JP2017200192A - Detouring transmission line estimation device and detouring canceller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a detouring transmission line estimation device for estimating a detouring transmission line, which not only starts or restarts under the constraints of an existing broadcasting system, and the like but also adapts flexibly to variation in the characteristics with time or due to the environment, thus achieving accurate and stable estimation of a detouring transmission line.SOLUTION: A detouring transmission line estimation device includes control means for shifting carrier frequencies or phases of a transmission wave radiated from a second antenna, under retransmission or relay of an incoming wave from a first antenna, relatively to carrier frequencies or phases of the incoming wave just by a single frequency shift amount or a single phase shift amount, and estimation means for performing transmission line estimation of a path as the resolution of a simultaneous equation consisting of a plurality of expressions indicating the total characteristics of a system performing retransmission and a detouring path from the second antenna to the first antenna, and individually reflected with a plurality of different carrier frequencies or a plurality of different phases of a reception wave received by the first antenna.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a sneaking transmission path estimation apparatus that estimates a sneaking transmission path from a second aerial line used for retransmission of an incoming wave that has arrived at a first aerial line to the first aerial line.

  2. Description of the Related Art Conventionally, in a relay device that rebroadcasts an AM radio broadcast wave in a tunnel or the like, for example, as shown in FIG. Band signal), converted into a rebroadcast wave of a desired frequency by the transmitter 43, and retransmitted from the antenna 44.

  Further, in such a conventional relay device, the rebroadcast wave is good in the tunnel by reducing the wraparound from the antenna 44 to the antenna 41 when the frequency is the same as or almost the same as the broadcast wave. In order to make it possible to audition radio broadcasts with a high quality, for example, all or part of the following items (a) to (c) have been attempted manually.

(A) Adjustment of position or attitude of both or one of antennas 41 and 44 (b) Adjustment of overall gain and phase shift amount of receiving unit 42 and transmitting unit 43 (c) Fine frequency of rebroadcast wave Adjustment

  As prior arts related to the present invention, there are Patent Documents 1 and 2 and Non-Patent Document 1 listed below.

(1) “Reception antenna, replica signal generated by multiplying cancellation signal by cancellation parameter, and reception signal are combined in at least one of radio frequency band, intermediate frequency band and baseband, and the combined signal A carrier combining unit that obtains and outputs a baseband combined signal; a transmitting unit that generates a transmission signal and the cancellation signal using a data signal obtained by demodulating the baseband combined signal; and The baseband composite signal and the cancellation signal so as to reduce the power of the transmission antenna unit for transmitting the transmission signal, the signal of the product of the cancellation parameter and the cancellation signal, and the difference signal of the reception signal And the step coefficient are added to the previous cancel parameter, and the cancel parameter updated sequentially. Including a parameter control unit that calculates the calculated cancellation parameter and outputs the calculated cancellation parameter to the carrier synthesizing unit ”, thereby canceling interference without adding disturbance such as superimposition or modulation of a pilot signal to the transmission wave. In addition, the booster device is characterized in that it can perform cancellation control with high accuracy.

(2) “Measure the transmission path characteristics based on the reciprocal of the spectrum of the received OFDM signal in the transmission path characteristics measuring device that measures the transmission path characteristics of the OFDM signal including the subcarrier signal of the predetermined frequency channel multiplexed. Thus, "a transmission line characteristic measuring device characterized in that it can respond more quickly to changes in transmission line characteristics after the start of relay processing".

(3) Providing economical and simple communication services in dead areas in the mobile communication system by using the direct relay system booster system and using different devices depending on the method of providing services in the dead areas and the size of the area The frequency offset booster that is characterized by the point that it is possible.

Japanese Patent No. 2878458 Japanese Patent No. 3713211

NTT Docomo Technical Journal Vol. 5 No. 1 pages 15-18

  By the way, in the above-described conventional example, any of the above-described matters (a) to (c) that are performed manually can not be realized unless a person in charge is on site, and requires a lot of man-hours and costs. There were many cases.

  Furthermore, since these items (a) to (c) must be achieved within the scope of legal restrictions and operator requirements, the work is often complicated.

  The present invention flexibly adapts not only to startup and restart, but also to changes in characteristics according to the environment and aging, under the constraints of existing broadcasting systems, etc., and accurately and stably circulates the transmission path. An object of the present invention is to provide a sneak path estimation apparatus that can realize estimation.

  In the invention according to claim 1, the control means determines the carrier wave frequency or phase of the transmission wave radiated from the second antenna under the retransmission or relay of the arrival wave arriving at the first antenna, as the arrival wave. Is shifted by a single frequency shift amount or a single phase shift amount with respect to the carrier frequency or phase of the signal. The estimating means shows a comprehensive characteristic of the re-transmission system and a wraparound path from the second antenna to the first antenna, and a plurality of received waves received by the first antenna The transmission path of the path is estimated as a solution of a simultaneous equation consisting of a plurality of equations in which different carrier frequencies or a plurality of different phases are individually reflected.

  That is, the transmission path estimation of the path in which the transmission wave radiated from the second antenna wraps around the first antenna is the arrival of arrival at the first antenna within the limit that the deviation of the carrier frequency of the transmission wave is allowed. It is realized with high accuracy without losing compatibility with waves.

  In the invention according to claim 2, the control means transmits the transmission radiated from the second antenna under re-transmission or relay of the first incoming wave that is the incoming wave that has arrived at the first antenna. The carrier frequency of the wave is set to a value fr1 ′ different from the frequency fr1 of the first incoming wave. The estimating means shows a comprehensive characteristic of the re-transmission system and a wraparound path from the second antenna to the first antenna, and together with the first incoming wave, the first antenna As a solution of a simultaneous equation consisting of a plurality of equations in which the frequency fr2 of the first incoming wave and the second incoming wave different from the second incoming wave and the value fr1 ′ are individually reflected, the transmission path estimation of the path I do.

  That is, the transmission path estimation of the path in which the transmission wave radiated from the second antenna wraps around the first antenna is the arrival of arrival at the first antenna within the limit that the deviation of the carrier frequency of the transmission wave is allowed. It is realized with high accuracy without losing compatibility with waves.

  In the invention according to claim 3, the control means sets the carrier frequency of the transmission wave radiated from the second antenna under the retransmission or relay of the arrival wave arriving at the first antenna. A predetermined value Δf is shifted with respect to the wave carrier frequency. The estimation means includes a system in which a plurality of p different values ft1 to ftp obtained by sequentially accumulating the value Δf by the re-transmission or the recursive repetition of the relay are individually reflected, and the second transmission is performed. The transmission path of the path is estimated as a solution of simultaneous equations consisting of a plurality of p expressions indicating the overall characteristics of the wraparound path from the antenna to the first antenna.

  That is, the transmission path estimation of the path in which the transmission wave radiated from the second antenna wraps around the first antenna is the arrival of arrival at the first antenna within the limit that the deviation of the carrier frequency of the transmission wave is allowed. It is realized with high accuracy without losing compatibility with waves.

  In the invention according to claim 4, the control means is configured to transmit the incoming wave to the transmission wave radiated from the second antenna under the retransmission or relay of the incoming wave that has arrived at the first antenna. A phase shift of a predetermined value Δφ with respect to the phase and a modulation based on the number of re-transmissions or recursive repetitions of the relay are performed. The estimation means individually identifies the incoming wave for each number of times, and a plurality of p different values φt1 to φtp sequentially subjected to the phase shift under the repetition are individually reflected, and the retransmission is performed. The transmission path of the path is estimated as a solution of simultaneous equations consisting of a plurality of p expressions indicating the overall characteristics of the system and the wraparound path from the second antenna to the first antenna.

  That is, the transmission path estimation of the path in which the transmission wave radiated from the second antenna wraps around the first antenna is the arrival of arrival at the first antenna within the limit that the deviation of the carrier frequency of the transmission wave is allowed. It is realized with high accuracy without losing compatibility with waves.

  In the invention described in claim 5, the sneak canceller cancels or suppresses the sneak from the second antenna to the first antenna used for retransmission of the incoming wave arriving at the first antenna. The transmission path estimation apparatus according to any one of 1, 2, 3, and 4 and a wraparound cancellation support unit that applies a result of transmission path estimation performed by the transmission path estimation apparatus to the cancellation or suppression. Prepare.

  In the sneak canceller having such a configuration, the transmission path estimation is performed in the sneak canceller that cancels or suppresses the sneak from the second antenna to the first antenna to be used for retransmission of the incoming wave that has arrived at the first antenna. The device is described in any one of claims 1 to 4. The wraparound cancellation support means applies the result of the transmission path estimation performed by the transmission path estimation apparatus to the cancellation or the suppression.

  That is, the wraparound is canceled or suppressed by applying the result of the transmission path estimation obtained by the transmission path estimation apparatus according to any one of claims 1 to 4 to the wraparound path. The

  Therefore, in the transmission system and the wireless transmission system to which the present invention is applied, high transmission quality is achieved at a low cost without a significant change in configuration.

  In a transmission system and a wireless transmission system to which the present invention is applied, high transmission quality is achieved at low cost without a significant change in configuration.

  The transmission system and wireless transmission system to which the present invention is applied can flexibly adapt to various radio frequencies under the restrictions of specifications and performance, and related laws and regulations.

  According to the transmission system and the wireless transmission system to which the present invention is applied, it is possible to flexibly adapt to various restrictions and environments.

  Therefore, according to the present invention, added value and overall reliability can be increased at low cost, and flexible adaptation to various systems is possible.

It is a figure which shows one Embodiment of this invention. It is a flowchart of the main processes performed in this embodiment. It is a figure explaining operation | movement of this embodiment. It is a figure (1/5) which shows the other aspect of the structure of this embodiment. It is a figure (2/5) which shows the other aspect of a structure of this embodiment. It is a figure (3/5) which shows the other aspect of the structure of this embodiment. It is a figure (4/5) which shows the other aspect of a structure of this embodiment. It is a figure (5/5) which shows the other aspect of the structure of this embodiment. It is a figure which shows the structural example of the conventional relay apparatus.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram showing an embodiment of the present invention.
In the figure, components having the same functions and configurations as those shown in FIG. 9 are given the same reference numerals, and descriptions thereof are omitted here. The receiver 42 and the transmitter 43 are not shown in this embodiment.
The difference between the present embodiment and the conventional example shown in FIG. 9 is as follows.

(1) The adder 11 is arranged at the subsequent stage of the receiving unit 42.
(2) The multiplier 12 is arranged in the previous stage of the transmission unit 43.
(3) A transversal filter 13 is arranged between the output of the multiplier 12 and the addend input of the adder 11.

(4) DFT units 14, 15, 16 each having a first input connected to the output of adder 11
(5) The outputs of these DFT units 14, 15, 16 are connected to the first, second and third inputs of the tap coefficient updating unit 17.

(6) The first output of the tap coefficient updating unit 17 is connected to the coefficient input of the transversal filter 13.
(7) The second output of the tap coefficient updating unit 17 is input to the frequency offset control unit 18, and the output of the frequency offset control unit 18 is connected to the multiplier input of the multiplier 12.

FIG. 2 is a flowchart of main processing performed in the present embodiment.
FIG. 3 is a diagram for explaining the operation of the present embodiment.
The operation of this embodiment will be described below with reference to FIGS.

In this specification, for the sake of simplicity, description will be made in an equivalent low-frequency system in which the carrier frequency f ₀ of the transmission wave from the master station (higher station) is “0”. Even in an actual apparatus, the frequency is often converted to treat the carrier frequency as zero. Both the broadcast wave X (f) arriving at the antenna 41 and a sneak wave C (f) Y (f) described later are converted into a signal Z (f) by a frequency converter (not shown) and input to the adder 11. . The adder 11 generates a complex signal W (f) by adding a complex signal calculated and updated by the transversal filter 13 as described later to the signal Z (f). The complex signal W (f) is converted into a retransmitted wave Y (f) by being multiplied by the local signal of the frequency Δf ₂ or (Δf ₂ + k) generated by the frequency offset control unit 18 and the multiplier 12. And retransmitted via the antenna 44.

Such a retransmitted wave Y (f) arrives at the antenna 41, passes through the wraparound transmission path C (f), and wraps around as a wraparound wave C (f) Y (f).
The feature of the present invention is that the DFT units 14, 15, 16, the tap coefficient updating unit 17, the transversal filter 13, the multiplier 12, and the frequency offset control unit 18 cooperate in the present embodiment as will be described later. In the procedure.

[Principle of this embodiment]
Hereinafter, the principle of this embodiment will be described prior to the procedure of such processing.
As shown in FIG. 3A, the line spectrum Z (0) of the carrier component of the signal Z (f) corresponding to the carrier component of the broadcast wave X (f) has a level A and a phase θ _{0 of the} carrier component. On the other hand, it is generally represented by the following formula (1).
Z (0) = A · exp (jθ ₀ ) (1)

The line spectrum at the frequency Δf ₂ of the signal Y (f) in the state where the frequency set by the frequency offset control unit 18 is Δf ₂ (that is, the line spectrum of the carrier component of the retransmission signal) Y (Δf ₂ ) is When the frequency offset Δf ₂ is added in the frequency offset control unit 18, the phase θ ₂ is added at the same time.
Y (Δf ₂ ) = A · exp {j (θ ₀ + θ ₂ )}

Similarly, when the frequency offset (Δf ₂ + k) is added in the frequency offset control unit 18, the phase θ ₂ is added at the same time, so that the line spectrum at the frequency (Δf ₂ + k) of the signal Y (f) (that is, The line spectrum (Y (Δf ₂ + k) of the carrier component of the retransmission signal) is expressed by the following equation.
Y (Δf ₂ + k) = A · exp {j (θ ₀ + θ ₂ )}

However, the phase θ ₂ is matched between the case where the frequency offset Δf ₂ is added and the case where the frequency offset (Δf ₂ + k) is added.

Each of the sneak waves in the state where the frequency set by the frequency offset control unit 18 is (Δf ₂ + k) and Δf _2, and the line spectrum Z (Δf ₂ + k) of the carrier component of the signal Z (f). , Z (Δf ₂ ) is given by the following (2) and (3) with respect to the values listed below, as shown in FIGS. 3 (b) and 3 (c).

A sneak wave from the antenna 44 to the antenna 41 is represented by a retransmitted wave and a sneak path, and in the time domain, ∫y (τ) c (t−τ) dτ
Y (f) · C (f) in the frequency domain
It is represented by

Hereinafter, impulse response value c (t) of the sneak path
c (t) = ρexp (jθ) δ (t−τ)
Will be described. However, ρ, θ, and τ represent the amplitude ratio, phase, and propagation delay time of the wraparound transmission path, respectively.

The frequency characteristic (transfer function) C (f) corresponding to the impulse response c (t) of the wraparound transmission line is obtained by Fourier transforming c (t), and the following expression C (f) = ρexp (jθ) exp (-J2πfτ)
It is represented by

Here, in the state where the sneak wave is not canceled, Y (f) is a signal obtained by adding the frequency offset Δf ₂ in the frequency offset control unit 18 to the reception signal W (f) = Z (f).
Y (f) = Z (f−Δf ₂ ) exp (jθ ₂ )
And
Z (f) = X (f) + C (f) · Y (f)
It is. That is, the frequency (Δf ₂ + k) and the line spectra Z (Δf ₂ + k) and Z (Δf ₂ ) at the frequency Δf ₂ are obtained, respectively.
Z (Δf ₂ + k) = A · exp (jθ ₀ ) · ρexp {j (θ + θ ₂ )} · exp {−j2π (Δf ₂ + k) τ} (2)
Z (Δf ₂ ) = A · exp (jθ ₀ ) · ρexp {j (θ + θ ₂ )} · exp (−j2πΔf ₂ τ) (3)

Therefore, the ratio of both sides of the above formulas (1) and (2) and the ratio of both sides of the above formulas (1) and (3) are expressed by the following formulas (4) and (5), respectively.
Z (Δf ₂ + k) / Z (0) = ρexp {j (θ + θ ₂ )} · exp {−j2π (Δf ₂ + k) τ} (4)
Z (Δf ₂ ) / Z (0) = ρexp {j (θ + θ ₂ )} · exp (−j2π (Δf ₂ ) τ) (5)

  From these equations (4) and (5), the propagation delay time τ of the sneak wave, the amplitude ρ, and the phase θ are calculated.

τ = −1 / (2πk) · tan ⁻¹ [Im {Z (Δf ₂ + k) / Z (Δf ₂ )} / Re {Z (Δf ₂ + k) / Z (Δf ₂ )}] (6 )
ρ = | Z (Δf ₂ ) / Z (0) |
ρ = | Z (Δf ₂ + k) / Z (0) |
The amplitude ρ is calculated by one of the following (hereinafter referred to as “Expression (7)”).
Further, θ + θ ₂ = tan ⁻¹ [Z (Δf ₂ ) / {Z (0) · ρexp (−j2πΔf ₂ τ)}] using the delay time τ already calculated.
θ + θ ₂ = tan ⁻¹ [Z (Δf ₂ + k) / {Z (0) · ρexp (−j2π (Δf ₂ + k) τ)}]
The phase θ is calculated by one of the following (hereinafter referred to as “Expression (8)”).

For amplitude ρ and phase θ,
ρexp {j (θ + θ ₂ )} = Z (Δf ₂ ) / {Z (0) exp (−j2πΔf ₂ τ)}
ρexp {j (θ + θ ₂ )} = Z (Δf ₂ + k) / {Z (0) exp (−j2π (Δf ₂ + k) τ)}
May be calculated as a complex value including the amplitude and phase (hereinafter referred to as “Expression (9)”).

Here, θ ₂ is added when calculating the phase θ of the sneak wave, but since θ ₂ is known, θ is obtained by subtracting θ ₂ from Equation (8), and Equation (9) ) Is multiplied by exp (−jθ ₂ ) corresponding to θ ₂ to obtain a complex value ρ exp (jθ) including the amplitude ρ and phase θ of the sneak wave.

[Linkage of each part in this embodiment]
The frequency offset control unit 18 gives the above-described frequency (Δf ₂ + k) and Δf ₂ sequentially at predetermined intervals in time series. However, the order of the frequencies (Δf ₂ + k) and Δf ₂ may be reversed.

  The multiplier 12 generates a frequency of the complex signal W (f) over such a local oscillator signal (or a signal such as a numerically controlled oscillator (NCO) or a direct digital synthesizer (DDS)). Shift.

On the other hand, the DFT units 14, 15, and 16 add the complex signal W (f) (the broadcast wave X (f) and the sneak component C (f) · Y (f) of the retransmitted wave Y (f). After the sneak cancel operation is started, a sneak cancel wave is also added.) By performing a discrete Fourier transform, the complex corresponding to each of the frequencies (Δf ₂ + k), Δf ₂ , and 0 is obtained. The line spectrum of the carrier component of the signal W (f) is obtained.

  The tap coefficient updating unit 17 calculates the propagation delay time τ of the sneak wave that wraps around from the antenna 44 to the antenna 41 by performing the arithmetic operation shown in the above equation (6) based on these line spectra (FIG. 2). Step S1).

The tap coefficient updating unit 17 performs the arithmetic operation shown in the above equations (7) and (8) on the basis of these line spectra, so that the frequency offset Δf ₂ and the frequency offset (Δf ₂ + k), the amplitude ρ and the phase θ of the sneak wave are obtained (step S2 in FIG. 2).

  The tap coefficient updating unit 17 obtains a tap coefficient corresponding to the impulse response indicating the propagation delay time τ, the amplitude ρ, and the phase θ obtained in this way (step S3 in FIG. 2).

In the tap coefficient updating unit, the delay time τ of the sneak wave calculated by the equations (7) and (8) (or the equation (9) equivalent to the equations (7) and (8)), and the amplitude ratio ρ, And an impulse response r (t) indicating the phase θ (strictly, the cancellation residual after canceling the sneak wave after the second update) (the first update (first) is r (τ) = ρexp ( jθ), r (t) = 0.0 (t ≠ τ)), and tap coefficients corresponding to the respective delay times t are, for example,
h (t) = h (t) −μ · r (t) (10)
The tap coefficient is updated by an adaptive updating formula such as Here, μ is an update coefficient that satisfies 0 <μ ≦ 1.0. However, when updating the tap coefficient according to the equation (10), W (f) = Z (f) is not satisfied after the start of the sneak wave cancellation. Therefore, in the equations (7) and (8), Z (f ) To calculate using W (f).

  The transversal filter 13 performs a filtering process based on the tap coefficient on the retransmitted wave Y (f) given to the feeding point of the antenna 44 by the multiplier 12, thereby transmitting the retransmitted wave Y from the antenna 44 to the antenna 41. A feedback signal that enables suppression (cancellation) of the wraparound (f) is given to the adder 11.

  Therefore, a pilot signal or the like that is not inherently included in the broadcast wave X (f) is not superimposed on the retransmitted wave Y (f), and further, hardware associated with the superimposition of the pilot signal is provided. Instead, the wraparound from the antenna 44 to the antenna 41 is suppressed.

In the present embodiment, the frequency (Δf ₂ + k) and Δf ₂ set by the frequency offset control unit 18 are switched only once at a predetermined interval at the time of starting, but both deviations are within the limits of the law. Maintained.

  However, the present invention is not limited to such a configuration. For example, the frequency may be set to three or more values as long as all of the requirements listed below are satisfied.

(1) At least one frequency offset (hereinafter referred to as “specific frequency”) is applied in the steady operating state of the present embodiment.

(2) The frequency deviation between the retransmitted wave Y (f) retransmitted from the antenna 44 in accordance with such a specific frequency and the broadcast wave X (f) described above is within the limits of the above law. To within the limits allowed.

(3) The level of all or part of the retransmitted wave Y (f) retransmitted from the antenna 44 in response to a frequency other than the specific frequency is set to a value that allows transmission within the limits of the law. The difference between such a value and the level is given in advance as a known value.

(4) The above-described delay time τ, amplitude ρ, and phase θ are calculated as solutions of a set of simultaneous equations composed of at least two of the equations individually corresponding to the above three or more signals. Or calculated by a plurality of sets of simultaneous equations.

In the present embodiment, the frequency of the retransmitted wave Y (f) is set to a predetermined value at the time of start-up by the frequency offset control unit 18 setting the above-described frequencies to (Δf ₂ + k) and Δf ₂ , respectively. It can be switched only once at intervals.

However, the present invention is not limited to such a configuration. For example, any frequency of a retransmitted wave retransmitted from the antenna 44 in accordance with the above-described frequency (Δf ₂ + k) and Δf ₂ is kept within legal limits. In such a case, these frequencies may be alternately set to (Δf ₂ + k) and Δf ₂ at a predetermined period or interval.

Furthermore, in this embodiment, the frequency (Δf ₂ + k) and Δf ₂ are alternately switched and set by the frequency offset control unit 18.
However, the present invention is not limited to such a configuration, and may be configured as follows, for example.
(1) The frequency set by the frequency offset control unit 18 is fixed only to a constant Δf ₂ .
(2) The term k included in the simultaneous equations (4) and (5) is expressed as Δf ₂ generated by recursively arriving at the antenna 41 and retransmitted from the antenna 44 or an integer multiple thereof. Given.
(3) By applying such a term k to the simultaneous equations (4) and (5), the function and effect of the present embodiment are similarly achieved.

  In the present embodiment, the present invention is applied to a wraparound canceller that is adapted to an existing AM broadcasting system in the medium wave band and is used to rebroadcast a broadcast wave in a tunnel.

  However, the present invention is not limited to such a configuration, and it is required to suppress or reduce the sneak in the retransmitted wave Y (f), and the occupied band includes a line spectrum indicating a single carrier component. Any transmission system or wireless transmission system can be applied regardless of the frequency band and modulation method.

  Further, as shown in a block diagram in FIG. 1, the main part of the present embodiment can be configured by dedicated hardware such as an FPGA that performs the signal processing described above in the digital domain, or a general-purpose digital signal processor.

  However, the present invention is not limited to such a configuration, and if predetermined performance, accuracy, and responsiveness are ensured, any part of the signal processing can be replaced with an analog circuit that performs equivalent processing.

  In the present embodiment, the simultaneous equations (4) and (5) are expressed by the ratio of both sides of the above equations (1) and (2) and the ratio of both sides of the above equations (1) and (3). Is given by being taken.

  However, the present invention is not limited to such a configuration. For example, by changing the phase in a plurality of ways instead of the frequency of the retransmitted wave Y (f), the simultaneous equations (4) and (5) When an alternative simultaneous equation is given, the solution of the simultaneous equation may be obtained based on any numerical calculation method or algorithm.

The configuration in which the phase is changed in plural ways instead of the frequency is as follows: “In the process in which the sneak wave recursively arrives at the antenna 41 and is retransmitted from the antenna 44, the antenna 41 The phase shift amount Φ in the section from the feed point to the feed point of the antenna 44 via the adder 11 and the multiplier 12 is reflected in the phase of each retransmitted wave. May be.
(1) The phase shift amount Φ is set to a constant value.
(2) In the above-mentioned “simultaneous equations in place of the simultaneous equations (4) and (5)”, the “variable phase” means that the two values of the phase θ ₂ are the phase shift amounts Φ or It is given as an integer multiple.
(3) In order to ensure the presence of such simultaneous equations, the retransmitted wave that is recursively transmitted has a “superimposition of information that makes it possible to identify the number of recursive transmissions, or modulation by that information. Is given.

Moreover, this embodiment is not limited to the above-mentioned structure, For example, you may be comprised by either of the aspect (a)-(d) listed below.
(A) As shown in FIG. 4, the DFT unit 16 has its input connected to the output of the multiplier 12, and obtains the aforementioned line spectrum of the frequency Δf ₂ and the frequency (Δf ₂ + k). In such a configuration, the above-described equation (6) for calculating the propagation delay time τ is replaced by the following equation.
τ = −1 / (2πk) · tan ⁻¹ [Im [{W (Δf ₂ + k) Y (Δf ₂ )} / {Y (Δf ₂ + k) W (Δf ₂ )}] / Re [{W (Δf ₂ + k) Y (Δf ₂ )} / {Y (Δf ₂ + k) W (Δf ₂ )}]]

Expression (7) described above for calculating the amplitude ρ is replaced by the following expression.
ρ = | W (Δf ₂ ) / Y (Δf ₂ ) |
ρ = | W (Δf ₂ + k) / Y (Δf ₂ + k) |
Further, the above-described equation (8) for calculating the phase θ is replaced by the following equation.

θ = tan ⁻¹ [Im [W (Δf ₂ ) / {Y (Δf ₂ ) · ρexp (−j2πΔf ₂ τ)}] / Re [W (Δf ₂ ) / {Y (Δf ₂ ) · ρexp (−j2πΔf ₂ τ)}]]
θ = tan ⁻¹ [Im [W (Δf ₂ + k) / {Y (Δf ₂ + k) · ρexp (−j2π (Δf ₂ + k) τ)}] / Re [W (Δf ₂ + k) / {Y (Δf ₂ + k) · ρexp (−j2π (Δf ₂ + k) τ)}]

For amplitude ρ and phase θ,
ρexp (jθ) = W (Δf ₂ ) / {Y (Δf ₂ ) · exp (−j2πΔf ₂ τ)}
ρexp (jθ) = W (Δf ₂ + k) / {Y (Δf ₂ + k) · exp (−j2π (Δf ₂ + k) τ)}
It may be calculated as a complex value including amplitude and phase by either of the above.

(B) As shown in FIG. 5, the DFT units 14, 15, and 16 each take in the signal W (f) described above, and generate line spectra of frequency zero, frequency Δf ₂ , and frequency (Δf ₂ + k), respectively. Ask. In such a configuration, the above-described expression (10) is replaced with the following expression.
h (t) = − r (t)

(C) As shown in FIG. 6, the signal Z (f) described above is input to the inputs of the DFT units 14 and 15, and the line spectra of the frequency Δf ₂ and the frequency (Δf ₂ + k) are obtained, respectively. Further, the input of the DFT unit 16 is connected to the output of the multiplier 12 obtains a line spectrum frequency Delta] f _2. In such a configuration, the above-described expression (10) is replaced with the following expression.
h (t) = − r (t)

(D) As shown in FIG. 7, the DFT units 14, 15, and 16 obtain the frequency zero, the frequency Δf ₂ , and the frequency (Δf ₂ + k) by taking in the signal Z (f), and the tap coefficient updating unit. 17 calculates the delay time of the sneak wave based on these. The DFTs 14A, 15A, and 16A take the complex signal W (f) to obtain the frequency zero, the frequency Δf ₂ , and the frequency (Δf ₂ + k), respectively, and the tap coefficient updating unit 17 calculates the amplitude and phase of the sneak wave based on these And update as appropriate.

Further, the present embodiment may be configured as follows.
(1) As shown in FIG. 8, DFT units 14A, 15A, and 16A are provided instead of the DFT units 14, 15, and 16, respectively, and tap coefficient updating is performed instead of the tap coefficient updating unit 17 and the frequency offset control unit 18. This embodiment differs from the embodiment shown in FIG. 1 in that a section 17A and a frequency offset control section 18A are provided.

(2) The frequency offset control unit 18A continues to provide the above-described frequency Δf ₂ to the multiplier 12, but does not generate the above-described frequency (Δf ₂ + k).
(3) The antenna 41 includes the broadcast wave X (f) and the broadcast wave X (f) together with the wraparound component C (f) · Y (f) of the retransmitted wave Y (f). A broadcast wave X ′ (f ′) of a known frequency f ′ that is different from the frequency f of FIG.

(4) The DFT units 14A, 15A, and 16A regard the value (Δf ₂ + δf) determined with respect to the difference δf (= f′−f) between these frequencies as the frequency (Δf ₂ + k) described above (that is, f ₂ = δf), and by performing a discrete Fourier transform on the complex signal W (f), the carrier component of the complex signal W (f) corresponding to the frequencies (Δf ₂ + k), Δf ₂ , and 0 respectively. Determine the line spectrum.

(5) The tap coefficient updating unit 17A performs the following processing, similarly to the tap coefficient updating unit 17 shown in the embodiment shown in FIG. 1, as listed below.

(5-1) The propagation delay time τ of the sneak wave that wraps around from the antenna 44 to the antenna 41 is calculated by performing the arithmetic operation shown in the above equation (6) based on the above-described line spectrum (step S1 in FIG. 2). ).

(5-2) By performing the arithmetic operations shown in the above equations (7) and (8) based on these line spectra, the above-described frequency offset Δf ₂ and frequency offset (Δf ₂ + k ) To obtain the amplitude ρ and phase θ of the sneak wave (step S2 in FIG. 2).

(5-3) A tap coefficient corresponding to the impulse response indicating the propagation delay time τ, the amplitude ρ, and the phase θ obtained in this way is obtained (step S3 in FIG. 2).

That is, in the configuration shown in FIG. 8, it is obvious that the frequency offset control unit 18A generates only one frequency (= Δf ₂ ) and arrives at the antenna 41 as the above-described frequency (Δf ₂ + k). By applying a value that can be converted based on the frequency f ′ of a certain broadcast wave X ′ (f ′), simultaneous equations can be obtained as in the embodiment shown in FIG.

Therefore, compared with the embodiment shown in FIG. 1, the configuration is simplified without lowering the performance and responsiveness, and the frequency of the retransmitted wave is kept constant.
In the configuration shown in FIG. 8, when the transmission path estimation of the sneak path from the antenna 44 to the antenna 41 should be obtained as four or more unknowns, two or more simultaneous equations that give these unknowns as solutions May be determined based on the known frequency of the broadcast wave.

  Further, the present invention is not limited to the above-described embodiments, and various configurations of the embodiments are possible within the scope of the present invention, and any improvements may be made to all or some of the components.

DESCRIPTION OF SYMBOLS 11 Adder 12 Multiplier 13 Transversal filter 14, 14A, 15, 15A, 16, 16A DFT part 17, 17A Tap coefficient update part 18, 18A Frequency offset control part 41, 44 Antenna 42 Reception part 43 Transmission part

Claims (5)

A single frequency shift of the carrier frequency or phase of the transmitted wave radiated from the second antenna under the retransmission or relay of the incoming wave arriving at the first antenna with respect to the carrier frequency or phase of the incoming wave A control means for shifting by an amount or a single phase shift amount;
A plurality of different carrier frequencies of the received wave received by the first antenna, showing overall characteristics of the re-transmission system and a sneak path from the second antenna to the first antenna Alternatively, a sneak path estimation apparatus comprising: an estimation unit configured to estimate a transmission path of the path as a solution of simultaneous equations including a plurality of expressions in which a plurality of different phases are individually reflected. In the sneak path estimation device according to claim 1,
The control means includes
The carrier frequency of the transmission wave radiated from the second antenna under the re-transmission or relay of the first arrival wave that is the incoming wave that has arrived at the first antenna is the frequency of the first arrival wave. Set to a value fr1 ′ different from fr1,
The estimation means includes
The overall characteristics of the re-transmission system and the wraparound path from the second antenna to the first antenna, and the first antenna that has arrived at the first antenna The transmission path of the path is estimated as a solution of simultaneous equations composed of a plurality of expressions in which the frequency fr2 of the first incoming wave and another second incoming wave and the value fr1 ′ are individually reflected. A sneak path estimation device. In the sneak path estimation device according to claim 1,
The control means includes
The carrier frequency of the transmission wave radiated from the second antenna under the re-transmission or relay of the arrival wave arriving at the first antenna is shifted by a predetermined value Δf with respect to the carrier frequency of the arrival wave. ,
The estimation means includes
A plurality of different values ft1 to ftp in which the value Δf is sequentially accumulated by the re-transmission or the recursive repetition of the relay are individually reflected, and the system that performs the re-transmission, and the second antenna A sneak path estimation apparatus for performing a sneak path estimation of a path as a solution of simultaneous equations consisting of a plurality of p expressions showing overall characteristics with a sneak path leading to a first antenna. In the sneak path estimation device according to claim 1,
The control means includes
A phase shift of a predetermined value Δφ with respect to the phase of the incoming wave to the transmission wave radiated from the second antenna under re-transmission or relay of the incoming wave that has arrived at the first antenna; and Modulation based on the number of retransmissions or recursive iterations of the relay,
The estimation means includes
A system for individually identifying the incoming wave for each number of times, reflecting a plurality of p different values φt1 to φtp individually subjected to the phase shift under the repetition, and performing the retransmission; and A wraparound transmission characterized in that a transmission path of the path is estimated as a solution of simultaneous equations composed of a plurality of p expressions showing a comprehensive characteristic with a wraparound path from a second antenna to the first antenna. Road estimation device. A wraparound canceller that cancels or suppresses wraparound from a second antenna to the first antenna that is used for retransmission of incoming waves that arrive at the first antenna,
The transmission path estimation apparatus according to any one of claims 1, 2, 3, and 4,
A sneak canceller comprising: a sneak cancel support means for applying a result of the transmission path estimation performed by the transmission path estimation device to the cancellation or the suppression.