Each step of the interference wave power measurement method according to claim 7,
A SIR calculating step (S20) for calculating a ratio between the power of the desired wave signal component and the power of the interference wave signal component;
SIR measurement method characterized by including.

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