WO2011086609A1 - Digital broadcast reception apparatus and delay profile generation method - Google Patents
Digital broadcast reception apparatus and delay profile generation method Download PDFInfo
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- WO2011086609A1 WO2011086609A1 PCT/JP2010/000235 JP2010000235W WO2011086609A1 WO 2011086609 A1 WO2011086609 A1 WO 2011086609A1 JP 2010000235 W JP2010000235 W JP 2010000235W WO 2011086609 A1 WO2011086609 A1 WO 2011086609A1
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2647—Arrangements specific to the receiver only
- H04L27/2655—Synchronisation arrangements
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J11/00—Orthogonal multiplex systems, e.g. using WALSH codes
- H04J11/0023—Interference mitigation or co-ordination
- H04J11/0063—Interference mitigation or co-ordination of multipath interference, e.g. Rake receivers
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/0202—Channel estimation
- H04L25/0212—Channel estimation of impulse response
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/0202—Channel estimation
- H04L25/022—Channel estimation of frequency response
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/0202—Channel estimation
- H04L25/0224—Channel estimation using sounding signals
- H04L25/0228—Channel estimation using sounding signals with direct estimation from sounding signals
- H04L25/023—Channel estimation using sounding signals with direct estimation from sounding signals with extension to other symbols
- H04L25/0232—Channel estimation using sounding signals with direct estimation from sounding signals with extension to other symbols by interpolation between sounding signals
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2647—Arrangements specific to the receiver only
- H04L27/2655—Synchronisation arrangements
- H04L27/2668—Details of algorithms
- H04L27/2681—Details of algorithms characterised by constraints
- H04L27/2688—Resistance to perturbation, e.g. noise, interference or fading
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2647—Arrangements specific to the receiver only
- H04L27/2655—Synchronisation arrangements
- H04L27/2689—Link with other circuits, i.e. special connections between synchronisation arrangements and other circuits for achieving synchronisation
- H04L27/2695—Link with other circuits, i.e. special connections between synchronisation arrangements and other circuits for achieving synchronisation with channel estimation, e.g. determination of delay spread, derivative or peak tracking
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L5/00—Arrangements affording multiple use of the transmission path
- H04L5/003—Arrangements for allocating sub-channels of the transmission path
- H04L5/0048—Allocation of pilot signals, i.e. of signals known to the receiver
- H04L5/005—Allocation of pilot signals, i.e. of signals known to the receiver of common pilots, i.e. pilots destined for multiple users or terminals
Definitions
- the present invention relates to a digital broadcast receiving apparatus and a delay profile creating method for receiving a digital broadcast wave using an OFDM (Orthogonal Frequency Division Multiplexing) system.
- OFDM Orthogonal Frequency Division Multiplexing
- information to be transmitted is allocated to a plurality of subcarriers and digitally modulated on each subcarrier.
- the digital modulation method include a QPSK (Quadrature Phase Shift Keying) method, a QAM (Quadrature Amplitude Modulation) method, a multilevel PSK (Phase Shift Keying) method, and the like.
- a known signal is multiplexed on a specific subcarrier, and on the receiving side, the subcarrier is demodulated using this known signal.
- subcarriers that multiplex known signals are orthogonally transformed by inverse Fourier transform processing and frequency-converted to a desired transmission frequency before being transmitted.
- a transmission unit on which the inverse Fourier transform process is performed is called a symbol.
- the last part of the signal after the inverse Fourier transform process is copied and added to the head of the symbol. This added portion is called a guard interval, and even if there is an incoming wave having a delay time equal to or shorter than the guard interval length, a signal can be reproduced without interference between symbols on the receiving side.
- the scattered pilot is taken as an example of the ISDB-T system which is a domestic terrestrial digital broadcasting and the DVB-T system adopted in Europe.
- SP signal a signal
- This SP signal is periodically inserted into the transmission signal.
- the reception side has in advance the value of each SP signal periodically inserted into the transmission signal as a known SP signal, and the amplitude of each SP signal is obtained by dividing the received SP signal by the known SP signal.
- transmission path characteristics a phase fluctuation amount
- transmission path estimation a delay profile indicating the intensity of the received signal for each arrival time can be obtained.
- the delay profile obtained from the transmission path characteristic value is referred to as an SP-based delay profile.
- Another method for obtaining the delay profile is to use the power spectrum of the received signal (see, for example, Patent Document 1).
- a received signal is squared in the frequency domain, converted into a power dimension, and then subjected to inverse Fourier transform to obtain a delay profile.
- this delay profile is called a power-based delay profile.
- the power-based delay profile when the effective symbol length is Ts, the maximum delay time in which an incoming wave can be detected is Ts / 2, which is a time range longer than ⁇ Ts / 6 in the SP-based delay profile.
- the power-based delay profile has a problem that the relative time difference between the preceding wave and the delayed wave with respect to the main wave cannot be obtained, and the preceding wave and the delayed wave cannot be distinguished.
- there are a plurality of incoming waves there is a problem that intermodulation occurs due to interference between the incoming waves, and an incoming wave that does not exist originally appears on the delay profile.
- Patent Document 2 discloses an OFDM wave delay profile measuring apparatus that uses a combination of a delay profile based on the transfer function method corresponding to the SP base delay profile described above and a delay profile based on the power spectrum method corresponding to the power base delay profile. It is disclosed. In this apparatus, by using both delay profiles, in the delay profile measurement method, the length of the maximum delay time in which the delay wave can be measured, the time resolution in which the delay wave can be measured, the level in which the delay wave can be measured, The accuracy of the delay wave level and the false pulse response can be eliminated.
- the present invention has been made to solve the above-described problems, and is an environment in which a mobile body equipped with the mobile device moves at high speed, or has a time range in which an incoming wave can be detected with an SP-based delay profile.
- An object of the present invention is to provide a digital broadcast receiving apparatus and a delay profile creating method capable of providing an error-free delay profile to eliminate erroneous control and improving reception performance even when there are exceeding arriving waves.
- a digital broadcast receiver includes a Fourier transform unit that performs Fourier transform on a received orthogonal frequency division multiplex signal for each transmission unit, and subcarrier power data that is calculated from data Fourier-transformed by the Fourier transform unit.
- a power calculation unit, a first inverse Fourier transform unit that generates a first delay profile by performing an inverse Fourier transform on the subcarrier power data calculated by the subcarrier power calculation unit, and a Fourier transform performed by the Fourier transform unit A pilot signal extraction unit that extracts a pilot signal from data, a division unit that calculates transmission path characteristic data for the pilot signal of each transmission unit by dividing the pilot signal extracted by the pilot signal extraction unit by a known value; To the pilot signal of each transmission unit calculated by the division unit A time direction interpolation unit for interpolating transmission line characteristic data in the time direction, and generating a second delay profile by performing inverse Fourier transform on the transmission line characteristic data interpolated in the time direction by the time direction interpolation unit Main wave arrival times of the second inverse Fourier
- an error-free delay profile can be provided to eliminate erroneous control and improve reception performance.
- FIG. 10 is a flowchart showing a flow of operation by a delay profile synthesis unit according to the second embodiment.
- FIG. 10 is an explanatory diagram for explaining delay profile synthesis processing according to Embodiment 3; It is a block diagram which shows the structure of the digital broadcast receiver by Embodiment 4 of this invention. It is a block diagram which shows the structure of the digital broadcast receiver by Embodiment 5 of this invention.
- FIG. 1 is a diagram showing an arrangement pattern of SP signals in a transmission signal.
- Black circle symbols in FIG. 1 indicate SP signals, and white circle symbols indicate signals such as data.
- the SP signals are distributed for every 4 symbols in the time direction and every 12 carriers in the frequency direction, and for each symbol so that their insertion positions are the same frequency position in a 4 symbol period. It is arranged while shifting 3 carriers at a time.
- the received SP signal is divided by a known SP signal to estimate the channel characteristics of each SP signal.
- FIG. 2 is a diagram showing the estimation result of the transmission path characteristic of the SP signal interpolated in the time direction.
- the black circle symbol in FIG. 2 indicates the estimated value of the transmission path characteristic of the SP signal, and the black triangle symbol is The estimated value of the transmission path characteristic interpolated in the time direction is shown, and the white circle symbol indicates a signal such as data.
- FIG. 3 is a diagram showing the estimation results of the SP signal transmission path characteristics interpolated in the time direction and the frequency direction, and the black circle symbols in FIG. 3 indicate the SP signal transmission path characteristic estimation values.
- the black triangle symbol indicates the estimated value of the transmission path characteristic interpolated in the time direction
- the black square symbol indicates the estimated value of the transmission path characteristic interpolated in the frequency direction.
- the estimated values of the SP signal transmission path characteristics are interpolated in the time direction as shown in FIG. 2, and then further interpolated in the frequency direction as shown in FIG. It is possible to obtain road characteristics.
- the transmission path estimation values are dispersed by 3 carriers in the frequency direction. For this reason, the time range in which the transmission path characteristics can be estimated is expanded from Ts / 12 to Ts / 3, and even in an environment where the arrival time difference of the incoming waves is large, the transmission path is correctly within the expanded time range.
- the characteristics can be estimated.
- FIG. 4 is a diagram showing an example of the SP base delay profile.
- a delay profile (SP base delay profile) indicating the intensity of each received signal as shown in FIG. 4 is obtained.
- the main wave is an incoming wave having the highest level among a plurality of incoming waves included in the received signal.
- a main wave delay wave or a preceding wave (not shown in FIG. 4) is generated.
- a moving body for example, a vehicle
- the received signal of the receiving device undergoes Doppler fluctuations, and the transmission path characteristics for each symbol vary.
- FIG. 5 is a diagram showing estimation results of transmission path characteristics including errors by interpolation in the time direction.
- the black circle symbol in FIG. 5 indicates the estimated value of the transmission path characteristics of the SP signal, and the cross symbol is the time direction.
- the estimated values of the transmission path characteristics including errors are shown by interpolation, and white circles indicate signals such as data.
- the maximum frequency (also referred to as the maximum Doppler frequency) of transmission path characteristic fluctuation due to Doppler fluctuation exceeds 1 / ((Ts + Tg) / 8) (Hz), which is the maximum frequency that can be interpolated by interpolation in the time direction. Then, as shown in FIG. 5, the transmission path characteristic includes an error, and interpolation in the time direction cannot be performed correctly.
- Ts is the effective symbol length
- Tg is the guard interval length
- the above equation indicating the maximum frequency that can be interpolated by interpolation is derived from the sampling theorem and the SP signal interpolated in a 4-symbol period.
- FIG. 6 is a diagram showing an SP base delay profile and a pseudo incoming wave generated in the SP base delay profile.
- FIG. 6 shows the SP base delay profile obtained from the estimation result of the transmission path characteristics in which the interpolation in the time direction is erroneously performed as shown in FIG. 5 due to the high-speed movement of the mobile body equipped with the receiving apparatus.
- FIG. 7 is a diagram illustrating an example of a problem caused by a delayed wave exceeding the detection range in the SP base delay profile.
- the arrival wave is within the detection range from the original delay time on the delay profile. It appears as a return signal that returns as a signal. For this reason, the arrival wave that was originally a delayed wave becomes like a preceding wave with respect to the main wave, and the preceding wave and the delayed wave cannot be distinguished.
- the time range in which an incoming wave can be detected is up to Ts / 2, but only the relative time difference between the delayed wave and the preceding wave with respect to the main wave can be obtained. For this reason, as shown in FIG. 8, in the power-based delay profile, it is not possible to distinguish between the preceding wave and the delayed wave.
- cross-modulation occurs due to interference between the incoming waves, and an originally existing incoming wave appears on the delay profile.
- Patent Document 1 since the power-based delay profile is used, the above-described problem occurs.
- the apparatus of Patent Document 2 uses a combination of an SP base delay profile and a power base delay profile, but uses an incoming wave that appears only in the SP base delay profile as a detection result. For this reason, the pseudo arrival wave on the SP-based delay profile that occurs during high-speed movement cannot be removed.
- the receiving apparatus described in Patent Document 3 prevents false control by determining a pseudo incoming wave that occurs during high-speed movement, but has a limitation that the detection range of the incoming wave is ⁇ Ts / 6, and delay There is a possibility that erroneous control is performed for an incoming wave having a long time.
- the error signal included in the SP base delay profile is canceled using the power base delay profile, and the SP base delay profile in which the error signal is canceled is used as an advantage of both delay profiles.
- FIG. 9 is a block diagram showing the configuration of the digital broadcast receiving apparatus according to Embodiment 1 of the present invention.
- a digital broadcast receiving apparatus 1 according to Embodiment 1 is a receiving apparatus that receives a digital broadcast wave using the OFDM method, and as shown in FIG. 9, a Fourier transform unit 2, a pilot signal extraction unit 3, a known signal, Generation unit 4, division unit 5, time direction interpolation unit 6, frequency direction interpolation unit 7, equalization unit 8, subcarrier power calculation unit 9, first inverse Fourier transform unit 10a, second inverse Fourier transform unit 10b and a delay profile synthesis unit 11.
- the Fourier transform unit 2 is a configuration unit that generates a frequency axis signal by cutting out a time axis signal (a signal of a transmission unit) of one symbol period from a received signal and performing a Fourier transform. Perform transform (FFT; Fast Fourier Transform). By performing the Fourier transform, the received time axis signal is converted into a signal for each subcarrier which is a carrier unit of the frequency axis signal.
- FFT Fast Fourier Transform
- the pilot signal extraction unit 3 is a configuration unit that extracts the SP signal inserted at a predetermined subcarrier position from the signal for each subcarrier obtained by the Fourier transform unit 2.
- the known signal generation unit 4 is a component that generates a known value of the SP signal corresponding to a predetermined subcarrier position from which the SP signal is extracted by the pilot signal extraction unit 3.
- the SP signal having a known value is the value of the SP signal at the time of transmission, and is hereinafter referred to as a known SP signal.
- the divider 5 is a component that obtains a transmission line characteristic value by dividing the value of the SP signal extracted by the pilot signal extractor 3 by the value of the known SP signal corresponding thereto.
- the time direction interpolation unit 6 is a component that interpolates the transmission path characteristic value generated by the division unit 5 in the time direction, and uses linear interpolation or a FIR (Finite impulse response) filter of a plurality of symbols. Interpolate in the time direction. By performing interpolation processing in the time direction, a transmission path characteristic signal for every three carriers is obtained in the frequency direction as shown in FIG.
- the frequency direction interpolation unit 7 performs a frequency direction interpolation process on the transmission line characteristic signal obtained by the time direction interpolation unit 6 using a linear interpolation or a FIR filter of a plurality of symbols. Part. By performing this frequency direction interpolation processing, the transmission path characteristics of all subcarriers can be obtained as shown in FIG.
- the equalization unit 8 equalizes the received signal by dividing the signal for each subcarrier obtained by the Fourier transform unit 2 by the transmission path characteristic value for each subcarrier obtained by the frequency direction interpolation unit 7. It is a component.
- a signal reproduction unit is provided at the subsequent stage of the equalization unit 8, and the signal reproduction unit reproduces original transmission data from the equalization result obtained by the equalization unit 8.
- the subcarrier power calculation unit 9 is a component that calculates subcarrier power from the signal for each subcarrier obtained by the Fourier transform unit 2.
- the first inverse Fourier transform unit 10 a is a component that generates a power-based delay profile (first delay profile) from the calculation result of the subcarrier power calculation unit 9.
- the second inverse Fourier transform unit 10b generates an SP-based delay profile (second delay profile) using the result of performing the inverse Fourier transform on the transmission path characteristic signal obtained by the time direction interpolation unit 6. It is a component.
- the delay profile synthesizing unit 11 is a component that inputs a power base delay profile from the first inverse Fourier transform unit 10a and inputs an SP base delay profile from the second inverse Fourier transform unit 10b.
- the SP base delay profile value corresponding to the arrival time having a value equal to or greater than the threshold value is left, and other SP base delay profile values are replaced with the minimum value to generate a new delay profile.
- reflection or attenuation is performed from the time a signal is transmitted from a transmitting station until it is received by a receiving device, and a plurality of arriving waves reach the receiving device by being simultaneously transmitted from a plurality of transmitting sites. It becomes the signal of the path.
- Data indicating the arrival time and intensity (D / U ratio) of each incoming wave included in the multipath signal is called a delay profile.
- the strongest incoming wave is called the main wave
- the incoming wave that arrives later than the main wave is called the delayed wave
- the incoming wave that arrives earlier than the main wave is called the preceding wave.
- the subcarrier power calculation unit 9 squares the I axis (real axis) and Q axis (imaginary axis) of the frequency axis signal (complex signal) for each subcarrier obtained by the Fourier transform unit 2. Addition is performed, and the addition result is input to the I axis of the inverse Fourier transform by the first inverse Fourier transform unit 10a, and zero is input to the Q axis.
- the first inverse Fourier transform unit 10a performs the inverse Fourier transform, squares the I-axis and the Q-axis after the inverse Fourier transform, and adds the result as a power-based delay profile (first delay profile). Output to the profile composition unit 11.
- the power-based delay profile is characterized in that the main wave is the center, the time range in which the incoming wave can be detected is from 0 to Ts / 2, and both the delayed wave and the preceding wave appear symmetrically around the main wave. Note that the power-based delay profile obtained here may be used after being smoothed.
- the second inverse Fourier transform unit 10b performs inverse Fourier transform on the output (complex signal) of the time direction interpolation unit 6, squares the I axis and Q axis of the output of the inverse Fourier transform, and adds the result.
- the SP base delay profile (second delay profile) is output to the delay profile synthesis unit 11.
- the center position of the time range in which the incoming wave can be detected in the SP-based delay profile is called a demodulation reference point. That is, in the SP base delay profile, it is possible to detect an incoming wave in a range up to ⁇ Ts / 6 with the demodulation reference point as the center.
- the SP-based delay profile obtained here may be used after being smoothed.
- the order of each data in the delay profiles of both the power-based delay profile and the SP-based delay profile is called an index, and each index corresponds to the arrival time.
- FIG. 10 is a flowchart showing an operation flow by the delay profile synthesis unit of the first embodiment
- FIG. 11 is an explanatory diagram for explaining delay profile synthesis processing.
- a new delay profile generation process will be described with reference to FIG.
- the delay profile synthesis unit 11 detects the index of the main wave of the SP base delay profile (step ST1). Since the main wave has the largest value in the delay profile, the index corresponding to the largest value is detected as the main wave index among the data of the SP-based delay profile.
- the delay profile synthesis unit 11 calculates a main wave offset value corresponding to the difference between the main wave index of the SP base delay profile and the index of the center (demodulation reference point) of the SP base delay profile (step ST2). ).
- ⁇ which is an index difference between the center (demodulation reference point) of the SP base delay profile indicated by a broken line and the main wave, is the main wave offset value. Therefore, the delay profile synthesizing unit 11 obtains a value obtained by subtracting the index of the center (demodulation reference point) of the SP base delay profile from the main wave index of the SP base delay profile as the main wave offset value ⁇ .
- FIG. 11B in the power-based delay profile, the main wave is always the center of the delay profile.
- the delay profile synthesis unit 11 offsets the index of the power-based delay profile (step ST3).
- the index of the power-based delay profile is offset by the amount corresponding to the main wave offset value ⁇ to replace each data.
- the main wave index of the SP-based delay profile is matched with the main wave index of the power-based delay profile.
- the delay profile synthesizing unit 11 reads the power-based delay profile value obtained by offsetting the index in step ST3 one by one (step ST4), compares the value with a predetermined threshold (threshold), and determines whether or not the read value is smaller than the threshold. Is determined (step ST5). If the read value is equal to or greater than the threshold value (step ST5; NO), no processing is performed on the SP-based delay profile data corresponding to the arrival time (index) of the read value, and the process of step ST7 is performed.
- a predetermined threshold threshold
- step ST6 the delay profile synthesis unit 11 replaces the data of the SP base delay profile corresponding to the arrival time (index) of this read value with 0 (or incoming wave data). (Replaced with the smallest value that is not treated as) (step ST6).
- the delay time between the SP-based delay profile and the power-based delay profile may not uniquely correspond depending on the number of inverse Fourier transform points. In this case, the closest delay time (index) value is selected and replaced with 0 or the minimum value. Also, if there is no SP-based delay profile value for the corresponding delay time, no processing is performed. This is because the power-based delay profile has a delay time range (detection time range) up to Ts / 2, while the SP-based delay profile is ⁇ Ts / 6.
- step ST7 the delay profile synthesis unit 11 determines whether or not the processing has been completed for all indexes of the power-based delay profile.
- step ST7 the process returns to step ST4, the value corresponding to the next index of the power-based delay profile is read, and step ST4.
- the delay profile combining unit 11 sets the value corresponding to the value that does not satisfy the threshold in the power-based delay profile to 0 or the minimum value.
- the permuted SP-based delay profile is output as a so-called combined composite delay profile, where the advantages of both delay profiles are. That is, even if the original SP base delay profile includes a pseudo incoming wave, the advantage of the power base delay profile in which the pseudo incoming wave does not appear is used to eliminate the SP incoming delay pseudo incoming wave. Thus, the delay profile shown in FIG. 11D can be obtained as the combined delay profile, and the pseudo arrival wave does not appear.
- the power-based delay profile cannot distinguish between the preceding wave and the delayed wave, but by using the SP-based delay profile that can distinguish these, the combined delay profile has a preceding wave and a delayed wave as shown in FIG. Can distinguish waves. Furthermore, when there are a plurality of incoming waves, the power-based delay profile becomes intermodulation, and there is a drawback that an originally existing incoming wave appears on the delay profile, but it does not appear in the combined delay profile. Thus, in the first embodiment, the delay profile can be obtained more accurately than in the conventional technique.
- the Fourier transform unit 2 that performs Fourier transform on the received OFDM signal for each transmission unit, and subcarrier power data is calculated from the data that is Fourier transformed by the Fourier transform unit 2.
- a subcarrier power calculation unit 9 that performs inverse Fourier transform on the subcarrier power data to generate a power-based delay profile, and a pilot signal from data Fourier-transformed by the Fourier transform unit 2.
- a pilot signal extracting unit 3 for extracting, a dividing unit 5 for dividing the pilot signal by a known value to calculate transmission line characteristic data for the pilot signal of each transmission unit, and transmission line characteristic data for the pilot signal of each transmission unit
- the time direction interpolation unit 6 for interpolating in the time direction and the transmission path characteristic data interpolated in the time direction
- the second inverse Fourier transform unit 10b that generates an SP-based delay profile by Fourier transform, and the arrival wave of the power-based delay profile so that the arrival times of the main wave of the power-based delay profile and the SP-based delay profile match.
- a delay profile synthesis unit 11 that outputs a delay profile of the received OFDM signal by replacing the value corresponding to 1 with a value not treated as an incoming wave (0 or a minimum value not treated as an incoming wave).
- Embodiment 2 The basic structure of the digital broadcast receiving apparatus according to the second embodiment is the same as that of the first embodiment, but the method for creating a composite delay profile is different. Therefore, the configuration of the digital broadcast receiving apparatus according to the second embodiment will be described in detail below with reference to FIG. 9 shown in the first embodiment and the details of the composite delay profile creation process according to the second embodiment. .
- FIG. 12 is a flowchart showing a flow of operations performed by the delay profile synthesis unit according to the second embodiment of the present invention, and a new delay profile generation process will be described with reference to FIG.
- the delay profile synthesis unit 11 detects the index of the main wave of the SP base delay profile (step ST1a). Since the main wave has the largest value in the delay profile, the index corresponding to the largest value is detected as the main wave index among the data of the SP-based delay profile.
- the delay profile synthesis unit 11 calculates a main wave offset value corresponding to the difference between the main wave index of the SP base delay profile and the index of the center (demodulation reference point) of the SP base delay profile (step ST2a).
- a value obtained by subtracting the index of the center (demodulation reference point) of the SP base delay profile from the index of the main wave of the SP base delay profile is obtained as the main wave offset value ⁇ .
- the delay profile synthesis unit 11 offsets the index of the power-based delay profile (step ST3a).
- the index of the power base delay profile is offset by the amount of the main wave offset value ⁇ to replace each data, and the main wave indexes of the SP base delay profile and the power base delay profile are matched.
- the delay profile synthesizing unit 11 reads the power-based delay profile value obtained by offsetting the index in step ST3a one index at a time (step ST4a), and the SP base corresponding to the read value and the arrival time (index) of the read value.
- the delay profile value is multiplied (step ST5a).
- the delay time between the SP base delay profile and the power base delay profile may not uniquely correspond.
- the closest delay time (index) value is selected and multiplied.
- no processing is performed. This is because in the power-based delay profile, the delay time range (detection time range) is up to Ts / 2, while the SP-based delay profile is ⁇ Ts / 6.
- step ST6a the delay profile synthesis unit 11 determines whether or not the processing has been completed for all indexes of the power-based delay profile.
- step ST6a the process returns to step ST4a, and a value corresponding to the next index of the power-based delay profile is read, and step ST4a To step ST6a are repeated.
- step ST6a When the above processing is completed for all indexes of the power base delay profile (step ST6a; YES), the delay profile synthesis unit 11 multiplies the values of the corresponding indexes between the power base delay profile and the SP base delay profile. The result is output as a delay profile of the received OFDM signal.
- the delay profile By generating the delay profile in this way, even if the SP-based delay profile includes a pseudo incoming wave, the pseudo-incoming wave does not appear in the power-based delay profile. The level can be reduced. In addition, the power-based delay profile cannot distinguish between the preceding wave and the delayed wave, but it is also possible to distinguish these by combining with the SP-based delay profile. Further, when there are a plurality of incoming waves, the power-based delay profile has cross-modulation, and there is a disadvantage that an incoming wave that does not exist originally appears on the delay profile, but an incoming wave that does not exist in the SP-based delay profile. Therefore, the level of the incoming wave can be reduced by combining by multiplication.
- the delay profile can be obtained more accurately than in the conventional technique.
- the apparatus configuration can be simplified as compared with the first embodiment.
- the Fourier transform unit 2 that performs Fourier transform on the received OFDM signal for each transmission unit, and subcarrier power data is calculated from the data that is Fourier transformed by the Fourier transform unit 2.
- a subcarrier power calculating unit 9 a first inverse Fourier transform unit 10 a that generates a power-based delay profile by performing inverse Fourier transform on the subcarrier power data, and a pilot signal from data Fourier transformed by the Fourier transform unit 2.
- Time direction interpolation unit 6 for interpolating characteristic data in the time direction and transmission interpolated in the time direction
- the second inverse Fourier transform unit 10b that generates an SP base delay profile by performing inverse Fourier transform on the characteristic data, and the power base delay profile so that the arrival times of the main waves of the power base delay profile and the SP base delay profile match.
- the detection time of the incoming wave is offset, and the power-based delay profile offset from the detection time of the incoming wave is multiplied by the corresponding arrival time value of the SP-based delay profile, and output as the delay profile of the received OFDM signal A delay profile synthesizing unit 11.
- the power base delay profile value and the SP base delay profile the error signal included in the power base delay profile and the error signal included in the SP base delay profile cancel each other, and a high-speed moving environment is obtained. Even so, it is possible to detect an accurate arrival time delay profile.
- the apparatus configuration is simplified as compared with the first embodiment.
- Embodiment 3 The basic structure of the digital broadcast receiving apparatus according to the third embodiment is the same as that of the first embodiment, but the method for creating a composite delay profile is different. Therefore, the configuration of the digital broadcast receiving apparatus according to the third embodiment will be described in detail below with reference to FIG. 9 shown in the first embodiment and the details of the composite delay profile creation process according to the third embodiment. .
- FIG. 13 is an explanatory diagram for explaining delay profile synthesis processing according to Embodiment 3 of the present invention.
- the SP-based delay profile turns back as a delayed wave
- the delayed wave turns back as a preceding wave and appears on the delay profile.
- FIG. 13A shows a case where a preceding wave earlier than the time range of ⁇ Ts / 6 from the demodulation reference point is turned back and appears on the delay profile like a delayed wave.
- FIG. 13A shows a case where a preceding wave earlier than the time range of ⁇ Ts / 6 from the demodulation reference point is turned back and appears on the delay profile like a delayed wave.
- the power-based delay profile has a time range in which an incoming wave can be detected up to Ts / 2, but the relative time difference between the delayed wave and the preceding wave with respect to the main wave is obtained. I can't. For this reason, in the incoming wave detected in the time range of ⁇ Ts / 2 from the center (main wave) of the power-based delay profile, the preceding wave and the delayed wave cannot be distinguished.
- the delay profile synthesis unit 11 sets the delay profile contents in the detection time range of ⁇ Ts / 6 with the demodulation reference point in the SP base delay profile as the center.
- a delay profile (third delay profile) copied before and after the detection time range of the initial SP base delay profile is created. Since this delay profile coincides with the time range of ⁇ Ts / 2 from the center of the power-based delay profile, the delay profile of the received OFDM signal is determined in the same manner as in the first embodiment or the second embodiment. Can be created.
- the power-based delay profile in the time range of ⁇ Ts / 2 from the center is offset (the SP-based delay profile and the main wave index are matched), and the offset-based power-based delay profile is processed. Is read one index at a time, compared with a predetermined threshold (threshold), and the value of the SP base delay profile corresponding to the read value index smaller than the threshold is replaced with 0 or the minimum value.
- the delay profile of the OFDM signal is offset (the SP-based delay profile and the main wave index are matched), and the offset-based power-based delay profile is processed. Is read one index at a time, compared with a predetermined threshold (threshold), and the value of the SP base delay profile corresponding to the read value index smaller than the threshold is replaced with 0 or the minimum value.
- the power base delay profile value in the time range of ⁇ Ts / 2 from the center is offset processed (the SP base delay profile and the main wave index are matched), and the offset processed power base A delay profile of the received OFDM signal is obtained by reading the value of the delay profile one index at a time and multiplying the read value by the SP base delay profile value corresponding to the arrival time (index) of the read value.
- the delay profile synthesis unit 11 determines the delay profile contents in the detection time range of the incoming wave in the SP-based delay profile output from the second inverse Fourier transform unit 10b.
- a delay profile of the received OFDM signal is generated using a delay profile copied before and after the detection time range and a power-based delay profile in a time range of ⁇ Ts / 2 from the center.
- FIG. 14 is a block diagram showing a configuration of a digital broadcast receiving apparatus according to Embodiment 4 of the present invention.
- the digital broadcast receiving apparatus 1B according to the fourth embodiment includes only one inverse Fourier transform unit 10. That is, when the signal selection unit 12 switches between the output of the subcarrier power calculation unit 9 and the output of the time direction interpolation unit 6 and inputs the output to the inverse Fourier transform unit 10, one inverse Fourier transform unit 10 has the power.
- a base delay profile is generated and an SP base delay profile is generated.
- the memory unit 13 is a storage unit that stores the delay profile generated by the inverse Fourier transform unit 10, and the stored delay profile is appropriately read by the delay profile synthesis unit 11.
- FIG. 14 the same components as those in FIG.
- the signal selection unit 12 selects the output of the subcarrier power calculation unit 9 and the output of the time direction interpolation unit 6 for the same received signal, and inputs them to the inverse Fourier transform unit 10.
- the inverse Fourier transform unit 10 performs an inverse Fourier transform on the output signal of the subcarrier power calculation unit 9 and the output signal of the time direction interpolation unit 6 input via the signal selection unit 12, respectively,
- Each of the Q axes is squared and added to be stored in the memory unit 13 as a power base delay profile and an SP base delay profile.
- the inverse Fourier transform unit 10 obtains a profile obtained by copying the content of the detection time range of the SP base delay profile before and after the time series with respect to the SP base delay profile. It may be created and stored in the memory unit 13.
- the delay profile synthesizing unit 11 uses the power-based delay profile and the SP-based delay profile stored in the memory unit 13 in the same manner as in any one of the first to third embodiments to receive the received OFDM signal. Create a delay profile.
- the Fourier transform unit 2 that performs Fourier transform on the received OFDM signal for each transmission unit, and subcarrier power data is calculated from the data that is Fourier transformed by the Fourier transform unit 2.
- the subcarrier power calculating unit 9 for outputting, the pilot signal extracting unit 3 for extracting the pilot signal from the data Fourier-transformed by the Fourier transform unit 2, and dividing the extracted pilot signal by a known value to each transmission unit
- a division unit 5 that calculates transmission line characteristic data for each pilot signal, a time direction interpolation unit 6 that outputs the transmission line characteristic data for pilot signals of each transmission unit in the time direction, and a subcarrier power calculation unit 9
- the signal selection unit 12 for switching and selecting the output data of the time direction interpolation unit 6 and the signal selection unit 12
- An inverse Fourier transform unit 10 that performs inverse Fourier transform on the output data, a power-based delay profile obtained by performing inverse Fourier transform on the output data of the subcarrier power calculation unit 9 by the inverse Fourier transform unit 10, and
- FIG. FIG. 15 is a block diagram showing a configuration of a digital broadcast receiving apparatus according to Embodiment 5 of the present invention.
- the digital broadcast receiving apparatus 1C according to the fifth embodiment has a Fourier transform timing generation unit 14 added to the configuration of the fourth embodiment.
- the Fourier transform timing generation unit 14 is a component that generates an optimal Fourier transform timing (start time position of Fourier transform) based on the output (synthesis delay profile) of the delay profile synthesis unit 11.
- the generated Fourier transform timing is notified from the Fourier transform timing generation unit 14 to the Fourier transform unit 2. For example, when an arrival wave having an arrival time exceeding the guard interval appears on the delay profile, the Fourier transform timing generation unit 14 changes the Fourier transform timing so as to be within the guard interval. Thereby, reception performance can be improved.
- the delay profile synthesis unit 11 creates a synthesis delay profile by a method similar to any one of the first to third embodiments.
- the time direction interpolation unit 6 and the frequency direction interpolation unit 7 each determine an optimum interpolation coefficient based on the output (synthesis delay profile) of the delay profile synthesis unit 11. For example, when an incoming wave that exceeds the band of the interpolation coefficient appears on the delay profile, the coefficient is changed to the interpolation coefficient so as to be within the band.
- the digital broadcast receiving apparatus includes the above-described Fourier transform timing control by the Fourier transform timing generation unit 14, control of the interpolation coefficient by the time direction interpolation unit 6, and interpolation by the frequency direction interpolation unit 7.
- control of the insertion coefficient at least one control is executed, and all the controls may be combined and executed.
- the Fourier transform timing generation unit 14 that determines the start timing (start time position) of the Fourier transform from the combined delay profile generated by the delay profile combining unit 11 is provided.
- the accurate start timing of the Fourier transform can be determined using the accurate delay profile that does not include the error signal generated by the delay profile synthesis unit 11.
- the delay profile combining unit 11 since at least one of the time direction interpolation unit 6 and the frequency direction interpolation unit 7 determines an interpolation coefficient from the combined delay profile generated by the delay profile combining unit 11, the delay profile combining unit 11 generates the interpolation coefficient.
- An accurate delay profile that does not include the generated error signal can be used to determine the optimal interpolation factor.
- the concept of the fifth embodiment can be applied to any one of the first to third embodiments. Is applied, and at least one of the control of the Fourier transform timing by the Fourier transform timing generation unit 14, the control of the interpolation coefficient by the time direction interpolation unit 6, and the control of the interpolation coefficient by the frequency direction interpolation unit 7 is applied. May be configured to execute, or may be configured to execute all controls in combination.
- the digital broadcast receiving apparatus is an environment in which a mobile body on which the digital broadcast receiver is mounted moves at high speed or there is an incoming wave that exceeds the time range in which the incoming wave can be detected with the SP-based delay profile. Since a delay profile that does not include an error can be provided and accurate reception is possible without erroneous control, it is suitable for an on-vehicle digital broadcast receiving apparatus.
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Abstract
Description
また、特定のサブキャリアには、既知の信号が多重されており、受信側において、この既知信号を利用してサブキャリアの復調が行われる。
一方、既知信号を多重するサブキャリアは、逆フーリエ変換処理により直交変換され、所望の送信周波数に周波数変換されてから伝送される。この逆フーリエ変換処理が行われる伝送単位をシンボルと呼ぶ。
逆フーリエ変換処理後の信号の最後部は、コピーされてシンボルの先頭に付加される。この付加された部分は、ガードインターバルと呼ばれ、ガードインターバル長以下の遅延時間を有する到来波があっても、受信側においてシンボル間で干渉することなく、信号を再生することができる。 In the OFDM scheme, information to be transmitted is allocated to a plurality of subcarriers and digitally modulated on each subcarrier. Examples of the digital modulation method include a QPSK (Quadrature Phase Shift Keying) method, a QAM (Quadrature Amplitude Modulation) method, a multilevel PSK (Phase Shift Keying) method, and the like.
Further, a known signal is multiplexed on a specific subcarrier, and on the receiving side, the subcarrier is demodulated using this known signal.
On the other hand, subcarriers that multiplex known signals are orthogonally transformed by inverse Fourier transform processing and frequency-converted to a desired transmission frequency before being transmitted. A transmission unit on which the inverse Fourier transform process is performed is called a symbol.
The last part of the signal after the inverse Fourier transform process is copied and added to the head of the symbol. This added portion is called a guard interval, and even if there is an incoming wave having a delay time equal to or shorter than the guard interval length, a signal can be reproduced without interference between symbols on the receiving side.
受信側は、送信信号に周期的に挿入される各SP信号の値を既知のSP信号として予め有しており、受信したSP信号を既知のSP信号で除算することによって、各SP信号における振幅と位相の変動量(以下、伝送路特性と呼ぶ)を推定(以下、伝送路推定と呼ぶ)することができる。
また、この伝送路特性の値を逆フーリエ変換することにより、受信信号の到来時間ごとの強度を示す遅延プロファイルを得ることができる。ここでは、伝送路特性値から求めた遅延プロファイルをSPベース遅延プロファイルと呼ぶ。 As the known signal inserted in advance in the transmission signal, the scattered pilot (SP) is taken as an example of the ISDB-T system which is a domestic terrestrial digital broadcasting and the DVB-T system adopted in Europe. There is a signal (hereinafter referred to as SP signal). This SP signal is periodically inserted into the transmission signal.
The reception side has in advance the value of each SP signal periodically inserted into the transmission signal as a known SP signal, and the amplitude of each SP signal is obtained by dividing the received SP signal by the known SP signal. And a phase fluctuation amount (hereinafter referred to as transmission path characteristics) can be estimated (hereinafter referred to as transmission path estimation).
In addition, by performing inverse Fourier transform on the value of the transmission path characteristic, a delay profile indicating the intensity of the received signal for each arrival time can be obtained. Here, the delay profile obtained from the transmission path characteristic value is referred to as an SP-based delay profile.
しかしながら、電力ベース遅延プロファイルでは、主波に対して先行波と遅延波との相対的な時間差しか求められず、先行波と遅延波との見分けがつかないという問題点があった。また、複数の到来波がある場合には、到来波相互の干渉によって混変調が生じ、本来存在しない到来波が遅延プロファイル上に現れるという問題点があった。 In the power-based delay profile, when the effective symbol length is Ts, the maximum delay time in which an incoming wave can be detected is Ts / 2, which is a time range longer than ± Ts / 6 in the SP-based delay profile.
However, the power-based delay profile has a problem that the relative time difference between the preceding wave and the delayed wave with respect to the main wave cannot be obtained, and the preceding wave and the delayed wave cannot be distinguished. In addition, when there are a plurality of incoming waves, there is a problem that intermodulation occurs due to interference between the incoming waves, and an incoming wave that does not exist originally appears on the delay profile.
しかしながら、伝達関数法による遅延プロファイル(SPベース遅延プロファイル)にのみ現れている到来波については、そのまま測定結果として出力されるために、当該受信装置を搭載した移動体の高速移動時に発生する疑似到来波を削除できないという問題点があった。 On the other hand,
However, since the incoming wave that appears only in the delay profile (SP-based delay profile) by the transfer function method is output as a measurement result as it is, the pseudo arrival that occurs when the mobile body equipped with the receiving device moves at high speed There was a problem that the waves could not be deleted.
しかしながら、到来波を検出可能な時間範囲が±Ts/6までという制限があり、遅延時間の長い到来波に対しては誤制御する可能性があるという問題点があった。
また、特許文献3に記載の受信装置は、疑似到来波が現れない正確な遅延プロファイルを出力する機能を備えていない。 In the OFDM receiver described in
However, there is a problem that the time range in which an incoming wave can be detected is limited to ± Ts / 6, and an incoming wave with a long delay time may be erroneously controlled.
Further, the receiving apparatus described in
実施の形態1.
先ず、OFDM方式の送信信号に挿入するSP信号、SPベース遅延プロファイル及び電力ベース遅延プロファイルについて説明する。
図1は、送信信号におけるSP信号の配置パターンを示す図であり、図1中の黒丸記号がSP信号を示しており、白丸記号がデータ等の信号を示している。図1に示すように、SP信号は、時間方向に4シンボルごと、周波数方向に12キャリアごとに分散配置されており、かつそれらの挿入位置が4シンボル周期で同じ周波数位置になるようにシンボルごとに3キャリアずつシフトしながら配置されている。受信側では、受信したSP信号を既知のSP信号で除算することにより、各SP信号における伝送路特性の推定を行う。 Hereinafter, in order to explain the present invention in more detail, modes for carrying out the present invention will be described with reference to the accompanying drawings.
Embodiment 1 FIG.
First, an SP signal, an SP base delay profile, and a power base delay profile to be inserted into an OFDM transmission signal will be described.
FIG. 1 is a diagram showing an arrangement pattern of SP signals in a transmission signal. Black circle symbols in FIG. 1 indicate SP signals, and white circle symbols indicate signals such as data. As shown in FIG. 1, the SP signals are distributed for every 4 symbols in the time direction and every 12 carriers in the frequency direction, and for each symbol so that their insertion positions are the same frequency position in a 4 symbol period. It is arranged while shifting 3 carriers at a time. On the receiving side, the received SP signal is divided by a known SP signal to estimate the channel characteristics of each SP signal.
また、図3は、時間方向と周波数方向に内挿補間したSP信号の伝送路特性の推定結果を示す図であり、図3中の黒丸記号がSP信号の伝送路特性の推定値を示し、黒三角記号が時間方向に内挿補間した伝送路特性の推定値を示しており、黒四角記号が周波数方向に内挿補間した伝送路特性の推定値を示している。 FIG. 2 is a diagram showing the estimation result of the transmission path characteristic of the SP signal interpolated in the time direction. The black circle symbol in FIG. 2 indicates the estimated value of the transmission path characteristic of the SP signal, and the black triangle symbol is The estimated value of the transmission path characteristic interpolated in the time direction is shown, and the white circle symbol indicates a signal such as data.
FIG. 3 is a diagram showing the estimation results of the SP signal transmission path characteristics interpolated in the time direction and the frequency direction, and the black circle symbols in FIG. 3 indicate the SP signal transmission path characteristic estimation values. The black triangle symbol indicates the estimated value of the transmission path characteristic interpolated in the time direction, and the black square symbol indicates the estimated value of the transmission path characteristic interpolated in the frequency direction.
ここで、図2のように、12キャリアずつ分散配置されたSP信号の伝送路推定値を時間方向に内挿補間することで、伝送路推定値が周波数方向に3キャリアずつ分散される。このため、伝送路特性を推定可能な時間範囲がTs/12からTs/3へ拡張され、到来波の到来時間差が大きい環境であっても、拡張された時間範囲内であれば、正しく伝送路特性の推定が可能となる。 The estimated values of the SP signal transmission path characteristics are interpolated in the time direction as shown in FIG. 2, and then further interpolated in the frequency direction as shown in FIG. It is possible to obtain road characteristics.
Here, as shown in FIG. 2, by interpolating the SP channel transmission path estimation values dispersed and arranged in units of 12 carriers in the time direction, the transmission path estimation values are dispersed by 3 carriers in the frequency direction. For this reason, the time range in which the transmission path characteristics can be estimated is expanded from Ts / 12 to Ts / 3, and even in an environment where the arrival time difference of the incoming waves is large, the transmission path is correctly within the expanded time range. The characteristics can be estimated.
図7は、SPベース遅延プロファイルで検出範囲を超えた遅延波による不具合の一例を示す図である。図7に示すように、SPベース遅延プロファイルでは、±Ts/6の時間範囲を超える遅延時間の到来波があると、当該到来波が、遅延プロファイル上で、本来の遅延時間から検出範囲内の信号として折り返す折り返し信号となって現れる。このため、主波に対して、本来遅延波であった到来波が先行波のようになり、先行波と遅延波の見分けがつかなくなる。
一方、電力ベース遅延プロファイルでは、到来波を検出可能な時間範囲がTs/2まであるが、主波に対する遅延波と先行波との相対的な時間差しか求められない。このため、図8に示すように、電力ベース遅延プロファイルにおいては、先行波と遅延波の見分けがつかない。また、複数の到来波がある場合には、電力ベース遅延プロファイルにおいて、到来波相互の干渉によって混変調が生じ、本来存在しない到来波が遅延プロファイル上に現れる。 In the SP-based delay profile, if there is an incoming wave with a delay time exceeding the time range of ± Ts / 6, which is the detection range of the incoming wave, the following problems occur.
FIG. 7 is a diagram illustrating an example of a problem caused by a delayed wave exceeding the detection range in the SP base delay profile. As shown in FIG. 7, in the SP-based delay profile, if there is an arrival wave with a delay time exceeding the time range of ± Ts / 6, the arrival wave is within the detection range from the original delay time on the delay profile. It appears as a return signal that returns as a signal. For this reason, the arrival wave that was originally a delayed wave becomes like a preceding wave with respect to the main wave, and the preceding wave and the delayed wave cannot be distinguished.
On the other hand, in the power-based delay profile, the time range in which an incoming wave can be detected is up to Ts / 2, but only the relative time difference between the delayed wave and the preceding wave with respect to the main wave can be obtained. For this reason, as shown in FIG. 8, in the power-based delay profile, it is not possible to distinguish between the preceding wave and the delayed wave. In addition, when there are a plurality of incoming waves, in the power-based delay profile, cross-modulation occurs due to interference between the incoming waves, and an originally existing incoming wave appears on the delay profile.
先ず、サブキャリア電力算出部9は、フーリエ変換部2で得られたサブキャリアごとの周波数軸の信号(複素信号)のI軸(実軸)とQ軸(虚数軸)とをそれぞれ二乗して加算し、この加算結果を、第1の逆フーリエ変換部10aによる逆フーリエ変換のI軸の入力とし、Q軸にはゼロを入力する。
第1の逆フーリエ変換部10aは、逆フーリエ変換を実行し、逆フーリエ変換後のI軸とQ軸をそれぞれ二乗して加算した結果を、電力ベース遅延プロファイル(第1の遅延プロファイル)として遅延プロファイル合成部11へ出力する。
電力ベース遅延プロファイルは、主波が中心となり、到来波の検出可能な時間範囲が0からTs/2までであり、遅延波と先行波ともに主波を中心に左右対称に現れるという特徴がある。なお、ここで得られた電力ベース遅延プロファイルは平滑処理して用いてもよい。 Next, the operation will be described.
First, the subcarrier
The first inverse
The power-based delay profile is characterized in that the main wave is the center, the time range in which the incoming wave can be detected is from 0 to Ts / 2, and both the delayed wave and the preceding wave appear symmetrically around the main wave. Note that the power-based delay profile obtained here may be used after being smoothed.
また、電力ベース遅延プロファイル及びSPベース遅延プロファイルの双方の遅延プロファイルにおける各データの順番をインデックスと呼び、それぞれのインデックスは到来時間に相当する。 The second inverse
The order of each data in the delay profiles of both the power-based delay profile and the SP-based delay profile is called an index, and each index corresponds to the arrival time.
遅延プロファイル合成部11は、SPベース遅延プロファイルの主波のインデックスを検出する(ステップST1)。遅延プロファイルにおいて、主波は最も大きな値を有するので、SPベース遅延プロファイルの各データのうち、最も大きな値に対応するインデックスを、主波のインデックスとして検出する。 FIG. 10 is a flowchart showing an operation flow by the delay profile synthesis unit of the first embodiment, and FIG. 11 is an explanatory diagram for explaining delay profile synthesis processing. A new delay profile generation process will be described with reference to FIG.
The delay
つまり、元のSPベース遅延プロファイルに疑似到来波が含まれる場合であっても、疑似到来波が現れない電力ベース遅延プロファイルの利点を利用して、SPベース遅延プロファイルの疑似到来波を除去することで、合成遅延プロファイルとして、図11(d)に示す遅延プロファイルを得ることができ、疑似到来波が現れなくなる。
また、電力ベース遅延プロファイルでは先行波と遅延波を区別ができないが、これらを区別できるSPベース遅延プロファイルを利用することで、合成遅延プロファイルでは、図11(d)に示すように先行波と遅延波を区別できる。
さらに、複数の到来波がある場合、電力ベース遅延プロファイルでは混変調となって、本来存在しない到来波が遅延プロファイル上に現れるという欠点があったが、合成遅延プロファイルには現れない。このように、実施の形態1では、従来の技術と比べて正確に遅延プロファイルを求めることができる。 When the above processing is completed for all indexes of the power-based delay profile (step ST7; YES), the delay
That is, even if the original SP base delay profile includes a pseudo incoming wave, the advantage of the power base delay profile in which the pseudo incoming wave does not appear is used to eliminate the SP incoming delay pseudo incoming wave. Thus, the delay profile shown in FIG. 11D can be obtained as the combined delay profile, and the pseudo arrival wave does not appear.
In addition, the power-based delay profile cannot distinguish between the preceding wave and the delayed wave, but by using the SP-based delay profile that can distinguish these, the combined delay profile has a preceding wave and a delayed wave as shown in FIG. Can distinguish waves.
Furthermore, when there are a plurality of incoming waves, the power-based delay profile becomes intermodulation, and there is a drawback that an originally existing incoming wave appears on the delay profile, but it does not appear in the combined delay profile. Thus, in the first embodiment, the delay profile can be obtained more accurately than in the conventional technique.
このように、電力ベース遅延プロファイルを利用してSPベース遅延プロファイルの疑似到来波を削除することで、電力ベース遅延プロファイルとSPベース遅延プロファイルの双方の遅延プロファイルの利点を合成した遅延プロファイルを得ることができ、高速移動環境であっても、正確な到来時間と正確な電力の遅延プロファイルが得られる。 As described above, according to the first embodiment, the
In this way, by deleting the pseudo-arrival wave of the SP-based delay profile using the power-based delay profile, a delay profile that combines the advantages of both the power-based delay profile and the SP-based delay profile is obtained. Even in a high-speed moving environment, an accurate arrival time and accurate power delay profile can be obtained.
この実施の形態2によるデジタル放送受信装置は、上記実施の形態1と基本的な構成は同一であるが、合成遅延プロファイルの作成方法が異なる。
そこで、実施の形態2のデジタル放送受信装置の構成については、上記実施の形態1で示した図9を参照しながら、以下、上記実施の形態2による合成遅延プロファイルの作成処理の詳細を説明する。
The basic structure of the digital broadcast receiving apparatus according to the second embodiment is the same as that of the first embodiment, but the method for creating a composite delay profile is different.
Therefore, the configuration of the digital broadcast receiving apparatus according to the second embodiment will be described in detail below with reference to FIG. 9 shown in the first embodiment and the details of the composite delay profile creation process according to the second embodiment. .
遅延プロファイル合成部11は、SPベース遅延プロファイルの主波のインデックスを検出する(ステップST1a)。遅延プロファイルにおいて、主波は最も大きな値を有するので、SPベース遅延プロファイルの各データのうち、最も大きな値に対応するインデックスを、主波のインデックスとして検出する。 FIG. 12 is a flowchart showing a flow of operations performed by the delay profile synthesis unit according to the second embodiment of the present invention, and a new delay profile generation process will be described with reference to FIG.
The delay
また、対応する遅延時間のSPベース遅延プロファイルの値が存在しない場合は処理を行わない。これは、電力ベース遅延プロファイルでは、遅延時間範囲(検出時間範囲)がTs/2までであるのに対し、SPベース遅延プロファイルは±Ts/6のためである。 Depending on the number of points of the inverse Fourier transform, the delay time between the SP base delay profile and the power base delay profile may not uniquely correspond. In this case, the closest delay time (index) value is selected and multiplied.
Also, if there is no SP-based delay profile value for the corresponding delay time, no processing is performed. This is because in the power-based delay profile, the delay time range (detection time range) is up to Ts / 2, while the SP-based delay profile is ± Ts / 6.
また、電力ベース遅延プロファイルでは先行波と遅延波を区別することができないが、SPベース遅延プロファイルと合成することにより、これらの区別も可能である。
さらに、複数の到来波がある場合、電力ベース遅延プロファイルでは混変調となって、本来存在しない到来波が遅延プロファイル上に現れるという欠点があったが、SPベース遅延プロファイルには存在しない到来波であるので、乗算により合成すると当該到来波のレベルを低減することができる。
このように、実施の形態2では、従来の技術に比べて正確に遅延プロファイルを求めることができる。また、電力ベース遅延プロファイルの値と所定の閾値とを比較する必要がなく、当該閾値の調整も必要ないため、上記実施の形態1と比べて装置構成を簡素化することが可能である。 By generating the delay profile in this way, even if the SP-based delay profile includes a pseudo incoming wave, the pseudo-incoming wave does not appear in the power-based delay profile. The level can be reduced.
In addition, the power-based delay profile cannot distinguish between the preceding wave and the delayed wave, but it is also possible to distinguish these by combining with the SP-based delay profile.
Further, when there are a plurality of incoming waves, the power-based delay profile has cross-modulation, and there is a disadvantage that an incoming wave that does not exist originally appears on the delay profile, but an incoming wave that does not exist in the SP-based delay profile. Therefore, the level of the incoming wave can be reduced by combining by multiplication.
Thus, in the second embodiment, the delay profile can be obtained more accurately than in the conventional technique. In addition, since it is not necessary to compare the value of the power-based delay profile with a predetermined threshold, and it is not necessary to adjust the threshold, the apparatus configuration can be simplified as compared with the first embodiment.
このように、電力ベース遅延プロファイルの値とSPベース遅延プロファイルとを合成することで、電力ベース遅延プロファイルに含まれる誤差信号と、SPベース遅延プロファイルに含まれる誤差信号とが打ち消しあい、高速移動環境であっても、正確な到来時間の遅延プロファイルを検出することが可能になる。また、閾値を備える必要がないため、上記実施の形態1と比べて装置構成が簡素になる。 As described above, according to the second embodiment, the
In this way, by combining the power base delay profile value and the SP base delay profile, the error signal included in the power base delay profile and the error signal included in the SP base delay profile cancel each other, and a high-speed moving environment is obtained. Even so, it is possible to detect an accurate arrival time delay profile. Moreover, since it is not necessary to provide a threshold value, the apparatus configuration is simplified as compared with the first embodiment.
この実施の形態3によるデジタル放送受信装置は、上記実施の形態1と基本的な構成は同一であるが、合成遅延プロファイルの作成方法が異なる。
そこで、実施の形態3のデジタル放送受信装置の構成については、上記実施の形態1で示した図9を参照しながら、以下、上記実施の形態3による合成遅延プロファイルの作成処理の詳細を説明する。
The basic structure of the digital broadcast receiving apparatus according to the third embodiment is the same as that of the first embodiment, but the method for creating a composite delay profile is different.
Therefore, the configuration of the digital broadcast receiving apparatus according to the third embodiment will be described in detail below with reference to FIG. 9 shown in the first embodiment and the details of the composite delay profile creation process according to the third embodiment. .
一方、電力ベース遅延プロファイルは、図13(c)に示すように、到来波を検出可能な時間範囲がTs/2まであるが、主波に対する遅延波と先行波との相対的な時間差しか求められない。このため、電力ベース遅延プロファイルの中心(主波)から±Ts/2の時間範囲で検出された到来波において、先行波と遅延波の見分けがつかない。 FIG. 13 is an explanatory diagram for explaining delay profile synthesis processing according to
On the other hand, as shown in FIG. 13C, the power-based delay profile has a time range in which an incoming wave can be detected up to Ts / 2, but the relative time difference between the delayed wave and the preceding wave with respect to the main wave is obtained. I can't. For this reason, in the incoming wave detected in the time range of ± Ts / 2 from the center (main wave) of the power-based delay profile, the preceding wave and the delayed wave cannot be distinguished.
この遅延プロファイルは、電力ベース遅延プロファイルの中心から±Ts/2の時間範囲と一致するので、上記実施の形態1又は上記実施の形態2と同様な方法で、受信されたOFDM信号の遅延プロファイルを作成することができる。 Therefore, as shown in FIG. 13B, the delay
Since this delay profile coincides with the time range of ± Ts / 2 from the center of the power-based delay profile, the delay profile of the received OFDM signal is determined in the same manner as in the first embodiment or the second embodiment. Can be created.
また、上記実施の形態2のように、中心から±Ts/2の時間範囲の電力ベース遅延プロファイルの値をオフセット処理(SPベース遅延プロファイルと主波のインデックスを合わせる)し、オフセット処理した電力ベース遅延プロファイルの値を1インデックスずつ読み出して、この読み出し値と、この読み出し値の到来時間(インデックス)に該当する上記SPベース遅延プロファイルの値とを乗算したものを、受信されたOFDM信号の遅延プロファイルとする。 That is, as in the first embodiment, the power-based delay profile in the time range of ± Ts / 2 from the center is offset (the SP-based delay profile and the main wave index are matched), and the offset-based power-based delay profile is processed. Is read one index at a time, compared with a predetermined threshold (threshold), and the value of the SP base delay profile corresponding to the read value index smaller than the threshold is replaced with 0 or the minimum value. The delay profile of the OFDM signal.
Further, as in the second embodiment, the power base delay profile value in the time range of ± Ts / 2 from the center is offset processed (the SP base delay profile and the main wave index are matched), and the offset processed power base A delay profile of the received OFDM signal is obtained by reading the value of the delay profile one index at a time and multiplying the read value by the SP base delay profile value corresponding to the arrival time (index) of the read value. And
このようにすることで、上記実施の形態1又は上記実施の形態2と同様の効果が得られるとともに、SPベース遅延プロファイルにおける到来波の検出時間範囲を3倍に拡張することができる。 As described above, according to the third embodiment, the delay
By doing this, the same effects as those of the first embodiment or the second embodiment can be obtained, and the detection time range of the incoming wave in the SP-based delay profile can be expanded three times.
図14は、この発明の実施の形態4によるデジタル放送受信装置の構成を示すブロック図である。実施の形態1から実施の形態3までの構成では、第1の逆フーリエ変換部10aと第2の逆フーリエ変換部10bとの二つの逆フーリエ変換部を備えていたが、図14に示すように、実施の形態4によるデジタル放送受信装置1Bは、一つの逆フーリエ変換部10のみを備える。つまり、信号選択部12が、サブキャリア電力算出部9の出力と時間方向内挿部6の出力とを切り替えて逆フーリエ変換部10へ入力することにより、一つの逆フーリエ変換部10が、電力ベース遅延プロファイルの生成とSPベース遅延プロファイルの生成を行う。また、メモリ部13は、逆フーリエ変換部10により生成された遅延プロファイルを格納する記憶部であり、格納された遅延プロファイルは、遅延プロファイル合成部11によって適宜読み出される。なお、図14において、図9と同一の構成部には同一符号を付して説明を省略する。 Embodiment 4 FIG.
FIG. 14 is a block diagram showing a configuration of a digital broadcast receiving apparatus according to Embodiment 4 of the present invention. In the configuration from the first embodiment to the third embodiment, the two inverse Fourier transform units, the first inverse
信号選択部12が、受信された同一の信号に対する、サブキャリア電力算出部9の出力と時間方向内挿部6の出力とをそれぞれ選択して逆フーリエ変換部10へ入力する。
逆フーリエ変換部10では、信号選択部12を介して入力したサブキャリア電力算出部9の出力信号と時間方向内挿部6の出力信号とをそれぞれ逆フーリエ変換し、これら変換結果のI軸とQ軸をそれぞれ二乗して加算することにより、電力ベース遅延プロファイル及びSPベース遅延プロファイルとしてメモリ部13に格納する。
なお、このとき、逆フーリエ変換部10が、実施の形態3で示したように、SPベース遅延プロファイルに対して、当該SPベース遅延プロファイルの検出時間範囲の内容を時系列前後にコピーしたプロファイルを作成しメモリ部13に格納してもよい。
遅延プロファイル合成部11は、メモリ部13に格納された電力ベース遅延プロファイル及びSPベース遅延プロファイルを用いて実施の形態1から実施の形態3までのいずれかと同様な方法で、受信されたOFDM信号の遅延プロファイルを作成する。 Next, the operation will be described.
The
The inverse
At this time, as shown in the third embodiment, the inverse
The delay
図15は、この発明の実施の形態5によるデジタル放送受信装置の構成を示すブロック図である。実施の形態5によるデジタル放送受信装置1Cは、上記実施の形態4の構成にフーリエ変換タイミング生成部14を追加している。フーリエ変換タイミング生成部14は、遅延プロファイル合成部11の出力(合成遅延プロファイル)に基づいて、最適なフーリエ変換タイミング(フーリエ変換の開始時間位置)を生成する構成部である。生成されたフーリエ変換タイミングは、フーリエ変換タイミング生成部14からフーリエ変換部2へ通知される。例えば、ガードインターバルを超える到来時間の到来波が遅延プロファイル上に現れた場合には、フーリエ変換タイミング生成部14が、ガードインターバル内に収まるようにフーリエ変換タイミングを変更する。これにより、受信性能を向上させることができる。なお、遅延プロファイル合成部11は、上記実施の形態1から上記実施の形態3のうちいずれかと同様な方法で合成遅延プロファイルを作成する。
FIG. 15 is a block diagram showing a configuration of a digital broadcast receiving apparatus according to
また、時間方向内挿部6及び周波数方向内挿部7のうちの少なくとも一方が、遅延プロファイル合成部11によって生成された合成遅延プロファイルから内挿係数を決定するので、遅延プロファイル合成部11によって生成された誤差信号を含まない正確な遅延プロファイルが用いて最適な内挿係数を決定することができる。
このように誤りの無い遅延プロファイル合成結果を用いて制御を行うことにより、高速走行時や遅延の長い到来波があるような環境でも、誤制御をすることがなくなり、受信装置の受信性能を向上させることが可能となる。 As described above, according to the fifth embodiment, the Fourier transform
In addition, since at least one of the time
By performing control using the error-free delay profile synthesis result in this way, erroneous control is eliminated even at high speeds or in environments with long delays, improving the reception performance of the receiver. It becomes possible to make it.
Claims (24)
- 直交周波数分割多重された信号を受信するデジタル放送受信装置において、
受信された直交周波数分割多重信号を伝送単位ごとにフーリエ変換するフーリエ変換部と、
前記フーリエ変換部によってフーリエ変換されたデータからサブキャリア電力データを算出するサブキャリア電力算出部と、
前記サブキャリア電力算出部によって算出されたサブキャリア電力データを逆フーリエ変換して、第1の遅延プロファイルを生成する第1の逆フーリエ変換部と、
前記フーリエ変換部によってフーリエ変換されたデータからパイロット信号を抽出するパイロット信号抽出部と、
前記パイロット信号抽出部によって抽出されたパイロット信号を既知の値で除算して、各伝送単位のパイロット信号に対する伝送路特性データを算出する除算部と、
前記除算部によって算出された各伝送単位のパイロット信号に対する伝送路特性データを時間方向に内挿する時間方向内挿部と、
前記時間方向内挿部によって時間方向に内挿された伝送路特性データを逆フーリエ変換して、第2の遅延プロファイルを生成する第2の逆フーリエ変換部と、
前記第1の逆フーリエ変換部によって生成された第1の遅延プロファイルと前記第2の逆フーリエ変換部によって生成された第2の遅延プロファイルとの主波の到来時間が一致するように前記第1の遅延プロファイルの到来波の検出時間をオフセットするとともに、前記第2の遅延プロファイルのうち、前記到来波の検出時間をオフセットした第1の遅延プロファイルにおける所定の閾値以上の値の到来時間に対応する値を残し、前記閾値未満の値の到来時間に対応する値を到来波と扱わない値に置き換えて、前記受信された直交周波数分割多重信号の遅延プロファイルとして出力する遅延プロファイル合成部とを備えたことを特徴とするデジタル放送受信装置。 In a digital broadcast receiving apparatus that receives an orthogonal frequency division multiplexed signal,
A Fourier transform unit for Fourier transforming the received orthogonal frequency division multiplexed signal for each transmission unit;
A subcarrier power calculation unit that calculates subcarrier power data from data Fourier-transformed by the Fourier transform unit;
A first inverse Fourier transform unit that generates a first delay profile by performing an inverse Fourier transform on the subcarrier power data calculated by the subcarrier power calculation unit;
A pilot signal extraction unit for extracting a pilot signal from data Fourier-transformed by the Fourier transform unit;
Dividing the pilot signal extracted by the pilot signal extraction unit by a known value to calculate transmission line characteristic data for the pilot signal of each transmission unit; and
A time direction interpolation unit that interpolates transmission path characteristic data for the pilot signal of each transmission unit calculated by the division unit in the time direction;
A second inverse Fourier transform unit that generates a second delay profile by performing inverse Fourier transform on the transmission line characteristic data interpolated in the time direction by the time direction interpolation unit;
The first delay profile generated by the first inverse Fourier transform unit and the second delay profile generated by the second inverse Fourier transform unit match the first wave arrival times. And the arrival time of a value equal to or greater than a predetermined threshold in the first delay profile of the second delay profile offset from the detection time of the arrival wave. A delay profile synthesis unit that leaves a value and replaces a value corresponding to the arrival time of a value less than the threshold with a value not treated as an incoming wave, and outputs the value as a delay profile of the received orthogonal frequency division multiplexing signal A digital broadcast receiver characterized by that. - 前記遅延プロファイル合成部は、前記第2の逆フーリエ変換部によって生成された第2の遅延プロファイルの代わりに、当該第2の遅延プロファイルにおける到来波の検出時間範囲の内容を当該検出時間範囲の前後にそれぞれコピーした第3の遅延プロファイルと、前記第1の逆フーリエ変換部によって生成された第1の遅延プロファイルとの主波の到来時間が一致するように前記第1の遅延プロファイルの到来波の検出時間をオフセットするとともに、前記第3の遅延プロファイルのうち、前記到来波の検出時間をオフセットした第1の遅延プロファイルにおける所定の閾値以上の値の到来時間に対応する値を残し、前記閾値未満の値の到来時間に対応する値を到来波と扱わない値に置き換えて、前記受信された直交周波数分割多重信号の遅延プロファイルとして出力することを特徴とする請求項1記載のデジタル放送受信装置。 The delay profile synthesizing unit converts the contents of the detection time range of the incoming wave in the second delay profile before and after the detection time range instead of the second delay profile generated by the second inverse Fourier transform unit. Of the arrival wave of the first delay profile so that the arrival times of the main wave of the third delay profile copied to the first delay profile generated by the first inverse Fourier transform unit coincide with each other. While offsetting the detection time, a value corresponding to the arrival time of a value equal to or greater than a predetermined threshold in the first delay profile offset from the detection time of the incoming wave is left out of the third delay profile, and less than the threshold The value corresponding to the arrival time of the value is replaced with a value not treated as an incoming wave, and the received orthogonal frequency division multiplexing signal is received. Digital broadcast receiving apparatus according to claim 1, characterized in that the output as a delay profile.
- 前記遅延プロファイル合成部により生成された遅延プロファイルの内容に基づいて、前記フーリエ変換部によるフーリエ変換の開始タイミングを決定するフーリエ変換タイミング生成部を備えたことを特徴とする請求項1記載のデジタル放送受信装置。 2. The digital broadcast according to claim 1, further comprising a Fourier transform timing generation unit that determines a start timing of Fourier transform by the Fourier transform unit based on the content of the delay profile generated by the delay profile synthesis unit. Receiver device.
- 前記時間方向内挿部は、前記遅延プロファイル合成部により生成された遅延プロファイルの内容に基づいて、前記伝送路特性データの時間方向の内挿の内挿係数を決定することを特徴とする請求項1記載のデジタル放送受信装置。 The time direction interpolation unit determines an interpolation coefficient for the time direction interpolation of the transmission path characteristic data based on the content of the delay profile generated by the delay profile synthesis unit. The digital broadcast receiver according to 1.
- 前記時間方向内挿部により時間方向に内挿された伝送路特性データを周波数方向に内挿する周波数方向内挿部を備え、
前記周波数方向内挿部は、前記遅延プロファイル合成部により生成された遅延プロファイルの内容に基づいて、前記伝送路特性データの周波数方向の内挿の内挿係数を決定することを特徴とする請求項1記載のデジタル放送受信装置。 A frequency direction interpolation unit for interpolating the transmission line characteristic data interpolated in the time direction by the time direction interpolation unit in the frequency direction;
The frequency direction interpolation unit determines an interpolation coefficient for frequency direction interpolation of the transmission path characteristic data based on a content of a delay profile generated by the delay profile synthesis unit. The digital broadcast receiver according to 1. - 直交周波数分割多重された信号を受信するデジタル放送受信装置において、
受信された直交周波数分割多重信号を伝送単位ごとにフーリエ変換するフーリエ変換部と、
前記フーリエ変換部によってフーリエ変換されたデータからサブキャリア電力データを算出するサブキャリア電力算出部と、
前記サブキャリア電力算出部によって算出されたサブキャリア電力データを逆フーリエ変換して、第1の遅延プロファイルを生成する第1の逆フーリエ変換部と、
前記フーリエ変換部によってフーリエ変換されたデータからパイロット信号を抽出するパイロット信号抽出部と、
前記パイロット信号抽出部によって抽出されたパイロット信号を既知の値で除算して、各伝送単位のパイロット信号に対する伝送路特性データを算出する除算部と、
前記除算部によって算出された各伝送単位のパイロット信号に対する伝送路特性データを時間方向に内挿する時間方向内挿部と、
前記時間方向内挿部によって時間方向に内挿された伝送路特性データを逆フーリエ変換して、第2の遅延プロファイルを生成する第2の逆フーリエ変換部と、
前記第1の逆フーリエ変換部によって生成された第1の遅延プロファイルと前記第2の逆フーリエ変換部によって生成された第2の遅延プロファイルとの主波の到来時間が一致するように前記第1の遅延プロファイルの到来波の検出時間をオフセットするとともに、前記到来波の検出時間をオフセットした第1の遅延プロファイルと、前記第2の遅延プロファイルとの対応する到来時間の値を乗算して、前記受信された直交周波数分割多重信号の遅延プロファイルとして出力する遅延プロファイル合成部とを備えたことを特徴とするデジタル放送受信装置。 In a digital broadcast receiving apparatus that receives an orthogonal frequency division multiplexed signal,
A Fourier transform unit for Fourier transforming the received orthogonal frequency division multiplexed signal for each transmission unit;
A subcarrier power calculation unit that calculates subcarrier power data from data Fourier-transformed by the Fourier transform unit;
A first inverse Fourier transform unit that generates a first delay profile by performing an inverse Fourier transform on the subcarrier power data calculated by the subcarrier power calculation unit;
A pilot signal extraction unit for extracting a pilot signal from data Fourier-transformed by the Fourier transform unit;
Dividing the pilot signal extracted by the pilot signal extraction unit by a known value to calculate transmission line characteristic data for the pilot signal of each transmission unit; and
A time direction interpolation unit that interpolates transmission path characteristic data for the pilot signal of each transmission unit calculated by the division unit in the time direction;
A second inverse Fourier transform unit that generates a second delay profile by performing inverse Fourier transform on the transmission line characteristic data interpolated in the time direction by the time direction interpolation unit;
The first delay profile generated by the first inverse Fourier transform unit and the second delay profile generated by the second inverse Fourier transform unit match the first wave arrival times. And the first delay profile offset from the arrival time detection time and the corresponding arrival time value of the second delay profile, and A digital broadcast receiving apparatus comprising: a delay profile synthesis unit that outputs a delay profile of a received orthogonal frequency division multiplexed signal. - 前記遅延プロファイル合成部は、前記第2の逆フーリエ変換部によって生成された第2の遅延プロファイルの代わりに、当該第2の遅延プロファイルにおける到来波の検出時間範囲の内容を当該検出時間範囲の前後にそれぞれコピーした第3の遅延プロファイルと前記第1の逆フーリエ変換部によって生成された第1の遅延プロファイルとの主波の到来時間が一致するように前記第1の遅延プロファイルの到来波の検出時間をオフセットするとともに、前記到来波の検出時間をオフセットした第1の遅延プロファイルと、前記第3の遅延プロファイルとの対応する到来時間の値を乗算して、前記受信された直交周波数分割多重信号の遅延プロファイルとして出力することを特徴とする請求項6記載のデジタル放送受信装置。 The delay profile synthesizing unit converts the contents of the detection time range of the incoming wave in the second delay profile before and after the detection time range instead of the second delay profile generated by the second inverse Fourier transform unit. Detection of the arrival wave of the first delay profile so that the arrival times of the main wave of the third delay profile copied to the first delay profile and the first delay profile generated by the first inverse Fourier transform unit coincide with each other The received orthogonal frequency division multiplex signal is obtained by multiplying a corresponding arrival time value of the first delay profile offset from the time of arrival and offsetting the detection time of the incoming wave and the third delay profile. 7. The digital broadcast receiving apparatus according to claim 6, wherein the digital broadcast receiving apparatus outputs the delay profile as a delay profile.
- 前記遅延プロファイル合成部により生成された遅延プロファイルの内容に基づいて、前記フーリエ変換部によるフーリエ変換の開始タイミングを決定するフーリエ変換タイミング生成部を備えたことを特徴とする請求項6記載のデジタル放送受信装置。 7. The digital broadcast according to claim 6, further comprising a Fourier transform timing generation unit that determines a start timing of Fourier transform by the Fourier transform unit based on the content of the delay profile generated by the delay profile synthesis unit. Receiver device.
- 前記時間方向内挿部は、前記遅延プロファイル合成部により生成された遅延プロファイルの内容に基づいて、前記伝送路特性データの時間方向の内挿の内挿係数を決定することを特徴とする請求項6記載のデジタル放送受信装置。 The time direction interpolation unit determines an interpolation coefficient for the time direction interpolation of the transmission path characteristic data based on the content of the delay profile generated by the delay profile synthesis unit. 6. The digital broadcast receiver according to 6.
- 前記時間方向内挿部により時間方向に内挿された伝送路特性データを周波数方向に内挿する周波数方向内挿部を備え、
前記周波数方向内挿部は、前記遅延プロファイル合成部により生成された遅延プロファイルの内容に基づいて、前記伝送路特性データの周波数方向の内挿の内挿係数を決定することを特徴とする請求項6記載のデジタル放送受信装置。 A frequency direction interpolation unit for interpolating the transmission line characteristic data interpolated in the time direction by the time direction interpolation unit in the frequency direction;
The frequency direction interpolation unit determines an interpolation coefficient for frequency direction interpolation of the transmission path characteristic data based on a content of a delay profile generated by the delay profile synthesis unit. 6. The digital broadcast receiver according to 6. - 直交周波数分割多重された信号を受信するデジタル放送受信装置において、
受信された直交周波数分割多重信号を伝送単位ごとにフーリエ変換するフーリエ変換部と、
前記フーリエ変換部によってフーリエ変換されたデータからサブキャリア電力データを算出して出力するサブキャリア電力算出部と、
前記フーリエ変換部によってフーリエ変換されたデータからパイロット信号を抽出するパイロット信号抽出部と、
前記パイロット信号抽出部によって抽出されたパイロット信号を既知の値で除算して、各伝送単位のパイロット信号に対する伝送路特性データを算出する除算部と、
前記除算部によって算出された各伝送単位のパイロット信号に対する伝送路特性データを時間方向に内挿して出力する時間方向内挿部と、
前記サブキャリア電力算出部と前記時間方向内挿部の出力データを切り替えて選択する信号選択部と、
前記信号選択部によって選択された出力データを逆フーリエ変換する逆フーリエ変換部と、
前記逆フーリエ変換部によって、前記サブキャリア電力算出部の出力データを逆フーリエ変換して得られた第1の遅延プロファイルと、前記時間方向内挿部の出力データを逆フーリエ変換して得られた第2の遅延プロファイルとを記憶するメモリ部と、
前記メモリ部から読み出した前記第1の遅延プロファイルと前記第2の遅延プロファイルとの主波の到来時間が一致するように前記第1の遅延プロファイルの到来波の検出時間をオフセットするとともに、前記第2の遅延プロファイルのうち、前記到来波の検出時間をオフセットした前記第1の遅延プロファイルにおける所定の閾値以上の値の到来時間に対応する値を残し、前記閾値未満の値の到来時間に対応する値を到来波と扱わない値に置き換えて、前記受信された直交周波数分割多重信号の遅延プロファイルとして出力する遅延プロファイル合成部とを備えたことを特徴とするデジタル放送受信装置。 In a digital broadcast receiving apparatus that receives an orthogonal frequency division multiplexed signal,
A Fourier transform unit for Fourier transforming the received orthogonal frequency division multiplexed signal for each transmission unit;
A subcarrier power calculation unit that calculates and outputs subcarrier power data from data Fourier-transformed by the Fourier transform unit;
A pilot signal extraction unit for extracting a pilot signal from data Fourier-transformed by the Fourier transform unit;
Dividing the pilot signal extracted by the pilot signal extraction unit by a known value to calculate transmission line characteristic data for the pilot signal of each transmission unit; and
A time direction interpolation unit for interpolating in the time direction and outputting transmission path characteristic data for pilot signals of each transmission unit calculated by the division unit;
A signal selection unit that switches and selects output data of the subcarrier power calculation unit and the time direction interpolation unit;
An inverse Fourier transform unit that performs inverse Fourier transform on the output data selected by the signal selection unit;
Obtained by inverse Fourier transform of the first delay profile obtained by inverse Fourier transform of the output data of the subcarrier power calculation unit and the output data of the time direction interpolation unit by the inverse Fourier transform unit A memory unit for storing a second delay profile;
The detection time of the arrival wave of the first delay profile is offset so that the arrival time of the main wave of the first delay profile and the second delay profile read from the memory unit match, and the first delay profile Among the two delay profiles, a value corresponding to the arrival time having a value greater than or equal to a predetermined threshold in the first delay profile in which the detection time of the incoming wave is offset is left and corresponds to the arrival time having a value less than the threshold. A digital broadcast receiving apparatus comprising: a delay profile synthesizing unit that outputs a value as a delay profile of the received orthogonal frequency division multiplexed signal by replacing a value with a value that is not treated as an incoming wave. - 前記遅延プロファイル合成部は、前記第2の逆フーリエ変換部によって生成された第2の遅延プロファイルの代わりに、当該第2の遅延プロファイルにおける到来波の検出時間範囲の内容を当該検出時間範囲の前後にそれぞれコピーした第3の遅延プロファイルと前記第1の遅延プロファイルとの主波の到来時間が一致するように前記第1の遅延プロファイルの到来波の検出時間をオフセットするとともに、前記第3の遅延プロファイルのうち、前記到来波の検出時間をオフセットした第1の遅延プロファイルにおける所定の閾値以上の値の到来時間に対応する値を残し、前記閾値未満の値の到来時間に対応する値を到来波と扱わない値に置き換えて、前記受信された直交周波数分割多重信号の遅延プロファイルとして出力することを特徴とする請求項11記載のデジタル放送受信装置。 The delay profile synthesizing unit converts the contents of the detection time range of the incoming wave in the second delay profile before and after the detection time range instead of the second delay profile generated by the second inverse Fourier transform unit. And offsetting the detection time of the arrival wave of the first delay profile so that the arrival times of the main wave of the third delay profile copied to the first delay profile coincide with each other. Among the profiles, a value corresponding to the arrival time having a value greater than or equal to a predetermined threshold in the first delay profile offset from the detection time of the arrival wave is left, and a value corresponding to the arrival time having a value less than the threshold is set as the arrival wave. The value is replaced with a value that is not handled as a delay profile of the received orthogonal frequency division multiplexed signal. Digital broadcast receiving apparatus according to claim 11.
- 前記遅延プロファイル合成部により生成された遅延プロファイルの内容に基づいて、前記フーリエ変換部によるフーリエ変換の開始タイミングを決定するフーリエ変換タイミング生成部を備えたことを特徴とする請求項11記載のデジタル放送受信装置。 12. The digital broadcast according to claim 11, further comprising a Fourier transform timing generation unit that determines a start timing of Fourier transform by the Fourier transform unit based on the content of the delay profile generated by the delay profile synthesis unit. Receiver device.
- 前記時間方向内挿部は、前記遅延プロファイル合成部により生成された遅延プロファイルの内容に基づいて、前記伝送路特性データの時間方向の内挿の内挿係数を決定することを特徴とする請求項11記載のデジタル放送受信装置。 The time direction interpolation unit determines an interpolation coefficient for the time direction interpolation of the transmission path characteristic data based on the content of the delay profile generated by the delay profile synthesis unit. 11. A digital broadcast receiving apparatus according to 11.
- 前記時間方向内挿部により時間方向に内挿された伝送路特性データを周波数方向に内挿する周波数方向内挿部を備え、
前記周波数方向内挿部は、前記遅延プロファイル合成部により生成された遅延プロファイルの内容に基づいて、前記伝送路特性データの周波数方向の内挿の内挿係数を決定することを特徴とする請求項11記載のデジタル放送受信装置。 A frequency direction interpolation unit for interpolating the transmission line characteristic data interpolated in the time direction by the time direction interpolation unit in the frequency direction;
The frequency direction interpolation unit determines an interpolation coefficient for frequency direction interpolation of the transmission path characteristic data based on a content of a delay profile generated by the delay profile synthesis unit. 11. A digital broadcast receiving apparatus according to 11. - 直交周波数分割多重された信号を受信するデジタル放送受信装置において、
受信された直交周波数分割多重信号を伝送単位ごとにフーリエ変換するフーリエ変換部と、
前記フーリエ変換部によってフーリエ変換されたデータからサブキャリア電力データを算出して出力するサブキャリア電力算出部と、
前記フーリエ変換部によってフーリエ変換されたデータからパイロット信号を抽出するパイロット信号抽出部と、
前記パイロット信号抽出部によって抽出されたパイロット信号を既知の値で除算して、各伝送単位のパイロット信号に対する伝送路特性データを算出する除算部と、
前記除算部によって算出された各伝送単位のパイロット信号に対する伝送路特性データを時間方向に内挿して出力する時間方向内挿部と、
前記サブキャリア電力算出部と前記時間方向内挿部の出力データを切り替えて選択する信号選択部と、
前記信号選択部によって選択された出力データを逆フーリエ変換する逆フーリエ変換部と、
前記逆フーリエ変換部によって、前記サブキャリア電力算出部の出力データを逆フーリエ変換して得られた第1の遅延プロファイルと、前記時間方向内挿部の出力データを逆フーリエ変換して得られた第2の遅延プロファイルとを記憶するメモリ部と、
前記メモリ部から読み出した前記第1の遅延プロファイルと前記第2の遅延プロファイルとの主波の到来時間が一致するように前記第1の遅延プロファイルの到来波の検出時間をオフセットするとともに、前記到来波の検出時間をオフセットした第1の遅延プロファイルと前記第2の遅延プロファイルとの対応する到来時間の値を乗算して、前記受信された直交周波数分割多重信号の遅延プロファイルとして出力する遅延プロファイル合成部とを備えたことを特徴とするデジタル放送受信装置。 In a digital broadcast receiving apparatus that receives an orthogonal frequency division multiplexed signal,
A Fourier transform unit for Fourier transforming the received orthogonal frequency division multiplexed signal for each transmission unit;
A subcarrier power calculation unit that calculates and outputs subcarrier power data from data Fourier-transformed by the Fourier transform unit;
A pilot signal extraction unit for extracting a pilot signal from data Fourier-transformed by the Fourier transform unit;
Dividing the pilot signal extracted by the pilot signal extraction unit by a known value to calculate transmission line characteristic data for the pilot signal of each transmission unit; and
A time direction interpolation unit for interpolating in the time direction and outputting transmission path characteristic data for pilot signals of each transmission unit calculated by the division unit;
A signal selection unit that switches and selects output data of the subcarrier power calculation unit and the time direction interpolation unit;
An inverse Fourier transform unit that performs inverse Fourier transform on the output data selected by the signal selection unit;
Obtained by inverse Fourier transform of the first delay profile obtained by inverse Fourier transform of the output data of the subcarrier power calculation unit and the output data of the time direction interpolation unit by the inverse Fourier transform unit A memory unit for storing a second delay profile;
The arrival time of the arrival wave of the first delay profile is offset so that the arrival time of the main wave of the first delay profile and the second delay profile read from the memory unit match, and the arrival time Delay profile synthesis that multiplies the corresponding arrival time values of the first delay profile offset from the wave detection time and the second delay profile, and outputs the result as a delay profile of the received orthogonal frequency division multiplexed signal And a digital broadcast receiving apparatus. - 前記遅延プロファイル合成部は、前記第2の逆フーリエ変換部によって生成された第2の遅延プロファイルの代わりに、当該第2の遅延プロファイルにおける到来波の検出時間範囲の内容を当該検出時間範囲の前後にそれぞれコピーした第3の遅延プロファイルと前記第1の遅延プロファイルとの主波の到来時間が一致するように前記第1の遅延プロファイルの到来波の検出時間をオフセットするとともに、前記到来波の検出時間をオフセットした第1の遅延プロファイルと前記第3の遅延プロファイルとの対応する到来時間の値を乗算して、前記受信された直交周波数分割多重信号の遅延プロファイルとして出力することを特徴とする請求項16記載のデジタル放送受信装置。 The delay profile synthesizing unit converts the contents of the detection time range of the incoming wave in the second delay profile before and after the detection time range instead of the second delay profile generated by the second inverse Fourier transform unit. The detection time of the arrival wave of the first delay profile is offset so that the arrival time of the main wave of the third delay profile copied to each of the first delay profile and the first delay profile coincide with each other. The time delay offset first delay profile is multiplied by the corresponding arrival time value of the third delay profile and output as a delay profile of the received orthogonal frequency division multiplexed signal. Item 17. The digital broadcast receiver according to Item 16.
- 前記遅延プロファイル合成部により生成された遅延プロファイルの内容に基づいて、前記フーリエ変換部によるフーリエ変換の開始タイミングを決定するフーリエ変換タイミング生成部を備えたことを特徴とする請求項16記載のデジタル放送受信装置。 17. The digital broadcast according to claim 16, further comprising a Fourier transform timing generation unit that determines a start timing of Fourier transform by the Fourier transform unit based on the content of the delay profile generated by the delay profile synthesis unit. Receiver device.
- 前記時間方向内挿部は、前記遅延プロファイル合成部により生成された遅延プロファイルの内容に基づいて、前記伝送路特性データの時間方向の内挿の内挿係数を決定することを特徴とする請求項16記載のデジタル放送受信装置。 The time direction interpolation unit determines an interpolation coefficient for the time direction interpolation of the transmission path characteristic data based on the content of the delay profile generated by the delay profile synthesis unit. 16. The digital broadcast receiver according to 16.
- 前記時間方向内挿部により時間方向に内挿された伝送路特性データを周波数方向に内挿する周波数方向内挿部を備え、
前記周波数方向内挿部は、前記遅延プロファイル合成部により生成された遅延プロファイルの内容に基づいて、前記伝送路特性データの周波数方向の内挿の内挿係数を決定することを特徴とする請求項16記載のデジタル放送受信装置。 A frequency direction interpolation unit for interpolating the transmission line characteristic data interpolated in the time direction by the time direction interpolation unit in the frequency direction;
The frequency direction interpolation unit determines an interpolation coefficient for frequency direction interpolation of the transmission path characteristic data based on a content of a delay profile generated by the delay profile synthesis unit. 16. The digital broadcast receiver according to 16. - 直交周波数分割多重された信号を受信するデジタル放送受信装置による受信信号の遅延プロファイル作成方法において、
受信された直交周波数分割多重信号を伝送単位ごとにフーリエ変換したデータから算出されたサブキャリア電力データを逆フーリエ変換して第1の遅延プロファイルを生成するステップと、
前記受信された直交周波数分割多重信号を伝送単位ごとにフーリエ変換したデータから抽出したパイロット信号を既知の値で除算して得られた各伝送単位のパイロット信号に対する伝送路特性データを時間方向に内挿し、当該時間方向に内挿した伝送路特性データを逆フーリエ変換して、第2の遅延プロファイルを生成するステップと、
前記第1の遅延プロファイルと前記第2の遅延プロファイルとの主波の到来時間が一致するよう前記第1の遅延プロファイルの到来波の検出時間をオフセットするステップと、
前記第2の遅延プロファイルのうち、前記到来波の検出時間をオフセットした第1の遅延プロファイルにおける所定の閾値以上の値の到来時間に対応する値を残し、前記閾値未満の値の到来時間に対応する値を到来波と扱わない値に置き換えて、前記受信された直交周波数分割多重信号の遅延プロファイルとして出力するステップとを備えたことを特徴とする遅延プロファイル作成方法。 In a method for creating a delay profile of a received signal by a digital broadcast receiver that receives an orthogonal frequency division multiplexed signal,
Generating a first delay profile by performing inverse Fourier transform on subcarrier power data calculated from data obtained by performing Fourier transform on a received orthogonal frequency division multiplexed signal for each transmission unit;
The transmission path characteristic data for the pilot signal of each transmission unit obtained by dividing the pilot signal extracted from the data obtained by Fourier-transforming the received orthogonal frequency division multiplexing signal for each transmission unit by a known value is stored in the time direction. Inserting and inverse Fourier transforming the transmission path characteristic data interpolated in the time direction to generate a second delay profile;
Offsetting the detection time of the arrival wave of the first delay profile so that the arrival times of the main wave of the first delay profile and the second delay profile match;
Among the second delay profiles, a value corresponding to the arrival time of a value greater than or equal to a predetermined threshold in the first delay profile offset from the detection time of the incoming wave is left, and the arrival time of a value less than the threshold is supported And a step of replacing the value to be treated as a value not treated as an incoming wave and outputting the value as a delay profile of the received orthogonal frequency division multiplexing signal. - 直交周波数分割多重された信号を受信するデジタル放送受信装置による受信信号の遅延プロファイル作成方法において、
受信された直交周波数分割多重信号を伝送単位ごとにフーリエ変換したデータから算出されたサブキャリア電力データを逆フーリエ変換して第1の遅延プロファイルを生成するステップと、
前記受信された直交周波数分割多重信号を伝送単位ごとにフーリエ変換したデータから抽出したパイロット信号を既知の値で除算して得られた各伝送単位のパイロット信号に対する伝送路特性データを時間方向に内挿し、当該時間方向に内挿した伝送路特性データを逆フーリエ変換して、第2の遅延プロファイルを生成するステップと、
前記第2の遅延プロファイルにおける到来波の検出時間範囲の内容を当該検出時間範囲の前後にそれぞれコピーした第3の遅延プロファイルと、前記第1の逆フーリエ変換部によって生成された第1の遅延プロファイルとの主波の到来時間が一致するよう前記第1の遅延プロファイルの到来波の検出時間をオフセットするステップと、
前記第3の遅延プロファイルのうち、前記到来波の検出時間をオフセットした第1の遅延プロファイルにおける所定の閾値以上の値の到来時間に対応する値を残し、前記閾値未満の値の到来時間に対応する値を到来波と扱わない値に置き換えて、前記受信された直交周波数分割多重信号の遅延プロファイルとして出力するステップとを備えたことを特徴とする遅延プロファイル作成方法。 In a method for creating a delay profile of a received signal by a digital broadcast receiver that receives an orthogonal frequency division multiplexed signal,
Generating a first delay profile by performing inverse Fourier transform on subcarrier power data calculated from data obtained by performing Fourier transform on a received orthogonal frequency division multiplexed signal for each transmission unit;
The transmission path characteristic data for the pilot signal of each transmission unit obtained by dividing the pilot signal extracted from the data obtained by Fourier-transforming the received orthogonal frequency division multiplexing signal for each transmission unit by a known value is stored in the time direction. Inserting and inverse Fourier transforming the transmission path characteristic data interpolated in the time direction to generate a second delay profile;
A third delay profile obtained by copying the contents of the detection time range of the incoming wave in the second delay profile before and after the detection time range, and a first delay profile generated by the first inverse Fourier transform unit Offsetting the arrival time of the first delay profile so that the arrival times of the main waves coincide with each other;
Of the third delay profile, a value corresponding to the arrival time of a value greater than or equal to a predetermined threshold in the first delay profile offset from the detection time of the incoming wave is left, and the arrival time of a value less than the threshold is supported And a step of replacing the value to be treated as a value not treated as an incoming wave and outputting the value as a delay profile of the received orthogonal frequency division multiplexing signal. - 直交周波数分割多重された信号を受信するデジタル放送受信装置による受信信号の遅延プロファイル作成方法において、
受信された直交周波数分割多重信号を伝送単位ごとにフーリエ変換したデータから算出されたサブキャリア電力データを逆フーリエ変換して第1の遅延プロファイルを生成するステップと、
前記受信された直交周波数分割多重信号を伝送単位ごとにフーリエ変換したデータから抽出したパイロット信号を既知の値で除算して得られた各伝送単位のパイロット信号に対する伝送路特性データを時間方向に内挿し、当該時間方向に内挿した伝送路特性データを逆フーリエ変換して、第2の遅延プロファイルを生成するステップと、
前記第1の遅延プロファイルと前記第2の遅延プロファイルとの主波の到来時間が一致するよう前記第1の遅延プロファイルの到来波の検出時間をオフセットするステップと、
前記到来波の検出時間をオフセットした第1の遅延プロファイルと、前記第2の遅延プロファイルとの対応する到来時間の値を乗算して、前記受信された直交周波数分割多重信号の遅延プロファイルとして出力するステップとを備えたことを特徴とする遅延プロファイル作成方法。 In a method for creating a delay profile of a received signal by a digital broadcast receiver that receives an orthogonal frequency division multiplexed signal,
Generating a first delay profile by performing inverse Fourier transform on subcarrier power data calculated from data obtained by performing Fourier transform on a received orthogonal frequency division multiplexed signal for each transmission unit;
The transmission path characteristic data for the pilot signal of each transmission unit obtained by dividing the pilot signal extracted from the data obtained by Fourier-transforming the received orthogonal frequency division multiplexing signal for each transmission unit by a known value is stored in the time direction. Inserting and inverse Fourier transforming the transmission path characteristic data interpolated in the time direction to generate a second delay profile;
Offsetting the detection time of the arrival wave of the first delay profile so that the arrival times of the main wave of the first delay profile and the second delay profile match;
Multiplying the corresponding arrival time values of the first delay profile offset from the detection time of the incoming wave and the second delay profile, and outputs the result as the delay profile of the received orthogonal frequency division multiplexing signal A delay profile creating method comprising the steps of: - 直交周波数分割多重された信号を受信するデジタル放送受信装置による受信信号の遅延プロファイル作成方法において、
受信された直交周波数分割多重信号を伝送単位ごとにフーリエ変換したデータから算出されたサブキャリア電力データを逆フーリエ変換して第1の遅延プロファイルを生成するステップと、
前記受信された直交周波数分割多重信号を伝送単位ごとにフーリエ変換したデータから抽出したパイロット信号を既知の値で除算して得られた各伝送単位のパイロット信号に対する伝送路特性データを時間方向に内挿し、当該時間方向に内挿した伝送路特性データを逆フーリエ変換して、第2の遅延プロファイルを生成するステップと、
前記第2の遅延プロファイルにおける到来波の検出時間範囲の内容を当該検出時間範囲の前後にそれぞれコピーした第3の遅延プロファイルと、前記第1の遅延プロファイルとの主波の到来時間が一致するよう前記第1の遅延プロファイルの到来波の検出時間をオフセットするステップと、
前記到来波の検出時間をオフセットした第1の遅延プロファイルと、前記第3の遅延プロファイルとの対応する到来時間の値を乗算して、前記受信された直交周波数分割多重信号の遅延プロファイルとして出力するステップとを備えたことを特徴とする遅延プロファイル作成方法。 In a method for creating a delay profile of a received signal by a digital broadcast receiver that receives an orthogonal frequency division multiplexed signal,
Generating a first delay profile by performing inverse Fourier transform on subcarrier power data calculated from data obtained by performing Fourier transform on a received orthogonal frequency division multiplexed signal for each transmission unit;
The transmission path characteristic data for the pilot signal of each transmission unit obtained by dividing the pilot signal extracted from the data obtained by Fourier-transforming the received orthogonal frequency division multiplexing signal for each transmission unit by a known value is stored in the time direction. Inserting and inverse Fourier transforming the transmission path characteristic data interpolated in the time direction to generate a second delay profile;
The arrival time of the main wave of the first delay profile matches the third delay profile obtained by copying the contents of the detection time range of the incoming wave in the second delay profile before and after the detection time range, respectively. Offsetting the detection time of the incoming wave of the first delay profile;
Multiplying the corresponding arrival time values of the first delay profile offset from the detection time of the arrival wave and the third delay profile, and outputs the result as the delay profile of the received orthogonal frequency division multiplexing signal A delay profile creating method comprising the steps of:
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