JP2019062385A - Radio communication device - Google Patents

Abstract

To propose a technique capable of efficiently detecting noise interference waves.SOLUTION: A transmitter transmits a preamble signal (first known signal) of a pattern A having a length of 1/2 of a preamble section in a frame and a preamble signal (second known signal) identical to that of the pattern A every frame (in one frame cycle). A noise interference wave extraction unit 305 of a receiver adjusts the pattern A included in a received signal and a pattern A included in a delay signal so that they are in phase (delay processing of 1/2 preamble time) and extracts a noise interference wave component by subtracting the received signal and delay signal.SELECTED DRAWING: Figure 4

Description

  The present invention relates to digital wireless communication, and more particularly to a technique for calculating the level and frequency characteristics of noise and interference waves contained in a received signal.

  As one of the prior art related to wireless communication, there is a technology for improving the reception characteristic by calculating the level of noise interference included in the received signal and performing noise normalization and interference suppression filter processing on the received signal (Patent Document 1) 1).

  As a method of calculating the level or frequency of noise or interference waves, a method of subtracting a pilot carrier included in an orthogonal frequency division multiplexing (OFDM) symbol between symbols is used. In this method, when a format is used in which the time interval between pilot symbols is wide, channel fluctuation between pilot symbols is large in a mobile transmission environment, and noise interference calculation accuracy is degraded. Also, if the ratio of pilot carriers to data carriers is constant, in the format in which the pilot carriers are densely arranged in the time direction, the arrangement in the frequency direction becomes rough and many frequencies where narrowband interference waves can not be detected exist. It will

  As another prior art, there is also a technique of estimating the noise interference level of all bands from the noise interference level of out-of-band NULL carriers, but since the frequency characteristics of noise interference components can not be obtained, in-band interference waves can not be detected. There is a problem that it is impossible to detect the frequency characteristic difference of noise due to the problem or analog. As another prior art, there is a method of providing a non-signal time or frequency. In this case, although there is no problem regarding detection of the frequency characteristic of the noise interference wave or detection of the narrow band interference wave, it is necessary to provide a non-signal section, and the throughput is lowered. If the non-signal interval is reduced to avoid a decrease in throughput, the time required for interference detection will increase.

JP 2014-236337 A

As described above, in the conventional technology, there are problems such as detection of noise interference waves in a mobile environment, high-speed detection of interference waves, acquisition of frequency characteristics of noise interference waves, and high throughput not simultaneously realized.
The present invention has been made in view of the above-described circumstances, and an object thereof is to propose a technique capable of efficiently detecting a noise interference wave.

In order to achieve the above object, the present invention is configured as follows.
That is, the wireless communication apparatus for receiving a signal transmitted by radio from the other party apparatus includes extracting means for extracting a noise or interference wave component (hereinafter referred to as "noise and interference wave component") contained in the received signal, The counterpart apparatus transmits the first known signal and the second known signal identical to or sign-inverted from the first known signal at predetermined intervals, and the extraction means includes the received signal and the received signal. Extracting a noise interference component by subtracting or adding a delayed signal obtained by delaying the signal so that the second known signal contained in the received signal and the first known signal contained in the delayed signal cancel each other It is characterized by

  Here, as one configuration example, the counterpart apparatus includes a first known signal, a first frame into which a second known signal identical to the first known signal is inserted, a first known signal, and a first known signal. The second known signal in which the known signal of 1 is inverted and the second known signal are alternately transmitted, and the extraction means subtracts the received signal and the delayed signal when receiving the first frame to generate noise The interference wave component may be extracted, and the noise interference wave component may be extracted by adding the reception signal and the delay signal when the second frame is received.

  Further, as another configuration example, the opposite device transmits a frame in which a plurality of sets of the first known signal and the second known signal obtained by inverting the first known signal are inserted, and the extraction unit A process of extracting noise interference components by adding so that the second known signal included in the received signal and the first known signal included in the delay signal cancel each other, and a set on the rear side included in the received signal And the set on the front side included in the delay signal may be subtracted so as to cancel out each other to extract a noise interference wave component.

  Further, the wireless communication apparatus further includes frequency analysis means for performing frequency analysis on the noise interference wave component extracted by the extraction means, and a time window to be subjected to frequency analysis by the frequency analysis means of the noise interference wave component. And window adjustment means for setting the time window length equal to or less than the signal length of the first or second known signal.

  According to the present invention, since it is not necessary to provide a non-transmission period or a non-transmission frequency for detection of noise interference waves, noise interference waves can be efficiently detected, and throughput can also be improved. .

It is a figure which shows the example of a format of the radio | wireless frame used for transmission in the radio | wireless communication apparatus which concerns on one Embodiment of this invention. It is a figure which shows the structural example of the transmitter which concerns on Examples 1-3. It is a figure which shows the structural example of the receiver which concerns on Examples 1-3. FIG. 8 is a diagram showing an example of a time chart of the noise and interference wave extraction process according to the first embodiment. FIG. 6 is a diagram showing an example of the configuration of a noise and interference wave extraction unit according to the first embodiment. FIG. 7 is a diagram showing an example of a time chart of the noise and interference wave extraction process according to the second embodiment. FIG. 7 is a diagram showing an example of the configuration of a noise and interference wave extraction unit according to a second embodiment. FIG. 18 is a diagram showing an example of a time chart of the noise and interference wave extraction process according to the third embodiment. FIG. 16 is a diagram showing an example of a configuration of a noise and interference wave extraction unit according to a third embodiment. In Example 2, it is a figure which shows the result of a noise interference wave extraction simulation at the time of mixing noise in all the bands. In Example 2, it is a figure which shows the simulation result at the time of mixing the interference wave which becomes the same pattern in the first half and the second half of a preamble. In Example 2, it is a figure which shows the simulation result at the time of mixing the interference wave which becomes a reverse pattern in the first half and the second half of a preamble.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an example format of a wireless frame used for transmission in the wireless communication apparatus according to an embodiment of the present invention. The frame format in FIG. 1 has a first area in which a preamble, which is a known signal, is stored, and a second area in which pilots, data, and the like are stored. Here, three different preamble patterns are assumed in each embodiment. In the first embodiment, the preamble is divided into two and signals of the same pattern A are used in the first half and the second half. In the second embodiment, two types of preambles are prepared for the even frame and the odd frame. For example, the even frame is the same as that of the first embodiment, and the second half of the preamble is a signal obtained by inverting the code of pattern A for the odd frame. In the third embodiment, the preamble is divided into four, and signals from the top of the pattern B, the pattern B, the pattern B, and the pattern B, the pattern B, are arranged in order.

In the following, the configuration of a wireless device for performing noise interference wave detection, which is the focus of the present invention, will be described using FIGS. 2 and 3, and the details of the noise interference wave detection will be described later.
FIG. 2 is a block diagram showing a configuration example of a transmitter that is an example of a wireless communication apparatus on the transmission side. The transmitter has a function of inserting a preamble pattern according to the embodiment into the transmission signal. The transmitter includes an encoding unit 201, a modulation unit 202, an IFFT (Inverse Fast Fourier transform) unit 203, a selection unit 204, a preamble pattern memory 205, a code inversion unit 206, a frame timing unit 207, and a DA unit 208. , Transmitting antenna 209.

  The encoding unit 201 encodes information to be transmitted, and outputs the encoded information to the modulation unit 202. The modulation unit 202 modulates the input signal and outputs the modulated signal to the IFFT unit 203. The IFFT unit 203 converts the input frequency domain signal into a time domain signal, and outputs the signal to the selection unit 204. Further, in order to insert a preamble signal which is a known signal into the transmission signal, the preamble pattern held in advance in the preamble pattern memory 205 is output to the selecting unit 204 and the code inverting unit 206. The preamble pattern held in advance in the preamble pattern memory 205 differs depending on the embodiment, and the embodiment 1 or 2 holds the pattern A, and the embodiment 3 holds the pattern B. The code inverting unit 206 inverts the code of the inputted preamble pattern signal, and outputs the inverted signal to the selecting unit 204.

  The frame timing unit 207 generates frame timing information. The frame timing information differs depending on the embodiment, and a transmission signal switching signal is generated according to the preamble pattern to be transmitted, and is output to the selection unit 204. Selection unit 204 selects a transmission signal according to the transmission signal switching signal input from frame timing generation unit 207, and outputs the selected transmission signal to DA unit 208. Therefore, different preambles in each embodiment are output to the DA unit 208. The DA unit 208 converts the input signal into an analog signal, and outputs the analog signal to the transmission antenna 209 for transmission.

  FIG. 3 is a block diagram showing a configuration example of a receiver which is an example of the wireless communication apparatus on the receiving side. The receiver has a function of receiving the signal transmitted from the transmitter and calculating the frequency characteristic of the noise interference wave. The receiver includes a receiving antenna 301, an AD unit 302, a narrowband interference wave suppression filter 303, a preamble timing detection unit 304, a noise interference wave extraction unit 305, a window adjustment unit 306, a frequency analysis unit 307, an interference threshold judgment unit 308, an average. The unit 309 includes a frequency analysis unit 310, a noise normalization unit 311, and a demodulation / decoding processing unit 312.

  The AD unit 302 converts the signal received by the receiving antenna 301 into a digital signal, and outputs the digital signal to the narrowband interference wave suppression filter 303, the preamble timing detection unit 304, and the noise interference wave extraction unit 305. The narrow band interference wave suppression filter unit 303 will be described later. The preamble timing detection unit 304 detects the preamble position, for example, by performing cross correlation between the received signal and the preamble pattern that are input, and outputs a timing pulse signal indicating the preamble position to the window adjustment unit 306. The window adjustment unit 306 delays the timing pulse signal from the preamble timing detection unit 304 and outputs a pulse signal indicating the position of frequency analysis for the output signal from the noise interference wave extraction unit 305 described later to the frequency analysis unit 307. The noise interference wave extraction unit 305 extracts only the noise interference wave component using the feature of the preamble signal, and outputs the noise interference wave component to the frequency analysis unit 307. Since the internal configuration of the noise interference wave extraction unit 305 differs depending on the embodiment, it will be separately described using FIGS.

  The frequency analysis unit 307 performs frequency analysis on the signal input from the noise / interference wave extraction unit 305 according to a pulse signal indicating the position of frequency analysis input from the window adjustment unit 306, thereby the frequency characteristic of the noise / interference wave You can get The frequency analysis unit 307 outputs the obtained frequency characteristic of the noise interference wave to the interference threshold determination unit 308 and the averaging unit 309. The interference threshold value determination unit 308 outputs a signal indicating an interference frequency to the narrow band interference wave suppression filter 303 when a noise interference wave exceeding a preset threshold value is detected. In order to shorten the time required for the detection of noise interference waves, the signal used for the above threshold determination uses the signal of the input of the averaging unit 309. The averaging unit 309 performs averaging processing in a sufficiently short period with respect to the time constant of AGC (Automatic Gain Control) to improve the calculation accuracy of the noise interference wave, and outputs the result to the noise normalization 311.

  The narrowband interference wave suppression filter 303 performs a filtering process on the reception signal input from the AD unit 302 to suppress a signal of the target frequency according to the signal indicating the interference wave frequency input from the interference threshold value determination unit 308, Output to frequency analysis unit 310. The frequency analysis unit 310 converts the input signal into a frequency domain signal and inputs the signal to the noise normalization unit 311. The noise normalization unit 311 normalizes the level of the noise interference wave in the frequency and time direction with respect to the signal from the frequency analysis unit 310 so that the level of the noise interference wave input from the averaging unit 309 becomes constant. And output to the demodulation / decoding processing unit 312. By this normalization processing, weighting can be performed on the quality of the received signal, and decoding characteristics can be improved. Further, in the case of a receiver having a plurality of receiving antennas, it also normalizes the levels of noise and interference waves between the receiving systems, and outputs the result to the demodulation / decoding processing unit 312. The demodulation / decoding processing unit 312 performs demodulation / decoding processing of the input signal.

The noise interference wave extraction process will be described below with reference to Examples 1 to 3.
Example 1
A method of extracting noise interference waves according to the first embodiment will be described. FIG. 4 shows a time chart example of noise interference wave extraction processing according to the first embodiment.
As shown in FIG. 4, the pattern A coincides with the timing of the same pattern timing 401 between the received signal and the received signal with a 1⁄2 preamble delay (a received signal delayed by a half of one preamble time). Therefore, only the noise interference component can be extracted by subtracting the reception signal and the reception signal of 1/2 preamble delay. However, when interference waves that become the same pattern in the first half and the second half of the preamble pattern are mixed, interference waves can not be detected because the interference wave components cancel each other by subtraction. Measures for that will be described in a second embodiment described later.

  The internal configuration of the noise and interference wave extraction unit 305 that implements the process described in FIG. 4 will be described using FIG. The received signal input from the AD unit 302 to the noise interference wave extraction unit 305 is input to the subtraction unit 501 and the delay unit 502. The delay unit 502 delays the signal for half of one preamble time, and outputs the delayed signal to the subtraction unit 501. The subtraction unit 501 performs subtraction processing on each of the input signals (the reception signal and the reception signal of 1/2 preamble delay) to cancel out the preamble signal components and extract noise interference components. The extracted noise interference wave component is output to the frequency analysis unit 307.

(Example 2)
A method of extracting noise interference waves according to the second embodiment will be described. FIG. 6 shows an example of a time chart of noise interference wave extraction processing according to the second embodiment.
When the even frame is received, the process is the same as the process of the first embodiment, and the pattern A matches at the same pattern timing 601, so that only the noise interference wave component can be extracted by the subtraction process. At the time of reception of an odd frame, since the sign inversion of the pattern A and the pattern A appears at the timing of the reverse pattern timing 602 between the reception signal and the reception signal of 1⁄2 preamble delay, addition processing of these signals is performed. Thus, only the noise interference component can be extracted.

  In the even frame, as in the first embodiment, when interference waves having the same pattern are mixed in the first half and the second half of the preamble, the interference wave components cancel each other out by subtraction, and thus the interference wave components can not be detected. However, the interference wave component which becomes a reverse pattern can be detected. On the contrary, in the odd frame, when the interference wave having the reverse pattern in the first half and the second half of the preamble is mixed, the interference wave component can not be detected, but the interference wave component having the same pattern can be detected. Therefore, by adding the signals respectively calculated in the even frame and the odd frame, it becomes possible to detect when any interference wave is mixed. However, detection of noise interference components requires receiving even frames and odd frames, which requires two frame times. A countermeasure for that will be described in a third embodiment described later.

  The internal configuration of the noise and interference wave extraction unit 305 that implements the process described in FIG. 6 will be described using FIG. 7. The received signal input from the AD unit 302 to the noise interference wave extraction unit 305 is input to the frame pattern determination unit 701, the addition unit 702, the subtraction unit 703, and the delay unit 704. The frame pattern determination unit 701 determines which one of the even frame and the odd frame is being received using cross correlation, autocorrelation or the like, and outputs a switching signal indicating the determination result to the selection unit 705. The delay unit 704 outputs a signal obtained by delaying a half of the preamble signal time to the addition unit 702 and the subtraction unit 703. The addition unit 702 performs addition processing of each of the input signals (the reception signal and the reception signal of 1⁄2 preamble delay), and outputs the result to the selection unit 705. Subtraction unit 703 performs subtraction processing on each of the input signals (the reception signal and the reception signal of 1/2 preamble delay), and outputs the result to selection unit 705.

  The selection unit 705 selects the signal from the subtraction unit 703 when receiving even frames, and selects the signal from the addition unit 702 when receiving odd frames, according to the switching signal input from the frame pattern determination unit 701, and adds them. It outputs to the section 706 and the frame delay section 707. By this selection, only the signal from which the noise interference wave is extracted is output to the subsequent stage. The frame delay unit 707 delays the input signal by one frame and outputs the signal to the addition unit 706. The addition unit 706 adds the signal from the selection unit 705 and the signal output from the frame delay unit 707, and outputs the result to the frequency analysis unit 307. By such processing, it is possible to add and detect the noise interference wave detection result of the even frame and the noise interference wave detection result of the odd frame to detect all noise interference wave components.

(Example 3)
The noise interference wave extraction method according to the third embodiment will be described. FIG. 8 shows a time chart example of noise interference wave extraction processing according to the third embodiment.
First, the received signal and the received signal of 1/2 preamble delay become the same pattern at the same pattern timing 801 timing, and by performing subtraction processing of these signals, the preamble components cancel each other and only the noise interference wave component It is extracted. This signal is D1. In the calculation of the signal D1, as in the even frame of the second embodiment, although an interference wave having the same pattern as the known signal can not be detected, an interference wave having an opposite pattern can be detected.

  Next, for the reception signal and the reception signal of 1⁄4 preamble delay (the reception signal delayed by 1⁄4 of 1 preamble time), the pattern of each signal at the timing of reverse pattern timing 802 and reverse pattern timing 803 Is reversed. Therefore, by adding each signal, it is possible to cancel out the preamble signal component and extract only the noise interference component. Let this signal be D2. In the calculation of the signal D2, as in the odd frame of the second embodiment, although an interference wave having a reverse pattern to the known signal can not be detected, an interference wave having the same pattern can be detected. Since the position of the noise interference component is different between the signal D1 and the signal D2, the signal D2 is delayed by 1⁄4 preamble time. This signal is D3. As in the second embodiment, by adding the signal D1 and the signal D3, all interference waves can be comprehensively detected.

  The internal configuration of the noise and interference wave extraction unit 305 that implements the process described in FIG. 8 will be described using FIG. The reception signal input from the AD unit 302 to the noise interference wave extraction unit 305 is input to the A delay unit 901, the B delay unit 902, the subtraction unit 903, and the addition unit 904. The A delay unit 901 delays the received signal for half of one preamble time, and outputs the result to the subtraction unit 903. Subtraction unit 903 performs subtraction processing on each of the input signals (the reception signal and the reception signal of 1/2 preamble delay), and outputs the result to selection unit 705. This subtraction processing cancels the preamble signal and extracts only the noise interference wave by using the feature that the first half and the second half of the preamble are the same. B delay section 902 delays the received signal for 1⁄4 of one preamble time, and outputs the result to addition section 904. The addition unit 904 performs addition processing of each input signal (the reception signal and the reception signal of 1⁄4 preamble delay), and outputs the result to the B delay unit 906. This addition processing cancels the preamble signal and extracts only the noise interference wave, using the feature that the pattern of a partial section of the preamble is reversed. The B delay unit 906 delays the input signal by 1⁄4 preamble time and outputs the delayed signal to the addition unit 905 in order to match the timings of the extraction results. The addition unit 905 performs addition processing of the input signals, adds the extraction results of the noise interference waves by the subtraction unit 903 and the addition unit 904, and outputs the result to the frequency analysis unit 307.

Next, simulation results of the noise and interference wave extraction method according to the second embodiment will be described with reference to FIGS. 10 to 12.
FIG. 10 shows a simulation result of noise interference calculation in the case where only white noise of 0 dB is mixed in the received signal. Here, white noise is mixed in the entire band. According to FIG. 10, noise components are detected in both the subtraction result at the time of receiving even frames and the addition result at the time of receiving odd frames, and by analyzing the frequency of the result of addition and subtraction results, broadband noise can be obtained. It can be seen that detection is possible.

  FIG. 11 shows the simulation result of the noise interference wave calculation when the interference wave patterns included in the first half and the second half of the preamble are the same. In FIG. 11, because the interference wave patterns match, the interference wave can not be detected in the subtraction result, but can be detected in the addition result. Therefore, it is understood that the frequency and power of the interference wave can be detected by performing frequency analysis on the result of addition of the addition and subtraction results.

FIG. 12 shows a simulation result of noise interference calculation when the interference wave patterns included in the first half and the second half of the k preamble are reversed. In FIG. 12, since the interference wave pattern is reverse, in the addition result, the interference wave components cancel each other out and the interference wave can not be detected, but the subtraction result can be detected. Therefore, it is understood that the frequency and power of the interference wave can be detected by performing frequency analysis on the result of adding the addition and subtraction results.
From the above simulation results, it can be seen that the frequency and level of the noise interference can be detected regardless of the bandwidth and frequency of the noise interference.

  As described above, the transmitter of this example includes the noise interference wave extraction unit 305 that extracts the noise interference wave component included in the reception signal. Also, the transmitter transmits the first known signal and the second known signal that is identical to or sign-inverted from the first known signal at predetermined intervals. Then, the noise interference wave extraction unit 305 cancels the received signal and the delayed signal obtained by delaying the received signal, the second known signal contained in the received signal and the first known signal contained in the delayed signal. It is configured to extract noise interference components by subtraction or addition as described above.

  More specifically, in the first embodiment, the transmitter transmits the preamble signal of the pattern A (first known signal) having a half length of the preamble section in each frame (in one frame period). And a preamble signal (second known signal) identical to the pattern A. The noise interference wave extraction unit 305 adjusts the pattern A included in the received signal and the pattern A included in the delayed signal so as to be in phase with each other (delay processing of 1⁄2 preamble time), and the received signal and the delayed signal The noise interference wave component is extracted by subtraction. The transmitter transmits, as the second known signal, a preamble signal obtained by inverting the code of pattern A, and the noise interference wave extraction unit 305 includes the pattern A (code inversion) included in the received signal and the delayed signal. The noise interference wave component may be extracted by adjusting so that the pattern A to be processed is in phase (delay processing of 1⁄2 preamble time), and adding the reception signal and the delay signal.

  Further, in the second embodiment, the transmitter inserts an even frame (first frame) into which a preamble signal (first known signal) of pattern A and a preamble signal (second known signal) identical to that of pattern A are inserted. And an odd frame (second frame) in which a preamble of pattern A (first known signal) and a preamble (second known signal) obtained by inverting the sign of pattern A are inserted. When receiving an even frame, the noise interference wave extraction unit 305 performs adjustment so that the pattern A included in the received signal and the pattern A included in the delay signal are in phase (delay processing of 1⁄2 preamble time), A noise interference wave component is extracted by subtracting the reception signal and the delay signal. On the other hand, the noise interference wave extraction unit 305 adjusts the pattern A (sign inversion) included in the received signal and the pattern A included in the delay signal to be in phase when receiving an odd frame (1/2 preamble time Delay processing) and adds the received signal and the delayed signal to extract a noise interference component. Then, the noise interference wave component extracted in the even frame and the noise interference wave component extracted in the odd frame are added, and the result is output to the processing unit (frequency analysis unit 307) in the subsequent stage as the extraction result of the noise interference wave component. The processing contents may be interchanged between the odd frame and the even frame.

  Further, in the third embodiment, the transmitter transmits a preamble signal (first known signal) of pattern B having a length of 1⁄4 of the preamble period in the frame, and a preamble obtained by inverting the code of pattern B (second And a frame in which two sets of the known signal and the known signal) are inserted. The noise interference wave extraction unit 305 performs adjustment (delay processing of 1⁄4 preamble time) so that the pattern B (sign inversion) included in the received signal and the pattern B included in the delayed signal are in phase with each other. The delayed signal is added to extract the noise interference component (D2). Also, the noise interference wave extraction unit 305 performs adjustment so that the set on the rear side (pattern B and its code inversion) included in the received signal is in phase with the set on the front side included in the delay signal (1/2 preamble Time delay processing is performed, and the reception signal and the delay signal are subtracted to extract a noise interference component (D1). Then, the noise interference wave component (D2) is adjusted to be in phase with the noise interference wave component (D1) (delay processing of 1⁄4 preamble time), and the result (D3) is a noise interference wave component (D1) It adds and outputs to the process part (frequency analysis part 307) of a back | latter stage as a extraction result of a noise interference wave component.

  Furthermore, in the receiver according to the first to third embodiments, the frequency analysis unit 307 that performs frequency analysis on the noise interference wave component extracted by the noise interference wave extraction unit 305, and the frequency analysis of the noise interference wave component The window adjustment unit 306 is configured to set a time window to be subjected to frequency analysis by the unit 307 with a time window length equal to or less than the signal length of the first or second known signal.

According to the configuration as described above, since it is not necessary to provide a non-transmission period or a non-transmission frequency for detection of noise interference waves, noise interference waves can be efficiently detected, and throughput can also be improved. be able to. Moreover, the effect of following (1)-(3) is also expectable.
(1) By appropriately setting the range for performing frequency analysis on the extraction results of noise interference waves, it becomes possible to extract noise interference wave components that are not affected by multipath.
(2) By setting the position of frequency analysis such that a delayed wave component exceeding the guard length is regarded as noise, equivalent noise can be accurately calculated in the subsequent demodulation / decoding process (3) Bandwidth of interference wave The interference wave can be detected regardless of the frequency, and in the prior art, a narrow band interference wave orthogonal to the preamble symbol whose detection is limited can also be extracted, and the frequency characteristic can also be analyzed.
Further, in the second embodiment, a noise interference wave can be detected if there is a time of two frames, and in the third embodiment, a noise interference wave can be detected if there is a time of one frame.

In the above description, although the set of the first known signal and the second known signal is transmitted for each frame (one frame period), it is not necessary to transmit in all frames, for example, every one frame. It may be sent to
Further, in the above description, a preamble signal having a length obtained by dividing the preamble section into two or four is used as the first or second known signal, but this is merely an example. For example, known signals of any length capable of storing two or more in the preamble section can be used.

  Also, in the above description, the first known signal and the second known signal are transmitted continuously, but it is not necessary to transmit continuously, and the interval between them may be a non-transmission interval, or another data may be It may be a section to transmit. When the first known signal and the second known signal are continuously transmitted, the delay processing may be performed according to the signal length of the first or second known signal, and the first known signal and the second known signal may be transmitted. In the case where the known signal is not transmitted continuously, the delay processing may be performed in consideration of the section length between them.

The present invention can also be grasped as a wireless communication device as described below.
That is, in the wireless communication apparatus that receives a signal transmitted wirelessly from the other party apparatus, the other party apparatus repeatedly transmits the known signal at M sample intervals and at N sample intervals of M samples or more, and the wireless communication apparatus The received signal is delayed by M samples so that the known signal (X) included in the received signal and the known signal (Y) received thereafter have the same timing, and subtraction processing with the received signal before the delay is performed. Then, the known signal component is canceled to extract the noise interference component.

  Here, M is 0 or more and less than N. However, if the value of M is large, the channel fluctuation between known signals becomes large and the extraction accuracy of the noise interference wave decreases, so it is desirable that N be small. Since N determines the detection cycle of noise and interference components, a smaller value is desirable, but a smaller value increases the proportion of known signals in the transmission signal (that is, there is a trade-off relationship with the transmission rate) . As N, for example, the number of samples corresponding to the signal length of the radio frame can be used, and as M, for example, the number of samples of a length obtained by dividing the preamble section of the radio frame into two (or four) Can.

  Also, assuming that the length of the known signal is K samples, the acquisition time window length L of K samples or less is set for frequency analysis of the noise interference component, and the extraction result of the noise interference component has a time window length L The frequency characteristics of the noise interference wave may be calculated by performing frequency analysis in the range.

  In addition, interference waves interfering with the known signal in the same pattern can not be detected only by the above-described subtraction processing. Therefore, in addition to the known signal, the opposite device repeatedly transmits a signal obtained by reversing the sign of the known signal at P sample intervals and at Q sample intervals equal to or greater than P samples, and the wireless communication apparatus is included in the received signal. By delaying the received signal by P samples so that the known signal (X) and the known signal (Z) of the code inversion received thereafter have the same timing, and performing addition processing with the received signal before the delay, The known signal components are canceled to extract noise interference components. Thereby, an interference wave that interferes with the known signal in the same pattern can also be detected.

Although the present invention has been described above in detail, it goes without saying that the present invention is not limited to the wireless communication device described herein, and can be widely applied to other wireless communication devices.
The present invention can also be provided, for example, as a method or method for executing the process according to the present invention, a program for realizing such a method or method, or a storage medium for storing the program.

  The present invention can be used for a wireless communication apparatus that receives a signal transmitted wirelessly from a partner apparatus.

201: Encoding unit, 202: Modulation unit, 203: IFFT unit, 204: Selection unit, 205: Preamble pattern memory unit, 206: Code inversion unit, 207: Frame timing unit, 208: DA unit, 209: Transmission antenna,
301: reception antenna, 302: AD unit, 303: narrow band interference suppression filter, 304: preamble timing detection unit, 305: noise interference wave extraction unit, 306: window adjustment unit, 307: frequency analysis unit, 308: interference threshold determination Part 309: Averaging part 310: Frequency analysis part 311: Noise normalization part 312: Demodulation and decoding part
401: Same pattern timing,
501: Subtractor, 502: Delay,
601: same pattern timing, 602: reverse pattern timing,
701: frame pattern determination unit 702: addition unit 703: subtraction unit 704: delay unit 705: selection unit 706: addition unit 707: frame delay unit
801: identical pattern timing, 802: reverse pattern timing, 803: reverse pattern timing,
901: A delay unit, 902: B delay unit, 903: subtraction unit, 904: addition unit, 905: addition unit, 906: B delay unit

Claims (4)

In a wireless communication device that receives a signal transmitted wirelessly from a partner device,
An extraction unit that extracts a component of noise or interference included in the received signal;
The counterpart apparatus transmits a first known signal and a second known signal that is identical to or sign-inverted from the first known signal at a predetermined cycle.
The extraction means cancels the received signal and a delayed signal obtained by delaying the received signal, the second known signal contained in the received signal and the first known signal contained in the delayed signal. A wireless communication apparatus characterized in that the component is extracted by subtraction or addition. In the wireless communication device according to claim 1,
The other party device has a first frame into which the first known signal and the second known signal identical to the first known signal are inserted, and the first known signal is inverted in sign. Alternately transmitting a second known signal and a second frame inserted,
The extraction means subtracts the reception signal and the delay signal to receive the component when the first frame is received, and adds the reception signal and the delay signal when the second frame is received. Wireless communication device for extracting the component. In the wireless communication device according to claim 1,
The counterpart apparatus transmits a frame in which a plurality of sets of the first known signal and the second known signal obtained by inverting the first known signal are inserted.
A process of extracting the component by adding the second known signal included in the received signal and the first known signal included in the delayed signal so as to cancel out each other; And a process of extracting the component by performing subtraction so that the set on the rear side included in the signal and the set on the front side included in the delay signal cancel each other. The wireless communication apparatus according to any one of claims 1 to 3.
Frequency analysis means for performing frequency analysis on the component extracted by the extraction means;
Window adjustment means for setting a time window to be subjected to frequency analysis by the frequency analysis means among the components with a time window length equal to or less than the signal length of the first or second known signal;
A wireless communication device comprising:

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