JP4710733B2 - Wireless receiver - Google Patents

Description

  The present invention relates to a radio reception apparatus that receives a pulse-shaped radio signal having a predetermined period at a timing synchronized with the period and demodulates a baseband signal from the pulse train.

  In recent years, attention has been paid to an ultra wide band (UWB) communication system that performs ultra wide band communication using a pulse train of a pulse signal synchronized with a predetermined cycle timing as one of high-speed wireless transmission systems. As one aspect of the UWB communication, Patent Document 1 discloses that communication is performed using a pulse train made of an extremely short pulse signal such as a pulse width of 1 nsec (nanosecond) or less without using a carrier wave. .

Then, in synchronizing the reception timing of the receiving device with the short pulse signal, in Patent Document 2, if the pattern of the received signal (pulse train) is always 0, the gain of the amplifier is assumed to be too low and the gain is increased. It is shown that when the pattern of the received signal is always 1, the gain of the amplifier is too high and the gain is reduced to search for the synchronization signal pattern and obtain synchronization.
Japanese National Patent Publication No. 10-508725 JP 2006-94169 A

  The conventional technique of Patent Document 2 corresponds to the gain of the amplifier, and is suitable for extracting the pulse train by optimizing the noise floor level due to the thermal noise of the receiving apparatus with respect to the received signal level. However, there is a problem that reception is disabled when there is an interference wave in the reception band, and particularly when the interference wave power is large.

  The objective of this invention is providing the radio | wireless receiver which can improve the tolerance with respect to an interference wave.

The radio reception apparatus of the present invention receives a pulsed radio signal having a predetermined period at a timing synchronized with the period, and demodulates a baseband signal from the pulse train.
A filter unit that receives a received signal and can extract at least a part of a frequency band used in the radio signal, a detection unit that detects an envelope or peak of an output from the filter unit, and the filter An amplifier interposed between the detector and the detector, an integrator for integrating the output of the detector over a predetermined integration period, and an analog / digital conversion for analog / digital conversion of the output voltage of the integrator A signal demodulator that adjusts the integration period of the integrator and demodulates the baseband signal based on the A / D conversion value in the analog / digital converter, and the analog / digital converter depending on the variance value of the a / D conversion value at, as well as adjust the pass frequency band of the filter unit, the dispersion value of the a / D conversion value by disturbance is large That when, decreases a gain of the amplifying section, wherein the dispersion value is characterized by comprising a sensitivity control unit for gain adjustment to be substantially constant.

  According to the above configuration, the wireless reception device that receives a pulse-shaped radio signal of a predetermined period such as a UWB signal at a timing synchronized with the period and demodulates the baseband signal from the pulse train is received by the wideband antenna. The signal component is extracted from the frequency band used in the radio signal in the filter unit, envelope-detected or peak-detected in the detector, and then integrated over a predetermined integration period in the integrator. By performing analog / digital conversion in the digital conversion unit, when the A / D conversion value is compared with a predetermined threshold value in the signal demodulation unit, it can be determined as data of “1” or “0”. The signal demodulating unit demodulates the baseband signal from the obtained “1” or “0” data, and when no synchronizing pulse train is detected, the synchronizing pulse train is detected. The timing of the integration period is controlled.

  In the present invention, the filter unit can extract at least a component of a frequency band used in the radio signal, and a sensitivity control unit is provided. The pass frequency band of the filter unit is adjusted according to the variance value of the A / D conversion value in the conversion unit. For example, when the filter unit is configured to include a filter that passes a low-frequency component of a frequency band used in the radio signal and a filter that passes a high-frequency component, When a filter that passes a component is selected and the dispersion value of the A / D conversion value, that is, the width of the fluctuation increases due to an interference wave, a pulse is detected other than the original synchronization timing. Then, switch to a filter that passes the high-frequency component. Alternatively, in the case where the filter unit is configured to include a filter that passes the entire band of the frequency band used in the radio signal and a filter that passes a component on the low frequency side or the high frequency side, If the filter to be passed is selected, the dispersion value of the A / D conversion value becomes large due to the interference wave, and a pulse is detected in addition to the original synchronization timing, the low frequency side or the high frequency range For example, the filter is switched to a filter that passes the component on the side.

  Therefore, even when the level of the interference wave is large and the transmission signal is buried, the baseband component of the transmission signal can be demodulated from the band component not buried in the interference wave in the broadband wireless signal. . Thus, when there is an interfering wave in the frequency band used for the radio signal, by avoiding the band of the interfering wave, tolerance against the interfering wave can be increased without reducing the reception sensitivity.

The front Symbol further comprising an amplification section which is interposed between the filter portion and the detection portion, the amplified portion signal from the sensitivity control unit, since the gain adjustment, the A / D conversion value by disturbance When the dispersion value of the filter section increases, the gain of the amplification section is preferably reduced after the pass frequency band of the filter section is adjusted, and the reception sensitivity is lowered by controlling the dispersion value to be substantially constant. However, if a received signal having a level larger than the interference wave is input, it can be demodulated. Accordingly, when the interference wave is unavoidable, it can be received if it is a received signal exceeding the power of the interference wave.

Furthermore, the radio reception apparatus of the present invention receives a pulsed radio signal having a predetermined period at a timing synchronized with the period, and the radio reception apparatus that demodulates the baseband signal from the pulse train receives the received signal. A filter unit capable of extracting a component of at least a part of a frequency band used in the radio signal; a detection unit detecting an envelope or a peak of an output from the filter unit; and an output of the detection unit Based on the integration unit that integrates over the integration period, the analog / digital conversion unit that performs analog / digital conversion on the output voltage of the integration unit, and the A / D conversion value in the analog / digital conversion unit, A signal demodulator that adjusts the integration period and demodulates the baseband signal, and an A / D converter in the analog / digital converter. Get the variance value, in accordance with the variance value, as well as adjust the pass frequency band of the filter unit, determines the presence of a received signal from the variance of the A / D conversion value, the received signal has integrated And a sensitivity control unit that limits the acquisition of the variance value over a period.

  According to the above configuration, when the dispersion value of the A / D conversion value increases as described above, it is determined that an interference wave is generated and the adjustment of the pass frequency band of the filter unit is performed from the dispersion value. Accurately determine the variance value of noise components such as thermal noise and jamming waves during periods when there is no received signal by determining the presence or absence of the received signal and limiting the acquisition of variance values during the integration period when the received signal is present Therefore, it is possible to appropriately adjust the pass frequency band of the filter unit and the gain of the amplifier unit.

  As described above, the radio receiving apparatus of the present invention inputs a pulse-like radio signal having a predetermined period, such as a UWB signal, from the filter unit to the detection unit and detects the envelope or peak, and outputs the predetermined signal at the integration unit. After the integration over the integration period, the value converted by the analog / digital converter is compared with a predetermined threshold value in the signal demodulator to determine the data as “1” or “0”, and the baseband signal So that the synchronization can be obtained by controlling the timing of the integration period so that the synchronization pulse train is detected when the synchronization pulse train is not detected. In the wireless receiving apparatus, the filter unit can extract a component of at least a part of a frequency band used in the wireless signal. The sensitivity control unit is provided, the variance of the A / D conversion value of the sensitivity control unit in the analog / digital converter unit, i.e. according to the width of the fluctuation, to adjust the pass frequency band of the filter unit.

  Therefore, even when the level of the interference wave is large and the transmission signal is buried, the baseband component of the transmission signal can be demodulated from the band component that is not buried in the interference wave, thereby reducing the reception sensitivity. In addition, it is possible to increase the resistance to interference waves.

Further, by interposing a amplifying portion between the front Symbol filter unit and the detection unit, by the sensitivity control unit, when the dispersion value of the A / D conversion value by disturbance is large, preferably the pass frequency band of the filter section After the gain is adjusted, the gain of the amplifying unit is reduced and the dispersion value is controlled so as to be substantially constant, so that the reception sensitivity is lowered, but when a reception signal having a level larger than the interference wave is input, It can be demodulated, and when a jamming wave is unavoidable, any received signal that exceeds the power of the jamming wave can be received.

  Furthermore, as described above, the radio reception apparatus of the present invention determines that an interference wave is generated when the variance of the A / D conversion value increases, and adjusts the pass frequency band of the filter unit. The sensitivity control unit limits the acquisition of the dispersion value during the integration period in which the received signal is present.

  Therefore, it is possible to accurately obtain a variance value of noise components such as thermal noise and interference wave during a period in which no received signal exists, and to appropriately adjust the pass frequency band of the filter unit and the gain of the amplifier unit. it can.

  FIG. 1 is a block diagram showing an electrical configuration of a UWB receiver 1 which is a wireless receiver according to an embodiment of the present invention. The UWB receiver 1 includes an antenna 2, a filter unit 3, an amplifier 4, a detector 5, an integrator 6, an analog / digital converter 7, a signal demodulator 8, and a sensitivity controller 9. It is prepared for.

The radio signal transmitted from the transmitter is a pulse signal as shown in FIG. 2 (a), and the UWB receiver 1 synchronizes with the pulse and the data (baseband) to be transmitted. Signal) and a pulse train corresponding to the signal). The synchronization pulse train, as shown in FIG. 2 (b), a signal of a UWB pulse is repeated at a predetermined period Trep, repeat count is set so that the pulse position is detectable by the UWB receiver 1 side Then, the presence or absence of a pulse train indicating the end of pulse synchronization is added. In the example of FIG. 2, when the data value is “1”, the UWB pulse is repeated N times in the cycle Trep. In the case of “0”, the transmission data is a period TD of Trep × N when nothing is output. It has a configuration that only continues. This period TD is a 1-bit period of the data to be transmitted (baseband signal). In the above example, the data to be transmitted is indicated by on-off keying, but may be expressed by other modulation schemes such as bi-phase modulation.

  The radio signal from the transmitter is received by the wideband antenna 2, the frequency band component used in the radio signal is extracted by the filter unit 3, envelope detection or peak detection is performed by the detector 5, and then integration is performed. Is input to the device 6. The integrator 6 is output from the signal demodulator 8 and responds to an integration control signal Tint that controls the timing of the integration period within the period Trep. When the integration control signal Tint is active high level, the detector 6 The operation of integrating the detection outputs of 5 is performed N times by the integration control signal Tint.

  The integrated value is subjected to analog / digital conversion in the analog / digital converter 7, and the pulse determination circuit 8a of the signal demodulator 8 compares the A / D conversion value with a predetermined threshold value. It is determined as data of “0”. The pulse determination circuit 8a of the signal demodulator 8 further demodulates the baseband signal from the obtained data “1” or “0”, and during the period when the synchronization pulse train is not detected, The timing of the integration period is controlled so that a pulse train is detected.

  Specifically, the UWB pulse transmitted from the transmitter is a pulse of about 2 to 3 nsec, for example, which is repeated every cycle Trep as shown in FIG. In addition, the generation timing (time slot = window phase) of the UWB pulse is shifted by φ1, φ2,..., Shifted by a predetermined time period Ton longer than 2 to 3 nsec within the period Trep, as shown in FIG. .., φm (for example, m = 50).

  Therefore, the signal demodulator 8 controls the integration period of the integrator 6 by the integration control signal Tint, and outputs the detection output from the detector 5 as shown in FIG. 3B for each phase φ1 to φm. Over the period TD, that is, the integration is performed N times to obtain the integrated value. As shown in FIG. 4B, when the A / D conversion value of the integrated value is not less than the predetermined threshold value TH, it is determined as the data “1”, and when it is less than the threshold value TH, data “0” is obtained. Then, a demodulated signal as shown in FIG. 4 (c) corresponding to the transmission signal as shown in FIG. 4 (a) is obtained.

  When the pulse determination circuit 8a performs integration by shifting the time slot by a period Ton between synchronization pulse trains and searches for the synchronization timing, the time slot corresponding to its own device (the phase of φ3 in FIG. 3). Is detected, the subsequent search is stopped (in FIG. 3, the search is made up to the phase of φ4, the A / D conversion value at the phase of φ3 is larger, and the phase is determined as the synchronization slot). ) As a result, power consumption for searching for synchronization timing can be reduced.

  In the UWB receiver 1 configured as described above, it should be noted that the filter unit 3 is configured to extract at least part of a frequency band used in the radio signal, and The sensitivity control unit 9 is provided. FIG. 5 is a block diagram illustrating a configuration example of the filter unit 3. In the example of FIG. 5, the filter unit 3 is provided with switch elements 3c and 3d for switching the signal path to either one of the filters 3a and 3b before and after the two filters 3a and 3b provided in parallel to each other. Configured. The switching elements 3c and 3d are controlled to be switched in conjunction with each other by the filter switching signal SEL from the sensitivity control unit 9.

  The transmission signal from the transmitter is an impulse signal having a wide band of 3 to 5 GHz as shown in FIG. 6 (a), for example, and the characteristics of the filters 3a and 3b are as shown in FIG. 6 (b), for example. In addition, the filter 3a passes the low-frequency component, and the filter 3b passes the high-frequency component.

  Further, as the filter unit 3, for example, the filter 3a passes the entire band shown in FIG. 6A, and the filter 3b has a low possibility of generating an interference wave in the low band side or the high band side. It may be configured to pass the components. Furthermore, the filter unit 3 may be provided with three filters, a filter that allows the entire band to pass, a filter that allows the low-frequency side and the high-frequency side to pass therethrough, and these filters may be switched. That is, the filter unit 3 only needs to be able to extract at least a part of the frequency band used in the radio signal as described above. Furthermore, the filters 3a and 3b may be provided in series with each other, and the switch elements 3c and 3d may be provided so as to bypass the filters 3a and 3b, respectively.

  The sensitivity control unit 9 is input from the pulse determination circuit 8a, and the pulse determination circuit 8a responds to the pulse detection signal SEN indicating whether or not the received pulse is synchronized while the pulse is not detected. The dispersion value of the A / D conversion value in the analog / digital converter 7 is obtained, the filter switching signal SEL is output according to the dispersion value, and the pass frequency band of the filter unit 3 is adjusted. 7 to 11 are diagrams for explaining the adjustment operation. For example, as shown in FIG. 7, it is assumed that an interference wave that becomes a CW wave is generated in the filter 3a from the interference wave generation source 12 in the transmission signal from the transmission antenna 11 of the transmitter. In this case, the waveform of each signal reaching the receiving antenna 2 is as shown in FIG. 8A, and the frequency spectrum is as shown in FIG. 9A.

  Therefore, similarly to the above-described FIG. 6B, when the filter unit 3 is composed of the low-frequency filter 3a and the high-frequency filter 3b as shown in FIG. In the filter 3a on the side, the combined wave of the transmission signal and the interference wave as shown in FIG. 8B passes, and if the interference wave has a higher electric field strength than the transmission signal, the transmission signal is transmitted. The signal will be buried in the jamming wave. In the case of interference wave >> transmission signal, only the interference wave is output. In this case, the transmission signal shown in FIG. 10A passes through the filter 3a of the filter unit 3 and is output from the amplifier 4 as shown in FIG. As shown in FIG. 10 (c), most of the A / D values detected, integrated N times by the integrator 6 and further converted by the analog / digital converter 7 are equal to or greater than the threshold value TH. The pulse determination unit 8a of the unit 8 cannot capture synchronization, and a demodulated signal cannot be obtained as shown in FIG.

On the other hand, in the high frequency side filter 3b, the interference wave is attenuated as shown in FIG. 8C, and when the transmission signal >> the interference wave in that band, only the transmission signal is extracted. It becomes possible. In this case, the transmission signal shown in FIG. 11A passes through the filter 3b of the filter unit 3 and is output from the amplifier 4 as shown in FIG. is detected is integrated N times by the integrator 6, further converted a / D value in the analog / digital converter 7, as shown in FIG. 1 1 (c), first component in the phase φ3 is the threshold Since it becomes TH or higher, the pulse determination unit 8a of the signal demodulation unit 8 captures synchronization, and a demodulated signal corresponding to the transmission signal is obtained from the subsequent transmission data sequence as shown in FIG. 1 1 (d). .

The sensitivity control section 9 periodically selects the filters 3a and 3b for a predetermined time , searches for the state of the interference wave in each band, and switches to the one with less interference wave to perform reception. Alternatively, when synchronization acquisition cannot be performed with the currently switched filter, the filter may be switched to the other filter.

  With this configuration, even when the level of the interference wave is large and the transmission signal is buried, the baseband component of the transmission signal is changed from the band component not buried in the interference wave in the broadband wireless signal. Can be demodulated. As a result, when there is an interference wave in the frequency band used in the radio signal, by avoiding the interference wave band, it is possible to increase the resistance to the interference wave without reducing the reception sensitivity.

  The amplifier 4 is a variable gain amplifier, and its gain is adjusted by an amplification factor switching signal CTL from the sensitivity control unit 9. The sensitivity control unit 9 switches between the two filters 3a and 3b as described above, and the dispersion value of the A / D conversion value in each case, that is, the fluctuation width is both equal to or higher than a predetermined level, and both are disturbed. When it is determined that there is a wave, the gain of the amplifier 4 is increased as the dispersion value is further increased by the amplification factor switching signal CTL after selecting the one having a smaller interference wave power, that is, a smaller dispersion value. Change to smaller.

  Here, when there is no signal received by the antenna 2, the received power is thermal noise, but the noise generated by the amplifier 4 is larger than this, so the A / D conversion value is as shown in FIG. , And fluctuates in time due to the self-noise of the amplifier 4, and the fluctuation amount becomes a Gaussian distribution.

  On the other hand, it is assumed that the variance value of the A / D value of the unit time W1 when there is no power received by the antenna 2 is given in advance as an initial value. When a disturbing wave is generated in this state, the dispersion value increases according to the power level of the disturbing wave as shown by time W2 in FIG. However, according to the increased dispersion value, the filter 3a, 3b is switched to the one with the smaller interference wave power (the frequency side where the sensitivity is good) as described above, and the amplification factor of the amplifier 4 is lowered. In the signal demodulator 8, the variance value of the A / D value is the same as the initial setting value indicated by the time W1. As a result, the reception sensitivity is lowered by the power of the jamming wave. However, if a transmission signal greater than the power of the jamming wave is received when the jamming wave is unavoidable, synchronization acquisition and signal demodulation are possible. 1 can perform a receiving operation stably. In addition, the level of decrease in the reception sensitivity can be suppressed to a minimum level according to the power of the interference wave.

  Furthermore, the sensitivity control unit 9 obtains the dispersion value while no pulse is detected in response to the pulse detection signal SEN from the pulse determination circuit 8a as described above. Variations in the dispersion value due to fluctuations in the value (φ3 interval in FIG. 4) can be eliminated, and dispersion values of noise components such as thermal noise and interference waves during a period in which no received signal exists can be accurately obtained. Thereby, the pass frequency band adjustment of the filter unit 3 and the gain adjustment of the amplifier 4 can be appropriately performed.

It is a block diagram which shows the electric constitution of the UWB receiver which is a radio | wireless receiver which concerns on one Embodiment of this invention. It is a wave form diagram of the transmission signal used for UWB communication. It is a wave form diagram for demonstrating the reception timing with respect to a UWB signal. It is a wave form diagram for demonstrating the demodulation method of the said UWB signal. It is a block diagram which shows one structural example of a filter part. It is a graph which shows an example of the passage characteristic of a filter to a UWB signal. It is a figure for demonstrating the adjustment operation of the pass frequency band of the said filter part. It is a wave form diagram for demonstrating the passage characteristic of the filter with respect to a transmission signal and an interference wave. It is a graph for demonstrating the passage characteristic of the filter with respect to a transmission signal and an interference wave. It is a wave form diagram for demonstrating a demodulated signal when the said interference wave cannot be attenuated with a filter. It is a wave form diagram for demonstrating the demodulation signal when the said interference wave can be attenuated with the filter. It is a wave form diagram for demonstrating the gain adjustment of the amplifier with respect to the said interference wave.

DESCRIPTION OF SYMBOLS 1 UWB receiver 2 Antenna 3 Filter part 3a, 3b Filter 3c, 3d Switch element 4 Amplifier 5 Detector 6 Integrator 7 Analog / digital converter 8 Signal demodulation part 8a Pulse determination circuit 9 Sensitivity control part 11 Transmission antenna 12 Interference wave Generation source

Claims (2)

In a wireless receiver that receives a pulse-shaped radio signal of a predetermined period at a timing synchronized with the period, and demodulates a baseband signal from the pulse train,
A filter unit that receives a received signal and can extract a component of at least a part of a frequency band used in the radio signal;
A detector for detecting an envelope or a peak of the output from the filter unit;
An amplification unit interposed between the filter unit and the detection unit;
An integrator for integrating the output of the detector over a predetermined integration period;
An analog / digital conversion unit for analog / digital conversion of the output voltage of the integration unit;
A signal demodulator that adjusts the integration period of the integrator and demodulates the baseband signal based on an A / D conversion value in the analog / digital converter;
According to the dispersion value of the A / D conversion value in the analog / digital conversion unit, the pass frequency band of the filter unit is adjusted, and when the dispersion value of the A / D conversion value is increased by an interference wave, the amplification And a sensitivity control unit that adjusts the gain so that the dispersion value becomes substantially constant . In a wireless receiver that receives a pulse-shaped radio signal of a predetermined period at a timing synchronized with the period, and demodulates a baseband signal from the pulse train,
A filter unit that receives a received signal and can extract a component of at least a part of a frequency band used in the radio signal;
A detector for detecting an envelope or peak of an output from the filter unit;
An integrator for integrating the output of the detector over a predetermined integration period;
An analog / digital conversion unit for analog / digital conversion of the output voltage of the integration unit;
A signal demodulator that adjusts the integration period of the integrator and demodulates the baseband signal based on an A / D conversion value in the analog / digital converter;
Obtains a dispersion value of the A / D conversion value in the analog / digital conversion unit, adjusts a pass frequency band of the filter unit according to the dispersion value, and receives from the dispersion value of the A / D conversion value determines the presence of the signal, no line receiving apparatus you; and a sensitivity control unit for limiting the acquisition of the variance value in the integration period in which the received signal is present.

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