JP2009182595A - Interference wave canceler - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an interference wave canceler which follows high-speed phase variation and also follows amplitude variation even when amplitude variation is large. <P>SOLUTION: The phase variation and level variation of the interference wave are detected from an adaptive filter coefficient and a cancellation error in a polar coordinate system, and an estimated variation amount is selected or synthesized from rectangular coordinate system calculation results or polar coordinate system calculation results to thereby follow the high-speed phase variation and also follow the amplitude variation even when the amplitude variation is large. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a relay device, and more particularly to an interference wave canceller that removes an interference wave signal using an adaptive filter.

  Conventionally, in a multipath or SFN (Single Frequency Network) relay system, an interference wave signal canceller using an adaptive filter is generally used as a measure for removing an interference wave signal such as a sneak wave from a received signal. . Such an interference wave signal canceller eliminates the influence of the interference wave signal by generating a signal having the same characteristics as the interference wave by an adaptive filter and subtracting it from the received signal in which the desired wave signal and the interference wave signal are mixed. (See Patent Document 1).

  However, the received signal may fluctuate due to fading, and the interference wave signal canceller must follow such fluctuation.

Japanese Patent Laid-Open No. 2002-152065

In order to follow the above-described fluctuation, the filter coefficient is updated at certain intervals. However, since this update interval depends on the calculation time until the filter coefficient is calculated, it is difficult to update every symbol.
As the above countermeasure, optimization is performed by estimating the value at the time of the next filter coefficient update from the past value with respect to the filter coefficient of the orthogonal coordinate system.
However, especially for high-speed phase fluctuations, the tracking accuracy can be improved by detecting the amplitude and phase fluctuation amounts in the polar coordinate system and performing the detected method, rather than the orthogonal coordinate system. However, when the amplitude fluctuation is severe, there is a high possibility that the estimation of the fluctuation amount of the amplitude and the phase is erroneous. In such a case, the tracking accuracy may be improved by estimating the fluctuation amount in the orthogonal coordinate system.
An object of the present invention is to provide an interference wave canceller that follows high-speed phase fluctuations and follows even when amplitude fluctuations are severe, in order to solve the above problems.

  In order to achieve the above object, the interference wave canceller of the present invention detects the phase variation and level variation of the interference wave in the polar coordinate system from the coefficient and cancellation error of the adaptive filter, and calculates the estimated variation amount as a result of calculating the orthogonal coordinate system. Or it is what was selected or synthesize | combined from the polar coordinate system calculation result.

  That is, an interference wave canceller of the present invention cancels an interference wave signal from a received signal, and retransmits the canceled output signal. In the interference wave canceller, the adaptive filter that removes the interference wave signal from the received signal; Means for calculating a filter coefficient for the adaptive filter to generate a signal having the same characteristics as the interference wave signal; cancellation error means for calculating a cancellation error from the output signal; the filter coefficient calculation means; and the cancellation error calculation means. Fluctuation detection means for detecting fluctuations of the interference wave signal from the detection means, the fluctuation detection means is a detection means based on a polar coordinate system, a detection means based on an orthogonal coordinate system, and an interference wave signal obtained from the detection means based on the orthogonal coordinate system From the estimated fluctuation amount of the interference wave signal obtained from the detection means based on the polar coordinate system. And it has a means for switching or synthesizing results of results or the orthogonal coordinate system fluctuation detecting means according to the polar coordinate system variation detecting means a value to be used as the estimated variation amount of the signal.

  According to the present invention, high-accuracy tracking can be provided by improving resistance to high-speed fluctuation, particularly phase fluctuation. Also, in a fluctuation environment where a favorable fluctuation amount cannot be estimated in the polar coordinate system, the fluctuation amount estimation is switched to the orthogonal coordinate system, or the estimated fluctuation amount estimated in the orthogonal coordinate system and the estimated fluctuation amount estimated in the polar coordinate system are By synthesizing, a stable interference wave removing device (interference wave canceller) can be provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In each drawing, components having common functions are denoted by the same reference numerals, and description thereof is omitted to avoid duplication as much as possible. An embodiment of the present invention may be described with reference to the drawings.

A first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram illustrating a configuration of an interference wave removing unit of an OFDM (Orthogonal Frequency Division Multiplexing) signal relay transmission apparatus according to an embodiment of the present invention. 100 is an interference wave removing unit, 11 is a subtractor, 12 is an error calculating unit, 13 is a filter coefficient updating unit, 14 is an update interval delay memory, 15 is a polar coordinate system variation detector, 16 is an orthogonal coordinate system detector, and 17 is The fluctuation estimation coordinate system selection unit 18 is an adaptive filter.
In FIG. 1, in each element constituting the interference wave removal unit 100, coefficient values and mathematical expressions initialized with predetermined values are registered.

In FIG. 1, a subtractor 11 subtracts the signal u output from the adaptive filter 18 as a replica signal of the interference wave from the input signal x, outputs the signal y to the error calculator 12 and the adaptive filter 18 as a signal y, and the interference wave Output as an output signal of the removal unit 100.
The error calculation unit 12 calculates an ideal value yp from the output signal y obtained from the subtractor 11, calculates an error e between the ideal value yp and the output signal y, and a signal obtained by multiplying the error e by a weighting coefficient μ. (Error signal) {μ · e (n)} is output to the filter coefficient updating unit 13, the polar coordinate system variation detector 15, and the orthogonal coordinate system variation detector 16. Here, μ is an update weighting coefficient and takes a value of 0 <μ ≦ 1. N is the symbol number of the input signal.
The filter coefficient updating unit 13 uses the error signal {μ · e (n)} input from the error calculation unit 12 and the estimated fluctuation amount {μ ₁ · L} input from the fluctuation estimation coordinate system selection unit 17. w (n) is updated, and the updated coefficient w (n) is output to the adaptive filter 18 and the update interval delay memory 14. The update of the coefficient w (n) is calculated from the equation (1) when, for example, the coefficient update interval symbol number is D and the coefficient before the update once is w (n−D).

なお、推定変動量｛μ_１・Ｌ｝については後述する。

The estimated fluctuation amount {μ ₁ · L} will be described later.

  The update interval delay memory 14 delays the number of symbols D required for updating the interference wave removing unit 100 with respect to the manually-manufactured coefficient w (n), and sends the delayed signal {w (n−D)} to the polar coordinate system. Output to the fluctuation detector 15 and the Cartesian coordinate system fluctuation detector 16.

The polar coordinate system fluctuation detector 15 includes two input signals {w (n−D)} and {μ · e (n)}, and the input signal {w (n−D)} inside the polar coordinate system fluctuation detector 15. And a signal obtained by delaying the input signal {μ · e (n)} by the update interval (number of symbols D), respectively, a fluctuation difference Lp and a fluctuation determination signal Sw by the polar coordinate system are calculated, and the calculated fluctuation difference Lp And the variation determination signal Sw are output to the variational coordinate system selection unit 17.
Specifically, the update coefficient w (n) currently scheduled (see formula (2)), the update coefficient w (n−D) scheduled at the previous update (see formula (3)), and The variation amount L can be obtained by obtaining the difference between the two (see equation (4)).

From equation (4), the fluctuation amount L can be obtained as the sum of the difference value of the coefficient and the difference value of the error.
The adaptive filter 18 in FIG. 1 calculates an interference wave replica signal u using the output signal y of the interference wave removing unit 100 and the coefficient w obtained from the filter coefficient updating unit 13, and outputs the signal to the subtractor 11. It is. Such an adaptive filter 18 is composed of, for example, a FIR (Finite Impulse Response) filter.

The polar coordinate system fluctuation detector 15 will be described in more detail with reference to FIG.
FIG. 2 is a block diagram showing a configuration of one embodiment of the polar coordinate system fluctuation detector 15 of FIG. 21 is a polar coordinate converter, 22 and 24 are update interval delay memories, 23-r, 23-θ, 25-r, and 25-θ are subtractors, 26-r and 26-θ are adders, and 27 is a fluctuation amount. A detector 28 is an orthogonal coordinate converter.

In FIG. 2, a polar coordinate converter 21 performs polar coordinate conversion on an input signal in an orthogonal coordinate system (for example, input signal f (x, y) → output signal f (r, θ)).
First, the polar coordinate converter 21 converts the coefficient {w (n−D)} input from the update interval delay memory 14 into polar coordinates, and converts the amplitude signal {w _r (n−D)} into the update interval delay memory 22. Are output to the subtracter 23-r, and the phase signal { _wθ (n−D)} is output to the update interval delay memory 22 and the subtractor 23-θ.
Similarly, the polar coordinate converter 21 performs polar coordinate conversion of the error signal {μ · e (n)} input from the error calculation unit 12, and converts the amplitude signal e _r (n) into the update interval delay memory 24 and the subtractor. The phase signal e _θ (n) is output to the update interval delay memory 24 and the subtractor 25-θ.

The update interval delay memory 22 delays the amplitude signal {w _r (n−D)} input from the polar coordinate converter 21 by the number of symbols required for the update of the interference wave removing unit 100 (D), and the delayed amplitude. The signal {w _r (n−2D)} is output to the subtractor 23-r. Similarly, the input phase signal { _wθ (n−D)} is delayed, and the delayed phase signal { _wθ (n−2D)} is output to the subtractor 23-θ. The update interval delay memory 22 is used to calculate the difference between coefficients at the time of update.
The subtracter 23-r subtracts {w _r (n−D)} input to the subtracted input terminal by the amplitude signal {w _r (n−2D)} manually input from the subtraction input terminal. △ to output a _{w r} to the adder 26-r. The subtractor 23-θ subtracts {w _θ (n−D)} input to the subtracted input terminal by the phase signal {w _θ (n−2D)} input from the subtraction input terminal. and it outputs a difference signal _△ w θ to the adder 26-θ.

Further, the update interval delay memory 24 delays the signal _er (n) of the error signal amplitude manually applied from the polar coordinate converter 21 by the number of symbols required for the update of the interference wave removing unit 100 (D). The amplitude signal { _er (nD)} is output to the subtractor 25-r. Similarly, the manually phased signal {e _θ (n)} is delayed and the delayed phase signal {e _θ (n−D)} is output to the subtractor 25-θ.
The update interval delay memory 24 is used to calculate a difference in interference wave removal error at the time of update.
The subtractor 25-r subtracts the difference signal Δe _r obtained by subtracting the _er (n) input to the subtracted input terminal by the amplitude signal { _er (n−D)} input from the subtraction input terminal. The data is output to the adder 26r. Further, the subtracter 25-θ subtracts e _θ (n) manually input to the subtracted human power terminal by the phase signal {e _θ (n−D)} input from the subtraction input terminal. _θ is output to the adder 26-θ.

The adder 26-r outputs a signal L _r taking the sum of the input difference signal △ w _r and △ e _r to change detector 27 and the orthogonal coordinate detector 28. This signal L _r is an amplitude component signal of the polar coordinate system fluctuation estimation signal.
The adder 26-theta outputs a signal L _theta took the sum of the difference signal △ w _theta and △ e _theta which is human power to change detector 27 and the orthogonal coordinate converter 28. This signal _Lθ is a phase component signal of the polar coordinate system fluctuation estimation signal.
The fluctuation detector 27 detects a fluctuation state from the polar coordinate system fluctuation estimation signals L _r and L _θ and outputs a determination signal Sw to the fluctuation estimation coordinate system selection unit 17 as to whether or not to adopt fluctuation estimation in the polar coordinate system. The determination signal Sw is expressed as, for example, Expression (5).

ここで、Ｔｈは予め定められたしきい値である。
Ｓｗ＝１であれば、極座標系で算出した変動結果を選択する。

Here, Th is a predetermined threshold value.
If Sw = 1, the variation result calculated in the polar coordinate system is selected.

The orthogonal coordinate converter 28 performs orthogonal coordinate conversion on the input signals L _r and L _θ (for example, input signal f (r, θ) → output signal f (x, y)).
Then, the signal Lp converted into the orthogonal coordinate system signal is output to the fluctuation estimation coordinate system selection unit 17.

  Next, the orthogonal coordinate system fluctuation detector 16 of FIG. 1 will be described in more detail with reference to FIG. FIG. 3 is a block diagram showing a configuration of an embodiment of the orthogonal coordinate system fluctuation detector 16 of FIG. 31 and 33 are update interval delay memories, 32 and 34 are subtractors, and 35 is an adder.

In FIG. 1 or FIG. 3, the orthogonal coordinate system variation detector 16 includes an error signal {μ · e (n)} input from the error calculation unit 12 and a coefficient w (n−) input from the update interval delay memory 14. From (D), a difference signal Lp is calculated from a signal obtained by delaying the update interval for each signal generated internally in the orthogonal coordinate system, and is output to the fluctuation estimation coordinate system selection unit 17.
In FIG. 3, the coefficient w (n−D) input from the update interval delay memory 14 is input to the update interval memory 31 and the subtracter 32. Further, the error signal {μ · e (n)} manually input from the error calculation unit 12 is input to the update interval memory 33 and the subtractor 34.

The update interval delay memory 31 delays the input coefficient w (n−D) by the number of symbols (D) required for updating the interference wave removing unit 100 and subtracts the delayed coefficient w (n−2D). Output to the device 32.
The subtracter 32 subtracts the coefficient w (n−D) input to the subtracted input terminal by the delayed coefficient w (n−2D) input from the subtraction input terminal, and adds the difference signal Δw ₀ . Output to the device 35.
Similarly, the update interval delay memory 33 delays the error signal {μ · e (n)}, which is manually input, by the number of symbols (D) required for the update of the interference wave removal unit 100, and delays the error signal. {Μ · e (n−D)} is output to the subtractor 34.
The subtracter 34 subtracts the error signal {μ · e (n)} input to the subtracted input terminal by the delayed error signal {μ · e (n−D)} input from the subtraction input terminal. The difference signal Δe ₀ is output to the adder 35.
The adder 35 calculates the sum of two difference signals inputted △ w ₀ and △ e _0, and outputs a signal L ₀ obtained by adding the condition estimation coordinate system selecting section 17.

Next, the variation estimation coordinate system selection unit 17 in FIG. 1 will be described in more detail with reference to FIG. FIG. 4 is a block diagram showing a configuration of an embodiment of the fluctuation estimation coordinate system selection unit 17 of FIG. 41 is a selector, and 42 is a multiplier.
In FIG. 1 or 4, the fluctuation estimation coordinate system selection unit 17 receives the determination signal Sw and the fluctuation amount Lp from the polar coordinate fluctuation detector 15, and the fluctuation amount calculated in the orthogonal coordinate system from the orthogonal coordinate system fluctuation detector 16. L ₀ is input. Then, based on the determination signal Sw, the fluctuation estimated coordinate system selection unit 17 selects the fluctuation amount Lp calculated in the polar coordinate system and the fluctuation amount L ₀ calculated in the orthogonal coordinate system, and the selected estimated fluctuation amount L and it outputs a signal {μ _l · _L} multiplied by the estimated fluctuation amount weighted constant mu ₁ to the coefficient updating unit 13 with respect to.

In the fluctuation estimation coordinate system selection unit 17 in FIG. 4, the selector 25 selects either the input signal Lp or L ₀ according to the value of the input Sw, and outputs the selected signal as the signal L to the multiplier 42. .
The multiplier 42 multiplies the input signal L by the estimated variation weighting constant μ ₁ and outputs the multiplied signal {μ ₁ · L} to the coefficient updating unit 13. Here, μ ₁ assumes a value of 0 ≦ μ ₁ <1. Therefore, when μ ₁ = 0, the fluctuation estimation amount L is not taken into account when updating the coefficient.

  As described above, according to the first embodiment described with reference to FIGS. 1 to 4, it is possible to estimate the fluctuation in the polar coordinate system, and when there is a possibility that the fluctuation estimation amount in the polar coordinate system may greatly deviate. A variation estimation amount in an orthogonal coordinate system can be used.

A second embodiment of the present invention will be described with reference to FIG. FIG. 5 is a block diagram showing a configuration of an interference wave removing unit of an OFDM (Orthogonal Frequency Division Multiplexing) signal relay transmission apparatus. 500 is an interference wave removing unit, 53 is a filter coefficient updating unit, 55 is a polar coordinate system variation detector, 56 is an orthogonal coordinate system detector, and 57 is an estimated variation amount synthesizing unit. The subtractor 11, the error calculation unit 12, the update interval delay memory 14, and the adaptive filter 18 are the same as those in FIG.
In FIG. 5, coefficient values and mathematical formulas initialized with predetermined values are registered in each element constituting the interference wave removing unit 500.

In FIG. 5, the subtractor 11 subtracts the signal u output from the adaptive filter 18 as an interference wave replica signal from the input signal x, outputs the signal u to the error calculator 12 and the adaptive filter 18 as a signal y, and Output as an output signal of the removal unit 500.
The error calculation unit 12 calculates an ideal value yp from the output signal y obtained from the subtractor 11, calculates an error e between the ideal value yp and the output signal y, and a signal obtained by multiplying the error e by a weighting coefficient μ. (Error signal) {μ · e (n)} is output to the filter coefficient updating unit 53, the polar coordinate system variation detector 55, and the orthogonal coordinate system variation detector 56. Here, μ is an update weighting coefficient and takes a value of 0 <μ ≦ 1. N is the symbol number of the input signal.
The filter coefficient updating unit 53 receives the error signal {μ · e (n)} input from the error calculation unit 12 and the estimated variation w ′ (w ′ = {μ ₁ · L) input from the estimated variation combining unit 57. ′}) Is used to update the coefficient w ′ (n), and the updated coefficient w ′ (n) is output to the adaptive filter 18 and the update interval delay memory 14. The update of the coefficient w ′ (n) is calculated in the same manner as in the expression (1), for example, when the number of update interval symbols of the coefficient is D and the coefficient before one update is w ′ (n−D). .

The update interval delay memory 14 delays the delayed signal {w ′ (n−D)} by delaying the number of symbols D required for the update of the interference wave removing unit 500 with respect to the manually operated coefficient w ′ (n). Output to the polar coordinate system fluctuation detector 55 and the orthogonal coordinate system fluctuation detector 56.
The Cartesian coordinate system variation detector 56 uses the orthogonal coordinates based on the error signal {μ · e (n)} input from the error calculator 12 and the coefficient w ′ (n−D) input from the update interval delay memory 14. A difference signal w ₀ from a signal obtained by delaying each signal generated internally in the system by the update interval is calculated and output to the estimated fluctuation amount combining unit 57.

The polar coordinate system fluctuation detector 55 includes two input signals {w ′ (n−D)} and {μ · e (n)}, and the input signal {w ′ (n−D) inside the polar coordinate system fluctuation detector 55. )} And signals {w ′ (n−2D)} and {μ · e (n−D)} obtained by delaying the input signal {μ · e (n)} by the update interval (number of symbols D), respectively, The fluctuation difference wp ′ and fluctuation determination signal α by the polar coordinate system are calculated, and the calculated fluctuation difference wp ′ and fluctuation determination signal α are output to the estimated fluctuation amount combining unit 57.
In this way, the variation L ′ can be obtained by the sum of the difference value of the coefficient and the difference value of the error in the same manner as in the expressions (1) to (4).

The polar coordinate system fluctuation detector 55 in FIG. 5 will be described in more detail with reference to FIG.
FIG. 6 is a block diagram showing a configuration of one embodiment of the polar coordinate system fluctuation detector 55 of FIG. 61 is a polar coordinate converter, 62 and 24 are update interval delay memories, 63-r and 63-θ are subtractors, 66-r and 66-θ are adders, 67 is a variation weighting detector, and 68 is a rectangular coordinate transform. It is a vessel. Other components are the same as those in FIG.

In FIG. 6, a polar coordinate converter 61 performs polar coordinate conversion of an input signal in an orthogonal coordinate system.
First, the polar coordinate converter 61 converts the coefficient {w ′ (n−D)} input from the update interval delay memory 14 into polar coordinates, and converts the amplitude signal {w _r ′ (n−D)} into an update interval delay. The signal is output to the memory 62 and the subtracter 63-r, and the phase signal { _wθ ′ (n−D)} is output to the update interval delay memory 62 and the subtractor 63-θ.
Similarly, the polar coordinate converter 61 performs polar coordinate conversion of the error signal {μ · e (n)} input from the error calculation unit 12, and converts the amplitude signal e _r (n) into the update interval delay memory 24 and the subtractor. The phase signal e _θ (n) is output to the update interval delay memory 24 and the subtractor 25-θ.

The update interval delay memory 62 delays the amplitude signal {w _r ′ (n−D)} input from the polar coordinate converter 61 by the number of symbols required for the update of the interference wave removal unit 500 (D). The amplitude signal { _wr ′ (n−2D)} is output to the subtractor 63-r. Similarly, the input phase signal { _wθ ′ (n−D)} is delayed, and the delayed phase signal { _wθ ′ (n−2D)} is output to the subtractor 63-θ. The update interval delay memory 62 is used to calculate a difference in coefficients at the time of update.
The subtracter 63-r subtracts {w _r ′ (n−D)} input to the subtracted input terminal by the amplitude signal {w _r ′ (n−2D)} input from the subtraction input terminal. The difference signal Δw _r ′ is output to the adder 66-r. Further, the subtractor 63-θ converts { _wθ ′ (n−D)} input to the subtracted input terminal into an amplitude signal { _wθ ′ (n−2D)} input from the subtraction input terminal. The subtracted difference signal Δw is output to the adder 66-θ.

The update interval delay memory 24, the subtractor 25-r, and the subtractor 25-θ are the same as those in FIG. Then, it outputs a difference signal △ _{e r} by subtracting the amplitude of the signal of the subtractor _{25-r {e r (n} -D)} to the adder 66-r. Further, the subtractor 25-θ subtracts e _θ (n) input to the subtracted human power terminal by the amplitude signal {e _θ (n−D)} input from the subtraction input terminal. _θ is output to the adder 66-θ.

The adder 66-r outputs a _'signal L _r taking the sum of △ e _r' manpower have been difference signal △ w _r and variation weighting detector 67 in the orthogonal coordinate detector 68. This signal L _r ′ is an amplitude component signal of the polar coordinate system fluctuation estimation signal.
The adder 66-theta outputs 'signal L _theta took the sum of △ e _theta' manpower have been difference signal △ w _theta and variation weighting detector 67 to the orthogonal coordinate converter 68. This signal L _θ ′ is a phase component signal of the polar coordinate system fluctuation estimation signal.

The fluctuation amount weighting detector 67 outputs a combined weighting coefficient α (0 ≦ α ≦ 1) corresponding to the human power signals L _r and L _θ to the estimated fluctuation amount combining unit 57. Here, for example, when α _r is a variation amount of α = 0 and α = 1 is a variation amount of L _rb , n is given as a possible value of α, and a threshold value h _mn (L _{When ra} <h _r1 <... <h _rm <L _rb : m = 1, 2,..., n−1) is set, it is calculated as the following equation (Equation (6)).

即ち、変動量重み付け検出器６７は、入力された極座標系変動推定信号Ｌ_ｒ′とＬ_θ′から変動状態を検知し、検知した変動状態に応じた合成重み付け係数αを推定変動量合成部５７に出力する。
また、直交座標変換器６８は、人力された信号Ｌ_ｒ′及びＬ_θ′を直交座標変換する。そして、直交座標系の信号に変換した信号Ｗｐ′を推定変動量合成部５７に出力する。

That is, the fluctuation amount weighting detector 67 detects a fluctuation state from the input polar coordinate system fluctuation estimation signals L _r ′ and L _θ ′, and calculates a synthetic weighting coefficient α corresponding to the detected fluctuation state as an estimated fluctuation amount synthesis unit 57. Output to.
Further, the Cartesian coordinate converter 68 performs Cartesian coordinate transformation of the manually signaled signals L _r ′ and L _θ ′. Then, the signal Wp ′ converted into the orthogonal coordinate system signal is output to the estimated fluctuation amount combining unit 57.

As described above, the polar coordinate system fluctuation detector 55 includes the combined weighting coefficient α, L _r ′, and L _r ′ and L _θ ′ calculated by the same method as the polar coordinate system fluctuation detector 15 of FIG. A fluctuation amount signal Wp ′ (L ₀ ′ and Lp ′) obtained by orthogonally transforming L _θ ′ is output to the estimated fluctuation amount combining unit 57.

Next, the estimated variation combining unit 57 in FIG. 5 will be described in more detail with reference to FIG. FIG. 7 is a block diagram showing a configuration of one embodiment of the estimated variation combining unit 57 of FIG. 71 is an adder, 72 and 73 are multipliers, 74 is an adder, and 75 is a multiplier.
The estimated fluctuation amount combining unit 57 performs a synthetic fluctuation amount on the signals L ₀ ′ and Lp ′ input from the polar coordinate system fluctuation detector 55 by combining processing using the signal α input from the update interval delay memory 14. L ′ is calculated, further weighted, and the combined fluctuation amount μ · L ′ is output to the filter coefficient updating unit 53. Specifically, when the composite weighting coefficient of Lp ′ is α and the composite weighting coefficient of L ₀ ′ is β, L ′ is expressed as the following expression (Expression (7)).

ここで、重み付け係数の和を一定（＝１）とすると、

Here, if the sum of the weighting coefficients is constant (= 1),

となり、式（８）から

From equation (8)

が得られる。
これを式（７）に代入すると

Is obtained.
Substituting this into equation (7)

となる。
このようにして、合成変動量Ｌ′を算出する。

It becomes.
In this way, the combined fluctuation amount L ′ is calculated.

7 includes the subtractor 71, the multiplier 72, the multiplier 73, the adder 74, and the multiplier 76 by configuring the above-described equations (7) to (10). It is a materialization.
That is, the integer value 1 and the input signal α are input to the subtracter 71, and a signal (1−a) obtained by the difference is output to the multiplier 72.
The multiplier 72 outputs a signal {(1-α) · L ₀ ′} obtained by multiplying the input signal L ₀ ′ and (1-α) to the adder 74.
Multiplier 73 multiplies input signal Lp ′ by α, and outputs the multiplied signal {α · Lp ′} to adder 74.
The adder 74 calculates the sum of the input signals {(1-α) · L ₀ ′} and {α · Lp ′}, and outputs the added signal L ′ to the multiplier 75.
The multiplier 75 multiplies the input signal L ′ by the estimated variation weighting coefficient μ ₁ and outputs the multiplied signal {μ ₁ · L ′} to the filter coefficient update unit 53 of FIG.

  According to the second embodiment described above, the fluctuation amounts of the polar coordinate system and the orthogonal coordinate system are weighted according to the fluctuation amount, and the estimation error of the fluctuation amount is suppressed, and a stable operation is possible.

Next, a third embodiment of the present invention will be described with reference to FIGS. FIG. 8 is a block diagram showing the configuration of the interference wave removing unit of one embodiment of the present invention. FIG. 8 is a diagram illustrating a configuration of an interference wave removal unit of the OFDM signal relay transmission apparatus. 800 is an interference wave removing unit, and 85 is a polar coordinate system variation detection / alarm output unit.
FIG. 9 is a block diagram showing a configuration of the polar coordinate system fluctuation detector 85 of FIG.

In FIG. 8, the interference wave removing unit 800 includes a subtractor 11, an error calculating unit 12, a filter coefficient updating unit 53, an update interval delay memory 14, a polar coordinate system variation detection / alarm output unit 85, an orthogonal coordinate system variation detector 56, An estimated fluctuation amount synthesis unit 57 and an adaptive filter 18 are provided.
The subtractor 11, the error calculation unit 12, the filter coefficient update unit 53, the update interval delay memory 14, the orthogonal coordinate system variation estimation unit 56, the estimated variation amount synthesis unit 57, and the adaptive filter 18 are the same as those in the second embodiment. Therefore, the description is omitted.

A more detailed description of the polar coordinate system variation detection / alarm output unit 85 of FIG. 8 will be described with reference to FIG.
The configuration of FIG. 9 is provided with a fluctuation alarm detector 91 in addition to the configuration of FIG.
The fluctuation alarm detector 91 detects a fluctuation state from the input signals L _r ′ and L _θ ′, and outputs an alarm signal _Ar having an amplitude corresponding to the fluctuation state and an alarm signal A _θ having a phase to the inside or outside of the apparatus. To do. As the alarm signals _Ar and _Aθ , for example, values corresponding to preset threshold values are output.
According to the third embodiment described above, it is possible to output an alarm according to the fluctuation of the interference wave.

  According to the first to third embodiments described above, it is possible to provide a high-precision fluctuation tracking function by improving resistance to high-speed fluctuations, particularly phase fluctuations, and in a fluctuation environment where good estimation cannot be performed with a polar coordinate system. A stable interference wave removal apparatus can be provided by switching or synthesizing the fluctuation estimation to an orthogonal coordinate system. Further, according to the third embodiment, it is possible to obtain the fluctuation state information of the amplitude and phase of the interference wave in the transmission line.

As described above, the interference wave canceller of the present invention cancels an interference wave signal by receiving a transmission signal, for example, and removes the interference wave signal from the reception signal of the transmission signal in an interference wave canceller that retransmits. A cancellation error is calculated from the adaptive filter, a means for generating a signal having the same characteristics as the interference wave signal from the received signal and calculating a filter coefficient in the adaptive filter, and an output signal of the adaptive filter Means, filter coefficient difference value calculating means, cancellation error difference value calculating means, filter coefficient difference value calculating means, and cancellation error difference value calculating means from the interference wave signal fluctuation detecting means,
The variation detection means includes a detection means based on a polar coordinate system and a detection means based on an orthogonal coordinate system,
The polar coordinate system detecting means includes a temporal difference value calculating means for the amplitude component of the filter coefficient and the cancellation error, and a temporal difference value calculating means for the phase component, and an interference wave obtained from the fluctuation detecting means by the two coordinate systems. From the estimated fluctuation amount, a value used by the fluctuation detecting means as the interference wave estimated fluctuation amount is provided with a switching means or a synthesizing means for switching the result of the detecting means by the polar coordinate system and the result of the detecting means by the orthogonal coordinate system.
Preferably, the interference wave canceller according to the present invention further comprises means for reporting the alarm signal to the inside or outside of the apparatus by means for outputting an alarm signal according to the result obtained by the amplitude fluctuation detecting means and the phase fluctuation detecting means. Prepare.

The block diagram which shows the structure of the interference wave removal part of one Example of this invention. The block diagram which shows the structure of one Example of the polar coordinate system fluctuation | variation detector of this invention. The block diagram which shows the structure of one Example of the orthogonal coordinate system fluctuation | variation detector of this invention. The block diagram which shows the structure of one Example of the fluctuation | variation estimation coordinate system selection part of this invention. The block diagram which shows the structure of the interference wave removal part of one Example of this invention. The block diagram which shows the structure of one Example of the polar coordinate system fluctuation | variation detector of this invention. The block diagram which shows the structure of one Example of the estimated fluctuation amount synthetic | combination part of this invention. The block diagram which shows the structure of the interference wave removal part of one Example of this invention. The block diagram which shows the structure of one Example of the polar coordinate system fluctuation | variation detector of this invention.

Explanation of symbols

  11: Subtractor, 12: Error calculation unit, 13: Filter coefficient update unit, 14: Update interval delay memory, 15: Polar coordinate system variation detector, 16: Cartesian coordinate system detector, 17: Variation estimation coordinate system selection unit, 18: adaptive filter, 21: polar converter, 22: update interval delay memory, 23-r, 23-θ: subtractor, 24: update interval delay memory, 25-r, 25-θ: subtractor, 26-r , 26-θ: adder, 27: variation detector, 28: Cartesian coordinate converter, 31, 33: update interval delay memory, 32, 34: subtractor, 35: adder, 41: selector, 42: multiplication 53: Filter coefficient updating unit, 55: Polar coordinate system variation detector, 56: Cartesian coordinate system detector, 57: Estimated variation synthesis unit, 61: Polar coordinate converter, 62: Update interval delay memory, 63-r, 3-θ: Subtractor, 66-r, 66-θ: Adder, 67: Variation weighting detector, 68: Cartesian coordinate converter, 85: Polar coordinate system variation detection / alarm output device, 91: Variation alarm detector 100, 500, 800: interference wave removing unit.

Claims (1)

In an interference wave canceller that cancels an interference wave signal from a received signal and retransmits the canceled output signal,
An adaptive filter for removing the interference wave signal from the received signal; means for calculating a filter coefficient for the adaptive filter to generate a signal having the same characteristics as the interference wave signal; and calculating a cancellation error from the output signal A cancellation error means; a fluctuation detection means for detecting a fluctuation of the interference wave signal from the filter coefficient calculation means and the cancellation error calculation means;
The fluctuation detection means includes a detection means based on a polar coordinate system, a detection means based on an orthogonal coordinate system, an estimated fluctuation amount of an interference wave signal obtained from the detection means based on the orthogonal coordinate system, and an interference wave signal obtained from the detection means based on the polar coordinate system. And a means for switching or combining a value used as an estimated fluctuation amount of the received signal from a result of the polar coordinate system fluctuation detection means or a result of the orthogonal coordinate system fluctuation detection means from Wave canceller.

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