JP2010220159A - Apparatus and method for receiving orthogonal frequency division multiplex signal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the reception performance, using a small-scaled circuit or a simple method, even when a receiving apparatus for an orthogonal frequency division multiplex signal is installed in a mobile that is moving at a high speed. <P>SOLUTION: A Fourier transformation section 1 applies Fourier transformation on a reception signal, obtained by performing frequency conversion on a predetermined frequency band for an orthogonal frequency division multiplex signal; a pilot-extracting section 2 extracts a pilot signal from output of the Fourier transformation section 1; a divider 3 divides output of the pilot extracting section 2 with a known signal; and a time interpolation filter section 4 interpolates output of the divider 3 in the time direction. A misdetection component suppressing section 5 suppresses misdetection component for outputting the time interpolation filter section 4 in the same symbol and includes a band element filter, such as, IIR filter. A frequency interpolation filter section 6 interpolates the output of the misdetection component suppressing section 5 in the frequency direction, and an equalizer 7 divides the output of the Fourier transformation section 1 by the output of the frequency interpolation filter section 6 and demodulates the reception signal for each carrier. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a technique for receiving and demodulating an orthogonal frequency division multiplexed signal (hereinafter referred to as “orthogonal frequency division multiplexed signal”).

  A conventional orthogonal frequency division multiplexing signal receiving apparatus demodulates a carrier wave modulated by a QPSK (Quadrature Phase Shift Keying) method or a QAM (Quadrature Amplitude Modulation) method. (Also referred to as “pilot signal”) is used to estimate the amplitude fluctuation amount and phase fluctuation amount of each carrier wave in the transmission line (hereinafter referred to as “transmission path estimation”), and based on the estimation result, the amplitude of the carrier wave The signal is demodulated by correcting the phase (hereinafter referred to as “equalization”) (see, for example, Patent Document 1).

  Here, when the pilot signal is not continuously inserted using a predetermined carrier wave, in other words, when the pilot signal is inserted at a specific interval in time, it extends over a plurality of symbols. Pilot signals are extracted, and a transmission path estimation result for a predetermined symbol is obtained based on these pilot signals.

JP 2001-292122 A (FIG. 1)

  When a pilot signal demodulates an orthogonal frequency division multiplexed signal inserted at specific intervals in the time direction (corresponding to the symbol direction) and the frequency direction (corresponding to the subcarrier direction), transmission for a predetermined symbol The path estimation is realized by interpolating the transmission path estimation result for the pilot signal in the time direction and the frequency direction.

  However, when the receiving device is installed in a moving body (for example, an automobile) that moves at high speed, the false detection component of the transmission path estimation increases as the moving speed of the receiving device increases, and the signal is demodulated correctly. There was a problem that it was impossible to do.

  Hereinafter, a transmission path estimation error that occurs when a transmission path is estimated using a conventional technique when the receiving apparatus is installed on a moving body that moves at high speed will be described with reference to FIG.

  An interpolation filter for interpolating the pilot signal in the time direction needs to have a pass band sufficient to reproduce the temporal variation of the pilot signal. For example, it is assumed that the insertion interval Tp of the pilot signal in the time direction is m times the symbol interval (given as the sum of the guard interval and the effective symbol interval length, and the unit is sec.) Ts. At this time, in order to interpolate the transmission path estimation value in the time direction, a zero value is inserted between the transmission path estimation values obtained from the pilot signal, and the reciprocal m of the insertion interval Tp in the time direction of the pilot signal. Oversampling is performed at a double frequency (oversampling frequency = m / Tp), and filtering may be performed using a filter having a pass band as shown in FIG.

  However, when the moving speed of the moving body including the receiving device is fast, the maximum frequency component of the input of the time interpolation filter is high, and the relationship between the filter amplitude characteristic and the input signal component is shown in FIG. As shown in In such a case, the filter having the ideal amplitude characteristic shown in FIG. 6B cannot be realized by a small circuit, and the actual amplitude characteristic of the filter is shown in FIG. The filter characteristics are as follows. In this case, as shown in FIG. 6C, sufficient attenuation characteristics cannot be obtained in the stop band of the time interpolation filter, and unnecessary frequency components (hereinafter referred to as “error”) are output in the output of the time interpolation filter. "Detected component") will remain. The output of the time interpolation filter at this time is as shown in FIG. 6D, and the signal equalized using the transmission path estimation value obtained thereby cannot be demodulated correctly.

  The present invention has been made to solve the above-mentioned problems. Even in a receiver installed in a moving body that moves at high speed, the accuracy can be reduced by a small circuit configuration or a simple software function. The main purpose is to perform the channel estimation well and demodulate the signal correctly.

  The subject of the present invention is a receiving apparatus for an orthogonal frequency division multiplexed signal transmitted by inserting a known pilot signal on the transmitting side, and performs Fourier transform on the received orthogonal frequency division multiplexed signal at a predetermined timing A Fourier transform unit, a pilot extraction unit that extracts a pilot signal from the output of the Fourier transform unit, a division unit that divides the output of the pilot extraction unit by a known signal, and an output of the division unit that is interpolated in the time direction An output time interpolation filter unit; an erroneous detection component suppression unit that suppresses an erroneous detection component with respect to an output of the temporal interpolation filter unit for the same symbol; and an output of the erroneous detection component suppression unit in a frequency direction. A frequency interpolation filter unit for interpolation, and an equalization unit for performing demodulation for each carrier by dividing the output of the Fourier transform unit by the output of the frequency interpolation filter unit, And said that there were pictures.

  According to the subject matter of the present invention, the moving speed of the moving body in which the receiving apparatus is installed is increased, and the transmission path estimation values of all carrier waves are obtained by interpolating the transmission path estimation values of the pilot signal in the time direction and the frequency direction. The estimation error that occurs during calculation can be reduced by providing a small-scale circuit or a simple software function unit, and transmission path estimation and equalization can be performed with high accuracy without performing complex processing. Therefore, the mobile reception performance of the receiving apparatus can be improved.

  Hereinafter, various embodiments of the present invention will be described in detail along with the effects and advantages thereof with reference to the accompanying drawings.

It is a figure which shows the example of insertion of a scattered pilot. It is a block diagram which shows the structure of the receiver which concerns on Embodiment 1 of this invention. It is a figure which shows the output signal of a time interpolation filter. It is a block diagram which shows the structure of the receiver which concerns on Embodiment 2 of this invention. It is a block diagram which shows the structure of the receiver which concerns on Embodiment 3 of this invention. In order to point out a problem, it is a figure showing the relationship between the input of a time interpolation filter and the amplitude characteristic of the said filter.

  In the following, embodiments of the receiving apparatus according to the present invention will be described in detail. Prior to that, transmission technology and receiving technology of the orthogonal frequency division multiplexing system used in the present invention are necessary to understand the present invention. Is briefly described.

  The digital transmission technique based on the orthogonal frequency division multiplexing system is a transmission system that modulates and multiplexes information using a plurality of carrier waves whose frequencies are orthogonal to each other, and is being put to practical use particularly in the fields of broadcasting and communication.

  In orthogonal frequency division multiplexing transmission, information to be transmitted (hereinafter referred to as “transmission data”) is allocated to a plurality of carriers on the transmission side, and QPSK (Quadrature Phase Shift Keying) is assigned to each carrier. ) Method, QAM (Quadrature Amplitude Modulation) method, multi-level PSK method or the like. Further, as a signal used when demodulating a carrier wave on the receiving side, a known signal (hereinafter also referred to as “pilot signal”. The standard of the signal is predetermined in the system) is used as a specific carrier wave on the transmitting side. Is multiplexed. These multiplexed carriers are orthogonally transformed by inverse Fourier transform processing, frequency-converted to a predetermined transmission frequency, and transmitted.

  Specifically, transmission data to be transmitted at the time of transmission is mapped according to the modulation scheme of each carrier wave, and these are subjected to inverse discrete Fourier transform. Next, the last part of the signal after the inverse discrete Fourier transform is copied to the head of the signal. This part is called “guard interval”. By adding a signal for transmitting the guard interval, even if there is a delayed wave having a delay time shorter than the guard interval length, the signal can be reproduced without causing intersymbol interference on the receiving side.

  In the orthogonal frequency division multiplexing method, since all the carriers are orthogonal to each other, transmission data can be correctly reproduced when the carrier frequency is correctly reproduced on the receiving side. Therefore, a demodulator that receives an orthogonal frequency division multiplex signal performs frequency shift by orthogonally demodulating the input complex digital signal of the orthogonal frequency division multiplex method and frequency-converting it to a predetermined frequency band, and then setting a guard interval. After removal, each carrier wave is demodulated by performing a Fourier transform to convert from a time domain signal to a frequency domain signal and then detecting.

  When each carrier wave in the orthogonal frequency division multiplexing system (each carrier wave is also referred to as a “subcarrier”) transmits transmission data by a modulation method such as multilevel PSK or multilevel QAM, For the purpose of demodulating the carrier waves, pilot signals may be periodically inserted in these carrier waves in the frequency direction and the time direction. For example, in Japan's terrestrial digital TV broadcasting system, scattered pilots are inserted periodically, and an orthogonal frequency division multiplex receiver estimates the characteristics of the transmission path based on the scattered pilots. Thus, each carrier wave is demodulated.

  Here, FIG. 1 is a diagram illustrating an example of a method of multiplexing a scattered pilot and a carrier wave for transmission data. In the example of FIG. 1, scattered pilots are inserted at a rate of 1 in 12 carriers in the frequency direction and at a rate of 1 in 4 symbols in the time direction. Three carriers are offset for each symbol so that the same frequency position is obtained in four symbol periods. The “symbol” means a collection of carrier waves subjected to inverse Fourier transform at the same timing on the transmission side.

In general, when a pilot signal is inserted as shown in FIG. 1, scattered pilots are extracted over a plurality of symbols, and transmission path estimation for a predetermined symbol is performed. Now, the n-th transmission carrier c _m in the m-th _{symbol, n,} the frequency response of the channel as h _{m, n} thereto, the n in the m-th symbol of the receiver side Assuming that the Fourier transform output of the 1st carrier wave is rm _{, n} , when the signal from which the guard interval has been accurately removed is subjected to Fourier transform on the receiving device side, if the noise component is ignored, the equation shown in Equation 1 holds. .

Here, it is assumed that the scattered pilot is inserted in the Nth carrier wave in the Mth symbol. _{Assuming that} this carrier wave is s _{M, N} , when a scattered pilot is inserted as shown in FIG.

On the receiver side, the Mth symbol (carrier wave surrounded by a solid line in FIG. 1) is demodulated at time t = T (M). Assuming that the result of dividing the Fourier transform output for the scattered pilot by the known signal is h ′ _{m, n} , h ′ _{m, n} is expressed by the following equation (3). In Equation 3, z _{m, n} represents a noise component superimposed on the nth carrier wave in the mth symbol.

  When channel estimation is performed for the Mth symbol, the channel estimation value given by the equation shown in Equation 3 is interpolated in the time direction and then further interpolated in the frequency direction. All carrier waves can be demodulated by dividing the Fourier transform output by the transmission path estimation result obtained by interpolating the transmission path estimation values in the time direction and the frequency direction. If there is no noise and the transmission path estimation result is correct, the demodulation result matches the transmission data.

(Embodiment 1)
FIG. 2 is a block diagram showing a configuration example of the receiving apparatus according to the present embodiment. In FIG. 2, each reference numeral indicates the following component. That is, 1 is a Fourier transform unit, 2 is a pilot extraction unit, 3 is a division unit, 4 is a time interpolation filter unit, 5 is a false detection component suppression unit which is the core of the present embodiment, and 6 is a frequency interpolation filter unit. , And 7 are equalization sections. The output of the equalization unit 7 is a demodulated signal of a carrier wave.

  The components 1 to 7 of the receiving apparatus in FIG. 2 can be realized as a hardware circuit, or can be realized as a functional unit by software using a microcomputer or a DSP (Digital Signal Processor). This point is also valid for receiving apparatuses according to Embodiments 2 and 3 described later.

  Next, the overall operation of the receiving apparatus in FIG. 2 will be described.

  First, the front stage (not shown) of the receiving apparatus in FIG. 2 performs frequency shift processing by frequency-converting the received orthogonal frequency division multiplexed signal, which is a time domain signal, into a predetermined frequency band. However, this process is not an essential process, and the Fourier transform described later may be directly performed on the orthogonal frequency division multiplexed signal except for the process.

  The Fourier transform unit 1 performs Fourier transform on the signal section determined by the Fourier transform timing signal and outputs the received signal (time domain signal) received from the preceding stage. From this comparison, the Fourier transform in this case can be said to be a Fourier transform that is indirectly performed on the input orthogonal frequency division multiplexed signal. The signal interval for performing the Fourier transform is, for example, a signal interval (hereinafter referred to as “effective symbol interval”) from which the guard interval is removed from the transmission signal received by the receiver.

  The pilot extraction unit 2 receives the output of the Fourier transform unit 1 as an input, and extracts and outputs a pilot signal inserted on the transmission side and subjected to fluctuations during transmission through the transmission path.

  Next, the output of the pilot extraction unit 2 is input to the division unit 3, and the division unit 3 inserts each extracted pilot signal into a known signal (equivalent to a pilot signal inserted on the transmission side and having a predetermined standard). This is a signal having a standard. At this time, the output of the division unit 3 represents the frequency response of the transmission line with respect to the pilot signal.

  Next, the time interpolation filter unit 4 interpolates the output of the division unit 3 in the time direction and outputs the result.

  The erroneous detection component suppression unit 5, which is the core of the present embodiment, receives the output of the time interpolation filter unit 4 as input, and suppresses the erroneous detection component included in the output of the time interpolation filter unit 4. The operation of the erroneous detection component suppression unit 5 will be described in detail later.

  The output of the erroneous detection component suppression unit 5 is input to the frequency interpolation filter unit 6, which performs an interpolation process in the frequency direction. As a result, transmission path estimation values for all carriers belonging to each symbol can be obtained.

  The equalization unit 7 divides the output of the Fourier transform unit 1 by the output of the frequency interpolation filter unit 6 corresponding to the output, that is, the transmission path estimation value, and outputs the division result as a demodulated signal of the carrier wave.

  The configuration and operation of the erroneous detection component suppression unit 5 will be described below.

  The false detection component suppression unit 5 is configured by a band rejection filter that receives as input a signal sequence in which the outputs of the time interpolation filter unit 4 for the same symbol are arranged in order from the lowest carrier frequency.

  Here, the output signal of the time interpolation filter unit 4 when the erroneous detection component remains will be described with reference to FIG. FIG. 3 shows an output signal of the time interpolation filter unit 4 when the effective symbol section from which the guard interval is removed is Fourier-transformed with respect to the signal received through the ideal transmission path without reflection of radio waves. In FIG. 3, the effective symbol period is defined as Tu, and the insertion interval in the frequency direction of the pilot signal in the same symbol is n times the interval (1 / Tu) in the frequency direction of the carrier wave. FIG. 3A shows a case where there is no false detection component, and FIG. 3B shows a case where there is a false detection component. As shown in FIG. 3B, when a false detection component remains in the output of the time interpolation filter unit 4, it is separated by a frequency that is an integer multiple of Tu / n with the frequency of the original signal component as a reference. At each frequency, a signal component due to a false detection component that does not actually exist is generated.

  Therefore, the erroneous detection component suppression unit 5 functions as a band rejection filter that suppresses signal components due to these unnecessary erroneous detection components.

  For example, the stop band of the band stop filter constituting the false detection component suppression unit 5 is the most DC component among the input signal components when the insertion interval of the pilot signal in the time direction is m times the symbol interval. It is set so that a component having a frequency separated by 1 / m of the sampling frequency of the filter is blocked based on the frequency of the near component. As a result, the erroneous detection component suppression unit 5 determines a frequency that is separated from the frequency of the component closest to the direct current component by the Tu / n frequency among the multiple erroneous detection components included in the output of the time interpolation filter unit 4. It has the characteristic of suppressing the component (see FIG. 3B). Therefore, the signal components due to all the erroneous detection components are not completely suppressed, but the effect that the signal components due to some erroneous detection components are completely suppressed is expected. Such a band rejection filter can be realized by, for example, an IIR (Infinite Impulse Response) filter. In this case, it is easy to reduce the size of the erroneous detection component suppression unit 5 or simply configure the erroneous detection component suppression unit 5 as a software function unit.

  Alternatively, the false detection component suppression unit 5 can be realized by a configuration of another band rejection filter. Such a configuration example is described below. That is, the false detection component suppression unit 5 arranges the outputs of the time interpolation filter unit 4 for the same symbol in order from the lowest carrier frequency, and the frequency interval of the output of the unit 4 is the same as the carrier wave being transmitted. In order to be the same frequency interval, it is composed of a band rejection filter that receives as input a signal sequence in which zero values are inserted between the outputs of the time interpolation filter unit 4. Since the sampling frequency of the band rejection filter in this case corresponds to the effective symbol interval Tu, the insertion band of the pilot signal in the same symbol in the frequency direction is equal to the frequency interval 1 / Tu of the carrier wave. 1 / n of the sampling frequency of the band rejection filter and its integral multiple (2 / n, n), based on the frequency of the component closest to the DC component among the input signal components. 3 / n,...)) Is set so that each signal component having a frequency separated by a frequency of 3 / n is blocked (however, the maximum frequency of the blocked signal component exceeds 1/2 of the sampling frequency). I don't get it.) As a result, the erroneous detection component suppression unit 5 has a characteristic capable of suppressing all the erroneous detection components included in the output of the time interpolation filter unit 4.

  As described above, according to the receiving apparatus according to the present embodiment, between the time interpolation filter unit 4 and the frequency interpolation filter unit 6, the erroneous detection component suppression unit 5 that suppresses erroneous detection components. As a result, the performance degradation due to the influence of the erroneous detection component of the time interpolation filter unit 4 caused by the high-speed movement of the moving body in which the receiving device is installed increases the size of the receiving device or complicates its software function. Therefore, it can be reduced and the high-speed mobile reception performance of the receiving apparatus can be dramatically improved.

(Embodiment 2)
In the first embodiment, the output of the erroneous detection component suppression unit 5 in FIG. 2 is directly input to the frequency interpolation filter unit 6. On the other hand, the feature point of the present embodiment is that the interpolation processing method is switched according to the speed information of the moving body in which the receiving device is installed. More specifically, the erroneous detection component suppression unit 5 A “filter switching unit” that switches any one of the output and the output of the time interpolation filter unit 4 according to the speed information and outputs the output to the frequency interpolation filter unit 6 is additionally provided.

  Here, FIG. 4 is a block diagram showing a configuration of the receiving apparatus according to the present embodiment. In FIG. 4, constituent elements 1, 2, 3, 4, 5, 6 and 7 are the same as the corresponding constituent elements denoted by the same reference numerals in FIG. 2 of the first embodiment. The only difference between FIG. 4 and FIG. 2 is that the above-described filter switching unit 8 is additionally provided.

  Next, the operation of each part in FIG. 4 will be described. Each component 1, 2, 3, 4, 5, 6 and 7 in FIG. 4 operates in the same manner as the corresponding component in FIG. 2 of the first embodiment. However, the frequency interpolation filter unit 6 receives the output signal of the filter switching unit 8 as its input signal.

  The filter switching unit 8 switches and outputs the output of the time interpolation filter unit 4 and the output of the erroneous detection component suppression unit 5 according to the speed information. Here, the speed information is a signal indicating binary information “0”, “1” corresponding to the result of whether or not the speed of the moving object in which the receiving apparatus is installed exceeds the threshold value. When the moving body is, for example, a car, the speed information can be obtained from the output information of the navigation mounted on the car or the output information of the speed detection unit mounted on the car body. Now, when the speed information indicates that the speed of the moving object is high (for example, when the level is “1”), the filter switching unit 8 receives the output of the false detection component suppression unit 5. The same output is output to the frequency interpolation filter unit 6 as it is. On the other hand, when the speed information indicates that the speed of the moving object is not high (for example, when the level is “0”, corresponding to low-speed traveling), the filter switching unit 8 includes a time interpolation filter unit. 4 is switched in symbol units and output to the frequency interpolation filter unit 6.

  As described above, in the receiving apparatus according to the present embodiment, since the input of the frequency interpolation filter unit 6 is switched according to the speed of the moving body in which the receiving apparatus is installed, the time interpolation filter unit In the output of 4, even when the multipath component generated in the actual transmission path is present in the same frequency component as the erroneous detection component of the transmission path estimation generated at the time of high-speed mobile reception, it is correctly signaled during low-speed traveling. In addition, transmission path estimation and equalization can be achieved with high accuracy without complicated processing by adding a small circuit configuration or a simple software function section when traveling at high speed. I can do it.

(Embodiment 3)
The feature of the present embodiment is that the circuit of the receiving device is further improved by the provision of the erroneous detection suppression frequency interpolation filter unit having both the above-described erroneous detection component suppression function and the frequency interpolation filter function. This is to improve high-speed mobile reception performance while reducing the size of the configuration or simplifying the software function unit.

  FIG. 5 is a block diagram showing a configuration example of the receiving apparatus according to the present embodiment. In FIG. 5, reference numerals 1, 2, 3, 4 and 7 are the same as the corresponding components to which the same reference numerals are assigned in FIG. 2 of the first embodiment. The only difference between FIGS. 2 and 5 is that an erroneous detection suppression frequency interpolation filter unit 9 is provided instead of the erroneous detection component suppression unit 5 and the frequency interpolation filter unit 6 of FIG. .

  Next, the operation of each part in FIG. 5 will be described. Each component 1, 2, 3, 4, and 7 in FIG. 5 operates in the same manner as the corresponding component in FIG. 2 of the first embodiment. However, the equalization unit 7 receives the output signal of the erroneous detection suppression frequency interpolation filter unit 9 as an input signal.

  The erroneous detection suppression frequency interpolation filter unit 9 arranges the outputs of the time interpolation filter unit 4 for the same symbol in order from the lowest carrier frequency, and the frequency interval of the output of the unit 4 is the carrier wave being transmitted. So that the frequency interval is the same as that of the time-interpolation filter unit 4, a signal sequence in which a zero value is inserted between the outputs of the time interpolation filter unit 4 is input. The section 9 has a bandpass characteristic for interpolating the output of the time interpolation filter section 4 in the frequency direction, and at the same time, the stopband of the bandpass filter is in the frequency direction of the pilot signal in the same symbol. When the insertion interval corresponds to n times the frequency interval of the carrier wave, 1 / n of the sampling frequency of the filter and its integer on the basis of the frequency of the input signal component closest to the DC component Each signal component having a frequency separated by twice (2 / n, 3 / n,...) Is configured to have a characteristic of being blocked (however, the maximum frequency of the blocked signal component is , Cannot exceed half the sampling frequency.) For example, the false detection suppression frequency interpolation filter unit 9 can be configured with an FIR (Finite Impulse Response) filter. Therefore, by using such a filter, it is possible to promote downsizing of the receiving apparatus or simplification of the software function unit.

  As described above, according to the receiving apparatus according to the present embodiment, the function of suppressing the erroneous detection component and the frequency interpolation function are realized by a single filter. With the provision of a software function unit or even simpler, it is possible to realize transmission path estimation and equalization at high speeds with high accuracy.

(Appendix)
“Fourier transform of received orthogonal frequency division multiplex signal” means 1) Fourier transform of a received signal obtained by performing frequency conversion to a predetermined frequency band on the received orthogonal frequency division multiplex signal at a predetermined timing. This is a concept that includes a case (indirect Fourier transform on an orthogonal frequency division multiplexed signal) and 2) a case in which a received orthogonal frequency division multiplexed signal is directly Fourier transformed at a predetermined timing.

  While the embodiments of the present invention have been disclosed and described in detail above, the above description exemplifies aspects to which the present invention can be applied, and the present invention is not limited thereto. In other words, various modifications and variations to the described aspects can be considered without departing from the scope of the present invention.

  As a preferred application example of the present invention, there is application to a digital terrestrial broadcast receiver using an orthogonal frequency division multiplexing system.

  1 Fourier transform unit, 2 pilot extraction unit, 3 division unit, 4 time interpolation filter unit, 5 false detection component suppression unit, 6 frequency interpolation filter unit, 7 equalization unit, 8 filter switching unit, 9 false detection suppression frequency Interpolation filter section.

Claims (9)

An apparatus for receiving an orthogonal frequency division multiplex signal in which a known pilot signal is inserted and transmitted on the transmission side,
A Fourier transform unit that performs Fourier transform on the received orthogonal frequency division multiplexed signal at a predetermined timing;
A pilot extraction unit for extracting a pilot signal from the output of the Fourier transform unit;
A division unit for dividing the output of the pilot extraction unit by a known signal;
A time interpolation filter unit for interpolating and outputting the output of the division unit in the time direction;
An erroneous detection component suppression unit that suppresses an erroneous detection component with respect to the output of the time interpolation filter unit in the same symbol;
A frequency interpolation filter unit for interpolating the output of the erroneous detection component suppression unit in the frequency direction;
An equalizer that divides the output of the Fourier transform unit by the output of the frequency interpolation filter unit and performs demodulation for each carrier wave,
It is characterized by having,
Orthogonal frequency division multiplexed signal receiver. An apparatus for receiving an orthogonal frequency division multiplex signal in which a known pilot signal is inserted and transmitted on the transmission side,
A Fourier transform unit that performs Fourier transform on the received orthogonal frequency division multiplexed signal at a predetermined timing;
A pilot extraction unit for extracting a pilot signal from the output of the Fourier transform unit;
A division unit for dividing the output of the pilot extraction unit by a known signal;
A time interpolation filter unit for interpolating and outputting the output of the division unit in the time direction;
An erroneous detection component suppression unit that suppresses an erroneous detection component with respect to the output of the time interpolation filter unit in the same symbol;
A filter switching unit that switches and outputs either one of the output of the erroneous detection component suppression unit and the output of the time interpolation filter unit according to speed information;
A frequency interpolation filter unit for interpolating the output of the filter switching unit in the frequency direction;
An equalizer that divides the output of the Fourier transform unit by the output of the frequency interpolation filter unit and performs demodulation for each carrier wave,
It is characterized by having,
Orthogonal frequency division multiplexed signal receiver. An orthogonal frequency division multiplex signal receiver according to claim 1 or 2,
The erroneous detection component suppression unit is configured by a band rejection filter that receives as input a signal sequence in which the outputs of the time interpolation filter unit for the same symbol are arranged in order from the lowest carrier frequency, and the stop band of the band rejection filter If the pilot signal insertion interval in the time direction is m times the symbol interval, m of the sampling frequency of the band rejection filter based on the frequency of the component closest to the DC component among the input signal components The signal component having a frequency separated by a fraction of a frequency is set to be blocked,
Orthogonal frequency division multiplexed signal receiver. An orthogonal frequency division multiplex signal receiver according to claim 1 or 2,
The erroneous detection component suppression unit arranges the outputs of the time interpolation filter unit for the same symbol in order from the lowest carrier frequency, and the frequency interval of the output of the time interpolation filter unit is the same as the transmitted carrier wave The band rejection filter is configured to receive a signal sequence in which a zero value is inserted between the outputs of the time interpolation filter unit so as to be a frequency interval, and the stop band of the band rejection filter is the same symbol. When the insertion interval of the pilot signal in the frequency direction is n times the carrier frequency interval, n minutes of the sampling frequency of the band rejection filter based on the frequency of the input signal component closest to the DC component. It is set so that each component having a frequency separated by 1 and an integer multiple of the frequency is blocked.
Orthogonal frequency division multiplexed signal receiver. An apparatus for receiving an orthogonal frequency division multiplex signal in which a known pilot signal is inserted and transmitted on the transmission side,
A Fourier transform unit that performs Fourier transform on the received orthogonal frequency division multiplexed signal at a predetermined timing;
A pilot extraction unit for extracting a pilot signal from the output of the Fourier transform unit;
A division unit for dividing the output of the pilot extraction unit by a known signal;
A time interpolation filter unit for interpolating and outputting the output of the division unit in the time direction;
An erroneous detection suppression frequency for suppressing an erroneous detection component with respect to an output of the temporal interpolation filter unit in the same symbol and interpolating an output of the temporal interpolation filter unit in which the erroneous detection component is suppressed in a frequency direction An interpolation filter unit;
An equalizer that divides the output of the Fourier transform unit by the output of the erroneous detection suppression frequency interpolation filter unit and performs demodulation for each carrier wave,
It is characterized by having,
Orthogonal frequency division multiplexed signal receiver. An orthogonal frequency division multiplex signal receiver according to claim 7,
The erroneous detection suppression frequency interpolation filter unit arranges the outputs of the time interpolation filter unit for the same symbol in order from the lowest carrier frequency, and the frequency interval of the output of the time interpolation filter unit is a transmitted carrier wave. Is composed of a band-pass filter that receives a signal sequence in which a zero value is inserted between the outputs of the time interpolation filter unit so as to have the same frequency interval, and the output of the time interpolation filter unit is inserted in the frequency direction. When the insertion band of the pilot signal in the frequency direction in the same symbol is n times the carrier frequency interval, the input signal component A frequency separated by 1 / n of the sampling frequency of the bandpass filter and an integer multiple thereof with reference to the frequency of the component closest to the DC component Characterized in that it is configured so as to have a characteristic that each component is blocked with,
Orthogonal frequency division multiplexed signal receiver. A method of receiving an orthogonal frequency division multiplex signal in which a known pilot signal is inserted and transmitted on the transmission side,
A Fourier transform step of Fourier transforming the received orthogonal frequency division multiplexed signal at a predetermined timing;
A pilot extraction step of extracting a pilot signal from the output of the Fourier transform step;
A division step of dividing the output of the pilot extraction step by a known signal;
A time interpolation filter step of interpolating and outputting the output of the division step unit in the time direction;
A false detection component suppression step for suppressing false detection components with respect to the output of the time interpolation filter step in the same symbol;
A frequency interpolation filter step of interpolating the output of the erroneous detection component suppression step in the frequency direction;
An equalization step of dividing the output of the Fourier transform step by the output of the frequency interpolation filter step and performing demodulation for each carrier wave,
It is characterized by having,
A method for receiving orthogonal frequency division multiplexed signals. A method of receiving an orthogonal frequency division multiplex signal in which a known pilot signal is inserted and transmitted on the transmission side,
A Fourier transform step of Fourier transforming the received orthogonal frequency division multiplexed signal at a predetermined timing;
A pilot extraction step of extracting a pilot signal from the output of the Fourier transform step;
A division step of dividing the output of the pilot extraction step by a known signal;
A time interpolation filter step of interpolating and outputting the output of the division step in the time direction;
A false detection component suppression step for suppressing false detection components with respect to the output of the time interpolation filter step in the same symbol;
A filter switching step of switching and outputting either one of the output of the erroneous detection component suppression step and the output of the time interpolation filter step according to speed information;
A frequency interpolation filter step of interpolating the output of the filter switching step in the frequency direction;
An equalization step of dividing the output of the Fourier transform step by the output of the frequency interpolation filter step and performing demodulation for each carrier wave,
It is characterized by having,
A method for receiving orthogonal frequency division multiplexed signals. A method of receiving an orthogonal frequency division multiplex signal in which a known pilot signal is inserted and transmitted on the transmission side,
A Fourier transform step of Fourier transforming the received orthogonal frequency division multiplexed signal at a predetermined timing;
A pilot extraction step of extracting a pilot signal from the output of the Fourier transform step;
A division step of dividing the output of the pilot extraction step by a known signal;
A time interpolation filter step of interpolating and outputting the output of the division step in the time direction;
An erroneous detection suppression frequency for suppressing an erroneous detection component with respect to an output of the temporal interpolation filter step in the same symbol and interpolating an output of the temporal interpolation filter step in which the erroneous detection component is suppressed in a frequency direction An interpolation filter process;
An equalization step of dividing the output of the Fourier transform unit by the output of the false detection suppression frequency interpolation filter step and performing demodulation for each carrier wave,
It is characterized by having,
A method for receiving orthogonal frequency division multiplexed signals.

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