JP4975691B2 - Receiving apparatus and waveform processing method - Google Patents

Description

  The present invention relates to a receiving apparatus and a waveform processing method, and more particularly, to a receiving apparatus and a waveform processing method that extract a signal obtained by mixing a plurality of original signals by blind separation processing and sequentially connecting them.

  As a technique for separating and extracting an original signal from a signal received by mixing a plurality of original signals, a blind separation process technique typified by independent component analysis is known. In blind separation processing, these original signals are received by multiple sensors and analyzed based on the statistical independence of each original signal without using any foresight information such as the direction of arrival or modulation format of the signal. The original signals up to the number of signals corresponding to the number of sensors are separated and extracted.

  In this blind separation processing method, a series of data sampled during a predetermined period corresponding to one cycle of processing is used as one data block, and separation processing is sequentially performed in units of this data block. Each time the separation process is completed, the number of separated signals and the separated signal waveforms and mixed vectors are output in parallel from a plurality of ports on the output side corresponding to the number of sensors. In order to extract the original signal, it is necessary to sequentially connect the signal waveforms after separation processing that are output at each processing cycle to a continuous signal. However, in the blind separation process, the relationship between the signal waveform after the separation process and the number of the port from which these signals are output is not always kept the same between successive processing cycles. That is, the signal waveform after separation processing corresponding to the same original signal is not always output from a specific port, and the appearance order cannot be specified.

For this reason, a technique for extracting the original signal by sequentially and reliably connecting the signal waveforms after separation processing while dealing with such ambiguity of the appearance order is disclosed (for example, Patent Document 1 and (See Patent Document 2). In the case disclosed in Patent Document 1, the connection destination of the signal waveform immediately after separation is sequentially specified based on the correlation with the signal waveform separated in the immediately preceding processing cycle, and the continuous signal after connection is used as the original signal. Extracting. Further, in the case disclosed in Patent Document 2, they are connected to each other based on the arrival direction of each separated signal waveform derived from the mixture vector of the separation processing result.
Japanese Patent Laying-Open No. 2006-178314 (9th page, FIG. 1) Japanese Patent Laying-Open No. 2008-39693 (7th page, FIG. 1)

  However, a signal received in a real environment is not always received in a stable state, and often includes a lot of distortion and an insufficient signal-to-noise ratio. Further, when the original signal is an intermittent signal or the like, or when the original signal is strongly influenced by the propagation path, the received signal is temporarily lost. For this reason, when the separated signal waveforms are sequentially connected after the blind separation process, the connection may fail due to an inaccurate connection. In particular, when the original signal is temporarily lost, the result of blind separation processing is not obtained during the loss period, and there is no signal waveform that is a candidate for connection, so a partially missing original signal is extracted. It was. And since this missing part is no signal, it becomes an unnatural signal with a discontinuous part before and after that, and the quality of the signal is deteriorated. In particular, when the extracted original signal is processed as a signal in the audible region, this no-signal period has a significant influence such as silence, which causes a sense of incongruity and a sense of incongruity.

  The present invention has been made in consideration of the above circumstances, and when separating signal waveforms after blind separation processing are sequentially connected and extracted as an original signal, even when a separation candidate separation signal waveform does not exist, An object of the present invention is to provide a receiving apparatus and a waveform processing method for suppressing signal quality deterioration after concatenation and performing concatenation of signal waveforms in a more natural state.

  In order to achieve the above object, a receiving apparatus according to the present invention includes a plurality of sensors arranged in a predetermined shape and receiving a signal in which a plurality of original signals are mixed, and the signals received by the plurality of sensors. Sampling means for sampling each sample at a predetermined interval to obtain sample data, and subjecting the sample data within one cycle to blind separation processing at a predetermined cycle, and a maximum m-wave component corresponding to the number of sensors for each cycle. Signal separation means for acquiring the separated signal waveform and mixed vector and the number of separated signals, waveform storage means for storing the separated signal waveform in time series, separated signal waveform separated this time, and waveform storage means until immediately before Correlation value calculating means for calculating a correlation value with a stored separated signal waveform, and calculating a direction of arrival for each separated signal waveform based on the mixed vector The direction-of-arrival calculation storage means for storing and the frequency of arrival directions calculated and stored by this direction-of-arrival calculation storage means are counted, and the arrival of the original signal to be extracted for up to m arrival directions based on the frequency. A signal direction designating means for designating as a signal direction to be performed, and a direction designating for performing waveform extraction processing on the sample data with the signal direction designated by the signal direction designating means as a processing target direction and acquiring the processed signal waveform For each signal direction designated by the signal direction designating means, and the number of separated signal waveforms separated this time by the signal separating means coming from within a predetermined direction range with respect to these signal directions, and The separated signal waveforms are sequentially connected based on the correlation value with the separated signal waveform up to immediately before calculated by the correlation value calculating means, and When the separated signal waveform does not exist, the processing signal waveform from the waveform extraction means by the direction designation with the designated signal direction as a processing target is coupled, and the result of the coupling is obtained from the designated signal direction. And connecting means for extracting the original signal.

  In addition, the connecting means, for sequentially connecting the separated signal waveforms, for each separated signal waveform after the current separation calculated by the arrival direction calculating storage means based on the signal direction designated by the signal direction designating means. When there is only one separated signal waveform that comes from within a predetermined direction range with respect to the designated signal direction with reference to the direction of arrival, this separated signal waveform is from the designated signal direction. In other cases, reference is made to the correlation value with the separated signal waveform calculated immediately before by the correlation value calculation means. In the other cases, it is connected to the connection destination of the immediately preceding separated signal waveform having the maximum correlation value, and in other cases, the designated signal direction is processed and acquired by the waveform extraction means by the direction designation. Characterized by connecting the processed signal waveform.

  Further, the waveform processing method of the present invention receives a signal in which a plurality of original signals are mixed by a plurality of sensors arranged in a predetermined shape, performs a blind separation process every predetermined period, and a separated signal waveform The vector and the number of separated signals are continuously acquired, the arrival directions of these separated signal waveforms and the separated signal waveforms calculated from the mixed vectors are stored in time series, and the objects to be extracted based on the results of these blind separation processes A waveform processing method for designating a direction of the incoming signal of the original signal, sequentially connecting the separated signal waveforms after the blind separation processing based on the designated signal direction, and extracting the original signal from the designated signal direction. When there is only one separated signal waveform by the current blind separation process that comes from within the predetermined direction range with respect to the specified signal direction. In this case, the separated signal waveform is connected as that from the designated signal direction, and in other cases, a correlation value with the separated signal waveform subjected to the blind separation processing until immediately before is calculated, and a predetermined value is obtained. If there is a value exceeding the threshold, it is linked to the destination of the separated signal waveform up to the previous one having the maximum correlation value, and in other cases, this designated signal direction is processed. As described above, the received signal is subjected to waveform extraction processing by direction designation to connect a processed signal waveform.

  Further, the waveform extraction processing by the direction designation is characterized in that its processing algorithm is a DCMP method or an MSN method.

  According to the present invention, when the separated signal waveforms after the blind separation processing are sequentially connected and extracted as an original signal, deterioration of signal quality after the connection can be suppressed even when there is no connection candidate separated signal waveform. In addition, it is possible to obtain a receiving apparatus and a waveform processing method that can be taken out as being connected in a more natural state.

  The best mode for carrying out a receiving apparatus and a waveform processing method according to the present invention will be described below with reference to FIGS.

  FIG. 1 is a block diagram showing an embodiment of a receiving apparatus according to the present invention. As illustrated in FIG. 1, the receiving device includes a sensor unit 11, a sampling unit 12, a blind separation processing unit 13, a connected waveform storage unit 14, a correlation value calculation unit 15, an arrival direction calculation unit 16, and a connected arrival direction storage unit. 17, a signal direction specifying unit 18, a specified direction waveform extraction processing unit 19, a connection control unit 20, a connection unit 21, and an operation / display unit 22.

  The sensor unit 11 includes m sensors arranged in a predetermined shape. These sensors are antennas arranged in, for example, a circle or a straight line, and receive original signals arriving at the antennas and send them to the sampling unit 12. The sampling unit 12 performs reception processing such as filtering, frequency conversion, amplification, and the like on the signal from each sensor of the sensor unit 11 and obtains sample data by sampling at a predetermined interval. And sent to the designated direction waveform extraction processing section 19.

  The blind separation processing unit 13 performs blind separation processing on the sample data from the sampling unit 12, acquires the number of separated signal waveforms and mixed vectors and the number of separated signals that do not exceed the number of sensors m, To send. As a technique of blind separation processing, for example, a technique called independent component analysis can be applied. When executing the process, a predetermined period as a unit of the separation process is set as one cycle, and the sample data in this period is sequentially processed for the processing target, and the separation result is obtained for each processing period. Yes. An example of the result output after the separation by the blind separation process is modeled in a tabular form and illustrated in FIG. In the example shown in FIG. 2, for example, the number of sensors is three, the number of output ports after blind separation processing is three ports corresponding to the number of sensors, and the original of the three waves of A wave, B wave, and C wave. The separation result of each signal in each processing cycle is modeled and shown. As a result of separation, three signals are separated for each processing cycle, but a separated signal waveform and a mixed vector corresponding to the same original signal always appear in the same port at each port. The case where it is not necessarily illustrated is illustrated.

  The connected waveform storage unit 14 receives the result of connecting the separated signal waveforms sequentially output from the blind separation processing unit 13 and stores them in time series. The stored contents are modeled and illustrated in FIG. FIG. 3 is an explanatory diagram illustrating modeled storage contents following FIG. 2. The separated signal waveform output from each port in each processing cycle of FIG. The example is stored along the passage of time after sorting. The correlation value calculation unit 15 calculates a brute force correlation value between the separated signal waveform separated this time and the separated signal waveform separated immediately before and stored in the connected waveform storage unit 14, and a connection control unit described later 20 to send. In calculating the correlation value, it is possible to target only the separated signal waveform separated in the immediately preceding processing cycle, but the target range such as targeting the separated signal waveform for several times that goes back several cycles from immediately before. Can be variously selected.

  The arrival direction calculation unit 16 calculates the arrival direction of the signal for each corresponding separated signal waveform based on the mixed vector from the blind separation processing unit 13. The arrival direction is calculated by, for example, correlation processing between a steering vector representing a directivity pattern formed by an array of a plurality of sensors in the sensor unit 11 and a mixed vector, or the like. The connection arrival direction storage unit 17 receives the connection result of the arrival directions for each separated signal waveform calculated by the arrival direction calculation unit 16 and stores them in time series. The stored contents of the connection arrival direction storage unit 17 are modeled and illustrated in FIG. FIG. 4 is an explanatory diagram exemplifying the storage contents modeled according to FIGS. 2 and 3, and the separated signal waveform calculated based on the mixture vector output from each port for each processing period of FIG. The case where each arrival direction is memorize | stored along time passage after the rearrangement in the connection part 21 similarly to a separated signal waveform is shown. The signal direction designating unit 18 counts the frequency of arrival directions stored in the connected arrival direction storage unit 17, and sets the number of high arrival directions corresponding to the number of sensors m as an upper limit to the original signal to be extracted Is designated as the direction of the incoming signal, and notified to the designated direction waveform extraction processing unit 19 and the connection control unit 20. In addition, in this embodiment, the signal direction can also be specified based on the contents from the operation / display unit 22 described later.

  The designated direction waveform extraction processing unit 19 performs waveform extraction processing on the sample data from the sampling unit 12 with the signal direction designated by the signal direction designation unit 18 as the direction to be processed, and acquires the processed signal waveform. . In the present embodiment, as a waveform extraction processing algorithm by direction designation, a DCMP (Directional Constrained Minimization of Power) method or MSN (Maximum Signal-to--) that controls to minimize received power from other than the designated direction. (Noise ratio) method is applied. Note that these processing algorithms are described in detail in the non-patent document “Adaptive Antenna Technology” (Nobuyoshi Kikuma, Ohmsha Oct. 2003) and the like.

  The connection control unit 20 uses the signal direction specified by the signal direction specifying unit 18 as the arrival direction of the original signal to be extracted, and extracts the original signal by sequentially connecting the separated signal waveforms for each of the specified signal directions. Control signal is generated and sent to the connecting portion 21 in the subsequent stage. In this embodiment, based on the number of separated signal waveforms arriving from within a predetermined range with respect to the designated signal direction and the correlation between the separated signal waveform up to the previous time and the current separated signal waveform, for each period. When the separated signal waveforms to be connected do not exist, the processed signal waveforms acquired by the designated direction waveform extraction processing unit 19 are connected with the designated signal direction as a processing target. Thus, the control signal is generated. That is, when there is one separated signal waveform coming from within a predetermined range with respect to the designated signal direction, the separated signal waveforms are controlled to be sequentially connected. In other cases, that is, in the case where there are plural or not present in the direction range, the correlation value with the previous separated signal waveform is calculated, and if there is one that exceeds a predetermined threshold, The separated signal waveforms having high correlation values are sequentially connected. On the other hand, when there is nothing exceeding the predetermined threshold value, that is, there are a plurality of separated signal waveforms coming from within a predetermined range with respect to the designated signal direction, all of which are separated from the previous separated signal waveform. If the correlation is not high, or if there is no separated signal waveform coming from a predetermined range with respect to the specified signal direction and the correlation with the previous separated signal waveform is not high, the separated signal waveform that is a concatenation candidate is It is assumed that it does not exist. In such a case, control is performed so as to connect the processing signal waveforms by the waveform extraction processing by direction designation.

  The connecting unit 21 sequentially connects the separated signal waveforms from the blind separation processing unit 13 based on the control signal from the connection control unit 20, and from the designated direction waveform extraction processing unit 19 when no separated signal waveform exists. The processed signal waveforms are connected so as to be interpolated and extracted as an original signal. Also, the arrival directions that make a pair with the separated signal waveform are similarly connected. The operation / display unit 22 accepts various operations including an operation of designating the direction of the signal from which the original signal to be extracted, which is performed by an operator, sends the operation to each unit in the apparatus, and includes an operation input result Display data from each part is displayed.

  Next, the operation of the receiving apparatus according to the present embodiment configured as described above will be described with reference to the flowcharts of FIGS. 1 to 4 and FIG. FIG. 5 is a flowchart for explaining the operation of the receiving apparatus according to the present invention.

  When the original signals of a plurality of waves are mixed and received by the sensor unit 11 (ST501), the received signals are subjected to reception processing and sampling by the sampling unit 12, and sent to the blind separation processing unit 13. The blind separation processing unit 13 performs blind separation processing on the sample data from the sampling unit 12 at a predetermined cycle, and as illustrated in FIG. 2, the separated signal waveform corresponding to the original signal with the number m of sensors as the upper limit. And the mixing vector and the number of separated signals are obtained. As a technique of the blind separation process, for example, a technique such as independent component analysis can be applied. Further, the obtained mixed vector is sent to the arrival direction calculation unit 16, and the arrival direction for each separated signal waveform is calculated by correlation processing with the steering vector or the like (ST502). Next, the signal direction designation unit 18 counts the arrival direction frequency stored in the connected arrival direction storage unit 17. As a result, it is assumed that the arrival direction with high frequency is the arrival direction of the original signal, and the arrival direction of the original signal to be extracted is set to “signal” with the number corresponding to the number m of sensors as the upper limit among these arrival directions with high frequency. Specify as direction. The signal direction is specified based on the counting result of the arrival direction, and is also specified by a designation operation from the operation / display unit 22 in this embodiment. Then, the designated signal direction is notified to the connection control unit 20 (ST503).

  The connection control unit 20 generates a control signal for sequentially connecting the separated signal waveforms with the signal direction specified by the signal direction specifying unit 18 as a key. This control signal controls the connection destination when the separated signal waveforms separated in the current cycle are sequentially connected in the connecting unit 21 at the subsequent stage as follows. That is, when there is one separated signal waveform having an arrival direction within a predetermined range with respect to the designated signal direction (single ST504), the original signal arriving from the designated signal direction is regarded as one wave. Then, control is performed so as to sequentially connect to the separated signal waveform until just before the signal direction matches (ST505). On the other hand, if a plurality of separated signal waveforms are present or not present in the determination in ST504, it is considered that concatenation using only the signal direction as a key is difficult, and the correlation value calculation unit 15 immediately before stored in the concatenated waveform storage unit 14 The correlation value with the separated signal waveform is calculated (ST506). Then, the calculation result is compared with a predetermined threshold value, and if there is a value exceeding the threshold value (Y in ST507), control is performed so as to sequentially connect to the separated signal waveform immediately before having the maximum correlation value. To do. By controlling in this way, for example, when the arrival directions of the original signals of multiple waves are congested, or when the arrival direction of the original signals changes temporarily due to the influence of the propagation path, etc., and greatly deviates from the predetermined range Etc., the separated signal waveforms can be reliably connected (ST508).

  On the other hand, when there is no signal exceeding the threshold value (N in ST507), this indicates that there is no separated signal waveform to be connected as from the designated signal direction in this period. Therefore, in this case, the designated direction waveform extraction processing unit 19 performs the waveform extraction process by the direction designation with the designated signal direction as the processing target, and acquires the processed signal waveform (ST509). In this embodiment, the processing algorithm at this time is the DCMP method or the MSN method. These processing algorithms are designed to receive a signal from a specified direction including background noise and the like by specifying a target direction and suppress signals from other than the specified direction. Then, control is performed so that the acquired processed signal waveform is connected to the connected signal up to the previous time. By controlling in this way, for example, when the original signal is temporarily lost due to the influence of the propagation path, when the original signal is an intermittent signal, or when the result of the blind separation process is insufficient In addition, since the missing part can be eliminated from the signal extracted from the connecting unit 21 and the actual signal received from the designated signal direction is connected, a more natural connection result can be obtained (ST510).

  When the control signal generated in this way is sent to the connecting unit 21, the connecting unit 21 sequentially connects the separation signal waveforms from the blind separation processing unit 13 in accordance with the control signal, and the separation signal to be connected. When there is no waveform, the processing signal waveforms from the designated direction waveform extraction processing unit 19 are connected so as to interpolate them, and these connection results are output from the connecting unit 21 as original signals. Further, at the time of connection, since the difference in the appearance ports of the signal immediately after the blind separation process is rearranged, the separated signal waveform and the arrival direction rearranged after the connection are respectively connected to the connection waveform storage unit 14 and the connection arrival direction storage unit 17. And stored in time series as illustrated in FIGS. 3 and 4 (ST511). Thereafter, the above-described operation steps are repeated until an operation end is instructed (ST512).

  As described above, in the present embodiment, when the separated signal waveforms obtained by blind separation processing of a signal in which a plurality of original signals are mixed are sequentially connected using a designated signal direction as a key, When the separated signal waveform with the specified signal direction as the arrival direction is one wave, these are sequentially connected, and when there are multiple waves or not, the most significant of the separated signal waveforms up to the previous one Link to a link destination that has a strong correlation. Furthermore, if the signal direction does not match and does not have a significant correlation, the processed signal waveform obtained by adaptive array antenna processing for the specified signal direction is assumed as the separated signal waveform to be connected has not been obtained. Are interpolated.

  As a result, even if the separated signal waveform does not exist due to the temporary disappearance of the original signal, no signal is lost after connection, and the missing signal is connected to the actual received signal. As a result, it is possible to suppress degradation due to the discontinuity of the signal quality extracted as, and to obtain a more natural connection result. Even when there are irregular signal environment conditions where the original signal exists but the blind separation process cannot obtain a sufficient separation result, the result of the waveform extraction process by direction designation can be used together. As a result, good connection results can be obtained.

  Note that the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

The block diagram which shows one Example of the receiver which concerns on this invention. Explanatory drawing which models and shows an example of the separation result by a blind separation process. Explanatory drawing which models and shows an example of the memory content of a connection waveform memory | storage part. Explanatory drawing which models and shows an example of the memory content of a connection arrival direction memory | storage part. 3 is a flowchart for explaining the operation of the receiving apparatus illustrated in FIG. 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Sensor part 12 Sampling part 13 Blind separation process part 14 Connection waveform memory | storage part 15 Correlation value calculation part 16 Arrival direction calculation part 17 Connection arrival direction memory | storage part 18 Signal direction designation | designated part 19 Designated direction waveform extraction process part 20 Connection control part 21 Connection Part 22 Operation / display part

Claims (6)

A plurality of sensors arranged in a predetermined shape and receiving a signal in which a plurality of original signals are mixed;
Sampling means for obtaining sample data by sampling the signals received by the plurality of sensors, respectively, at predetermined intervals;
Signal separation means for performing blind separation processing on the sample data within one period at a predetermined period, and obtaining a separation signal waveform, a mixing vector, and the number of separation signals for the maximum m waves corresponding to the number of sensors for each period When,
Waveform storage means for storing the separated signal waveform in time series;
Correlation value calculating means for calculating a correlation value between the separated signal waveform separated this time and the separated signal waveform stored in the waveform storage means until immediately before;
Arrival direction calculation storage means for calculating the arrival direction for each separated signal waveform based on the mixed vector and storing it in time series;
Signal direction designation that counts the frequency of arrival direction calculated and stored by this arrival direction calculation storage means, and designates the arrival direction as the signal direction from which the original signal to be extracted arrives, based on the high frequency Means,
Waveform extraction means by direction designation for performing waveform extraction processing on the sample data with the signal direction designated by the signal direction designation means as the direction to be processed, and acquiring the processed signal waveform;
For each signal direction designated by the signal direction designating means, the number of separated signal waveforms currently separated by the signal separating means coming from within a predetermined direction range with respect to these signal directions, and the correlation value calculating means The separated signal waveforms are sequentially linked based on the calculated correlation value with the separated signal waveform up to immediately before, and when the separated signal waveform to be linked does not exist, the designated signal direction is set as the processing target. And a connecting means for connecting the processed signal waveforms from the waveform extracting means by specifying the direction and extracting the result of the connection as an original signal from the specified signal direction. When the connecting means sequentially connects the separated signal waveforms,
Refer to the arrival direction for each separated signal waveform after the current separation calculated by the arrival direction calculation storage means based on the signal direction designated by the signal direction designation means,
When there is only one separated signal waveform coming from within a predetermined direction range with respect to the designated signal direction, the separated signal waveform is connected as from the designated signal direction,
In other cases, the correlation value with the separated signal waveform calculated immediately before by the correlation value calculation means is referred to. Connected to the connection destination of the separated signal waveform up to immediately before having a value,
In other cases, the receiving apparatus according to claim 1, wherein the processing signal waveform acquired by the waveform extracting means by the direction specification is connected to the specified signal direction as a processing target.   3. The method according to claim 1, wherein the waveform extraction means by the direction designation uses a DCMP (Directly Constrained Minimization of Power) method or an MSN (Maximum Signal-to-Noise ratio) method as a processing algorithm. The receiving device described.   The receiving apparatus according to claim 1, further comprising an operation input unit that receives an input operation by an operator for designating a signal direction in the signal direction designating unit. A signal in which a plurality of original signals are mixed is received by a plurality of sensors arranged in a predetermined shape and subjected to blind separation processing every predetermined period to continuously generate a separated signal waveform, a mixed vector, and the number of separated signals. In addition to acquiring the separated signal waveform and the arrival direction of the separated signal waveform calculated from the mixed vector in time series, the direction of the arrival of the original signal to be extracted is determined based on the result of the blind separation process. A waveform processing method for sequentially specifying the separated signal waveforms after the blind separation processing based on the designated signal direction and extracting as an original signal from the designated signal direction,
When there is only one separated signal waveform by the current blind separation process that comes from within a predetermined direction range with respect to the designated signal direction, this separated signal waveform is from the designated signal direction. Concatenated as
In other cases, the correlation value with the separated signal waveform subjected to the blind separation processing until immediately before is calculated. Connect to the connection destination of the separated signal waveform until just before,
In other cases, a waveform processing method is characterized in that a processing signal waveform obtained by performing waveform extraction processing by direction designation on the received signal is connected to the designated signal direction as a processing target.   6. The waveform processing method according to claim 5, wherein the waveform extraction processing by the direction designation uses a DCMP method or an MSN method as its processing algorithm.

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