JP4506248B2 - Synchronization apparatus and synchronization method - Google Patents

Description

  The present invention relates to a synchronization apparatus and synchronization method for establishing synchronization between transmitters and receivers in a wireless or wired digital communication system, and more particularly to a synchronization apparatus and synchronization method for detecting synchronization timing using preamble correlation.

  More particularly, the present invention relates to a synchronization apparatus and synchronization method for detecting synchronization timing based on a correlation result between a received signal and a known signal, and in particular, a good error regardless of a low signal-to-noise ratio. The present invention relates to a synchronization device and a synchronization method for detecting synchronization timing at a rate.

  By connecting multiple computers and configuring a LAN, you can share information such as files and data, share peripheral devices such as printers, and exchange information such as e-mail and data / content transfer Can be done.

  Further, wireless LANs are attracting attention as a system for releasing users from wired LAN connection. Particularly recently, introduction of a personal area network (PAN) has been studied in order to construct a small-scale wireless network between a plurality of electronic devices existing around a person and perform information communication. For example, different radio communication systems and radio communication apparatuses are defined using frequency bands that do not require a license from a supervisory agency, such as 2.4 GHz band and 5 GHz band.

  For example, in recent years, a method called “ultra-wide band (UWB) communication” for performing wireless communication by placing information on a very weak impulse train has attracted attention as a wireless communication system that realizes short-range ultrahigh-speed transmission, and its practical use. Is expected. Currently, in IEEE802.15.3, etc., a data transmission system having a packet structure including a preamble has been devised as an access control system for ultra-wideband communication.

  In addition, when a wireless network is constructed indoors, a multipath environment is formed in which a receiving device receives a superposition of a direct wave and a plurality of reflected waves / delayed waves, and intersymbol interference occurs due to delay distortion. For this reason, a multicarrier transmission scheme typified by an OFDM (Orthogonal Frequency Division Multiplexing) scheme is applied.

  For example, even in IEEE 802.15.3, standardization of a UWB communication scheme that employs an OFDM modulation scheme is underway. In the case of the OFDM_UWB communication system, three subbands each having a frequency of 3.1 to 4.8 GHz are frequency hopped (FH) each having a width of 528 MHz, and OFDM modulation using IFFT / FFT in which each frequency band is composed of 128 points. (For example, see Non-Patent Document 1).

IEEE 802.15.3a TI Document <URL: http: // grouper. iee. org / groups / 802/15 / pub / 2003 / May03 File name: 03142r2P802-15_TI-CFP-Document. doc>

  In a digital communication system configured by a combination of a transmitter and a receiver, in order to demodulate data on the receiver side, it is necessary to first establish synchronization of received signals. In this synchronization processing, the transmitter side transmits a signal including a known pattern for synchronization acquisition as a preamble (or midamble) together with the transmission data body (Body), and the receiver side synchronizes using preamble correlation. It is common to detect timing. The timing detected by the synchronization acquisition is the clock starting point.

  In the OFDM_UWB communication system described above, a time sequence is used as a preamble signal for acquiring synchronization (see Non-Patent Document 1). Furthermore, in order to reduce the amount of calculation of correlation processing on the receiving side, the preamble signal is composed of a plurality of known symbols having a pattern of ± 1 (because the multiplication processing for correlation calculation is performed in this case). Only need to reverse the sign). In this case, the correlation result is obtained by taking the sum of 128 multiplication results for each ± 1 pattern constituting the preamble signal.

  FIG. 14 shows a configuration example of the synchronization circuit. It is assumed that the transmission signal incorporates a preamble signal including a synchronization signal used for detection of synchronization timing.

  The received signal in the RF frequency band received from the antenna is frequency-converted into a received baseband signal in the baseband using the carrier signal generated by the carrier signal generator. Next, the received baseband signal is sampled and converted into a digital signal by an A / D converter.

  The correlator correlates the received baseband digital signal and the preamble code and outputs a correlation value. Since this correlation value is generally a complex number, the absolute square calculator calculates the absolute square of this correlation value and outputs it to the maximum value detection circuit.

  Then, the maximum value detector outputs the maximum of the correlation value or the timing exceeding a predetermined threshold as the synchronization timing.

  Here, in the case of the synchronous circuit configuration shown in FIG. 14, the maximum value of the correlation value fluctuates in the low signal-to-noise ratio situation, and therefore the threshold value needs to be determined by assuming various cases. .

  In general, an automatic gain control device (Auto Gain Control: AGC) is usually incorporated in the receiver around the front stage of the A / D converter (not shown in FIG. 14). This is to avoid fluctuations in the received power due to the distance between the antennas, but due to the delay in the AGC reaction, there is a time zone in which the input to the correlator is not properly amplified or suppressed. May be input to the local maximum detection circuit. In these cases, there is a problem that synchronization errors increase because the local maximum value fluctuates greatly.

  The present invention has been made in view of the above-described technical problems, and its main object is to provide an excellent synchronization device and synchronization method that can accurately detect synchronization timing using preamble correlation. There is to do.

  A further object of the present invention is to provide an excellent synchronization device and synchronization method capable of detecting synchronization timing based on a correlation result between a received signal and a known signal.

  A further object of the present invention is to provide an excellent synchronization device and synchronization method capable of detecting synchronization timing with a good error rate regardless of the low signal-to-noise ratio.

The present invention has been made in consideration of the above problems, and a first aspect thereof is a synchronization device that performs a synchronization process of a received signal based on a known signal included in transmission data,
Correlation calculating means for calculating a correlation between a received signal and a signal obtained by delaying a known signal by a time interval;
Moving average calculating means for calculating a moving average of correlation results by the correlation calculating means;
Synchronization detection means for determining the synchronization timing based on the maximum value of the moving average calculated by the moving average means;
It is characterized by comprising.

  In a digital communication system configured by a combination of a transmitter and a receiver, in order to demodulate data on the receiver side, it is necessary to first establish synchronization of received signals. Conventionally, it is common to detect synchronization timing using preamble correlation. In such a case, in the situation of a low signal-to-noise ratio, the maximum value of the correlation value fluctuates. Therefore, it is necessary to determine the threshold setting by assuming various cases.

  According to the present invention, the influence of noise can be reduced by performing a moving average calculation on the correlation calculation result.

The second aspect of the present invention is a synchronization device that performs synchronization processing of a received signal based on a known signal included in transmission data,
In a system in which known signals are repeatedly sent,
Correlation calculating means for calculating a correlation between a received signal and a signal obtained by delaying a known signal by a time interval;
First moving average means for calculating a moving average between the correlation results by the correlation calculating means;
Second moving average calculating means for calculating a moving average for the moving average calculated by the first moving average calculating means;
Synchronization detection means for determining synchronization timing based on the maximum value of the moving average calculated by the second moving average calculation means;
It is characterized by comprising.

  There is a wireless communication system in which a known symbol is repeatedly transmitted as a synchronization preamble. In such a case, the symbol moving average calculation is first performed to reduce the influence of noise, and then the normal moving average calculation is further performed, whereby a plurality of peaks due to multipath can be combined into one.

  In general, an automatic gain control device (AGC) is incorporated in the receiver, but due to the delay of the AGC reaction, the input to the correlator is not correctly amplified or suppressed, and as a result, the output from the correlator is reduced. The signal may be input to the local maximum detection circuit while changing. In such a case, the third moving average calculating means performs the moving average calculation on the correlation calculation result in a certain time interval, and further normalizes the moving average result by the second moving average calculating means, thereby receiving power. The influence of fluctuation can be canceled.

  The synchronization device according to the second aspect of the present invention provides a fourth moving average calculation for calculating a moving average between symbols by a method different from the first moving average calculating means in the previous period by using the correlation result by the correlation calculating means. And a fifth moving average calculating means for calculating a moving average for the moving average calculated by the fourth moving average calculating means, wherein the synchronization detecting means is the second moving average calculating means. In addition, the synchronization timing may be determined based on each moving average result by the fifth moving average means.

  For example, in a system in which a preamble signal is formed by repeating a plurality of known symbols, a process of indicating (terminating) the last symbol of the preamble by inverting the phase of the preamble is performed.

  In such a case, the fourth moving average means may calculate the moving average between symbols after inverting the phase of the correlation value obtained last. In the second moving average calculation means, the moving average calculation result of the last symbol is lowered by the phase inversion of the last symbol of the preamble, whereas in the fifth moving average calculation means, the moving average calculation result of the last symbol is Since it increases, the last symbol position can be detected.

  According to the present invention, it is possible to provide an excellent synchronization device and synchronization method capable of detecting synchronization timing using a maximum value of a correlation result between a received signal and a known signal.

  Furthermore, according to the present invention, it is possible to provide an excellent synchronization device and synchronization method capable of detecting synchronization timing with a good error rate regardless of the low signal-to-noise ratio.

  According to the present invention, the accuracy of capturing synchronization is high for a code string having a spread spectrum code or a predetermined code preamble pattern, and the time required for synchronization can be shortened. In addition, the accuracy of synchronization can be improved by having two series of processes of moving average between symbols and normal moving average, and comparing the results.

  Other objects, features, and advantages of the present invention will become apparent from more detailed description based on embodiments of the present invention described later and the accompanying drawings.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 schematically shows a configuration of a synchronization circuit according to an embodiment of the present invention.

  A received signal in the RF frequency band received from the antenna is frequency-converted into a received baseband signal in the baseband using the carrier signal generated by the carrier signal generator 11. Next, the received baseband signal is sampled and converted into a digital signal by the A / D converter 12. The correlator 13 performs a correlation operation between the received baseband digital signal and the preamble code and outputs a correlation value.

  Although not shown, an automatic gain control device (AGC) may be incorporated around the front stage of the A / D converter 12.

  The correlation calculation result by the correlator 13 is processed in three steps.

  The first step includes an absolute square calculator 14 and a moving averager 15. Since the correlation value is generally a complex number, the absolute square calculator 14 calculates the absolute square of the correlation value. Then, the moving average calculator 15 performs a moving average calculation on the correlation calculation result in a certain time interval.

  The second step includes a symbol moving averager 16, an absolute square calculator 17, and a moving averager 18, which first performs a moving average calculation between symbols, then performs an absolute square calculation, and finally In addition, a normal moving average calculation is performed. Here, the influence of noise can be reduced by the first symbol moving average calculation. Further, in a wireless communication system configured to repeatedly transmit a preamble signal for synchronization, an effect of combining a plurality of peaks due to multipaths into one by the second normal moving average calculation can be obtained.

  The third step includes a phase-inverted symbol moving averager 19, an absolute square calculator 20, and a moving averager 21. The phase of the correlation value obtained at the end is inverted, and the moving average between symbols is obtained. An operation is performed, and then the same process as in the second step is performed. The influence of noise can be reduced by the first symbol moving average calculation. Further, in a system in which a synchronization preamble signal is repeatedly sent, an effect of combining a plurality of peaks due to multipaths into one by the second normal moving average calculation can be obtained.

  Then, the calculation results in the second step and the third step are normalized by dividing by the result calculated in the first step, and are output to the synchronization detector 22. Depending on the distance between the antennas, fluctuations in received power fluctuate, resulting in a problem that synchronization errors increase. On the other hand, this problem can be avoided by normalizing based on the calculation result in the first step.

  Further, when the preamble signal is configured by repeating a plurality of known symbols, a process of indicating (terminating) the last symbol of the preamble by inverting the phase of the preamble is performed. In this case, the calculation result of the moving average of the last symbol in the second step decreases due to the phase inversion of the last symbol of the preamble, whereas the calculation result of the moving average of the last symbol in the third step increases. , The last symbol position can be detected.

  Hereinafter, the operation of the synchronization device according to the present embodiment will be described in detail.

  FIG. 2 shows a configuration example of the moving averager 15 in the first step. The moving average circuit shown in the figure can be divided into a first half and a second half. In the first half of the circuit, the input delayed by M times from the current time is subtracted from the input. The second half of the circuit is composed of an output from the first half and a positive feedback circuit having a value one time before, and adds them. The first half of the illustrated moving average circuit is represented by the following equation.

Here, z represents a delay operator. For example, z ⁻ⁿ represents n sampling times before. Further, since the latter half is a positive feedback circuit, it is expressed by the following equation.

  Therefore, the transfer function of the entire moving average circuit shown in FIG. 2 is expressed by the following equation.

  And the above equation can be expanded as follows.

  This calculation is nothing but a moving average of order M. Therefore, it can be seen that the circuit shown in FIG. 2 represents a moving average.

  Next, the moving average between symbols in the first half of the second step and the third step shown in FIG. 1 will be specifically described.

  Usually, the preamble code required for synchronization is often repeated over several cycles in order to improve accuracy. Noise superimposed on data has zero cross-correlation as a characteristic, and by averaging (moving average) the obtained signals over several cycles, noise components can be removed, and the accuracy of the synchronization data It is because it becomes possible to improve.

  The symbol moving averager 16 in the first half of the second step performs a moving average calculation between symbols. The moving average in this case is expressed by the following equation, where S is the repetition period of the transmission preamble code.

Here, x _i is an input, y _i is an output, s is a symbol period, and N is the number of moving averages. In FIG. 3, this arithmetic expression is expressed by a circuit. The first half of the illustrated circuit is a circuit that takes the difference between the current value and the value before S × N time, and the second half is composed of the output of the first half and the feedback circuit before S time.

  The phase-reversed symbol moving averager 19 in the first half of the third stroke takes a moving average after inverting the phase of the value obtained at the end. Expressed as an expression, it is as follows. Further, in FIG. 4, this arithmetic expression is expressed by a circuit.

  Further, the moving averagers 18 and 21 in the second half of the second step and the third step are the same as the normal moving average. That is, it is the same as the structure and calculation process of the moving averager 15 in the first step, and is expressed by the following equation.

  The order of the moving average in the second step and the third step is the same, but it does not have to coincide with the order of the first moving average.

  FIG. 5 specifically shows the overall configuration of the synchronization circuit constructed by the above-described elements. The order of the moving average (N, M, L) used in the first, second, and third steps usually depends on the influence of the multipath and the symbol period, so it is optimized depending on the system and environment to be used. Is to be done. Therefore, it cannot be determined uniquely.

  Thereafter, the output results of the second and third steps are normalized by dividing by the output result of the first step, and input to the synchronization detector 22.

  FIG. 6 shows a configuration example of the synchronization detector 22. First, the output from the second step and the output from the third step are input to the maximum value detectors 23 and 24, respectively. The maximum value detectors 23 and 24 output the value at which the data is maximized. The maximum values of the second stroke and the third stroke are input to the divider 25 and division is executed. The synchronization detection unit 26 considers synchronization when the output of the divider 25 and the output of the maximum value detector 24 in the third step exceed a certain threshold.

  Next, a specific operation of the synchronization device according to this embodiment will be described with reference to an example of actual output shown in FIG. However, it is assumed that the input to the correlator (Corr) 13 is Corr Input shown in FIG. The actual input pattern to the correlator 13 is as shown in FIG. 8, for example, but is simply shown in FIG. FIG. 8 shows a configuration example of a preamble pattern, which is composed of ± 1 binary sequences.

  In response to such an input, the correlator 13 performs correlation calculation and outputs the result. FIG. 9 shows an example of the correlator output. Normally, when the transmission path is ideal without multipath, fading, and noise, the correlator output has only one peak (maximum value) as shown in FIG. Here, it is assumed that the correlation calculation result is the correlator output (Corr Output) of FIG. The Corr Output in the figure is an example in the case where there are multipath and fading in the actual transmission path, and the peak of the Corr Output is divided, and many peaks appear positively and negatively. Further, in reality, Corr Output becomes a complex number due to the influence of multipath, but in the figure, only Real Part (real part) or Imaginary Part (imaginary part) is shown.

  This output is divided into two, and the moving average process in the second step and the third step is performed. First, in the second step, since it is a moving average in a simple symbol interval, as shown in A in the figure, the influence of noise is reduced and the peak is emphasized. The amplitude of the peak increases depending on the parameter N, and only the last output peak is decreased by two steps due to the termination preamble whose phase is reversed. That is, the influence of noise is reduced.

  On the other hand, in the third step, a moving average calculation between symbols is performed after inverting the phase of the correlation value obtained last. Therefore, as shown in B in the figure, the inverted version of A in the figure is output first, and the output is 0 because it is canceled out in the second symbol. However, in the third and subsequent symbols, it has the same phase as A. A signal having a small amplitude is output. Due to the terminal preamble having an inverted phase, the peak finally increases in two stages and becomes the maximum (when N = 2).

  Next, in the second step and the third step, the absolute square of the result of moving average between symbols is calculated, and then normal moving average processing is performed. In the figure, C and D indicate the respective output changes. However, in C and D in the figure, the absolute square calculation result and the result after moving average processing are shown together. After taking the moving average between symbols, a normal moving average process is further performed, so that a plurality of peaks generated by multipath can be combined into one as shown in the figure.

  Further, in a system in which the preamble signal is configured by repeating a plurality of known symbols, a process for indicating (terminating) the last symbol of the preamble by inverting the phase of the preamble is performed. Since the inter-symbol moving average process is performed in the previous stage of the second step and the phase-inverted symbol moving average process is performed in the previous stage of the third process, the peaks A and B in FIG. Correspondingly, the peak size is finally reversed by the termination preamble. Therefore, in the present embodiment, synchronization, that is, the end of the preamble signal can be determined based on the change (reversal) of the peaks of C and D in the figure.

  The processing results of the moving averagers 18 and 21 in the second process and the third process are input to the synchronization determination circuit 22. Then, after detecting the peak, the synchronization is determined based on the reversal of the peaks of C and D in the figure (see FIG. 6).

  Although various configurations can be considered for a specific method for performing synchronization detection based on the processing results obtained in the second step and the third step, for example, a two-stage configuration of a peak detection step and a synchronization determination step Can be considered. FIG. 10 shows the data flow shown in FIG. 5 or 6 in the form of a flowchart.

  For example, in the peak detection step shown in the figure, in the outputs of C and D in FIG. 7, if a certain maximum value is the maximum value after the M section, it is determined that it is a peak.

The result determined to be the peak is standardized and then input to the synchronization determination step to determine synchronization. For example, synchronization can be determined from peak reversal detection and the standardized peak D size. That is, when the ratio between the peak D and the peak C exceeds a certain value (T ₁ ) and the standardized peak D exceeds a certain value (T ₂ ), it is determined that synchronization is established. It should be noted that the effect of peak fluctuation due to S / N change can be suppressed by the standardization process using this synchronization detection algorithm.

  In order to verify the effectiveness of the synchronization detection according to the present embodiment, the synchronization circuit configuration shown in FIGS. 1 and 5 was compared with the conventional synchronization circuit configuration shown in FIG. 14 by computer simulation.

  In this simulation, it is assumed that the number of repetitions of the synchronization symbol is 8, and the phase is inverted for the last time. Further, S = 495, L = 495, N = 2, and M = 16. The preamble pattern shown in FIG. 8 is used, and a propagation path model is also used. As the noise, Gaussian noise was used.

  FIG. 11 shows the result of computer simulation. The horizontal axis represents S / N, and the vertical axis represents the rate at which synchronization was correctly performed (synchronization error rate). Conv in the figure shows the result of the conventional synchronization detection method, and New shows the result of the synchronization detection method according to the present embodiment. Compared to the conventional method, the method of the present embodiment has a lower required S / N for ensuring the error rate, that is, the rate of occurrence of an error is low even at a low S / N, which is superior to the conventional method. .

  FIG. 12 schematically shows a configuration of a synchronization circuit according to another embodiment of the present invention. The illustrated example is different from the embodiment shown in FIG. 1 in that the third step is omitted.

  A received signal in the RF frequency band received from the antenna is frequency-converted into a received baseband signal in the baseband using the carrier signal generated by the carrier signal generator 11. Next, the received baseband signal is sampled and converted into a digital signal by the A / D converter 12. The correlator 13 performs a correlation operation between the received baseband digital signal and the preamble code and outputs a correlation value. The correlation calculation result by the correlator 13 is processed in two steps.

  Although not shown, an automatic gain control device (AGC) may be incorporated around the front stage of the A / D converter 12. (Id.)

  The first step includes an absolute square calculator 14 and a moving averager 15. Since the correlation value is generally a complex number, the absolute square calculator 14 calculates the absolute square of the correlation value. Then, the moving average calculator 15 performs a moving average calculation on the correlation calculation result in a certain time interval.

  The second step includes a symbol moving averager 16, an absolute square calculator 17, and a moving averager 18. First, a moving average calculation between symbols is performed, and then an absolute square calculation is performed. Finally, a normal moving average calculation is performed. Here, the influence of noise can be reduced by the first symbol moving average calculation. Further, in a wireless communication system configured to repeatedly transmit a preamble signal for synchronization, an effect of combining a plurality of peaks due to multipaths into one by the second normal moving average calculation can be obtained.

  Then, the calculation result in the second step is normalized with the result calculated in the first step, and is output to the synchronization detector 22. Assuming fluctuations in received power due to the distance between antennas, AGC is usually incorporated in the receiver, but the input to the correlation value fluctuates due to a delay in the reaction speed of AGC. The maximum value of the correlation value output itself may fluctuate greatly, which may be one of the causes of synchronization errors. On the other hand, it is possible to reduce the influence of this problem by normalizing based on the calculation result in the first step.

  Various configurations are conceivable as specific methods for performing synchronization detection based on the processing result obtained in the second step. FIG. 13 shows an example of the synchronization detection method in the form of a flowchart. However, the signal output obtained in the first step is Norm, and the signal output obtained in the second step is c. Using these two signal outputs, a synchronization determination is made.

  First, the output signal c is obtained (step S1). Then, it is determined whether or not the output signal c is a peak (maximum value). If the output signal c is not peak, the process returns to step S1.

Next, it is determined whether c / Norm is larger than a predetermined threshold T ₁ (step S2). If c / Norm is not greater than a predetermined threshold value T _1, the flow returns to step S1.

Then, determine the ratio of the stored data and the c / Norm in buffer, with a predetermined threshold value T ₂ (step S3). If the ratio between the data stored in the buffer and c / Norm is not greater than T ₂ , the current value c / Norm is stored in the buffer as c ′ / Norm (step S 4), and the process returns to step S 1.

On the other hand, if the ratio between the data stored in the buffer and c / Norm is greater than T ₂ , it is regarded as synchronization (step S5).

  With the above flow, synchronization can be detected.

  Although not shown, it is also possible to detect synchronization from the preamble pattern using only the first step and the third step.

  The present invention has been described in detail above with reference to specific embodiments. However, it is obvious that those skilled in the art can make modifications and substitutions of the embodiment without departing from the gist of the present invention.

  In the present specification, the embodiment has been described by taking the case where the present invention is applied to a wireless communication system as an example. However, the gist of the present invention is not limited to this, and the wireless communication system adopts various communication methods. Alternatively, the present invention can be similarly applied to a wired communication system that needs to acquire synchronization between the transceivers.

  In short, the present invention has been disclosed in the form of exemplification, and the description of the present specification should not be interpreted in a limited manner. In order to determine the gist of the present invention, the claims section described at the beginning should be considered.

FIG. 1 is a diagram schematically showing a configuration of a synchronization circuit according to an embodiment of the present invention. FIG. 2 is a diagram illustrating a configuration example of a typical moving average circuit. FIG. 3 is a diagram showing a configuration example of the inter-symbol moving average circuit. FIG. 4 is a diagram showing a configuration example of a moving average circuit between phase inversion symbols. FIG. 5 is a diagram showing the overall configuration of the synchronization circuit. FIG. 6 is a diagram illustrating a configuration example of the synchronization detector 22. FIG. 7 is a diagram for explaining a specific operation of the synchronization device according to the present invention. FIG. 8 is a diagram illustrating a configuration example of a preamble pattern input to the correlator 13. FIG. 9 is a diagram illustrating an example of a correlator output. FIG. 10 is a flowchart showing an algorithm for performing synchronization detection based on the processing results obtained in the second step and the third step. FIG. 11 is a computer simulation result showing a comparison between the synchronization circuit according to the present invention and the synchronization circuit of the conventional configuration. FIG. 12 is a diagram schematically showing a configuration of a synchronization circuit according to another embodiment of the present invention. FIG. 13 is a flowchart showing a synchronization detection method by the synchronization circuit shown in FIG. FIG. 14 is a diagram showing a configuration example (conventional example) of the synchronization circuit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Carrier wave signal generator 12 ... A / D converter 13 ... Correlator 14 ... Absolute square calculator 15 ... Moving averager 16 ... Symbol moving averager 17 ... Absolute square calculator 18 ... Moving averager 19 ... Phase Inverted symbol moving average 20 ... Absolute square calculator 21 ... Moving average 22 ... Synchronization detector 23, 24 ... Maximum value detector 25 ... Divider 26 ... Synchronization detector

Claims (10)

A synchronization device that performs synchronization processing of a received signal based on a known signal included in transmission data,
In a system in which known signals are repeatedly sent,
Correlation calculation means for calculating a correlation between the received signal and the known signal;
A first moving average calculating means for calculating a moving average between the correlation results by the correlation calculating means;
Second moving average calculating means for calculating a moving average for the moving average calculated by the first moving average calculating means;
Synchronization detecting means for determining synchronization timing based on the moving average calculated by the second moving average calculating means;
A synchronization device comprising: The third moving average calculating means for calculating the moving average of the correlation result by the correlation calculating means;
A normalizing means for normalizing the moving average result by the second moving average calculating means using the moving average result by the third moving average calculating means;
The synchronization detection means determines the synchronization timing based on a standardized moving average result;
The synchronization device according to claim 1, wherein: Fourth moving average calculating means for calculating a moving average between symbols by a method different from the first moving average calculating means for the correlation result by the correlation calculating means;
A fifth moving average calculating means for calculating a moving average for the moving average calculated by the fourth moving average calculating means;
The synchronization detection means determines a synchronization timing based on each moving average result by the second moving average calculating means and the fifth moving average means;
The synchronization device according to claim 1 , wherein: In a system in which a known signal is repeatedly sent and the last signal is phase-inverted,
The fourth moving average means calculates a moving average between symbols after inverting the phase of the correlation value obtained last.
The synchronizing device according to claim 3 . Third moving average calculating means for calculating a moving average of the correlation result by the correlation calculating means;
Normalizing means for normalizing the moving average result by the second moving average calculating means and the moving average result by the fifth moving average calculating means, respectively, using the moving average results by the third moving average calculating means Prepared,
The synchronization detection means determines the synchronization timing based on each standardized moving average result.
The synchronization device according to claim 4 , wherein: A synchronization method for performing synchronization processing of a received signal based on a known signal included in transmission data,
In a system in which known signals are repeatedly sent,
A correlation calculation step for calculating a correlation between the received signal and the known signal;
A first moving average calculating step of calculating a moving average between the correlation results obtained by the correlation calculating step;
A second moving average calculating step for further calculating a moving average for the moving average calculated by the first moving average calculating step;
A synchronization detection step of determining a synchronization timing based on the moving average calculated by the second moving average calculation step;
A synchronization method comprising: The third moving average calculating step for calculating the moving average of the correlation result in the correlation calculating step;
A normalization step of normalizing the moving average result of the second moving average calculation step using the moving average result of the third moving average calculation step;
In the synchronization detection step, a synchronization timing is determined based on a standardized moving average result.
The synchronization method according to claim 6 . A fourth moving average calculating step of calculating a moving average between symbols by a method different from the first moving average calculating step in the correlation result of the correlation calculating step;
A fifth moving average calculating step of further calculating a moving average for the moving average calculated by the fourth moving average calculating step;
In the synchronization detection step, a synchronization timing is determined based on each moving average result obtained by the second moving average calculating step and the fifth moving average step.
The synchronization method according to claim 6 . In a system in which a known signal is repeatedly sent and the last signal is phase-inverted,
In the fourth moving average step, a moving average between symbols is calculated after inverting the phase of the correlation value obtained last.
The synchronization method according to claim 8, wherein: A third moving average calculating step of calculating a moving average of the correlation result by the correlation calculating step;
A normalizing step of normalizing the moving average result of the second moving average calculating step and the moving average result of the fifth moving average calculating step using the moving average result of the third moving average calculating step, respectively; Have
In the synchronization detection step, a synchronization timing is determined based on each standardized moving average result.
The synchronization method according to claim 9 .

Images