JP2016046559A - Satellite broadcast signal quality estimation device and leakage signal canceller device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To estimate the signal-to-noise ratio of an intermediate frequency signal by a simple method without mounting a demodulation device for a satellite broadcast signal when extracting a desired signal by removing a leakage signal from a mixed signal.SOLUTION: A satellite broadcast signal quality estimation device 5 of the present invention comprises: an intermediate frequency signal acquisition unit 51 for acquiring an intermediate frequency signal that is generated by converting the frequency of a satellite broadcast signal downward and has a signal band which may interfere with a communication band of a mobile communication network; a signal-with-noise probability density distribution calculation unit 52 for calculating the probability density distribution of the signal characteristic of an intermediate frequency signal including noise; a signal-without-noise probability density distribution storage unit 53 storing information on the probability density distribution of the signal characteristic of an intermediate frequency signal not including noise; and a signal-to-noise ratio estimation unit 6 for estimating the signal-to-noise ratio of the intermediate frequency signal including noise by comparing the probability density distribution of the signal characteristics of the intermediate frequency signals including/not including noise.SELECTED DRAWING: Figure 2

Description

  The present invention is capable of interfering with a communication band of a mobile communication network in which a desired signal transmitted from a mobile terminal of a mobile communication network and a satellite broadcast signal received by a satellite broadcast signal receiving apparatus are down-converted and leaked. The present invention relates to a technique for preventing interference between a leaky signal having a signal band.

  In the interference measurement system, the communication band (for example, 1) of the desired signal transmitted from the mobile terminal of the mobile communication network and the satellite broadcast signal received by the satellite broadcast signal receiving device and the satellite broadcast signal is leaked by frequency down-conversion. For example, Patent Document 1 discloses a technique for preventing interference between a leaky signal having a signal band (intermediate frequency band) that can interfere with the .5 GHz band).

  The interference measurement system can interfere with the communication band of the mobile communication network, in which the desired signal transmitted from the mobile terminal of the mobile communication network and the satellite broadcast signal received by the satellite broadcast signal receiving device are down-converted and leaked. An interference signal with a leakage signal having a wide signal band is received.

  At the same time, the interference measurement system receives the satellite broadcast signal and then down-converts the frequency to generate an intermediate frequency signal having a signal band that can interfere with the communication band of the mobile communication network.

  Then, the interference measurement system calculates the signal correlation between the interference signal and the intermediate frequency signal, and calculates the leakage signal from the interference signal based on the signal correlation between the interference signal and the intermediate frequency signal and the predetermined signal-to-noise ratio of the intermediate frequency signal. Remove the desired signal.

JP 2014-064139 A

  In this way, the interference measurement system extracts the desired signal by removing the leakage signal from the interference signal based on the predetermined signal-to-noise ratio of the intermediate frequency signal. However, the predetermined signal-to-noise ratio of the intermediate frequency signal is a fixed value determined by the administrator of the interference measurement system, and the interference measurement system itself does not actually calculate the estimated value. Because the predetermined signal-to-noise ratio of the intermediate frequency signal can be calculated based on the demodulation result of the satellite broadcast signal, the interference measurement system extracts the desired signal by removing the leakage signal from the interference signal This is because a satellite broadcast signal demodulator is not installed for cost reduction.

  Therefore, in the interference measurement system, there is a possibility that the cancellation parameter for removing the leakage signal from the interference signal is different from the actual one. In the interference measurement system, it is impossible to determine whether the intermediate frequency signal is generated as designed after the satellite broadcast signal is received as designed. Then, in the interference measurement system, when the leakage signal cannot be removed from the interference signal as designed, it is determined whether the device itself is defective or whether the satellite broadcasting signal is not received as designed due to the installation method failure. I can't.

  Therefore, in order to solve the above problems, the present invention eliminates a leakage signal from an interference signal and extracts a desired signal. An object is to provide a technique capable of estimating the ratio by a simple method.

  To achieve the above object, the probability density distribution of signal characteristics (calculated when estimating the signal-to-noise ratio for the intermediate frequency signal) for the intermediate frequency signal including noise and the noise is not included. By examining the degree of divergence between the probability density distribution of the signal characteristics for the intermediate frequency signal (known before estimating the signal-to-noise ratio for the intermediate frequency signal) and the intermediate frequency signal containing the noise We decided to estimate the signal-to-noise ratio.

  Specifically, the present invention provides an intermediate frequency signal acquisition unit that acquires an intermediate frequency signal having a signal band that can be interfered with a communication band of a mobile communication network, generated by down-converting a satellite broadcast signal. For the intermediate frequency signal including noise acquired by the intermediate frequency signal acquisition unit, the signal probability density distribution calculation unit with noise for calculating the probability density distribution of the signal characteristic, and for the intermediate frequency signal not including noise, the signal characteristic A noise-free signal probability density distribution storage unit storing probability density distribution information, and a signal characteristic probability density distribution for an intermediate frequency signal including noise, calculated by the signal probability density distribution calculation unit with noise; The noise-free signal probability density distribution storage unit stores information, and a probability density distribution of signal characteristics for an intermediate frequency signal that does not include noise, and A signal-to-noise ratio estimation unit for estimating a signal-to-noise ratio for an intermediate frequency signal including noise acquired by the intermediate frequency signal acquisition unit, Device.

  According to this configuration, the intermediate frequency based on the degree of deviation between the probability density distribution of the signal characteristic for the intermediate frequency signal including noise and the probability density distribution of the signal characteristic for the intermediate frequency signal not including noise. The signal to noise ratio of the signal can be estimated.

  In the present invention, the signal-to-noise ratio estimation unit stores information on probability density distributions of a plurality of types of noise characteristics for noise included in the intermediate frequency signal acquired by the intermediate frequency signal acquisition unit. A noise probability density distribution storage unit, a noise probability signal distribution distribution unit storing information, a probability density distribution of signal characteristics for an intermediate frequency signal not including noise, and the noise probability density distribution storage unit The intermediate frequency signal including the noise acquired by the intermediate frequency signal acquisition unit by combining the probability density distributions of a plurality of types of noise characteristics with respect to the noise included in the intermediate frequency signal. A first pseudo-noise-provided signal probability density distribution calculating unit that calculates probability density distributions of a plurality of types of pseudo-signal characteristics; The probability density distribution of the signal characteristics of the intermediate frequency signal including noise calculated by the probability density distribution calculation unit, and the intermediate frequency signal including noise calculated by the first pseudo noise-probable signal probability density distribution calculation unit By comparing the probability density distributions of a plurality of types of pseudo signal characteristics with respect to the plurality of types of noises included in the intermediate frequency signal, the noise probability density distribution storage unit stores information. A noise probability density distribution selection unit that selects a probability density distribution of a noise characteristic that matches an intermediate frequency signal including noise acquired by the intermediate frequency signal acquisition unit out of a probability density distribution of noise characteristics; and the signal probability without noise A probability density distribution of signal characteristics for an intermediate frequency signal that does not include noise, in which the density distribution storage unit stores information, and the noise The intermediate frequency signal acquisition unit selects the probability density distribution of the noise characteristics suitable for the intermediate frequency signal including noise selected by the probability density distribution selection unit while changing the parameters of the probability density distribution of the noise characteristics. A second pseudo-noise-provided signal probability density distribution calculating unit that calculates probability density distributions of a plurality of types of pseudo-signal characteristics for the acquired intermediate frequency signal, and the noisy signal probability density distribution calculating unit; The probability density distribution of the signal characteristics for the intermediate frequency signal including noise calculated by the above and a plurality of types of the intermediate frequency signal including noise calculated by the second pseudo noise-probable signal probability density distribution calculation unit The pseudo signal characteristic probability density distribution of the second pseudo noise characteristic calculation unit Among the parameters of the probability density distribution of the changed noise characteristic, a noise parameter selection unit that selects a parameter of the probability density distribution of the noise characteristic suitable for the intermediate frequency signal including the noise acquired by the intermediate frequency signal acquisition unit; Based on the probability density distribution of the noise characteristic selected by the noise probability density distribution selection unit and the parameter of the probability density distribution of the noise characteristic selected by the noise parameter selection unit, the noise acquired by the intermediate frequency signal acquisition unit is A satellite broadcast signal quality estimation device comprising: a signal-to-noise ratio determination unit that determines a signal-to-noise ratio for an intermediate frequency signal included.

  According to this configuration, the intermediate frequency based on the probability density distribution of the noise characteristic suitable for the intermediate frequency signal including noise and the parameter of the probability density distribution of the noise characteristic suitable for the intermediate frequency signal including noise. The signal to noise ratio of the signal can be estimated. In addition, according to this configuration, the noise probability distribution of noise characteristics and the calculation speed of the parameters are improved because the actual noise probability distribution with noise is reproduced while changing the noise parameter for one noise probability density distribution. can do.

  In the present invention, the signal-to-noise ratio estimation unit stores information on probability density distributions of a plurality of types of noise characteristics for noise included in the intermediate frequency signal acquired by the intermediate frequency signal acquisition unit. A noise probability density distribution storage unit, a noise probability signal distribution distribution unit storing information, a probability density distribution of signal characteristics for an intermediate frequency signal not including noise, and the noise probability density distribution storage unit Is obtained by combining the probability density distribution of each type of noise characteristic with respect to the noise contained in the intermediate frequency signal storing information while changing the parameter of the probability density distribution of the noise characteristic. For the intermediate frequency signal including noise acquired by the unit, a pseudo signal based on each probability density distribution of noise characteristics and its parameters A pseudo-noise signal probability density distribution calculation unit for calculating a probability density distribution of characteristics, and a probability density distribution of signal characteristics for an intermediate frequency signal including noise, calculated by the signal probability density distribution calculation unit with noise; The probability density distribution of the pseudo signal characteristics based on each probability density distribution of the noise characteristics and each parameter thereof for the intermediate frequency signal including the noise calculated by the signal probability density distribution calculator with pseudo noise, A noise parameter selection unit that selects a parameter of each probability density distribution of noise characteristics suitable for an intermediate frequency signal including noise acquired by the intermediate frequency signal acquisition unit, and the signal probability density distribution calculation with noise The probability density distribution of the signal characteristics for the intermediate frequency signal including noise calculated by the By comparing the probability density distribution of the noise characteristics and the probability density distribution of the pseudo signal characteristics based on the respective adaptation parameters for the intermediate frequency signal including noise selected by the meter selection unit, A noise probability density distribution selection unit that selects a probability density distribution of noise characteristics that matches an intermediate frequency signal including noise acquired by the frequency signal acquisition unit, and each probability density distribution of the noise characteristics selected by the noise parameter selection unit Based on the parameter and the probability density distribution of the noise characteristic selected by the noise probability density distribution selection unit, a signal-to-noise ratio for the intermediate frequency signal including the noise acquired by the intermediate frequency signal acquisition unit is determined. A satellite broadcast signal quality estimation device comprising: a signal-to-noise ratio determination unit.

  According to this configuration, the intermediate frequency based on the probability density distribution of the noise characteristic suitable for the intermediate frequency signal including noise and the parameter of the probability density distribution of the noise characteristic suitable for the intermediate frequency signal including noise. The signal to noise ratio of the signal can be estimated. In addition, according to this configuration, the noise probability distribution of noise characteristics and the calculation accuracy of the parameters are improved in order to reproduce the actual signal probability density distribution with noise while changing the noise parameters for a plurality of noise probability density distributions. can do.

  In addition, the present invention provides a satellite broadcast signal quality estimation apparatus as described above, a desired signal transmitted from a mobile terminal of the mobile communication network, and the satellite broadcast signal receiving apparatus for receiving the satellite broadcast signal. And a leaked signal having a signal band capable of interfering with the communication band of the mobile communication network, and a mobile communication receiving unit that receives an interference signal, and down-converting the frequency after receiving the satellite broadcast signal. A satellite broadcast receiver that generates the intermediate frequency signal having a signal band capable of interfering with a communication band of the mobile communication network, the interference signal received by the mobile communication receiver, and the satellite broadcast receiver A signal correlation calculation unit that calculates a signal correlation between the generated intermediate frequency signal, a signal correlation calculated by the signal correlation calculation unit, and a signal-to-noise ratio estimation unit of the satellite broadcast signal quality estimation device; A boss was signal-to-noise ratio, based on a leakage signal canceller, characterized in that it comprises, a leakage signal canceling unit configured to extract the desired signal by removing the leakage signal from the interference signal.

  According to this configuration, in the leakage signal canceller apparatus, when the desired signal is extracted by removing the leakage signal from the interference signal, the signal-to-noise ratio of the intermediate frequency signal can be increased without mounting the satellite broadcast signal demodulation apparatus. It can be estimated by a simple method.

  As described above, the present invention eliminates a leakage signal from an interference signal and extracts a desired signal, and does not include a satellite broadcast signal demodulator, so that the signal-to-noise ratio of an intermediate frequency signal can be reduced by a simple method. Techniques that can be estimated can be provided.

It is a figure which shows the structure of the leak signal canceller apparatus of this invention. It is a figure which shows the structure of the satellite broadcast signal quality estimation apparatus of Embodiment 1. FIG. It is a figure which shows the noise probability density distribution selection method of Embodiment 1. It is a figure which shows the noise parameter selection method of Embodiment 1. FIG. It is a figure which shows the structure of the satellite broadcast signal quality estimation apparatus of Embodiment 2. FIG. It is a figure which shows the noise parameter selection method of Embodiment 2. It is a figure which shows the noise parameter selection method of Embodiment 2. It is a figure which shows the noise probability density distribution selection method of Embodiment 2.

  Embodiments of the present invention will be described with reference to the accompanying drawings. The embodiments described below are examples of the present invention, and the present invention is not limited to the following embodiments. In the present specification and drawings, the same reference numerals denote the same components.

(Outline of the present invention)
The configuration of the leakage signal canceller apparatus of the present invention is shown in FIG. The leakage signal canceller apparatus C includes a mobile communication reception unit 1, a satellite broadcast reception unit 2, a signal correlation calculation unit 3, a leakage signal removal unit 4, and a satellite broadcast signal quality estimation device 5. For mobile communication, mobile terminals U1, U2,..., A leakage signal canceller apparatus C and a mobile communication network base station apparatus B are located in the mobile communication network M. As for the satellite broadcasting, the receiving devices R1, R2,... And the leakage signal canceller device C receive from the broadcasting satellite S.

  The mobile communication receiver 1 receives the desired signal transmitted from the mobile terminals U1, U2,... Of the mobile communication network M and the satellite broadcast signal receivers R1, R2,. The crosstalk signal of the leaked signal having a signal band (intermediate frequency band) that can be interfered with the communication band (for example, 1.5 GHz band) of the mobile communication network M that has been converted and leaked is received.

  After receiving the satellite broadcast signal, the satellite broadcast receiving unit 2 converts the frequency downward and generates an intermediate frequency signal having a signal band capable of interfering with the communication band of the mobile communication network M.

  The signal correlation calculation unit 3 calculates the signal correlation between the interference signal received by the mobile communication reception unit 1 and the intermediate frequency signal generated by the satellite broadcast reception unit 2.

  The leakage signal removal unit 4 includes the signal correlation calculated by the signal correlation calculation unit 3, the signal-to-noise ratio estimated by the signal-to-noise ratio estimation unit 6 of the satellite broadcast signal quality estimation device 5 described later with reference to FIGS. The desired signal is extracted by removing the leakage signal from the interference signal based on the above. The mobile communication network base station apparatus B processes the desired signal extracted by the leakage signal removal unit 4.

(Embodiment 1)
The configuration of the satellite broadcast signal quality estimation apparatus according to the first embodiment is shown in FIG. The satellite broadcast signal quality estimation device 5 includes an intermediate frequency signal acquisition unit 51, a signal probability density distribution calculation unit 52 with noise, a signal probability density distribution storage unit 53 without noise, and a signal-to-noise ratio estimation unit 6. The signal-to-noise ratio estimation unit 6 includes a noise probability density distribution storage unit 54, a first pseudo noise signal probability density distribution calculation unit 55, a noise probability density distribution selection unit 56, and a second pseudo noise signal probability density distribution calculation. Section 57, noise parameter selection section 58, and signal-to-noise ratio determination section 59.

  The intermediate frequency signal acquisition unit 51 acquires an intermediate frequency signal having a signal band that can be interfered with the communication band of the mobile communication network M, generated by down-converting the satellite broadcast signal. Here, the intermediate frequency signal acquisition unit 51 can buffer the intermediate frequency signal until an arbitrary read timing of the noisy signal probability density distribution calculation unit 52. The intermediate frequency signal is, for example, a reference signal having a known probability density distribution of signal characteristics when noise is not included. The signal characteristics include, for example, PAPR (Peak to Average Power Ratio), phase and delay.

  The signal probability density distribution calculation unit with noise 52 calculates the probability density distribution of the signal characteristics for the intermediate frequency signal including the noise acquired by the intermediate frequency signal acquisition unit 51. Here, the noisy signal probability density distribution calculation unit 52 can read the intermediate frequency signal at an arbitrary read timing using the buffering of the intermediate frequency signal acquisition unit 51.

  The noise-free signal probability density distribution storage unit 53 stores information on the probability density distribution of signal characteristics for intermediate frequency signals that do not contain noise.

  The signal-to-noise ratio estimator 6 calculates the probability density distribution of the signal characteristics for the intermediate frequency signal including noise and the signal probability density distribution storage unit 53 without noise calculated by the signal probability density distribution calculator 52 with noise. Is compared with the probability density distribution of the signal characteristics for the intermediate frequency signal that does not include noise, and the signal-to-noise for the intermediate frequency signal that includes the noise acquired by the intermediate frequency signal acquisition unit 51 Estimate the ratio.

  The noise probability density distribution storage unit 54 stores information on probability density distributions of a plurality of types of noise characteristics for noise included in the intermediate frequency signal acquired by the intermediate frequency signal acquisition unit 51. Here, the probability density distributions of a plurality of types of noise characteristics are, for example, a normal distribution, an exponential distribution, a power distribution, and the like, and the parameters of each distribution are variable.

  The first pseudo-noise-probable signal probability density distribution calculation unit 55 stores the information in the no-noise signal probability density distribution storage unit 53, and the probability density distribution of the signal characteristics for the intermediate frequency signal not including noise, The intermediate frequency signal acquisition unit 51 acquires the noise probability density distribution storage unit 54 by combining the probability density distributions of a plurality of types of noise characteristics with respect to the noise included in the intermediate frequency signal, in which information is stored. A probability density distribution of a plurality of types of pseudo signal characteristics is calculated for an intermediate frequency signal including noise.

  The noise probability density distribution selection unit 56 calculates the probability density distribution of the signal characteristics for the intermediate frequency signal including noise and the first signal probability density distribution calculation with pseudo noise calculated by the signal probability density distribution calculation unit 52 with noise. The noise probability density distribution storage unit 54 stores information by comparing the probability density distributions of a plurality of types of pseudo signal characteristics for the intermediate frequency signal including noise calculated by the unit 55. Among a plurality of types of probability density distributions of noise characteristics for noise included in the intermediate frequency signal, a probability density distribution of noise characteristics suitable for the intermediate frequency signal including the noise acquired by the intermediate frequency signal acquisition unit 51 is selected. .

  The noise probability density distribution selection method of the first embodiment is shown in FIG. Regarding the noise probability density distribution, the first candidate, the second candidate,... Will be described, but the first and second candidates will be described. Here, PAPR is adopted as the signal characteristic. Then, as the probability density, CCDF (Complementary Cumulative Distribution Function) is adopted. That is, the probability that the PAPR is greater than a certain value is the CCDF at that value.

  The first pseudo noise-probable signal probability density distribution calculation unit 55 combines the first candidate's noise probability density distribution with the parameter fixed to a certain value and the no-noise signal probability density distribution to match the first candidate's first noise probability density distribution. 1 Calculate signal probability density distribution with pseudo noise. The noise probability density distribution selection unit 56 compares the first candidate signal probability density distribution with pseudo noise with the actual signal probability density distribution with noise calculated by the signal probability density distribution calculation unit 52 with noise.

  The first pseudo noise-probable signal probability density distribution calculation unit 55 combines the second candidate's noise probability density distribution with the parameter fixed to a certain value and the no-noise signal probability density distribution to match the second candidate's noise probability density distribution. 1 Calculate signal probability density distribution with pseudo noise. The noise probability density distribution selection unit 56 compares the first candidate signal probability density distribution with pseudo noise with the actual signal probability density distribution with noise calculated by the signal probability density distribution calculation unit 52 with noise.

  The noise probability density distribution selection unit 56 selects, from the first and second candidate noise probability density distributions, the first candidate noise probability density distribution that matches the actual signal probability density distribution with noise.

  The second pseudo noise-probable signal probability density distribution calculation unit 57 stores the information in the no-noise signal probability density distribution storage unit 53, and the probability density distribution of the signal characteristics for the intermediate frequency signal not including noise, By combining the probability density distribution of the noise characteristics suitable for the intermediate frequency signal including the noise selected by the noise probability density distribution selection section 56 while changing the parameters of the probability density distribution of the noise characteristics, the intermediate frequency signal acquisition section A probability density distribution of a plurality of types of pseudo signal characteristics is calculated for the intermediate frequency signal including noise acquired by 51.

  The noise parameter selection unit 58 calculates the probability density distribution of the signal characteristics for the intermediate frequency signal including noise and the second signal probability density distribution calculation unit 57 with pseudo noise calculated by the signal probability density distribution calculation unit 52 with noise. The second pseudo-noise-provided signal probability density distribution calculation unit 57 changes the noise calculated by comparing the probability density distributions of a plurality of types of pseudo-signal characteristics with respect to the intermediate frequency signal including noise. Among the parameters of the probability density distribution of the characteristic, the parameter of the probability density distribution of the noise characteristic that matches the intermediate frequency signal including the noise acquired by the intermediate frequency signal acquisition unit 51 is selected.

  The noise parameter selection method of Embodiment 1 is shown in FIG. Regarding the noise parameter, the first candidate, the second candidate,... Will be described, but the first and second candidates will be described.

  The second pseudo noise noisy signal probability density distribution calculation unit 57 combines the suitable noise probability density distribution with the parameters fixed to the first candidate and the no-noise signal probability density distribution to match the second candidate second probability density distribution. Calculate signal probability density distribution with pseudo noise. The noise parameter selection unit 58 compares the second candidate signal probability density distribution with pseudo noise with the actual signal probability density distribution with noise calculated by the signal probability density distribution calculation unit 52 with noise.

  The second pseudo noise-probable signal probability density distribution calculation unit 57 combines the suitable noise probability density distribution with the parameters fixed to the second candidate and the no-noise signal probability density distribution to match the second candidate second probability density distribution. Calculate signal probability density distribution with pseudo noise. The noise parameter selection unit 58 compares the second candidate signal probability density distribution with pseudo noise with the actual signal probability density distribution with noise calculated by the signal probability density distribution calculation unit 52 with noise.

  The noise parameter selection unit 58 selects the first candidate noise parameter that matches the actual signal probability density distribution with noise from the first and second candidate noise parameters.

  The signal-to-noise ratio determination unit 59 is based on the noise characteristic probability density distribution selected by the noise probability density distribution selection unit 56 and the noise characteristic probability density distribution parameter selected by the noise parameter selection unit 58. The signal-to-noise ratio for the intermediate frequency signal including the noise acquired by the frequency signal acquisition unit 51 is determined.

  The leakage signal removal unit 4 removes the leakage signal from the interference signal based on the signal correlation calculated by the signal correlation calculation unit 3 and the signal-to-noise ratio determined by the signal-to-noise ratio determination unit 59 to obtain a desired signal To extract. Here, the leakage signal removal unit 4 is a FIR (Finite Impulse Response) filter or an IIR (Infinite Impulse Response) filter, and based on the signal correlation between the interference signal and the intermediate frequency signal and the signal-to-noise ratio of the intermediate frequency signal, Set the cancellation parameter for each tap.

(Embodiment 2)
The configuration of the satellite broadcast signal quality estimation apparatus of Embodiment 2 is shown in FIG. The satellite broadcast signal quality estimation device 5 includes an intermediate frequency signal acquisition unit 51, a signal probability density distribution calculation unit 52 with noise, a signal probability density distribution storage unit 53 without noise, and a signal-to-noise ratio estimation unit 7. The signal-to-noise ratio estimation unit 7 includes a noise probability density distribution storage unit 60, a signal probability density distribution calculation unit 61 with pseudo noise, a noise parameter selection unit 62, a noise probability density distribution selection unit 63, and a signal to noise ratio determination unit 64. Consists of Below, the difference part of Embodiment 1, 2 is demonstrated.

  The signal-to-noise ratio estimator 7 calculates the probability density distribution of the signal characteristics for the intermediate frequency signal including noise and the signal probability density distribution storage unit 53 without noise calculated by the signal probability density distribution calculator 52 with noise. Is compared with the probability density distribution of the signal characteristics for the intermediate frequency signal that does not include noise, and the signal-to-noise for the intermediate frequency signal that includes the noise acquired by the intermediate frequency signal acquisition unit 51 Estimate the ratio.

  The noise probability density distribution storage unit 60 stores information on probability density distributions of a plurality of types of noise characteristics for noise included in the intermediate frequency signal acquired by the intermediate frequency signal acquisition unit 51. Here, the probability density distributions of a plurality of types of noise characteristics are, for example, a normal distribution, an exponential distribution, a power distribution, and the like, and the parameters of each distribution are variable.

  The pseudo-noise signal probability density distribution calculation unit 61 includes a probability density distribution of signal characteristics for an intermediate frequency signal that does not include noise, and the noise probability, for which the signal probability density distribution storage unit 53 without noise stores information. By combining the probability density distribution of each type of noise characteristic with respect to the noise included in the intermediate frequency signal, in which the density distribution storage unit 60 stores information, while changing the parameters of the probability density distribution of the noise characteristic, For an intermediate frequency signal including noise acquired by the intermediate frequency signal acquisition unit 51, each probability density distribution of noise characteristics and a probability density distribution of pseudo signal characteristics based on each parameter thereof are calculated.

  The noise parameter selection unit 62 calculates the probability density distribution of the signal characteristics for the intermediate frequency signal including noise calculated by the signal probability density distribution calculation unit 52 with noise and the signal probability density distribution calculation unit 61 with pseudo noise. The intermediate frequency signal acquisition unit 51 acquires the probability density distribution of the noise characteristics and the probability density distribution of the pseudo signal characteristics based on each parameter for the intermediate frequency signal including noise. The parameter of each probability density distribution having a noise characteristic suitable for the intermediate frequency signal including the generated noise is selected.

  The noise parameter selection method of Embodiment 2 is shown in FIGS. The first candidate, the second candidate,... Are described for the noise probability density distribution and the noise parameter, respectively. Here, PAPR is adopted as the signal characteristic. Then, CCDF is adopted as the probability density. That is, the probability that the PAPR is greater than a certain value is the CCDF at that value.

  The pseudo noise-probable signal probability density distribution calculation unit 61 combines the noise probability density distribution of the first candidate with the parameter fixed to the first candidate and the signal probability density distribution without noise to thereby determine the 1-1 candidate candidate. Calculate signal probability density distribution with pseudo noise. The noise parameter selection unit 62 compares the first-first candidate signal probability density distribution with pseudo noise with the actual signal probability density distribution with noise calculated by the signal probability density distribution calculation unit 52 with noise.

  The pseudo noise-probable signal probability density distribution calculation unit 61 combines the noise probability density distribution of the first candidate with the parameter fixed to the second candidate and the signal probability density distribution of no-noise to obtain the first-second candidate. Calculate signal probability density distribution with pseudo noise. The noise parameter selection unit 62 compares the signal probability density distribution with pseudo noise No. 1-2 and the actual signal probability density distribution with noise calculated by the signal probability density distribution calculation unit 52 with noise.

  The noise parameter selection unit 62 selects the first parameter for the first candidate noise probability density distribution that matches the actual signal probability density distribution with noise among the first and second candidate noise parameters for the first candidate noise probability density distribution. One candidate noise parameter is selected.

  The pseudo noise noisy signal probability density distribution calculation unit 61 combines the second candidate noise probability density distribution with the parameters fixed to the first candidate and the no-noise signal probability density distribution, thereby obtaining the 2-1 candidate no. Calculate signal probability density distribution with pseudo noise. The noise parameter selection unit 62 compares the signal probability density distribution with pseudo noise No. 2-1 with the actual signal probability density distribution with noise calculated by the signal probability density distribution calculation unit 52 with noise.

  The pseudo noise noisy signal probability density distribution calculation unit 61 combines the second candidate noise probability density distribution with the parameters fixed to the second candidate and the no-noise signal probability density distribution to obtain the second candidate no. Calculate signal probability density distribution with pseudo noise. The noise parameter selection unit 62 compares the signal probability density distribution with pseudo noise No. 2-2 and the actual signal probability density distribution with noise calculated by the signal probability density distribution calculation unit 52 with noise.

  The noise parameter selection unit 62 selects the second candidate noise probability density distribution that matches the actual noise probability distribution with noise among the first and second candidate noise parameters for the second candidate noise probability density distribution. One candidate noise parameter is selected.

  The noise probability density distribution selection unit 63 calculates the probability density distribution of the signal characteristics for the intermediate frequency signal including noise calculated by the signal probability density distribution calculation unit 52 with noise and the noise selected by the noise parameter selection unit 62. The noise acquired by the intermediate frequency signal acquisition unit 51 is compared by comparing each probability density distribution of the noise characteristics and the probability density distribution of the pseudo signal characteristics based on the respective adaptation parameters for the included intermediate frequency signal. Select a probability density distribution with noise characteristics suitable for the included intermediate frequency signal.

  The noise probability density distribution selection method of Embodiment 2 is shown in FIG. Regarding the signal probability density distribution with pseudo noise, the 1-1 candidate shown in FIGS. 6 and 7, the 2-1 candidate,... Are described, but the 1-1 candidate shown in FIGS. The 2-1 candidate will be described.

  The noise probability density distribution selection unit 63 includes the pseudo-noisy signal probability density distribution 1-1 of FIG. 6 and the actual signal probability density distribution with noise calculated by the signal probability density distribution calculation unit 52 with noise. And compare. The noise probability density distribution selection unit 63 includes the 2-1 candidate pseudo-noise-provided signal probability density distribution shown in FIG. 7 and the actual noise-probable signal probability density distribution calculated by the noisy signal probability density distribution calculation unit 52. And compare.

  The noise probability density distribution selection unit 63 selects the first candidate noise probability density distribution that matches the actual signal probability density distribution with noise from the first and second candidate noise probability density distributions.

  The signal-to-noise ratio determination unit 64 is based on the parameters of each probability density distribution of the noise characteristics selected by the noise parameter selection unit 62 and the probability density distribution of the noise characteristics selected by the noise probability density distribution selection unit 63. The signal-to-noise ratio for the intermediate frequency signal including the noise acquired by the intermediate frequency signal acquisition unit 51 is determined.

(Summary of the present invention)
As described above, in the present invention, the probability density distribution of signal characteristics (calculated when estimating the signal-to-noise ratio for the intermediate frequency signal) and the noise for the intermediate frequency signal including noise and the noise. By examining the degree of divergence between the probability density distribution of signal characteristics for intermediate frequency signals not included (known before estimating the signal-to-noise ratio for intermediate frequency signals), and the intermediate frequency including noise Estimate the signal-to-noise ratio for the signal.

  Therefore, in the leaky signal canceller apparatus C, when removing the leaked signal from the interference signal and extracting the desired signal, a simple method of reducing the signal-to-noise ratio of the intermediate frequency signal without mounting a satellite broadcast signal demodulator Can be estimated.

  In the leakage signal canceller apparatus C, there is no possibility that the cancellation parameter for removing the leakage signal from the interference signal is different from the actual one. Further, the leakage signal canceller apparatus C can determine whether the intermediate frequency signal is generated as designed after receiving the satellite broadcast signal as designed. Then, in the leakage signal canceller apparatus C, when the leakage signal cannot be removed from the interference signal as designed, it is determined whether the apparatus itself has a problem or whether the satellite broadcast signal cannot be received as designed due to a problem in the installation method. can do.

  In the first embodiment, the actual noise probability distribution with noise is changed while changing the noise parameter for one noise probability density distribution, so that the probability density distribution of noise characteristics and the calculation speed of the parameter can be improved. it can.

  In Embodiment 2, since the actual noise probability distribution with noise is reproduced while changing the noise parameters for a plurality of noise probability density distributions, the probability density distribution of noise characteristics and the calculation accuracy of the parameters can be improved. it can.

  According to the satellite broadcast signal quality estimation device and the leak signal canceller device of the present invention, the desired signal transmitted from the mobile terminal of the mobile communication network and the satellite broadcast signal received by the satellite broadcast signal receiving device are leaked by frequency down-conversion. It can be applied for the purpose of preventing interference between a leaky signal having a signal band capable of interfering with a communication band of a mobile communication network.

S: broadcast satellite M: mobile communication network R1, R2: receiving device U1, U2: mobile terminal C: leakage signal canceller device B: mobile communication network base station device 1: mobile communication receiving unit 2: satellite broadcast receiving unit 3 : Signal correlation calculation unit 4: Leakage signal removal unit 5: Satellite broadcast signal quality estimation device 6: Signal to noise ratio estimation unit 7: Signal to noise ratio estimation unit 51: Intermediate frequency signal acquisition unit 52: Signal probability density distribution with noise Calculation unit 53: No-noise signal probability density distribution storage unit 54: Noise probability density distribution storage unit 55: First pseudo noise present signal probability density distribution calculation unit 56: Noise probability density distribution selection unit 57: Second pseudo noise present Signal probability density distribution calculation unit 58: Noise parameter selection unit 59: Signal-to-noise ratio determination unit 60: Noise probability density distribution storage unit 61: Pseudo noise signal probability density distribution calculation unit 62: Noise parameter Data selecting section 63: noise probability density distribution selector 64: signal-to-noise ratio determining section

Claims (4)

An intermediate frequency signal acquisition unit for acquiring an intermediate frequency signal having a signal band capable of interfering with a communication band of a mobile communication network, generated by down-converting a satellite broadcast signal;
For an intermediate frequency signal including noise acquired by the intermediate frequency signal acquisition unit, a noisy signal probability density distribution calculation unit that calculates a probability density distribution of signal characteristics; and
For an intermediate frequency signal that does not contain noise, a noise-free signal probability density distribution storage unit that stores information on the probability density distribution of signal characteristics;
The probability density distribution of the signal characteristics for the intermediate frequency signal including noise, which is calculated by the signal probability density distribution calculation section with noise, and the noise in which the signal probability density distribution storage section without noise stores information is included. The signal-to-noise ratio estimation for estimating the signal-to-noise ratio for the intermediate frequency signal including the noise acquired by the intermediate frequency signal acquisition unit by comparing the probability density distribution of the signal characteristics for the intermediate frequency signal And
A satellite broadcast signal quality estimation device comprising: The signal-to-noise ratio estimator is
A noise probability density distribution storage unit storing probability density distribution information of a plurality of types of noise characteristics for noise included in the intermediate frequency signal acquired by the intermediate frequency signal acquisition unit;
The noise-free signal probability density distribution storage unit stores information, the probability density distribution of signal characteristics for intermediate frequency signals not including noise, and the noise probability density distribution storage unit stores information, By combining the probability density distributions of a plurality of types of noise characteristics with respect to the noise included in the intermediate frequency signal, a plurality of types of pseudo signals are generated for the intermediate frequency signal including the noise acquired by the intermediate frequency signal acquisition unit. A first pseudo-noisy signal probability density distribution calculation unit for calculating a probability density distribution of a specific signal characteristic;
The probability density distribution of the signal characteristics for the intermediate frequency signal including noise calculated by the signal probability density distribution calculator with noise and the noise calculated by the signal probability density distribution calculator with first pseudo noise are included. By comparing the probability density distributions of a plurality of types of pseudo signal characteristics with respect to the intermediate frequency signal, the noise probability density distribution storage unit stores information about the noise included in the intermediate frequency signal. A noise probability density distribution selection unit that selects a probability density distribution of a noise characteristic suitable for an intermediate frequency signal including noise acquired by the intermediate frequency signal acquisition unit from among a plurality of types of probability density distributions of noise characteristics;
The noise-free signal probability density distribution storage unit stores information, the probability density distribution of signal characteristics for an intermediate frequency signal not including noise, and the noise selected by the noise probability density distribution selection unit are included A plurality of intermediate frequency signals including noise acquired by the intermediate frequency signal acquisition unit by combining the probability density distribution of the noise characteristics suitable for the intermediate frequency signal and changing the parameters of the probability density distribution of the noise characteristics. A second pseudo noise noisy signal probability density distribution calculating unit for calculating the probability density distribution of the types of pseudo signal characteristics;
The probability density distribution of the signal characteristics for the intermediate frequency signal including noise calculated by the signal probability density distribution calculation section with noise and the noise calculated by the second signal probability density distribution calculation section with pseudo noise are included. A probability density distribution parameter of a noise characteristic changed by the second pseudo noise-containing signal probability density distribution calculation unit by comparing the probability density distribution of a plurality of types of pseudo signal characteristics of the intermediate frequency signal Among them, a noise parameter selection unit that selects a parameter of probability density distribution of noise characteristics suitable for an intermediate frequency signal including noise acquired by the intermediate frequency signal acquisition unit,
The noise acquired by the intermediate frequency signal acquisition unit based on the probability density distribution of noise characteristics selected by the noise probability density distribution selection unit and the parameters of probability density distribution of noise characteristics selected by the noise parameter selection unit A signal-to-noise ratio determining unit that determines a signal-to-noise ratio for an intermediate frequency signal including:
The satellite broadcast signal quality estimation apparatus according to claim 1, comprising: The signal-to-noise ratio estimator is
A noise probability density distribution storage unit storing probability density distribution information of a plurality of types of noise characteristics for noise included in the intermediate frequency signal acquired by the intermediate frequency signal acquisition unit;
The noise-free signal probability density distribution storage unit stores information, the probability density distribution of signal characteristics for intermediate frequency signals not including noise, and the noise probability density distribution storage unit stores information, The noise acquired by the intermediate frequency signal acquisition unit is included by combining the probability density distribution of each type of noise characteristic with respect to the noise included in the intermediate frequency signal while changing the parameters of the probability density distribution of the noise characteristic. For the intermediate frequency signal, the probability density distribution of the pseudo noise characteristic based on each probability density distribution of the noise characteristics and the pseudo signal characteristics based on each parameter thereof,
The probability density distribution of the signal characteristics for the intermediate frequency signal including noise calculated by the signal probability density distribution calculator with noise and the intermediate including noise calculated by the signal probability density distribution calculator with pseudo noise An intermediate frequency including noise acquired by the intermediate frequency signal acquisition unit by comparing each probability density distribution of noise characteristics and a probability density distribution of pseudo signal characteristics based on each parameter for frequency signals. A noise parameter selector for selecting parameters of each probability density distribution of noise characteristics suitable for the signal;
The probability density distribution of the signal characteristics for the intermediate frequency signal including noise calculated by the signal probability density distribution calculation unit with noise and the noise for the intermediate frequency signal including noise selected by the noise parameter selection unit. Noise that matches the intermediate frequency signal including the noise acquired by the intermediate frequency signal acquisition unit by comparing each probability density distribution of the characteristics and the probability density distribution of the pseudo signal characteristics based on the respective adaptation parameters A noise probability density distribution selection unit for selecting a probability density distribution of the characteristic;
Based on the parameters of each probability density distribution of the noise characteristics selected by the noise parameter selection unit and the probability density distribution of the noise characteristics selected by the noise probability density distribution selection unit, the intermediate frequency signal acquisition unit acquired A signal-to-noise ratio determining unit that determines a signal-to-noise ratio for an intermediate frequency signal including noise;
The satellite broadcast signal quality estimation apparatus according to claim 1, comprising: The satellite broadcast signal quality estimation device according to any one of claims 1 to 3,
The desired signal transmitted from the mobile terminal of the mobile communication network can interfere with the communication band of the mobile communication network in which the satellite broadcast signal is down-converted and leaked by the receiver of the satellite broadcast signal. A mobile communication receiver that receives an interference signal of a leaky signal having a signal band;
After receiving the satellite broadcast signal, down-converting the frequency, a satellite broadcast receiving unit that generates the intermediate frequency signal having a signal band capable of interfering with the communication band of the mobile communication network;
A signal correlation calculation unit for calculating a signal correlation between the interference signal received by the mobile communication reception unit and the intermediate frequency signal generated by the satellite broadcast reception unit;
The leakage signal is removed from the interference signal based on the signal correlation calculated by the signal correlation calculation unit and the signal-to-noise ratio estimated by the signal-to-noise ratio estimation unit of the satellite broadcast signal quality estimation device. A leakage signal removing unit for extracting the desired signal;
A leakage signal canceller apparatus comprising:

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