WO2021149366A1 - Procédé de détection de temporisation et dispositif de communication sans fil - Google Patents

Procédé de détection de temporisation et dispositif de communication sans fil Download PDF

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Publication number
WO2021149366A1
WO2021149366A1 PCT/JP2020/045019 JP2020045019W WO2021149366A1 WO 2021149366 A1 WO2021149366 A1 WO 2021149366A1 JP 2020045019 W JP2020045019 W JP 2020045019W WO 2021149366 A1 WO2021149366 A1 WO 2021149366A1
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moving average
correlation calculation
wireless communication
signal
communication device
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PCT/JP2020/045019
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English (en)
Japanese (ja)
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小林　岳彦
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株式会社日立国際電気
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Priority to JP2021572991A priority Critical patent/JP7354297B2/ja
Publication of WO2021149366A1 publication Critical patent/WO2021149366A1/fr

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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
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W56/00—Synchronisation arrangements

Definitions

  • the present invention relates to a timing detection method by a wireless communication device on the receiving side that performs synchronization processing using a preamble signal transmitted from the transmitting side.
  • the transmitting side periodically transmits a known signal sequence together with the transmission information, and the receiving side uses this known signal sequence for synchronization.
  • This known signal sequence is called a preamble signal.
  • the transmission signal timing included in the received signal can be accurately known by correlating the received signal with the preamble signal and obtaining the timing of giving the maximum value (peak) of the amplitude.
  • OFDM Orthogonal Frequency Division Multiplex
  • Patent Document 1 provides an OFDM relay device capable of optimizing the position of the effective symbol cutout section and the transmission timing of the interfering wave according to the D / U value to prevent deterioration of reception quality due to the wraparound transmission wave. It is disclosed. Further, Patent Document 2 discloses an OFDM receiving device capable of estimating a transmission line with less error even when the reception timings of radio signals arriving from a plurality of transmitting devices connected in multiple access are deviated.
  • the correlation waveform may be significantly impaired by the interfering wave in a narrow band, making timing detection impossible. Therefore, in the conventional technique, there is a problem that timing synchronization cannot be ensured due to a narrow band interfering wave, and the interfering wave immunity of OFDM transmission may not be exhibited.
  • the present invention has been made in view of the above-mentioned conventional circumstances, and an object of the present invention is to ensure stable timing synchronization even in the presence of narrow-band interfering waves.
  • the timing detection method and the wireless communication device are configured as follows. That is, the timing detection method according to the present invention is a timing detection method by a wireless communication device on the receiving side that performs synchronization processing using a preamble signal transmitted from the transmitting side, and the wireless communication device on the receiving side uses the preamble signal.
  • a plurality of correlated signals which are time domain signals of different frequency portions, are stored in advance, and the received signal is subjected to a correlation calculation with each of the plurality of correlated signals to obtain each correlated signal. It is characterized in that the reception timing of the preamble signal is detected by using at least one of the obtained correlation calculation results.
  • the wireless communication device on the receiving side calculates a moving average for each of the correlation calculation results obtained for each correlated signal, and uses the correlation calculation result that minimizes the value of the moving average.
  • the reception timing of the preamble signal may be detected.
  • the wireless communication device on the receiving side calculates a moving average for each of the correlation calculation results obtained for each correlated signal, and weights according to the value of the moving average to each correlation calculation result.
  • the reception timing of the preamble signal may be detected by using the one obtained by applying and synthesizing.
  • the wireless communication device is a plurality of time domain signals of frequency portions of the preamble signals that are different from each other in the wireless communication device on the receiving side that performs synchronization processing using the preamble signal transmitted from the transmitting side.
  • a plurality of moving average calculators and a plurality of moving average calculators in which the wireless communication device on the receiving side calculates a moving average for each of the correlation calculation results for each correlated signal obtained by the plurality of correlators. It is further equipped with a comparator that compares the values of the moving averages calculated by the moving average calculator, and a selector that selects the correlation calculation result that is found to have the smallest value of the moving averages by comparison with the comparers.
  • the detector may detect the reception timing of the preamble signal by using the correlation calculation result selected by the selector.
  • a plurality of mobile averaging calculators and a plurality of mobile averaging calculators in which the wireless communication device on the receiving side calculates a moving average for each of the correlation calculation results for each correlated signal obtained by the plurality of correlators.
  • a plurality of coefficient calculators that calculate the weighting coefficient for each correlated signal based on the value of the moving average calculated by the moving average calculator, and the correlation calculation result for each correlated signal obtained by the plurality of correlators.
  • a plurality of multipliers for multiplying the weighting coefficients for each correlated signal calculated by a plurality of coefficient calculators and an adder for synthesizing the multiplication results of the plurality of multipliers are further provided, and the detector is synthesized by the adder. The result may be used to detect the reception timing of the preamble signal.
  • FIG. 1 shows the structural example of the wireless communication apparatus which concerns on one Embodiment of this invention. It is a figure explaining the frequency band division of a preamble signal. It is a figure which shows the structure of the test signal for simulation. It is a figure which shows an example of a frequency spectrum and a correlation output when there is no nuisance wave. It is a figure which shows an example of a frequency spectrum and a correlation output in the presence of a nuisance wave. It is a figure which shows the 1st structure example of the selective synthesizer of FIG. It is a figure which shows an example of the output of the moving average calculator which constitutes the selector of FIG. It is a figure which shows the 2nd structural example of the selective synthesizer of FIG.
  • FIG. 1 shows a configuration example of a wireless communication device according to an embodiment of the present invention.
  • the wireless communication device of this example is a wireless communication device on the receiving side in a wireless communication system using OFDM, and includes an input terminal 101, correlators 102-1 and 102-2, and memories 103-1 and 103-2. , A selective synthesizer 104, a peak detector 105, and an output terminal 106.
  • the received signal from the wireless communication device of this example is input to the input terminal 101.
  • the received signal input to the input terminal 101 is correlated with the correlated signal stored in the memories 103-1 and 103-2 by the correlators 102-1 and 102-2. That is, the input received signal is subjected to a correlation calculation with the correlated signal stored in the memory 103-1 by the correlator 102-1, and another correlated signal stored in the memory 103-2.
  • the correlation calculation with the signal is performed by the correlator 102-2.
  • the output values c (n) of the correlators 102-1 and 102-2 are as follows (formula). It can be calculated by 1).
  • L is the length of the correlated signal
  • x * represents the complex conjugate of x.
  • the two correlation calculation results output from the correlator 102-1 and 102-2 are input to the selector 104.
  • the selector 104 selects the more appropriate one, that is, the one that is not affected by the interfering wave (or the one that is less affected) from the two input correlation calculation results, and outputs the result to the peak detector 105. ..
  • the peak detector 105 detects the timing at which the correlation calculation result gives the maximum value (peak).
  • the timing detected by the peak detector 105 is output via the output terminal 106 as the reception timing of the preamble signal, and is used for timing control of the processing operation of the received signal.
  • the preamble signal 206 which is a known signal sequence used for synchronization with the transmitting side, allocates a subcarrier corresponding to the preamble inside a predetermined frequency band, and an IFFT (Inverse Fast Fourier Transform; It is converted into a time region signal by performing inverse fast Fourier transform) 205.
  • IFFT Inverse Fast Fourier Transform
  • the allocation shown by reference numeral 201 is divided into a negative frequency component 202-1 (band A) and a positive frequency component 202-2 (band B), which are IFFT203-1,203-, respectively. 2 is applied to convert it into a time domain signal.
  • the two signal sequences 204-1 and 204-2 generated in this way are stored as correlated signals in the memories 103-1 and 103-2 of FIG. 1, and are referred to when detecting the reception timing of the preamble signal. Will be done.
  • FIG. 3 shows the configuration of the simulation test signal performed for the purpose of explanation.
  • the test signal used in the simulation is composed of a non-transmission section, a preamble symbol having a fixed known pattern, and a data symbol.
  • FIG. 4 illustrates each signal output in the absence of nuisance waves.
  • FIG. 4A shows the frequency spectrum of the test signal, which is the normal spectrum of OFDM.
  • FIG. 4B is a correlation output for the entire band of the preamble signal according to the prior art. A sharp peak corresponding to the final point of the preamble signal is obtained at time 512, and timing synchronization can be performed by detecting this peak timing.
  • 4 (c) and 4 (d) are correlation outputs for each of the divided bands A and B by the wireless communication device of this example, and mean the outputs of the correlators 102-1 and 102-2 of FIG. Both of these correlation outputs show the same tendency as in FIG. 4B, and timing synchronization can be achieved by selecting either one or adding both.
  • FIG. 5A shows the frequency spectrum of the test signal, and it can be seen that in addition to the OFDM signal which is the desired wave, a narrow band interfering wave exists in the low frequency region.
  • This disturbing wave is GMSK (Gaussian-filtered Minimum Shift Keying) modulation with a Gaussian filter.
  • GMSK Gaussian-filtered Minimum Shift Keying
  • FIG. 5 (b) shows the correlation output for the entire band of the preamble signal according to the prior art, but the level is generally higher than that of FIG. 4 (b), the original peak is about to be buried, and the vicinity of the peak is formed.
  • the waveform also contains distortion. Depending on the phase and amplitude of the interfering wave, the peak may not be detected at all.
  • 5 (c) and 5 (d) are correlation outputs for each of the divided bands A and B by the wireless communication device of this example, and mean the outputs of the correlator 102-1 and 102-2 of FIG.
  • the correlation output with respect to the divided band A shown in FIG. 5 (c) is significantly affected by the interfering wave as in FIG. 5 (b).
  • the correlation output with respect to the divided band B shown in FIG. 5 (d) is almost unchanged as compared with FIG. 4 (d) and is hardly affected by the disturbing wave.
  • the correlation calculation result for band B is selected).
  • FIG. 6 shows a first configuration example of the selective synthesizer 104 of FIG. 1 as one of the methods for giving the above-mentioned selection criteria.
  • the selective synthesizer 104 of FIG. 6 includes input terminals 111-1 and 111-2, moving average calculators 112-1 and 112-2, a comparator 113, a selector 114, and an output terminal 115. There is.
  • the correlation calculation result by the correlator 101-1 of FIG. 1 is input to the input terminal 111-1, and the correlation calculation result by the correlator 101-2 of FIG. 1 is input to the input terminal 111-2.
  • the moving average calculators 112-1 and 112-2 calculate the moving average of the input correlation calculation result in a time interval of a predetermined length.
  • the calculation results by the moving average calculators 112-1 and 112-2 are input to the comparator 113.
  • the comparator 113 compares the instantaneous magnitude of each moving average output from the moving average calculators 112-1 and 112-2, and controls the input switching signal to the selector 114 according to the result.
  • the selector 114 is controlled so that the correlation calculation result having the smaller moving average value is selected from the two correlation calculation results input to the input terminals 111-1 and 111-2. ..
  • the correlation calculation result selected by the selector 114 is output from the output terminal 115 and input to the peak detector 105.
  • FIG. 7 shows an example of the output of the moving averages 112-1 and 112-2.
  • the moving average of the divided band B in which the interfering wave does not exist has a relatively low level
  • the divided band A in which the interfering wave exists The moving average of is higher overall. Therefore, it can be seen that the influence of disturbing waves can be determined by taking a moving average and comparing the levels.
  • FIG. 8 shows a second configuration example of the selective synthesizer 104 of FIG.
  • the selective synthesizer 104 of FIG. 8 includes input terminals 111-1 and 111-2, moving average calculators 112-1 and 112-2, coefficient calculators 116-1 and 116-2, and a multiplier 117-1. , 117-2, an adder 118, and an output terminal 115.
  • the correlation calculation result by the correlator 101-1 of FIG. 1 is input to the input terminal 111-1, and the correlation calculation result by the correlator 101-2 of FIG. 1 is input to the input terminal 111-2.
  • the moving average calculators 112-1 and 112-2 calculate the moving average of the input correlation calculation result in a time interval of a predetermined length.
  • the calculation result by the moving average calculator 112-1 is input to the coefficient calculator 116-1, and the calculation result by the moving average calculator 112-2 is input to the coefficient calculator 116-1.
  • the coefficient calculator 116-1 calculates the weighting coefficient for the division band A based on the value of the moving average output from the moving average calculator 112-1, and outputs it to the multiplier 117-1.
  • the coefficient calculator 116-1 is configured to output, for example, a larger weighting coefficient as the moving average value becomes smaller.
  • the multiplier 117-1 multiplies the correlation calculation result input to the input terminal 111-1 by the weighting coefficient output from the coefficient calculator 116-1, and outputs the result to the adder 118.
  • the coefficient calculator 116-2 calculates the weighting coefficient for the division band B based on the value of the moving average output from the moving average calculator 112-2, and outputs the weighting coefficient to the multiplier 117-2.
  • the multiplier 117-2 multiplies the correlation calculation result input to the input terminal 111-2 by the weighting coefficient output from the coefficient calculator 116-2, and outputs the result to the adder 118.
  • the adder 118 adds (combines) the output values of the multipliers 117-1 and 117-2.
  • the correlation calculation result weighted and synthesized in this way is output from the output terminal 115 and input to the peak detector 105. Even with such a configuration, it is possible to suppress the influence of narrow-band interfering waves on the synchronization processing and to achieve stable synchronization. If the weighting coefficient for the smaller moving average value is set to "1" and the weighting coefficient for the larger moving average value is set to "0", the same calculation result as in the first configuration example is obtained.
  • the wireless communication device on the receiving side stores the plurality of correlated signals which are the time domain signals of the frequency regions different from each other among the preamble signals 103-1 and 103. -2, and the correlation calculation results obtained by the correlators 102-1 and 102-2 that perform the correlation calculation with each of the plurality of correlated signals for the received signal, and the correlators 102-1 and 102-2. It includes a peak detector 105 that detects the reception timing of the preamble signal using at least one.
  • the wireless communication device is a moving average calculator that calculates a moving average for each of the correlation calculation results for each correlated signal obtained by the correlators 102-1 and 102-2.
  • the value of the moving average is smaller than that of the comparison device 113, which compares the values of the moving averages calculated by the moving average calculators 112-1 and 112-2 with 112-1, 112-2, and the comparison device 113.
  • a selector 114 for selecting the correlation calculation result found to be found is further provided, and the peak detector 105 is configured to detect the reception timing of the preamble signal using the correlation calculation result selected by the selector 114. ing.
  • the wireless communication device is a mobile averaging calculator 112-1, which calculates a moving averaging for each of the correlation calculation results for each correlated signal obtained by the correlators 102-1 and 102-2. 112-2 and the coefficient calculators 116-1 and 116-2 that calculate the weighting coefficient for each correlated signal based on the value of the moving average calculated by the mobile average calculators 112-1 and 112-2.
  • 1,117-2 and an adder 118 that synthesizes the multiplication results of the multipliers 117-1 and 117-2 are further provided, and the peak detector 105 uses the synthesis result of the multiplier 118 to generate a preamble signal. It is configured to detect the reception timing.
  • the preamble signal is band-divided into a plurality of correlated signals and stored in the wireless communication device on the receiving side, and the received signal is subjected to a correlation calculation with each correlated signal to obtain a narrow band. It is possible to obtain the correlation calculation result for the frequency portion that is not (or is small) affected by the interfering wave. Then, by preferentially using the correlation calculation result for the frequency portion that is not (or is small) affected by the narrow band interference wave to perform timing detection, stable timing is achieved even when the narrow band interference wave is present. It is possible to ensure synchronization. As a result, it is possible to effectively embody the interference wave resistance inherent in OFDM transmission including error correction, and it is possible to realize wideband OFDM transmission having excellent interference wave resistance.
  • the number of band divisions of the preamble signal is set to 2, but it is also possible to set this to 3 or more (that is, to divide into 3 or more correlated signals).
  • the smaller the moving average value the higher the priority (that is, the one with the smallest moving average value is selected, or the smaller the moving average value, the larger the weighting coefficient), and the preamble signal It is preferable to use it for detecting the reception timing. If the number of band divisions of the preamble signal is N, the processing load of the correlation calculation and the required memory will be N times, but stable timing synchronization is possible even when multiple interfering waves are scattered in the OFDM band. It becomes.
  • the preamble signal is evenly band-divided to obtain a plurality of correlated signals, but it may be band-divided with a bias. Further, in the above description, the preamble signals are band-divided so that the frequency components do not overlap with each other to obtain a plurality of correlated signals, but the frequency components of the correlated signals may partially overlap. do not have.
  • the present invention has been described above based on one embodiment, it goes without saying that the present invention is not limited to the wireless communication system described here, and can be widely applied to other wireless communication systems.
  • the present invention also provides, for example, a method including a technical procedure related to the above processing, a program for causing a computer to execute the above processing, a storage medium for storing such a program in a computer-readable manner, and the like. Is also possible.
  • the present invention can be used in a wireless communication system that performs synchronization processing using a preamble signal.
  • 101 Input terminal, 102-1, 102-2: Correlator, 130-1, 103-2: Memory, 104: Selective synthesizer: 105: Peak detector, 106: Output terminal, 111-1, 111-2 : Input terminal, 112-1, 112-2: Moving average calculator: 113: Comparator, 114: Selector, 115: Output terminal, 116-1, 116-2: Coefficient calculator, 117-2, 117- 2: Multiplier, 118: Adder

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  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Synchronisation In Digital Transmission Systems (AREA)

Abstract

Le problème décrit par la présente invention est de pouvoir garantir une synchronisation de temporisation stable même en présence d'une onde de perturbation à bande étroite.　La solution selon l'invention porte sur un dispositif de communication sans fil du côté réception pourvu : de mémoires 103-1, 103-2 dans lesquelles sont mémorisés les signaux d'une pluralité de signaux corrélés qui sont des signaux de domaine temporel de composantes de fréquence mutuellement différentes parmi des signaux de préambule ; de corrélateurs 102-1, 102-2 servant à calculer la corrélation d'un signal reçu avec chaque signal de la pluralité de signaux corrélés ; et d'un détecteur de crête 105 servant à détecter la temporisation de réception d'un signal de préambule à l'aide d'au moins l'un des résultats du calcul de corrélation obtenus par les corrélateurs 102-1, 102-2.
PCT/JP2020/045019 2020-01-24 2020-12-03 Procédé de détection de temporisation et dispositif de communication sans fil WO2021149366A1 (fr)

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008306367A (ja) * 2007-06-06 2008-12-18 Nec Corp 通信システムおよび同期検出装置
JP2010087745A (ja) * 2008-09-30 2010-04-15 Sony Corp 情報処理装置および方法、表示装置、並びにプログラム

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008306367A (ja) * 2007-06-06 2008-12-18 Nec Corp 通信システムおよび同期検出装置
JP2010087745A (ja) * 2008-09-30 2010-04-15 Sony Corp 情報処理装置および方法、表示装置、並びにプログラム

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