JP2009182414A - Reception device and reception control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reception device capable of appropriately setting a gain of a reception amplifier, and to provided a reception control method. <P>SOLUTION: The reception device which converts an analog signal from another radio station received by an antenna, into a digital signal and demodulates the digital signal, acquires information about a moving state of the other radio station and according to the acquired information, selects the reception signal being the analog signal or the reception signal resulting from converting the analog signal to the digital signal, as a reception signal for use in gain control of the reception amplifier, and the gain of the reception amplifier is controlled on the basis of the intensity of a received electric field of the selected reception signal. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a receiving apparatus that digitally converts and demodulates an analog signal received by an antenna, and a reception control method that digitally converts and demodulates an analog signal received by an antenna.

  As a conventional example of a receiving apparatus that digitally converts and demodulates an analog signal received by an antenna, there are those shown in FIGS.

  The conventional receiving apparatus shown in FIG. 3 is configured as a direct conversion type receiving apparatus, and an input signal from an antenna 100 passes through a band-pass filter 101 and an amplifier 102, and is a station from a local oscillation signal source 104. By the emitted signal, the quadrature demodulator 103 down-converts it into Ich and qch baseband signals. Each signal passes through the low-pass filter 105 and the variable amplifier 106, converted into a digital signal by the A / D converter 107, and then demodulated by the reception baseband unit (RXBB) 112. The RXBB 112 measures the reception level, sends gain data from the CONT unit 113 to the variable amplifier 106, and the gain is set by an automatic gain control circuit including the variable amplifier 106 based on this gain data.

  The conventional receiving apparatus shown in FIG. 4 is configured as a superheterodyne receiving apparatus, and an input signal from an antenna 100 passes through a bandpass filter 101 and an amplifier 102, and a local signal source 104 and a mixer 113. Is converted into a primary IF signal. After that, after passing through the low-pass filter 105 and amplified to an appropriate level by the variable amplifier 106, it is converted again to a secondary IF signal by the mixer 108. The secondary IF signal passes through the band-pass filter 110 and is digitally converted by the A / D converter 111. The RXBB unit 112 performs demodulation after converting the input signal into a baseband signal. In accordance with the RSSI level detected by the RXBB unit 112, the CONT unit 113 sends gain data to the variable amplifier 106, and the gain is set by an automatic gain control circuit including the variable amplifier 106 based on the gain data.

  As a conventional example of an automatic gain control circuit, there is an automatic gain control circuit that sets the gain of a variable amplifier by feedback control based on a detected fading pitch (see, for example, Patent Document 1).

In a radio station including TDMA and TDD receivers, in the conventional example shown in FIGS. 3 and 4, an analog signal received by an antenna is amplified by a receiving amplifier, and the amplified received signal is converted to A / D. After digital conversion by the converter, the baseband processing unit measures a received signal strength indicator (RSSI) of the digitally converted received signal. Then, based on the measured received electric field strength, a feedback process for setting the gain of the receiving amplifier for amplifying the next received signal is performed. Such a gain setting of the reception amplifier is performed in a slot next to the reception slot in which the reception electric field strength is measured.
JP 2001-230644 A

  However, a counterpart wireless station that is transmitting a radio signal to the radio station, for example, a mobile station is moving at high speed, or other communication devices or objects are moving between the radio station and the counterpart radio station. When the signal crosses the other side, an interference wave appears during data communication with the counterpart wireless station, and the received electric field strength fluctuates. Therefore, even if the gain of the receiving amplifier is set based on the received electric field strength, the frequency of deviating from the dynamic range of the A / D converter becomes extremely high. Moreover, since the same gain (gain) is set in the slot, it is difficult to cope with the level fluctuation in the slot. For this reason, when the reception level fluctuates between reception slots or within the reception slot, the contents cannot be reflected in the feedback loop, so the reception level fluctuation cycle is accelerated and there is a fluctuation within the slot. In this case, appropriate signal conversion processing from an analog signal to a digital signal cannot be performed, and reception performance may be deteriorated.

  Therefore, in order to avoid the above-described problem, it is conceivable to speed up a series of processing from measurement of the received electric field strength of the digitized received signal to setting of the gain of the receiving amplifier. However, since the amount of calculation increases, the processing load of the receiving apparatus increases.

  An object of the present invention is to provide a receiving apparatus and a receiving control method capable of appropriately setting a gain of a receiving amplifier in accordance with a moving state of a counterpart wireless station.

  The invention according to claim 1, which achieves the above object, obtains information relating to a movement state of another radio station in a receiving device that converts an analog signal received from an antenna from another radio station into a digital signal and demodulates it. Information acquisition grasping means, control means for controlling the gain of the reception amplifier based on the received electric field strength of the received signal, and gain control of the reception amplifier in the control means according to the information acquired by the information acquisition means And a selection means for selecting the received signal in the analog signal or the received signal in the digital signal after digital conversion of the analog signal.

  The invention according to claim 2 is the receiving apparatus according to claim 1, wherein the information related to the movement state acquired by the information acquisition unit is a value related to a variation in received electric field strength based on the analog signal, The selection means selects a reception signal in the analog signal when the value is equal to or greater than a predetermined value, and selects a reception signal in the digital signal when the value is less than a predetermined value. It is characterized by.

  According to a third aspect of the present invention, in the receiving device according to the second aspect, communication using an adaptive modulation method is employed, and the receiving device includes a modulation method grasping unit for grasping a modulation method of the receiving device; The value indicating the information acquired by the information acquisition unit is not less than a predetermined value, and the modulation scheme grasped by the modulation scheme grasping unit is a predetermined multi-value number. If the modulation method is less than the above, the received signal of the analog signal is selected, the value indicating the information acquired by the information acquisition unit is less than the predetermined value, and the modulation method grasping unit When the modulation method grasped by the above is a modulation method of a predetermined multi-value number or more, the received signal of the digital signal is selected.

  According to a fourth aspect of the present invention, in the receiving device according to any one of the first to third aspects, the control means includes a loop filter, and the value indicating the information acquired by the information acquisition means Is greater than or equal to a predetermined value, the time constant of the loop filter is controlled to be relatively small, and when the value indicating the information is less than a predetermined value, the time constant of the loop filter is It is controlled to become relatively large.

  According to a fifth aspect of the present invention, in the receiving apparatus according to the third aspect, the control means includes a loop filter, and the modulation method grasped by the modulation method grasping means satisfies a predetermined multi-value number. If the modulation method is not a modulation method, the time constant of the loop filter is controlled to be relatively small, and if the modulation method is a modulation method of a predetermined multi-level number or more, the time of the loop filter is controlled. The constant is controlled to be relatively large.

  The invention according to claim 6, which achieves the above object, is a reception control method in a receiving apparatus that converts an analog signal received from an antenna from another radio station into a digital signal and demodulates the analog signal. An information grasping step for obtaining information on a state, and a received signal in the analog signal or a digital conversion of the analog signal as a received signal used for controlling a gain of a receiving amplifier according to the obtained information. A selection step of selecting a reception signal in the digital signal after the digital conversion; and a control step of controlling the gain of the reception amplifier based on the reception electric field strength of the selected reception signal. .

  According to the present invention, the gain of the reception amplifier is controlled based on the received electric field strength of the analog signal according to the movement state of the counterpart radio station, or the reception based on the received electric field strength of the digitally converted received signal. Since the gain of the amplifier is controlled, it is possible to provide a reception device and a reception control method that can appropriately set the gain of the reception amplifier according to the movement state of the counterpart wireless station.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a circuit diagram illustrating the configuration of a receiving apparatus according to an embodiment of the present invention. The receiving apparatus according to the present embodiment is configured to switch a signal used for gain control of the receiving amplifier according to the level of the value indicating the fluctuation of the received electric field strength as information regarding the movement state of the counterpart wireless station of the receiving apparatus. As shown in FIG. 1, the antenna 10, the bandpass filter 11, the amplifier 12, the quadrature demodulator 13, the local oscillation signal source 14, the bandpass filter 15, the reception amplifier (variable amplifier) 16, and the quadrature demodulator 18. , Local oscillation signal source 19, band pass filter 20, A / D converter 21, reception baseband unit (RXBB) 22, CONT unit 23, log amplifier (Log AMP) 24, loop filter (variable low pass filter) 25, switch (SW ) 26, an arithmetic circuit (CAL) 27, and a selector (SEL) 28.

  This receiving apparatus is configured to switch data corresponding to the amplifier gain setting data from the CONT unit 113 and the feedback signal from the reception level detected by the LOG amplifier 24 in the conventional receiving apparatus shown in FIG. Is adopted. As the switching of the switch 26, the arithmetic circuit (CAL) 27 switches so that the feedback loop for guiding the output signal of the CONT unit 23 is selected when the value indicating the fluctuation of the received electric field strength is less than a predetermined value. (SW) 26 is switched, and when the value indicating the fluctuation of the received electric field intensity exceeds a predetermined value, the switch (SW) 26 is switched so that the signal from the feedback loop of the LOG amplifier 24 is selected.

  That is, in this receiving apparatus, the input signal from the antenna 10 passes through the band-pass filter 11 and the amplifier 12 and is down-converted to an IF signal by the orthogonal demodulator 13 by the local signal from the local signal source 14. Thereafter, the signal passes through the band pass filter 15 and is amplified to an appropriate level by the reception amplifier 16, and then passes through the reception amplifier 16, the quadrature demodulator 18 and the band pass filter 20, and is digitally processed by the A / D converter 21. After being converted into a signal, the reception baseband unit (RXBB) 22 performs demodulation processing. Then, the RXBB 22 measures the reception level and outputs an output signal from the CONT unit 23 to the selector (SEL) 28. The selector (SEL) 28 receives the output signal of the arithmetic circuit (CAL) 27 and the output signal of the CONT unit 23, and inputs the time constant control signal to the loop filter 25. An arithmetic circuit (CAL) 27 is obtained from the input training symbol timing signal and the detection signal of the Log amplifier 24 (details will be described later), and the switch 26 is switched according to a value indicating fluctuations in received electric field strength. By doing so, the gain is set in the receiving amplifier 16 in accordance with the signal selectively inputted to the receiving amplifier 16.

  In the receiving apparatus shown in FIG. 1, the time constant is controlled in two stages. However, the number of stages can be increased in accordance with a value indicating a variation in the modulation scheme and the received electric field strength.

  The receiving apparatus according to the present embodiment is changed to generate (estimate) “information on the movement state of the counterparty radio station” inside the receiving apparatus. Hereinafter, a detection method (estimation method) of a value indicating fluctuation in received electric field strength will be described with reference to FIG.

  FIG. 2 is a diagram illustrating various signals used in the receiving apparatus according to the embodiment. In FIG. 2, the received signal of the (N + 1) th frame composed of “training symbol (head part)”, “(N + 1 Flame) received data”, and “training symbol (tail part)” is received. In the meantime, as shown in the figure, a training symbol timing signal having a waveform that is switched only between “training symbol (head portion)” and “training symbol (tail portion)” together with the detection signal of the Log amplifier 24 is calculated by an arithmetic circuit (CAL). ) 28, the level fluctuation (the fluctuation of the received electric field intensity) between the rear end of the head and the tail of the training symbol of the reception slot (the reception level at the instant t1 of the variable low-pass filter 25 and the instant t2 Detected from the reception level difference that is the difference between the reception levels) When the fluctuation is greater than or equal to a predetermined threshold (predetermined value) (when the level fluctuation is large), the moving speed of the partner radio station is high or between the partner radio station that is communicating. If the level fluctuation is less than a predetermined threshold (when the level fluctuation is small), it is estimated that there is a case where another communication device moves at a high speed and crosses. It is estimated that there is no communication device or the like that is low speed or that is in communication with the counterpart wireless station that is performing communication. When the level fluctuation is less than a predetermined threshold (when the level fluctuation is small), the switch (SW) 26 is switched so that the feedback loop for guiding the output signal of the CONT unit 23 is selected, and the level fluctuation is predetermined. Switch (SW) 26 is switched so that “the feedback loop of LOG amplifier 24” is selected, the output signal of arithmetic circuit (CAL) 28 and CONT By supplying a time constant control signal output from the selector (SEL) 29 to which the output signal of the unit 23 is input to the loop filter (variable low-pass filter) 25, the time constant of the “feedback loop of the LOG amplifier 24” is variably controlled. To do.

Next, switching conditions and time constant control conditions of the switch 26 in the receiving apparatus will be described.
[Switching condition 1 of the switch 26; when only a value indicating fluctuations in received electric field strength is used]
When the analog signal received by the antenna 10 is digitally converted and demodulated and output as received data, (1) when the value indicating the variation in received electric field strength of the receiving device (mobile station) exceeds a predetermined value The switch 26 inputs a loop switching signal that selects the “feedback loop of the LOG amplifier 24” to the switch 26, so that the gain of the reception amplifier 16 is based on the received electric field strength of the analog signal received by the antenna 10. (2) When the value indicating the fluctuation of the received electric field strength is less than the predetermined value, the switch 26 is provided with a loop switching signal for selecting a feedback loop for leading the output signal of the CONT unit 23 to the switch 26. By inputting the gain of the reception amplifier based on the received electric field strength of the received signal obtained by digitally converting the analog signal. Gosuru so.
[Switching condition 2 of the switch 26; when a value indicating a variation in received electric field strength and a modulation method are used]
When the analog signal received by the antenna 10 is digitally converted and demodulated and output as received data, (1) the value indicating the fluctuation of the received electric field intensity exceeds a predetermined value and the receiving device (wireless station) When the modulation method (modulation class) is a modulation method (low modulation class) of the predetermined multi-value number or less, the switch 26 switches a loop switching signal that selects the “feedback loop of the LOG amplifier 24”. 26, the gain of the reception amplifier 16 is controlled based on the received electric field strength of the analog signal received by the antenna 10, and (2) the value indicating the fluctuation of the received electric field strength is less than a predetermined value, and When the modulation method (modulation class) of the receiving apparatus (wireless station) is a modulation method (high modulation class) exceeding the predetermined multi-value number, the switch 26 is set to “CONT unit 23. By inputting a loop switching signal for selecting a “feedback loop for guiding a force signal” to the switch 26, the gain of the reception amplifier is controlled based on the received electric field strength of the received signal obtained by digitally converting the analog signal. To do.
[Time constant control condition 1: When only a value indicating fluctuation in received electric field strength is used]
When the value indicating the fluctuation of the received electric field strength of the receiving device (wireless station) exceeds a predetermined value, the time constant of the loop filter 25 is controlled so that the time is shortened (the time constant of the loop filter 25 is relatively small). And the time constant of the loop filter 25 is controlled so that the time becomes longer (the time constant of the loop filter 25 is relatively set). Control to increase).
[Time constant control condition 2: When using only the modulation method of the receiving apparatus]
When the modulation method (modulation class) of the receiving apparatus (wireless station) is a modulation method (high modulation class) exceeding a predetermined multi-value number, the time constant of the loop filter 25 is controlled so that the time becomes longer (loop) When the time constant of the filter 25 is controlled to be relatively large), and the modulation method (modulation class) of the receiving device (wireless station) is a modulation method (low modulation class) that does not satisfy the predetermined multi-value number First, the time constant of the loop filter 25 is controlled so that the time is shortened (the time constant of the loop filter 25 is controlled to be relatively small).

  As a modulation method of the receiving apparatus, BPSK corresponding to modulation method 0, BPSK + corresponding to modulation method 1, QPSK corresponding to modulation method 2, QPSK + corresponding to modulation method 3, 8PSK corresponding to modulation method 4, There are 8PSK + corresponding to the modulation scheme 5, 12QAM corresponding to the modulation scheme 6, 16QAM corresponding to the modulation scheme 7, and 24QAM corresponding to the modulation scheme 8, and information on the modulation schemes of the modulation schemes of these receiving apparatuses is externally provided. It may be inputted or extracted from the received signal.

  According to the receiving apparatus of the embodiment and the receiving control method of the embodiment, when the gain of the receiving amplifier 16 is controlled based on the received electric field strength (for example, RSSI signal) of the received signal in the automatic gain control circuit included in the receiving apparatus. Further, based on the value indicating the fluctuation of the received electric field strength of the receiving device (wireless station), the “LOG amplifier 24 feedback loop that can follow the level fluctuation when the value indicating the fluctuation of the received electric field intensity exceeds a predetermined value. The value indicating the fluctuation of the received electric field strength is predetermined by switching the feedback loop to use the “feedback loop for guiding the output signal of the CONT unit 23” below the value indicating the fluctuation of the received electric field strength. Of course, when the value indicating the fluctuation of the received electric field strength exceeds a predetermined value, the A / D converter 21 is at the highest input level. Since the aim of reduction, optimum performance according to a value indicating variation of the received field strength of the receiving device (radio station) can be exhibited.

  Further, according to the receiving apparatus of the embodiment and the receiving control method of the embodiment, the time constant of the “feedback loop of the LOG amplifier 24” is controlled based on the value indicating the fluctuation of the received electric field strength of the receiving apparatus (wireless station). As a result, a stable feedback loop is realized when the value indicating the fluctuation of the received electric field strength is less than the predetermined value, and the level fluctuation is followed when the value indicating the fluctuation of the received electric field strength exceeds the predetermined value. Can be.

  Furthermore, according to the receiving apparatus of the embodiment and the reception control method of the embodiment, when the adaptive modulation scheme is adopted, when the modulation scheme is the low modulation scheme, the “feedback loop of the LOG amplifier 24” is used. When the modulation method is a high modulation method, the feedback loop is switched so as to use the “feedback loop for guiding the output signal of the CONT unit 23”, and “LOG” is set based on the modulation method (modulation class) of the receiving apparatus (wireless station). By varying the time constant of the “feedback loop of the amplifier 24” and variably controlling the integration time corresponding to the amplitude variation depending on the modulation method, the detection level accuracy varies depending on the modulation method when detecting the reception level with a constant integration time. So that the same detection level accuracy can be ensured. It is possible to reduce the instability.

  In addition, the receiving apparatus of the present embodiment generates (estimates) “information on the movement state of the counterparty radio station” inside the receiver, but the counterparty radio station itself Control using the received moving speed may be performed by receiving the acquired moving speed.

  According to the receiving apparatus of the embodiment and the receiving control method of the embodiment, since it is not necessary to input information from the outside in order to switch the feedback loop, there is an effect that the circuit configuration can be simplified.

It is a circuit diagram which illustrates the composition of the receiving device of the embodiment of the present invention. It is a figure which illustrates various signals used for the receiving device of an embodiment. It is a circuit diagram which illustrates the composition of the conventional receiving device. It is a circuit diagram which illustrates the composition of the receiving device of the conventional example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Antenna 11 Bandpass filter 12 Amplifier 13 Quadrature demodulator 14 Local signal source 15 Bandpass filter 16 Reception amplifier (variable amplifier)
18 Quadrature Demodulator 19 Local Signal Source 20 Band Pass Filter 21 A / D Converter 22 Reception Baseband Unit (RXBB)
23 CONT 24 Log Amplifier (LogAMP)
25 Loop filter 26 Switch (SW)
27 Arithmetic Circuit (CAL)
28 Selector (SEL)

Claims (6)

In a receiving apparatus that converts an analog signal received from an antenna from another radio station into a digital signal and demodulates it,
Information acquisition grasping means for obtaining information on the movement state of other wireless stations;
Control means for controlling the gain of the receiving amplifier based on the received electric field strength of the received signal;
In accordance with the information acquired by the information acquisition means, the reception signal used for gain control of the reception amplifier in the control means is digitally converted by converting the reception signal in the analog signal or the analog signal. A selection means for selecting a received signal in the digital signal;
A receiving apparatus comprising: The receiving device according to claim 1,
The information on the movement state acquired by the information acquisition means is a value related to a variation in received electric field strength based on the analog signal,
In the selection means,
If the value is greater than or equal to a predetermined value, select the received signal in the analog signal; if the value is less than the predetermined value, select the received signal in the digital signal;
A receiving apparatus. The receiving apparatus according to claim 2 employs communication using an adaptive modulation method,
The receiving device is:
A modulation method grasping means for grasping the modulation method of the receiver;
Further comprising
In the selection means,
When the value indicating the information acquired by the information acquisition means is a predetermined value or more, and the modulation method grasped by the modulation method grasping means is a modulation method less than a predetermined multi-value number The analog signal received signal is selected, the value indicating the information acquired by the information acquiring means is less than the predetermined value, and the modulation method grasped by the modulation method grasping means is a predetermined many. If the modulation method is greater than or equal to the number of values, the received signal of the digital signal is selected.
A receiving apparatus. The receiving apparatus according to any one of claims 1 to 3,
The control means includes a loop filter,
When the value indicating the information acquired by the information acquisition means is greater than or equal to a predetermined value, the time constant of the loop filter is controlled to be relatively small, and the value indicating the information is less than the predetermined value Is controlled such that the time constant of the loop filter is relatively large,
A receiving apparatus. The receiving apparatus according to claim 3,
The control means includes a loop filter,
When the modulation method grasped by the modulation method grasping means is a modulation method that does not satisfy a predetermined multi-value number, the time constant of the loop filter is controlled to be relatively small, and the modulation method is When the modulation method is a predetermined multi-value number or more, the time constant of the loop filter is controlled to be relatively large.
A receiving apparatus. In a reception control method in a receiving apparatus that converts an analog signal received from an antenna from another radio station into a digital signal and demodulates it,
An information grasping step for obtaining information on the movement state of other radio stations;
According to the acquired information, as a reception signal used for controlling the gain of the reception amplifier, the reception signal in the analog signal or the reception signal in the digital signal obtained by digital conversion of the analog signal and the digital conversion is selected. A selection step to
A control step of controlling the gain of the receiving amplifier based on the received electric field strength of the selected received signal;
A reception control method comprising:

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