JP2011055350A - Radio relay device and delay wave canceling method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radio relay device and a delay wave canceling method capable of stably canceling a delay wave even if a reception signal includes the delay wave generated by a multipath wave and a sneaking wave. <P>SOLUTION: The radio relay device 1 includes: a branch means 12 branched from a relay amplification circuit 11 for amplifying the reception signal; a canceling circuit 15 for canceling the delay wave included in the reception signal; a transversal filter 13 for generating a canceling signal; and an analysis control circuit 14 for updating a tap coefficient of the transversal filter 13. The radio relay device has a signal confirming section 17 for confirming the reception signal, and an attenuator 16 capable of attenuating the transmission signal. The analysis control circuit 14 performs non-reciprocal processing for the multipath wave or reciprocal processing to the sneaking wave depending on whether or not the attenuator 16 attenuates the transmission signal, and analyzes the waves. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a radio relay apparatus and a delayed wave canceling method. In particular, the present invention relates to a radio relay apparatus and a delay wave canceling method capable of canceling a delayed wave such as a sneak wave or a multipath wave by an apparatus such as a relay broadcaster.

  Broadcast using OFDM (Orthogonal Frequency Division Multiplexing) waves are resistant to interference and interference, and the influence of highly correlated interference waves can be removed to a certain extent by received signal processing, and obstacles such as ghosts in the viewer apparatus In a radio relay station for terrestrial digital television broadcasting, the use of a channel used as a reception channel as a transmission channel is being studied. If this can be realized, it is only necessary to use one channel to broadcast a broadcast wave of a certain content nationwide, so-called SFN (Single Frequency Network) can be realized, and frequency resources can be effectively used. It is thought that it can contribute to the use.

  On the other hand, the received signal by the radio relay station includes not only the main wave component but also a delayed wave component caused by a phenomenon such as multipath and wraparound. The delayed wave component is a component related to the broadcast wave that arrives at the radio relay station after being delayed with respect to the main wave, although it is essentially the same signal as the main wave. In general, a phenomenon in which a broadcast wave arrives at a wireless relay station via a propagation path different from the wireless propagation path followed by the main wave among a plurality of wireless propagation paths from the parent station to the wireless relay station (parent station / The generation of multipath waves between radio relay stations) and the phenomenon that broadcast waves transmitted from the radio relay stations are received by the same radio relay station (generation of sneak waves from the transmitter of the radio relay station to the receiver) . In addition, when a sneak wave is noticeably generated, a loop oscillates and the radio relay station cannot normally relay the broadcast wave. For example, a safety mechanism in the radio relay station may operate and transmission may stop.

  Therefore, careful measures against delayed waves due to multipath waves and sneak waves are intended to ensure that the relay operation by the radio relay station can be continued normally, and thus to continue the broadcast wave relay without interruption. There is a demand for canceling a delayed wave using a canceller or a wireless repeater including a canceller. In an apparatus for canceling a delayed wave such as a sneak wave or a multipath wave in the asynchronous FFT method, a delay profile value (impulse response) corresponding to the delay time, phase, and amplitude of the delayed wave such as a sneak wave or a multipath wave from the received signal. Value), update the tap coefficient set to reflect the estimated delay profile value, and pass the received signal through an FIR filter such as a transversal filter to reverse the phase of the delayed wave such as a sneak wave or multipath wave Waves are generated by serial processing and added to the received signal to remove delayed waves such as sneak waves and multipath waves from the received signal (see, for example, Patent Document 1).

  By the way, the delay profile analysis results of the sneak wave and the multipath wave are different, and the sneak wave receives the transmitted wave again and repeats it, so that the response of the delay profile is linked with an integer multiple of the sneak delay time. Is done. However, as the FIR filter tap, the response to be reflected is only the first response, and the second and subsequent components are unnecessary. Therefore, when canceling a sneak wave in a sneak canceller, since the second and subsequent components are not assigned as taps, the spectrum data is inversed to attenuate the second and subsequent components and cancel the harmonic components. There is provided means for performing (see, for example, Patent Document 2).

JP 2005-86377 A Japanese Patent No. 3713211

  However, in the field environment, sneak waves and multipath waves are often mixed, and if the received signal contains not only sneak waves but also multipath waves with delay waves, multipath waves are reversed. There was a problem that an unnecessary component was generated due to the waves, resulting in an erroneous operation.

  Therefore, the present invention provides a radio relay apparatus and a delay wave canceling method that can stably cancel a delay signal including a multipath wave and a delayed wave including a sneak wave. For the purpose.

  In order to achieve the above object, a wireless relay device according to the present invention is provided between a reception side and a transmission side, a relay amplification circuit for amplifying a reception signal, a branching unit for branching the reception signal, From the canceller input signal obtained by the branch, a transversal filter that generates a cancel signal that cancels the delayed wave included in the received signal, and FFT analysis of the canceller input signal to generate the cancel signal, An analysis control circuit for updating the tap coefficient of the transversal filter, and applying the cancellation signal generated by the transversal filter to the reception signal on the reception side from the branching unit, so that a delay wave included in the reception signal A wireless relay device including a cancel circuit for canceling a signal, a signal confirmation unit for confirming a received signal, The attenuator capable of attenuating the transmission signal is provided between the branching means and the transmission side, and the multipath included in the canceller input signal is provided while the analysis control circuit attenuates the transmission signal. A wave is subjected to non-reciprocal processing and analyzed. While the attenuator does not attenuate the transmission signal, a sneak wave included in the canceller input signal is subjected to reciprocal processing and analyzed.

In the wireless relay device according to the present invention, it is preferable that when the analysis control circuit is at least one of the following (1) to (3), the analysis is reset once and the analysis is executed again.
(1) When the signal output from the relay amplifier circuit is an abnormal value (2) When the D / U ratio is an abnormal value (3) When the calculated delay profile fluctuates

  The method for canceling a delayed wave according to the present invention generates a cancel signal for canceling a delayed wave included in the received signal by performing FFT analysis on a canceller input signal obtained by a branching unit that branches the received signal, A delay wave canceling method for canceling a delay wave included in the reception signal by applying a cancel signal to the reception signal on the receiving side from the branching means, wherein the reception signal is a delayed wave due to a multipath wave and a sneak wave After confirming the received signal, the transmission signal is attenuated, and in the state where the transmission signal is attenuated, the multipath wave included in the canceller input signal is analyzed by irreversible processing, and the multipath included in the reception signal is analyzed. After canceling the delayed wave due to the wave, the wraparound included in the canceller input signal in a state where the attenuation of the transmission signal is canceled The reciprocal process to analyze, characterized in that to cancel the delayed waves self interference in the received signal.

In the method for canceling a delayed wave according to the present invention, when the method is at least one of the following (1) to (3), the analysis is preferably reset and then executed again.
(1) When the received signal is amplified and the amplified received signal is an abnormal value (2) When the D / U ratio is an abnormal value (3) When the calculated delay profile fluctuates The residual of the delay profile is also expressed as “D / U ratio”. In the present application, since the D / U ratio is calculated by “−log (Desired signal / Undesired signal)”, the D / U ratio increases as the residual of the delay profile increases.

  The radio relay apparatus according to the present invention includes an attenuator capable of attenuating a transmission signal when canceling a delayed wave due to a multipath wave and a sneak wave, and while the analysis control circuit attenuates the transmission signal, The multipath wave included in the canceller input signal is analyzed by irreversible processing, and the sneak wave included in the canceller input signal is analyzed by reciprocal processing while the attenuator does not attenuate the transmission signal. Therefore, the delayed wave caused by the multipath wave and the delayed wave caused by the sneak wave can be canceled stably and reliably.

  Similarly, the delayed wave canceling method according to the present invention performs the irreversible processing on the multipath wave included in the canceller input signal in a state in which the transmitted signal is attenuated and no sneak wave is generated after confirming the received signal. After canceling the delayed wave due to the multipath wave included in the received signal, the sneak wave included in the canceller input signal is analyzed by reciprocal processing with the attenuation of the transmission signal released, and the received signal is analyzed. The delay wave caused by the included sneak wave is canceled, so even if the received signal contains a multipath wave and a sneak wave due to the sneak wave, the delay caused by the multipath wave and the sneak wave is delayed. Waves can be canceled stably and reliably.

It is the schematic which showed the one aspect | mode of the structure of the radio relay station containing the radio relay apparatus which concerns on this invention. It is the figure which showed the spectrum formed by a sneak wave being combined with an input wave (received signal). It is the figure which showed the spectrum formed by a multipath wave being synthesize | combined with an input wave (received signal). It is the figure which showed the delay profile analysis result in a sneak wave. It is the figure which showed the delay profile analysis result in a multipath wave. It is the figure which showed the procedure of the analysis in an analysis control circuit. It is the schematic which showed an example of the structure of the analysis control circuit which comprises a radio relay apparatus.

  Hereinafter, an aspect of an embodiment of the present invention will be described with reference to the drawings.

(1) Overview of the wireless relay device 1:
FIG. 1 is a schematic diagram showing an aspect of a configuration of a radio relay station A including a radio relay device 1 according to the present invention. In the radio relay station A in FIG. 1, the receiving unit 2 provided on the receiving side receives a master station wave using the receiving antenna 21 and converts the received signal from a radio frequency (RF) to an intermediate frequency (IF). To do. On the other hand, the transmission unit 3 provided on the transmission side converts the IF reception signal obtained from the reception unit 2 from IF to RF and wirelessly transmits it from the transmission antenna 31.

  As shown in FIG. 1, in the wireless relay station A, a part of the output of the transmission unit 3 reaches the reception antenna 21 of the reception unit 2 via the transmission antenna 31 and the wireless propagation path, and from the transmission side to the reception side. A sneak wave, for example, a multipath wave occurs on the receiving side, and a sneak wave or a delayed wave due to the multipath wave occurs. In order to cancel the delayed wave due to the sneak wave or multipath wave, the radio relay apparatus 1 of the present invention having a canceller function is provided in the system of the radio relay station A.

  The delay wave canceller including the radio relay apparatus 1 of the present invention estimates a delay profile value corresponding to the delay time, phase, and amplitude of a delay wave such as a sneak wave or multipath wave from the received signal received by the receiver 2. Then, the received signal is passed through the transversal filter 13 with the tap coefficient set by reflecting the estimated delay profile value, and an anti-phase wave of a delayed wave such as a sneak wave or a multipath wave is generated as a delayed wave cancel signal. Then, by adding to the received signal, delayed waves such as sneak waves and multipath waves are removed from the received signal.

  In this embodiment, the relay amplifier circuit 11 disposed between the reception side and the transmission side in the wireless relay device 1 of the present invention is provided between a cancel circuit 15 and a branching unit 12 which will be described later. Perform relay processing such as processing.

  In addition, the reception signal received by the reception unit 2 using the reception antenna 21 is transmitted to the transmission unit 3 by the branching unit 12 while being transmitted to the transmission unit 3, and the canceller input signal transmitted to the transversal filter 13. Fork. The branching means 12 may be performed by signal line branching or a coupler.

  As described above, it is necessary to generate a cancel signal by the transversal filter 13 in order to remove or suppress the influence of the delayed wave caused by the sneak wave and the multipath wave appearing in the received signal. The transversal filter 13 which is one form of the FIR filter changes the characteristics of the canceller input signal obtained by the branching based on a control parameter such as a tap coefficient, and generates a cancel signal for canceling the delay wave included in the received signal. To do.

  The analysis control circuit 14 that controls the characteristics of the transversal filter 13 and updates the tap coefficients performs FFT analysis on the canceller input signal to generate a cancel signal in the transversal filter 13, as will be described in detail later. Estimate delay profile values corresponding to delay time, phase, and amplitude of delayed waves such as sneak waves and multipath waves, and use wraparound waves and multipath waves from tap coefficients set to reflect the estimated delay profile values. The reverse phase wave of the delayed wave is generated as a delayed wave cancel signal.

  The cancel circuit 15 is disposed on the reception side from the branching unit 12 and applies the cancel signal generated by the transversal filter 13 to the reception signal on the reception side from the branching unit 12. By applying the cancel signal, a delayed wave due to a sneak wave or a multipath wave is removed from the received signal.

  The attenuator 16 is disposed between the branching unit 12 and the transmission side, and can attenuate the transmission signal. In the wireless relay device 1 of this embodiment, the operation of the attenuator 16 is controlled by the analysis control circuit 14 described above. Further, the signal confirmation unit 17 confirms that the signal is received on the receiving side, and when the signal is received, informs the fact to the attenuator instruction unit 140 (see FIG. 7) of the analysis control circuit 14.

(2) About sneak waves and multipath waves:
The radio relay apparatus 1 and the delay wave canceling method of the present invention are mainly intended for signals in which the received signal received by the radio relay station A in FIG. 1 includes a multipath wave and a delayed wave due to a sneak wave.

  FIG. 2 is a diagram showing a spectrum formed by combining a sneak wave with an input wave (received signal), and FIG. 3 is a diagram showing a spectrum formed by combining a multipath wave with an input wave (received signal). , Respectively. Comparing FIG. 2 and FIG. 3, it can be seen that when the sneak wave is combined with the input wave and when the multipath wave is combined with the input wave, the spectrum shapes are different (reverse).

  FIG. 4 shows a delay profile analysis result (delay profile and D / U ratio (desired to undesired signal ratio)) of a sneak wave. The same applies to FIG. 5 below. FIG. 5 and FIG. 5 are diagrams each showing a delay profile analysis result in a multipath wave. As described above (FIGS. 2 and 3), when the sneak wave is combined with the input wave and when the multipath wave is combined with the input wave, the spectrum shapes are opposite to each other. As shown in FIG. 5, the delay profile analysis results of the sneak wave and the multipath wave are different. In the sneak wave, the transmitted wave is received again and repeated as shown in FIG. Are analyzed in such a way that the responses are continuous with an integral multiple of the wraparound delay time. On the other hand, a secondary component is not generated in a multipath wave.

  Here, in the case of the sneak wave, the response to be reflected is only the first response for calculating the tap coefficient in the FIR filter such as the transversal filter 13, and the second and subsequent components are unnecessary. Therefore, when canceling the sneak wave, since the secondary component and subsequent components are not assigned as taps, the spectrum data is inversed to attenuate the secondary component and subsequent components, and the harmonic component is removed to cancel the sneak wave. It can be carried out.

  Also, since the sneak wave is generated after the signal is transmitted by the transmitter, the sneak wave is generated if the transmission signal is intentionally attenuated by delaying the transmission timing after the input is detected. In this state, the delayed wave due to the multipath wave included in the canceller signal is canceled, and then the delayed wave due to the sneak wave included in the canceller input signal is canceled in the state where the attenuation of the transmission signal is canceled. .

  As described above, first, after confirming the received signal, the transmission signal is attenuated and the multipath wave included in the canceller input signal is analyzed by irreversible processing in a state where no sneak wave is generated, and is included in the received signal. After canceling the delayed wave due to the multipath wave, in a state where the attenuation of the transmission signal is cancelled, the sneak wave included in the canceller input signal is analyzed by reciprocal processing and the delayed wave due to the sneak wave included in the received signal is canceled. Then, the delayed wave due to the sneak wave and the multipath wave is efficiently canceled.

(3) Configuration of analysis control circuit 14:
FIG. 6 is a diagram showing an analysis procedure in the analysis control circuit 14 (in FIG. 6, steps are represented by “S”). FIG. 7 is a schematic diagram illustrating an example of the configuration of the analysis control circuit 14 configuring the wireless relay device 1.

  Since the analysis control circuit 14 generates a cancel signal by the transversal filter 13 as a basic analysis configuration, the FFT analysis is performed on the canceller input signal obtained by branching when updating the tap coefficient of the transversal filter 13. The obtained data is further subjected to IFFT analysis to calculate a delay profile.

  In the present invention, the analysis control circuit 14 confirms the received signal, and analyzes the multipath wave included in the canceller input signal by irreversible processing while the attenuator 16 attenuates the transmission signal. As long as the attenuator 16 does not attenuate the transmission signal, the sneak wave included in the canceller input signal is inversely processed and analyzed.

  Here, “reciprocal processing” refers to performing an inverse analysis (corresponding to the contents of (3-2) and (b) described later) and performing an FFT analysis. “Frequency processing” refers to performing FFT analysis without performing reciprocal processing (the contents of (3-2) and (b) described later correspond).

(3-1) Cancellation of delayed wave by multipath wave:
To cancel a delayed wave due to a multipath wave, after confirming the received signal, attenuate the transmission signal and analyze the multipath wave included in the canceller input signal by irreversible processing in a state where no sneak wave is generated. Is done.

First, when the received signal is confirmed by the signal confirmation unit 17 (step 1 in FIG. 6) and communicated to the attenuator instruction unit 140 of the analysis control circuit 14, the signal transmitted from the attenuator support unit 140 to the attenuator 16. (Step 2 in FIG. 6), the signal is not transmitted, no sneak wave is generated, the branching means branches, and the canceller input signal input to the transversal filter 13 is also input. Therefore, the delayed wave due to the sneak wave is not included (only the delayed wave due to the multipath wave is included), and the multipath wave included in the canceller input signal is subjected to non-reciprocal processing and analyzed (step 3 in FIG. 6). ).

(A) FFT analysis The FFT (Fast Fourier Transform) analysis of the canceller input signal is performed by the FFT analysis unit 141 of the analysis control circuit 14, and the delay time, phase, and the like of the sneak wave and multipath wave in the received signal And signal intensity S (n) for each discrete frequency corresponding to the amplitude (where 0 ≦ n <N, N: the number of points of the discrete Fourier transform). This S (n) corresponds to a spectrum. Note that the acquisition point (ie, n) of S (n) is not necessarily matched to the frequency of the subcarrier signal, and the number N of acquisition points of n is also the frequency band of the OFDM signal (ie, the subcarrier signal included in the OFDM signal). Therefore, it may be appropriately selected to the extent that necessary accuracy can be ensured.

  In the FFT analysis, absolute value processing may be performed, for example, only the amplitude value may be extracted. Further, the data obtained by the FFT analysis may be averaged to improve C / N. In the averaging process, for example, an average processing unit (not shown) may calculate the average value for each frequency point of S (n) for OFDM signals acquired at a plurality of timings within a predetermined period. That's fine.

(B) IFFT analysis The spectrum data obtained by the FFT analysis is subjected to IFFT analysis, and a delay profile corresponding to the delay time, phase, and amplitude of the delayed wave is calculated by the IFFT analysis unit 143 of the analysis control circuit 14 The IFFT analysis is to perform inverse discrete Fourier transform on the spectrum data, and the calculation result of the inverse discrete Fourier transform by the IFFT analysis unit 143 is a complex value, and the amplitude and phase at each (delayed) time point. You can also get

  The IFFT analysis unit 143 may correct the calculation result based on the electric field strength. More specifically, for example, a value obtained by dividing the logarithm display value by the electric field strength (reception power) of the direct wave so as to indicate a relative value with the electric field strength (or reception power) of the direct wave as a reference (0 [dB]). Can be used as an output value.

  Then, by such IFFT analysis, a delay profile corresponding to the delay time, phase, and amplitude of the delay wave due to the multipath wave is calculated. Based on the obtained delay profile, the tap coefficient of the transversal filter 13 is updated, and an antiphase wave of the delayed wave due to the multipath wave is generated as a cancel signal. The cancel signal is applied to the reception signal on the receiving side from the branching means 12 in the cancel circuit 15 to cancel the delayed wave due to the multipath wave included in the reception signal (step 4 in FIG. 6).

(3-2) Cancellation of delayed wave due to sneak wave:
After the delay wave due to the multipath wave is canceled by the above (3-1), the delay wave due to the sneak wave is canceled. Canceling a delayed wave due to a sneak wave is performed by reversing the sneak wave included in the canceller input signal and analyzing it in a state where the attenuation of the transmission signal is canceled (a state in which transmission is transmitted from the transmitter). Is called.

  First, the attenuator instruction unit 140 of the analysis control circuit 14 issues an instruction to cancel the attenuation of the signal transmitted to the attenuator (step 5 in FIG. 6), so that the signal is transmitted and a sneak wave is generated. Therefore, the canceller input signal that is branched by the branching means and input to the transversal filter also includes a delayed wave due to the sneak wave, and the sneak wave included in the canceller input signal is subjected to inverse processing and analyzed. (Step 6 in FIG. 6).

  It should be noted that the cancellation of attenuation is preferably carried out step by step because if the transmission level is gradually increased, the delay wave of the sneak wave included will also gradually increase.

(A) FFT analysis The FFT analysis is the same as the FFT analysis of the canceller input signal including only the delayed wave due to the multipath wave in (3-1), and thus the description thereof is omitted.

(B) Reciprocalization process The reciprocalization process is performed by the reciprocalization processing unit 142 of the analysis control circuit 14, and the following formula ( The reciprocal obtained by taking an average value at a plurality of acquisition timings expressed in 2) is calculated.

  In Expressions (1) and (2), A is a correction coefficient and * indicates a complex conjugate. The correction coefficient A is set in order to adjust the electric field strength (reception power) level of the calculation results thereafter. This correction coefficient A is, for example, a value calculated from the spectrum S (n) (for example, an average value of the signal intensity of S (n) [an average value of the spectrum S (n) for a plurality of timings in a predetermined frequency band] ) Or a predetermined value determined in advance.

  The FFT processing unit 141 calculates the average value for each frequency point of S (n) above for the OFDM signal acquired at a plurality of timings within a predetermined period. Then, the reciprocalization processing unit 142 sets the reciprocal of the square value of the average value (that is, the time average value) for each frequency point of the spectrum S (n) for a plurality of acquisition timings as the reciprocal (energy) spectrum T (n). Output.

(C) IFFT analysis:
The IFFT processing unit 143 performs an inverse discrete Fourier transform on the reciprocal (energy) spectrum T (n). As a result of inverse discrete Fourier transform with the reciprocal (energy) spectrum T (n) as the real component and the imaginary component as 0, the second and higher harmonic components of the wraparound wave are removed, and the direct wave and the wraparound primary component are Therefore, characteristics (amplitude ratio, delay time, and phase) with respect to the primary component of the sneak wave can be obtained more easily. Further, the calculation result of the inverse discrete Fourier transform by the IFFT processing unit 143 is a complex value, and the amplitude and phase at each (delay) time point can also be acquired.

  Note that, similarly to the above (3-1), the IFFT processing unit 143 may correct the calculation result by the electric field strength.

  Then, by such IFFT analysis, a delay profile corresponding to the delay time, phase, and amplitude of the delayed wave due to the sneak wave is calculated. Based on the obtained delay profile, the tap coefficient of the transversal filter 13 is updated, and an antiphase wave of the delayed wave due to the sneak wave is generated as a cancel signal. The cancel signal is applied to the reception signal on the receiving side from the branching means 12 in the cancel circuit 15 to cancel the delayed wave due to the sneak wave included in the reception signal (step 7 in FIG. 6).

  As described above, the operations (3-1) and (3-2) cancel the delayed wave due to the sneak wave and the multipath wave efficiently. In the analysis, (1) the relay amplifier circuit 11 or the like When the received signal is amplified and the amplified received signal is an abnormal value, (2) when the D / U ratio (residual delay profile) is an abnormal value, (3) the calculated delay profile is In the case of at least one of the cases of fluctuation, it is preferable that the analysis in the analysis control unit is once reset and then the analysis is executed again. By resetting the analysis when such an abnormality occurs, accidents caused by various abnormalities are prevented in advance, and delay wave cancellation is performed more safely and reliably.

(4) Effects of the present invention:
According to the wireless relay device 1 of the present embodiment having the above-described configuration, the attenuator 16 capable of attenuating the transmission signal is provided in order to cancel the multipath wave and the delayed wave due to the wraparound, and the analysis control circuit 14 includes the attenuator 16. While the transmission signal is attenuated, the multipath wave included in the canceller input signal is subjected to non-reciprocal processing and analyzed. While the attenuator 16 does not attenuate the transmission signal, the sneak wave included in the canceller input signal is inverted. Therefore, the delay wave due to the multipath wave and the delay wave due to the sneak wave can be canceled stably and reliably.

  Similarly, the delayed wave canceling method according to the present invention performs the irreversible processing on the multipath wave included in the canceller input signal in a state in which the transmitted signal is attenuated and no sneak wave is generated after confirming the received signal. After canceling the delayed wave due to the multipath wave included in the received signal, the sneak wave included in the canceller input signal is analyzed by reciprocal processing with the attenuation of the transmission signal released, and the received signal is analyzed. The delay wave caused by the included sneak wave is canceled, so even if the received signal contains a multipath wave and a sneak wave due to the sneak wave, the delay caused by the multipath wave and the sneak wave is delayed. Waves can be canceled stably and reliably.

  The wireless relay device 1 and the delay wave canceling method of the present invention can cancel a delayed wave due to a sneak wave or a multipath wave using, for example, an asynchronous FFT analysis method for a terrestrial digital repeater. In addition, a modulation scheme having a continuous frequency bandwidth such as CDMA is also applicable.

(5) Variation of the embodiment:
The aspect described above shows one aspect of the present invention, and the present invention is not limited to the above-described embodiment, and has the configuration of the present invention and can achieve the objects and effects. It goes without saying that modifications and improvements within the scope are included in the content of the present invention. Further, the specific structure, shape, and the like in carrying out the present invention are not problematic as other structures, shapes, and the like as long as the objects and effects of the present invention can be achieved.

  For example, in the above-described embodiment, the relay amplifier circuit 11 in the wireless relay device 1 is provided between the cancel circuit 15 and the branching unit 12. However, the present invention is not limited to this. It can be arranged at any place between the sides (for example, between the branching means 12 and the transmitting unit 3 in FIG. 1).

  In the above-described embodiment, it is assumed that the cancel signal generated by the transversal filter 13 to cancel the delayed wave due to the sneak wave or the multipath wave is an antiphase wave of the delayed wave due to the sneak wave or the multipath wave. As described above, the cancel signal is not limited to the reverse phase wave of the delay wave, and the same phase wave of the delay wave may be used as the cancel signal.

  In the above-described embodiment, the mode in which the signal confirmation unit 17 is disposed between the cancel circuit 15 and the relay amplifier circuit 11 has been described. However, the present invention is not limited to this. For example, it may be provided inside the analysis control circuit 14 (as one of the components of the analysis control circuit 14).

  In the above-described embodiment, as a procedure of FFT analysis of the canceller input signal in the analysis control circuit, which is performed to generate the cancel signal, the FFT analysis is performed on the canceller input signal and then the IFFT analysis is performed. Although the delay profile is calculated (with an inverse number process between the analysis and the IFFT analysis), other procedures may be applied as long as the FFT analysis can calculate the delay profile.

  In addition, the specific structure, shape, and the like in the implementation of the present invention may be other structures as long as the object of the present invention can be achieved.

  INDUSTRIAL APPLICABILITY The present invention can be advantageously used as a radio relay apparatus that can cancel a delayed wave due to a sneak wave or a multipath wave between transmission / reception antennas of a radio relay station that performs retransmission at the same frequency constituting the SFN, For example, it becomes possible to perform severe SFN wireless relay in which the signal level of the sneak wave or multipath wave is larger than that of the master station wave, and effective use of the frequency can be realized at low cost.

DESCRIPTION OF SYMBOLS 1: Radio relay apparatus 11: Relay amplifier circuit 12: Branch means 13: Transversal filter 14: Analysis control circuit 140: Attenuator instruction | indication part 141: FFT analysis part 142: Inversion processing part 143: IFFT analysis part 144: Tap update Unit 15: Cancellation circuit 16: Attenuator 17: Signal confirmation unit 2: Reception unit 21: Reception antenna 3: Transmission unit 31: Transmission antenna A: Radio relay station

Claims (4)

A relay amplifier circuit that is disposed between the reception side and the transmission side and that amplifies the received signal;
Branching means for branching the received signal;
A transversal filter that generates a cancel signal for canceling a delayed wave included in the received signal, from a canceller input signal obtained by the branch;
An analysis control circuit for performing FFT analysis on the canceller input signal to update the tap coefficient of the transversal filter in order to generate the cancel signal;
A cancellation circuit configured to apply a cancellation signal generated by the transversal filter to a reception signal on a reception side from the branching unit and cancel a delayed wave included in the reception signal; ,
A signal confirmation unit for confirming a reception signal, and an attenuator capable of attenuating the transmission signal between the branching unit and the transmission side;
While the attenuator attenuates the transmission signal, the analysis control circuit analyzes the multipath wave included in the canceller input signal by performing an irreversible process,
While the attenuator does not attenuate the transmission signal, a radio relay apparatus characterized by reciprocalizing and analyzing a sneak wave included in the canceller input signal. 2. The wireless relay according to claim 1, wherein when the analysis control circuit is at least one of the following (1) to (3), the analysis is reset once and the analysis is executed again. apparatus.
(1) When the signal output from the relay amplifier circuit is an abnormal value (2) When the D / U ratio is an abnormal value (3) When the calculated delay profile fluctuates By performing FFT analysis on the canceller input signal obtained by the branching means for branching the received signal, a cancel signal for canceling the delayed wave included in the received signal is generated, and the cancel signal is received by the receiving side from the branching means. A method for canceling a delayed wave that is applied to a signal and cancels a delayed wave included in the received signal,
The received signal includes a multipath wave and a delayed wave due to a sneak wave;
After confirming the received signal, attenuate the transmitted signal,
In a state where the transmission signal is attenuated, the multipath wave included in the canceller input signal is analyzed by irreversible processing, and after the delayed wave due to the multipath wave included in the reception signal is canceled,
In a state in which the attenuation of the transmission signal is released, the sneak wave included in the canceller input signal is analyzed by reciprocal processing, and the delayed wave due to the sneak wave included in the reception signal is canceled. How to cancel. 4. The method of canceling a delayed wave according to claim 3, wherein if at least one of the following (1) to (3), the analysis is once reset and then the analysis is executed again.
(1) When the received signal is amplified and the amplified received signal is an abnormal value (2) When the D / U ratio is an abnormal value (3) When the calculated delay profile fluctuates