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WO2008023680A1 - dispositif de réception à porteuses multiples - Google Patents

dispositif de réception à porteuses multiples Download PDF

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Publication number
WO2008023680A1
WO2008023680A1 PCT/JP2007/066152 JP2007066152W WO2008023680A1 WO 2008023680 A1 WO2008023680 A1 WO 2008023680A1 JP 2007066152 W JP2007066152 W JP 2007066152W WO 2008023680 A1 WO2008023680 A1 WO 2008023680A1
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WO
WIPO (PCT)
Prior art keywords
delay profile
channel estimation
estimation value
path position
replica
Prior art date
Application number
PCT/JP2007/066152
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English (en)
Japanese (ja)
Inventor
Hidenori Kayama
Syuji Arai
Katsuyoshi Naka
Atsushi Sumasu
Original Assignee
Panasonic Corporation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Application filed by Panasonic Corporation filed Critical Panasonic Corporation
Priority to JP2008530905A priority Critical patent/JP4964242B2/ja
Publication of WO2008023680A1 publication Critical patent/WO2008023680A1/fr

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Classifications

    • 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
    • H04L25/0204—Channel estimation of multiple channels
    • 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
    • H04L25/0226—Channel estimation using sounding signals sounding signals per se
    • 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

Definitions

  • the present invention relates to a multicarrier receiver, and more particularly to a multicarrier receiver that demodulates data symbols using channel estimation values obtained from pilot symbols.
  • the standardization organization 3GPP (registered trademark) is studying 3GPP RAN LTE (Long Term Evolution) for the purpose of further improving the current third-generation mobile phone system.
  • 3GPP registered trademark
  • 3GPP RAN LTE Long Term Evolution
  • OFDM orthogonal frequency division multiple access
  • Non-Patent Document 1 discloses a method for removing this noise component.
  • the primary channel estimation value for each subcarrier in which pilot symbols are arranged is obtained, and the channel estimation value is averaged in the frequency direction to obtain the final estimation value for each subcarrier.
  • the white noise is suppressed by averaging.
  • Non-Patent Document 1 when averaging in the frequency direction is performed on a frame as proposed in 3GPP RAN LTE as disclosed in Non-Patent Document 1 above, the pilot symbol interval in the frequency direction is reduced.
  • a large TU (Typical Urban) 6-path model has high frequency selectivity, so averaging in the frequency domain direction cannot provide accurate channel estimates.
  • Non-Patent Document 2 a first-order channel estimation value (correlation value between a received pilot symbol and a pilot symbol replica) for each subcarrier in which pilot symbols are arranged is inversely dispersed Fourier transformed (IDFT: Obtain the channel response (delay profile) of the time domain 3 ⁇ 4 ⁇ by inverse discrete Fourier transform), replace the component that seems to be noise with 0, and then perform discrete Fourier transform (DFT: final Fourier transform) for the final estimation for each subcarrier A method for determining the value is disclosed.
  • IDFT inversely dispersed Fourier transformed
  • Non-Patent Document 2 a primary channel estimation value for each subcarrier in which pilot symbols are arranged. IDFT is used to obtain the channel response (delay profile) in the time domain, the component that seems to be noise is replaced with 0, and then the final estimate for each subcarrier is obtained by DFT. The resolution becomes lower, the channel response in the time domain after IDFT becomes wider, and the channel components that you do not want to remove when you replace the components that appear to be noise are also deleted, causing distortion. Due to the above, there is a problem that the error rate characteristic is deteriorated and the communication quality is lowered.
  • Patent Document 1 Japanese Unexamined Patent Application Publication No. 2006-54840
  • Non-Patent Document 1 Kawai et al., "Effect of multi-slot subcarrier averaging channel estimation using orthogonal pilot channel in OFCDM MMO multiplexing using QRM-MLD", IEICE RCS_2004-68 (2004-05)
  • Non-Patent Document 2 Yuping Zhao and Aiping Huang, A Novel Channel Estimation Method for OFDM Mobile Communication Systems Based on Pilot Signals and Transform Domain Processing ", Proc. IEEE VTC'97, pp. 2089— 2093, 1997.
  • Non-patent document 3 Kobayashi et al., "Proposal of OFDM channel estimation method using discrete cosine transform", IEICE Transactions, Vol.J88-B, No. l, pp.256-268, Jan.2005
  • Patent Document 1 can remove both noise and interference, so that it can be expected to improve reception performance.
  • the calculation amount becomes enormous.
  • the cost is extremely high because an arithmetic processing circuit capable of processing an enormous amount of processing and having a very high processing capability is required.
  • An object of the present invention is to provide a low-cost multi-carrier receiving apparatus that can reduce communication load by suppressing deterioration in channel estimation accuracy and can reduce the load on an arithmetic processing circuit.
  • the multicarrier receiving apparatus of the present invention includes a channel estimation value calculating means for calculating a channel estimation value from each pilot symbol force included in the received frame, and a delay by applying an inverse Fourier transform to the calculated channel estimation value.
  • a delay profile generation means for generating a profile, a detection means for detecting a path position and a complex amplitude at the path position from the delay profile, and multiplying each complex amplitude value by a basic impulse signal, corresponding to each complex amplitude value
  • Delay profile reproducing means for re-creating a delay profile by superimposing the multiplication result at the path position, and channel estimation value forming means for performing a Fourier transform on the re-created delay profile to form a channel estimate value
  • demodulating means for demodulating data symbols using the formed channel estimation value Employs a configuration having a.
  • FIG. 1 is a diagram for explaining pilot symbol arrangement in a conventional frame.
  • FIG. 2 is a block diagram showing a configuration of a multicarrier receiving apparatus according to Embodiment 1 of the present invention.
  • FIG. 3 is a block diagram showing a configuration of a noise suppression unit in FIG.
  • FIG. 4 is a diagram for explaining a process in a delay profile generation unit according to the first embodiment.
  • FIG. 5 is a diagram for explaining a basic impulse component replica generation method in the first embodiment.
  • FIG. 6 is a diagram showing an example of a basic impulse component replica in the first embodiment
  • FIG. 7 is a flowchart for explaining delay profile re-creation processing in the time-domain channel response replica generation unit according to the first embodiment.
  • FIG. 8 is a diagram comparing error rate characteristics between the multicarrier receiver according to Embodiment 1 and a conventional noise suppression method.
  • FIG. 9 is a diagram for explaining an operation of a time domain channel response replica generation unit according to the second embodiment.
  • FIG. 10 is a flowchart for explaining a process of generating a delay profile in a state where noise components are removed in the time domain channel response replica generation unit according to the second embodiment.
  • FIG. 11 is a diagram for explaining an operation of a time domain channel response replica generation unit according to the second embodiment.
  • FIG. 12 is a diagram for explaining an operation of a time domain channel response replica generation unit according to the third embodiment.
  • FIG. 13 is a diagram for explaining an operation of a time domain channel response replica generation unit according to the third embodiment.
  • multicarrier receiving apparatus 100 of the present embodiment particularly performs OF DM communication here, and includes FFT section 110, pilot / data symbol separation section 120, channel estimation value calculation section 130.
  • a noise suppression unit 140, a channel estimation value interpolation unit 150, A data symbol demodulation unit 160 and an error correction decoding unit 170 are included.
  • the FFT unit 110 receives an OFDM signal based on a frame in which pilot symbols received via an antenna as shown in FIG. Processed (down-conversion, A / D conversion, etc.), the signal after radio processing is converted from a time signal to a frequency signal, and a received frame is output.
  • Pilot / data symbol separation section 120 receives a received frame, separates it into pilot symbols and other data symbols, outputs the separated pilot symbols to channel estimation value calculation section 130, and outputs data. The symbol is output to the data symbol demodulator 160.
  • Channel estimation value calculation section 130 calculates a channel estimation value for each lot symbol from pilot / data symbol separation section 120, and outputs the calculated channel estimation value to noise suppression section 140.
  • the noise suppression unit 140 receives the channel estimation value for each of the noisy simponores (specified by the frequency and time in the frame) from the channel estimation value calculation unit 130, and the noise component is suppressed.
  • the channel estimation value is output to channel estimation value interpolation section 150.
  • noise suppression unit 140 includes delay profile generation unit 141, path position selection unit 142, time domain channel response replica generation unit 143, and basic impulse component replica storage unit. 144, DFT unit 145, and sequence length adjustment unit 146.
  • Delay profile generation section 141 calculates channel estimation values for each pilot symbol arranged in the same OFDM symbol (that is, subcarriers (frequency) are different in the same OF DM symbol) from the frequency direction to the time axis direction.
  • An observation delay profile is generated by conversion.
  • delay profile generation section 141 has sequence length adjustment section 147 and IDFT section 148.
  • Sequence length adjustment section 147 inserts a zero-value data string after a channel estimation value sample for each pilot symbol arranged in the same OFDM symbol, that is, a frequency direction channel estimation value sample (0 padding). Thus, the sequence length is adjusted so that the total data length becomes the number of delay profile samples.
  • IDFT section 148 is an insertion data comprising N channel estimation value samples and N zero values.
  • a delay profile (hereinafter sometimes referred to as an observation delay profile) is generated by applying an inverse discrete Fourier transform to a frequency sequence consisting of a data sequence and transforming it in the time direction.
  • the sequence length adjustment unit 147 the sum of N and N is a power of 2 (
  • the IDFT unit 148 can perform fast inverse Fourier transform (IFFT).
  • IFFT fast inverse Fourier transform
  • the path position selection unit 142 uses the observation delay profile file generated by the delay profile generation unit 141 to determine the timing (that is, the path position) of the peak point that is equal to or higher than a predetermined threshold and the peak point.
  • the complex amplitude value is detected, and the detected information is output to the time domain channel response replica generation unit 143.
  • the basic impulse component replica storage unit 144 stores the basic impulse component replica and outputs it to the time domain channel response replica generation unit 143.
  • the basic impulse response component replica has the shape of a delay profile for one path when there is no noise. A method for generating this basic innoc component replica will be described later.
  • Time domain channel response replica generation section 143 uses the detection information (peak point timing (path position) and its complex amplitude value) from path position selection section 142 and the basic impulse component replica to delay the time domain channel response replica generation section 143.
  • a delay profile in which noise components are removed from the observed delay profile generated by the profile generation unit 141 (hereinafter sometimes referred to as “delay profile”) is generated.
  • the delay profile replica with the noise component removed is superimposed by superimposing the multiplication result obtained by multiplying the complex amplitude value and the basic inner component replica at the timing of the peak point (path position).
  • the time domain channel response replica generation unit 143 multiplies each complex amplitude value detected by the path position selection unit 142 and the basic impulse signal, and outputs the result of multiplication at the path position corresponding to each complex amplitude value. Superimpose and recreate (play) the delay profile.
  • DFT section 145 converts the delay profile generated by time domain channel response replica generation section 143 from which the noise component has been removed from the time direction to the frequency direction, and converts the frequency direction sequence to the sequence length. Output to adjustment unit 146. That is, the DFT unit 145 performs a Fourier transform on the regenerated delay profile to form a channel estimation value.
  • Sequence length adjustment section 146 removes the portion corresponding to the 0-value data string inserted in sequence length adjustment section 146 from the sequence from DFT section 145, and determines "frequency direction channel estimation value". Only the portion corresponding to the sample ”is output to the channel estimation value interpolation unit 150. This “part corresponding to the frequency direction channel estimation value sample” is a highly accurate channel estimation value with suppressed noise.
  • channel estimation value interpolation section 150 Since channel estimation value from sequence length adjustment section 146 is originally a pilot symbol that is discrete in the frequency direction and time direction, channel estimation value interpolation section 150 has channel estimation values for subcarriers and time symbols in between. Is interpolated. Examples of interpolation methods include interpolation using linear interpolation and discrete cosine transform (DCT: Discrete Cosine Transform) (see Non-Patent Document 3). For example, the frequency selectivity is large and the fluctuation in the time direction is small. In the channel, for example, if interpolation using discrete cosine transform is used in the frequency direction and linear interpolation is used in the time direction, good channel estimation with less distortion can be achieved. Then, channel estimation value interpolation section 150 outputs the channel estimation value at each simponole of the frame to data symbol demodulation section 160.
  • DCT discrete cosine Transform
  • Data symbol demodulation section 160 demodulates the data symbol from pilot / data symbol separation section 120 using the channel estimation value from channel estimation interpolation section 150.
  • Error correction decoding section 170 performs error correction decoding on the demodulated signal.
  • FFT section 110 an OFDM signal based on a frame in which pilot symbols are scattered in the time direction and the frequency direction is subjected to radio processing (down-compression, A / D conversion, etc.) in the radio reception section.
  • the signal after radio processing is converted from a time signal to a frequency signal to form a reception frame.
  • Pilot / data symbol separation section 120 separates the constituent symbols of the received frame into pilot symbols and other data symbols.
  • Channel estimation value calculation section 130 calculates a channel estimation value for each pilot symbol.
  • delay profile generation section 141 of noise suppression section 140 pilots arranged in the same OFDM symbol (that is, subcarriers (frequency) are different in the same OFDM symbol).
  • the channel estimation value for each symbol is converted from the frequency direction to the time axis direction, and an observation delay profile is generated.
  • delay profile generation section 141 inserts a zero-value data string after channel estimation value samples for each pilot symbol from channel estimation value calculation section 130.
  • a sequence in which a 0-value data string is inserted after channel estimation value samples for each pilot symbol from channel estimation value calculation section 130 is input to IDFT section 148.
  • IDFT section 148 it is the output of IDFT unit 148 by increasing the number of data N in the inserted data row as much as possible.
  • IDFT processing can be made IFFT processing by reducing the sum of the number of channel estimation sample (number of configuration data) and the number of configuration data in the input data string to a power of 2, reducing the amount of computation. can do.
  • the path position selection unit 142 detects the timing of the peak point that is equal to or higher than a predetermined threshold and the complex amplitude value at the peak point from the observed delay profile generated by the delay profile generation unit 141.
  • Time domain channel response replica generation section 143 uses the detection information from the path position selection section 142 (the peak position path position index and its complex amplitude value) and the "basic impulse component replica" to generate a delay profile. A delay profile in which noise components are removed from the observation delay profile generated by the generation unit 141 is generated.
  • the "basic impulse component replica" needs to be in the form of a delay profile for one path when there is no noise. That is, in such an ideal state, the channel estimation value takes a value of “1” for each pilot symbol calculated by channel estimation value calculation section 130 (see FIG. 5). After this ideal channel estimate sample (number of samples N)
  • the IDFT is applied to the sequence created in this way, and the amplitude is adjusted so that the peak power is “1” to generate a basic impulse component replica.
  • the sum of N and N matches the DFT point that IDFTs the sequence It is preferable. I.e., from N to + N) /
  • DFT processing becomes FFT processing, and the power S can be reduced to reduce the amount of computation.
  • FIG. 1 An example of a basic impulse component replica created by the method as described above is shown in FIG.
  • the figure shows a basic impulse component replica when the 100-sample frequency direction channel estimate is extended to a 2000-sample delay profile, that is, 100 frequency-direction channel estimate samples, 1900 0s.
  • a basic impulse component replica is shown when an insertion data string having a value is inserted. Note that the basic impulse component replica is a complex power, which is inherently a complex number.
  • the time domain channel response replica generation unit 143 follows the flow shown in FIG. 7 and generates noise from the observed delay profile generated by the delay profile generation unit 141. A delayed profile replica with the components removed is generated.
  • step 1001 the complex amplitude of the path position is multiplied by the basic impulse component replica.
  • step 1002 the basic impulse response component replica is cyclically shifted by the index up to the next pass position.
  • step 1003 (S1003), the multiplication results multiplied in step 1001 are sequentially added.
  • step 1004 it is determined whether or not the processing in steps 1001 to 1003 has been performed on all the paths detected by the path position selection unit 142.
  • the replica generation process ends.
  • the result of the sequential addition is a delay profile replica in which the noise component is removed from the observed delay profile generated by the delay profile generation unit 141.
  • the delay profile is not obtained by calculating the inverse matrix of the circulant matrix of the basic impulse component (for example, sine function) and multiplying the delay profile as in the prior art. Multiply the basic impulse component replicas using the complex amplitude at the peak point of the file, repeat for the number of passes, and then add them. This reduces the load on the arithmetic processing circuit.
  • the delay profile replica is reproduced from the complex amplitude at the peak point of the observation delay profile and the basic impulse component replica without subtracting the noise from the observation delay profile power, as in the method disclosed in Non-Patent Document 2, the noise is recovered. This makes channel estimation with high tolerance possible, and improves the error rate performance.
  • Non-Patent Document 2 shows a comparison result between the method disclosed in Non-Patent Document 2 and the present embodiment. As shown in the figure, this embodiment shows that the error rate performance is improved by about 2.3 dB compared to the method disclosed in Non-Patent Document 2 in the case of 16QAM and coding rate 3/4. I understand. In addition, since the ideal channel estimation is performed, the degradation is only about 0.5 dB, and a good error rate characteristic is realized.
  • channel estimation value calculation section 130 as channel estimation value calculation means for calculating channel estimation value from each pilot symbol included in the received frame is received by multicarrier reception apparatus 100.
  • a delay profile generation unit 141 as a delay profile generation unit that performs an inverse Fourier transform on the calculated channel estimation value to generate an observation delay profile; and a path position and a complex amplitude at the path position from the observation delay profile.
  • the path position selection unit 142 as a detection means for detecting, each complex amplitude value and the basic impulse signal (basic impulse component replica) are multiplied, and the result of the multiplication at the path position corresponding to each complex amplitude value.
  • Time domain channel response level as a delay profile playback means Precursor generation unit 143, DFT unit 145 as channel estimation value forming means for applying a Fourier transform to the reproduced delay profile to form a channel estimation value, and using the formed channel estimation value, And a data symbol demodulator 160 as a demodulating means for performing demodulation.
  • the complex amplitude at the peak point of the delay profile is used.
  • the basic impulse signal is multiplied and the multiplication result is superimposed at the path position corresponding to each complex amplitude value to reproduce the delay profile.
  • the reproduced delay profile contains almost no noise component.
  • the channel estimation value obtained based on this reproduction delay profile can achieve good error rate characteristics and communication quality with good accuracy.
  • the basic impulse signal is “0” after a data string having a value “1” equal to the number of channel estimation values calculated by the channel estimation value calculation unit 130 as the channel estimation value calculation means.
  • the data with the “1” value is generated by performing an inverse Fourier transform on the entire sequence in which the insertion data sequence consisting of “values” is inserted and adjusting the amplitude so that the peak power becomes “1”.
  • the sum of the number of constituent data of the column and the number of constituent data of the insertion data sequence is the same as the number of points related to the inverse Fourier transform.
  • the resolution of the delay profile can be increased, so that the accuracy of the channel estimation value obtained based on the reproduction delay profile is improved, and the error rate specification is improved to improve the communication quality. Can do.
  • the sum of the number of component data of the data string having the value "1" and the number of component data of the insertion data string is a power of two.
  • IFFT fast inverse Fourier transform
  • the power described for the case where channel estimation is performed using frequency-domain pilot symbols and not limited to that, the case where channel estimation is performed using time-domain signals of pilot symbols is not limited thereto. Obviously, it can be used.
  • the power S described in the case of scattered mapping which is distributed in the pilot symbol time direction and the frequency direction, is not limited to this, and is not limited to all subcarriers in the same OF DM symbol. It is clear that the same can be used when pilot symbols are mapped.
  • the power required to obtain a delay profile with suppressed noise is used to measure the reception quality (eg, SINR) fed back to the base station apparatus during adaptive modulation, for example.
  • the reception quality eg, SINR
  • good quality is fed back as much as the noise component is suppressed, and in addition to improving the reception quality of the terminal, there is an effect of improving the throughput of the entire system.
  • the present embodiment is not limited to the power described in the case of OFDM, and can be applied to the case of CDMA, for example.
  • the impulse response of a low-pass filter (a cosine root Nyquist filter in 3GPP standardization) is used as the basic inol component.
  • the path positions of each other! / Are close to each other! /, Generate a delay profile.
  • the terminal according to the second embodiment operates as shown in Fig. 9 in time domain channel response replica generation section 143.
  • the main configuration of the terminal in Embodiment 2 is the same as the main configuration of multicarrier receiving apparatus 100 in Embodiment 1, and only the operation description of time domain channel response replica generation section 143 will be described.
  • the solid line shows an independent waveform for each path.
  • the dotted ridge line is the waveform of the observation delay profile, which is a superposition of the waveforms represented by the solid line.
  • the alternate long and short dash line represents the delay profile replica.
  • the time domain channel response replica generation unit 143 the multiplication result of the complex amplitude for each path at the path position selected by the path position selection unit 142 and the basic innox component replica is obtained. By adding sequentially at the path position, a delay profile re- plicator is generated. At this time, in the case of a propagation environment in which the path positions ( ⁇ 0, ⁇ 1) are close to each other, for example, the path position ⁇ 0 component is additionally added with the other path components for the arrow. A replica is generated.
  • the "differential delay profile” is calculated by subtracting the observed delay profile component from the delay profile replica component generated by adding the extra other path components, and the path is selected again from this differential delay profile. Generate a differential delay profile replica. Since this differential delay profile replica is an extra component, a delay profile replica with improved accuracy can be generated by subtracting the differential delay profile replica from the delay profile replica.
  • time domain channel response replica generation section 143 of Embodiment 2 from the observed delay profile generated by delay profile generation section 141 according to the flow shown in FIG. A delay profile replica with the noise component removed is generated. Note that step 2001 to step 2004 shown in FIG. 10 (or step 1001 to step 1004 ⁇ in FIG.
  • step 2001 the complex amplitude at the path position is multiplied by the basic impulse component replica.
  • step 2002 the calculation result of step 2001 is cyclically shifted by the index of the path position selected by the path position selection unit 142.
  • step 2003 the cyclically shifted component in step 2002 is added to the delayed profile replica.
  • step 2004 it is determined whether or not the processing in steps 200;! To 2003 has been performed for all the paths detected by the path position selection unit 142. If all the paths have been performed, the delay profile replica generation process ends.
  • step 2005 the observed delay profile is subtracted from the delay profile replica generated in step 2004 to generate a differential delay profile.
  • Step 2006 path selection is performed using the differential delay profile. Similar to the method of the path position selection unit 142, this path selection method detects the timing of the peak point above a predetermined threshold and the complex amplitude value at that peak point. Note that the threshold for selecting a path from the differential delay profile file may be set to a value different from the threshold set by the path position selection unit 142. Since the differential delay profile becomes almost zero when the paths detected by the path position selection unit 142 are moved away from each other, the path selection in step 2006 needs to be performed with the total sampling force of the delay profile length. As shown in FIG. 11, a small window (path position sample) may be set at the path position selected by the path position selection unit 142, and the path may be selected only from the index within the small window.
  • a small window path position sample
  • the solid line shows an independent waveform for each path.
  • the dotted ridge line is the waveform of the observation delay profile, which is a superposition of the waveforms represented by the solid line.
  • a one-dot chain line represents a delay profile replica. ⁇ indicates one sample.
  • step 2007 the complex amplitude at the path position detected in step 2006 is multiplied by the basic impulse component replica.
  • Step 2008 the calculation result in Step 2007 is cyclically shifted by the path position index.
  • step 2009 the cyclically shifted component forces in step 2008 are sequentially added at the corresponding path positions.
  • a differential delay profile replica is formed.
  • “addition of differential delay profile replica” sets a small window (path position soil N samples) at the path position selected by the path position selection unit 142, and creates a differential delay profile. It is good also as inside a small window.
  • the differential delay profile generation in Step 2005 and the differential delay profile replica generation in Step 2007 to Step 2009 are all limited to small windows, and the components other than the small windows are almost zero. Replicas can be generated with high accuracy, and the amount of calculation processing for differential delay profile replica generation can be greatly reduced.
  • step 2010 it is determined whether or not the processing in steps 2007 to 2009 has been performed for all the paths detected in step 2006. If all the paths are done, the differential delay profile replica generation process ends.
  • Step 2011 the differential delay profile replica generated in Step 2010 is also subtracted from the delay profile replica force generated in Step 2004.
  • the differential delay profile is generated by subtracting the observation delay profile from the delay profile replica, and the complex amplitude and basic impulse component replica of the path position of the differential delay profile are further generated.
  • the differential delay profile replica is generated by sequentially adding the multiplication results at the nose positions corresponding to the respective complex amplitudes, and the differential delay profile replica is subtracted from the delay profile replica to further increase the delay profile replica. It can be generated with high accuracy and can further improve the error rate characteristics.
  • the differential delay profile is generated only once and the subtraction is performed multiple times.
  • the time domain channel response replica generation unit 143 sequentially adds the multiplication result of the complex amplitude at each path position and the basic impulse response replica at the path position. Generate a delayed profile replica
  • the terminal according to Embodiment 3 operates as shown in FIG. 12 at time domain channel response replica generation section 143.
  • the main configuration of the terminal in Embodiment 3 is the same as the main configuration of multicarrier receiving apparatus 100 in Embodiment 1, and only the operation description of time domain channel response replica generation section 143 will be described.
  • ⁇ indicates one sample.
  • the time domain channel response replica generation unit 143 the multiplication result of the complex amplitude for each path and the basic Innors component replica is obtained at the path position selected by the path position selection unit 142.
  • a delay profile replica is generated by sequentially adding the path positions. At this time, considering the number of FFT points of the DFT (FFT) unit 145 in the subsequent stage, only the sample of the index input to the FFT unit is to be added.
  • FFT DFT
  • FIG. 12 shows frequency domain channel estimation value N calculated by channel estimation value calculation section 130.
  • the DFT (FFT) unit 145 may perform 8-point FFT.
  • the thinning points may be set so that the maximum path position of the observation delay profile, that is, the peak position where the power is maximum is included.
  • ⁇ indicates one sample.
  • the delay profile replica is added only at the thinning-out point. Therefore, when multiplying the complex amplitude of each path position and the basic inner component replica, it is sufficient to multiply only the components of the thinning points.
  • the decimation interval is 2, the number of complex multiplications is halved compared to the first or second embodiment.
  • the delay profile replica of each path is added only at the thinning point, the number of additions is also halved.
  • Time domain channel response replica generation section 143 outputs only the decimation component from the delay profile replica generated by adding only the decimation points to DFT (FFT) section 145.
  • FFT DFT
  • DFT (FFT) section 145 performs DFT (FFT), and outputs the frequency domain channel estimation value of the number of thinning points to sequence length adjustment section 146.
  • Sequence length adjustment unit 146 extracts the N samples at the front and N samples after noise removal.
  • each functional block used in the description of each of the above embodiments is typically realized as an LSI which is an integrated circuit. These may be individually made into one chip, or may be made into one chip so as to include a part or all of them.
  • IC system LSI
  • super LSI super LSI
  • ultra LSI depending on the degree of integration of LSI power.
  • the method of circuit integration is not limited to LSI, and may be realized by a dedicated circuit or a general-purpose processor.
  • Field programmable gate arrays (FPGAs) that can be programmed after LSI manufacturing and reconfigurable 'processors that can reconfigure the connection and settings of circuit cells inside the LSI may be used.
  • FPGAs Field programmable gate arrays
  • Locks may be integrated. For example, the possibility of applying technology is possible.
  • the multicarrier receiver of the present invention can reduce the load on the arithmetic processing circuit, and has an effect of improving communication quality by executing accurate channel estimation, and is particularly used for OFDM communication. Useful as.

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  • Noise Elimination (AREA)

Abstract

L'invention concerne un dispositif de réception à porteuses multiples de faible coût susceptible de maintenir une qualité de communication avec une faible charge sur le circuit de traitement de fonctionnement. Le dispositif de réception à porteuses multiples (100) comprend : une unité de calcul de valeur d'estimation de canal qui calcule une valeur d'estimation de canal à partir de chaque symbole pilote contenu dans une trame de réception ; une unité de génération de profil de retard (141) qui réalise une transformée de Fourier inverse sur la valeur d'estimation de canal pour générer un profil de retard d'observation ; une unité de sélection de chemin (142) qui détecte une position de chemin et une amplitude complexe de la position de chemin à partir du profil de retard d'observation ; une unité de génération de réplique de réponse de canal de domaine temporel (143) qui multiplie chacune des valeurs d'amplitudes complexes par la réplique de composant d'impulsion de base et superpose le résultat de multiplication au niveau de la position de chemin correspondant à chaque valeur d'amplitude complexe de façon à reproduire un profil de retard ; une unité DFT (145) qui réalise une transformée de Fourier sur le profil de retard reproduit de façon à former une valeur d'estimation de canal ; et une unité de démodulation de symbole de données qui démodule un symbole de données en utilisant la valeur d'estimation de canal formée.
PCT/JP2007/066152 2006-08-22 2007-08-21 dispositif de réception à porteuses multiples WO2008023680A1 (fr)

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JP2008113240A (ja) * 2006-10-30 2008-05-15 Matsushita Electric Ind Co Ltd マルチキャリア受信装置およびチャネル推定値補間方法
JP2008167088A (ja) * 2006-12-27 2008-07-17 Matsushita Electric Ind Co Ltd Ｏｆｄｍ受信装置
WO2009017083A1 (fr) * 2007-07-31 2009-02-05 Nec Corporation Procédé d'estimation de canal
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WO2009025376A1 (fr) * 2007-08-17 2009-02-26 Nec Corporation Procédé et appareil pour une estimation de canal dans ofdm
US8406355B2 (en) 2007-08-17 2013-03-26 Nec Corporation Method and apparatus for channel estimation in OFDM
WO2014017137A1 (fr) * 2012-07-27 2014-01-30 日本電気株式会社 Dispositif de réception, terminal de transmission et de réception, procédé de mesure de temps de retard de propagation, et programme d'ordinateur
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