JP2013070143A - Radio communication device, matching control circuit, and matching control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to achieve optimal receiving sensitivity although conventional power matching using RSSI (Received Signal Strength Indication) cannot achieve optimal receiving sensitivity because noise is not reflected.SOLUTION: A radio communication device according to the invention comprises: matching means for performing impedance matching to a reception signal received by an antenna; quality indicator calculation means for calculating a quality indicator in which noise of the reception signal to which the impedance matching was performed is reflected; and control means for controlling a matching constant of the impedance matching the matching means performs on the basis of the quality indicator in which the noise is reflected. According to the configuration, it is possible to optimize reception sensitivity as matching control can be performed taking noise into consideration.

Description

  The present invention relates to a matching control circuit and a wireless communication apparatus including the circuit.

  In the reception system circuit of the wireless communication device, the RF (Radio Frequency) signal received by the antenna is impedance-matched by the RF matching circuit, and the reception sensitivity is optimized by maximizing the reception signal and minimizing the noise. Processing is performed.

  Usually, the RF matching circuit is designed in advance so as to optimize the reception sensitivity in the reception signal band when the reception system circuit is designed. However, there is a problem that matching is shifted due to variations in PVTF (Process: manufacturing, Voltage: voltage, Temperature: temperature, Frequency: frequency), and reception sensitivity is deteriorated.

  As a technique for solving such a problem, there is an RF matching circuit described in Patent Document 1. In Patent Document 1, an RF matching circuit is arranged between an LNA (low noise amplifier) and a mixer (frequency mixer), and the RF matching is adjusted by controlling the RF matching circuit with an RSSI output. As the controlled element of the RF matching circuit, a varicap diode whose capacitance value changes with voltage is used. By adopting such a configuration, it is possible to maintain good reception sensitivity even if the PVTF fluctuates.

JP 2000-13190 A

  However, since the RF matching circuit disclosed in Patent Document 1 performs matching control using an RSSI (Received Signal Strength Indicator) output, power matching can be adjusted, but noise matching cannot be adjusted. There are challenges.

The best matching constant of the RF matching circuit differs between power matching and noise matching. As shown in FIG. 14, when the control voltage of the varicap diode is swept, the power matching best point _VP and noise matching best point V _N There is a difference in ΔV. Since RSSI can detect received signal strength but cannot detect noise, it cannot be adjusted from the viewpoint of noise. Since the reception sensitivity S greatly depends on noise, it is necessary to improve the total NF, that is, noise in order to improve the reception sensitivity. However, since the technique of Patent Document 1 cannot adjust the noise matching, the reception sensitivity is optimized. Could not do.

  In Patent Document 1, since the LNA is arranged before the RF matching circuit, reflection occurs at this portion due to the impedance shift, and the reception signal received via the antenna can be appropriately sent to the subsequent stage. There wasn't.

  The wireless communication apparatus according to the first aspect of the present invention calculates a matching unit that performs impedance matching on a received signal received by an antenna, and a quality index that reflects noise of the received signal subjected to the impedance matching And a control unit that controls a matching constant of impedance matching performed by the matching unit based on the quality index reflecting the noise. With this configuration, matching control can be performed in consideration of noise, and reception sensitivity can be optimized.

  The matching control circuit according to the second aspect of the present invention is based on a matching unit that performs impedance matching on an input received signal and a quality index that reflects noise of the received signal on which the impedance matching has been performed. Control means for controlling matching constants of impedance matching performed by the matching means. With this configuration, matching control can be performed in consideration of noise, and reception sensitivity can be optimized.

  Further, the matching control method according to the third aspect of the present invention performs impedance matching on the input received signal, calculates a quality index reflecting noise of the received signal subjected to the impedance matching, and The impedance matching matching constant is controlled based on a quality index reflecting noise. With this configuration, matching control can be performed in consideration of noise, and reception sensitivity can be optimized.

  According to the present invention, it is possible to further improve the reception sensitivity and to optimize the reception sensitivity as compared with the case of improving the reception sensitivity based only on power matching.

1 is a block diagram of a wireless communication apparatus according to Embodiment 1. FIG. 1 is a block diagram of a wireless communication apparatus according to Embodiment 1. FIG. 4 is a graph showing a relationship between a control voltage and an LQI output according to the first embodiment. 1 is a diagram illustrating a configuration of an RF matching circuit according to a first embodiment. 1 is a block diagram of a wireless communication apparatus according to Embodiment 1. FIG. 6 is a block diagram of a wireless communication apparatus according to Embodiment 2. FIG. 6 is a graph showing a relationship between BER (PER) and S / N according to the second embodiment. 6 is a block diagram of a wireless communication apparatus according to Embodiment 3. FIG. FIG. 10 is a block diagram of a wireless communication apparatus according to a fourth embodiment. It is a figure which shows the management table which described the relationship between VTF and control voltage value which concern on Embodiment 4. FIG. FIG. 10 is a block diagram of a modification of the wireless communication device according to the fourth embodiment. It is a figure which shows the management table which described the relationship between VTF and the peak search range which concerns on Embodiment 4. FIG. FIG. 10 is a block diagram of a modification of the wireless communication device according to the fourth embodiment. It is a figure which shows the relationship between the received signal strength when the control voltage is swept, and the noise strength.

  Embodiments of the present invention will be described below with reference to the drawings. The following description shows preferred embodiments of the present invention, and the scope of the present invention is not limited to the following embodiments. In the following description, the same reference numerals indicate substantially the same contents.

(Embodiment 1)
Hereinafter, the present embodiment will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of radio communication apparatus 100 according to the first embodiment.

  The wireless communication device 100 includes an antenna 101, an RF matching circuit 102, an LNA (Low Noise Amplifier) 103, a Mixer (frequency mixer) 104, a Filter (filter) 105, and a VGA (Variable Gain Amplifier). : Variable gain amplifier) 106, ADC (Analog Digital Converter) 107, DEM (Demodulator) 108, RSSI (Received Signal Strength Indicator) calculation circuit 109, and LQI (Link Quality Indicator) The calculation circuit 110 and the control circuit 111 are provided.

  A high frequency band received signal wirelessly received via the antenna 101 is input to the RF matching circuit 102. The RF matching circuit 102 performs impedance matching on the input received signal under the control of the control circuit 111 and outputs the received signal after the matching process to the LNA 103.

  Specifically, the RF matching circuit 102 is configured by an LC circuit in which an inductor 1021 and a variable capacitor 1022 are combined as shown in FIG. The control circuit 111 changes the matching constant in the impedance matching process by changing the control voltage applied to the variable capacitor 1021 to change the capacitance value. The variable capacitor 1021 is, for example, a varactor (PN junction diode), and the capacitance can be changed by changing the control voltage.

  The LNA 103 performs amplification processing while maintaining low noise for the received signal after matching processing input from the RF matching circuit 102, and outputs the received signal after amplification processing to the mixer 104.

  The mixer 104 down-converts the amplified reception signal input from the LNA 103 and converts the RF signal into an IF signal (intermediate frequency signal) or a BB signal (baseband signal). Mixer 104 outputs the received signal after frequency conversion to filter 105.

  The filter 105 performs a filtering process on the received signal after frequency conversion input from the mixer 104, extracts a received signal in a desired signal band, and outputs the received signal to the VGA 106.

  The VGA 106 amplifies the received signal input from the filter 105 after the filtering process with a variable gain so that the input level in the ADC 107 in the subsequent stage becomes constant. The reception signal amplified by the VGA 106 is output to the ADC 107 and the RSSI calculation circuit 109.

  The ADC 107 performs AD conversion processing on the received signal that is an analog signal after amplification input from the VGA 106 and converts the received signal into a digital signal. The received signal converted into the digital signal is output to the DEM 108.

  The DEM 108 performs demodulation processing corresponding to the modulation method of the received signal on the received signal after AD conversion processing input from the ADC 107. The DEM 108 further performs a decoding process on the received signal after the demodulation process using a corresponding encoding method, and finally extracts a data bit string. The DEM 108 outputs the demodulated and decoded data to the back-end digital LSI and also to the LQI calculation circuit 110.

  The RSSI calculation circuit 109 receives an output signal from the VGA 106 and calculates RSSI. The calculated RSSI is used for electric field strength display, transmission power control, AGC (Automatic Gain Control), vacant channel detection, squelch (to block noise when the received signal falls below a certain value), etc. Is done.

  The LQI calculation circuit 110 receives output data from the DEM 108 and calculates an LQI (link quality index) based on the received signal strength and noise strength when a frame is received. The calculated link quality indicator is used to notify the upper layer. In the present invention, the calculated LQI is supplied to the control circuit 111.

  The control circuit 111 receives the LQI from the LQI calculation circuit 110, changes the impedance of the RF matching circuit 102, performs a peak search of the LQI output, and detects the best point of reception sensitivity. The control circuit 111 performs control to set the impedance of the RF matching circuit 102 at a location corresponding to the peak position of the LQI output.

  Specifically, as shown in FIG. 2, the control circuit 111 includes a control voltage changing unit 1111, a monitor 1112, and a control voltage determining unit 1113. The control voltage changing unit 1111 sweeps the control voltage applied to the varactor 1022 in a predetermined voltage range in accordance with an instruction from the control voltage determining unit 1113.

  The monitor 1112 monitors the value of LQI obtained through impedance matching performed with a matching constant corresponding to the control voltage applied by the control voltage changing unit 1111. The monitor 1112 outputs the LQI monitoring result to the control voltage determination unit 1113.

  The control voltage determining unit 1113 compares the LQI value according to the control voltage value swept by the control voltage changing unit 1111 and determines the voltage value having the best LQI value as the final control voltage. The change unit 1111 is instructed. The control voltage changing unit 1111 sets the control voltage to the value instructed from the control voltage determining unit 1113.

  FIG. 3 shows the relationship between the control voltage applied to the varactor and the LQI output. FIG. 3 shows the LQI value observed by the monitor unit 1112 when the control voltage changing unit 1111 sweeps the control voltage. The control voltage determining unit 1113 uses the point with the highest LQI value as the reception sensitivity best point. The control voltage is determined as Vg.

  As described above, according to the wireless communication apparatus in the first embodiment, matching control is performed using a quality index that reflects noise obtained after demodulation processing. Specifically, the LQI value is obtained based on the intensity of the signal itself and the noise intensity obtained after the demodulation process, and the matching control is performed by the control circuit 111 so that the LQI value becomes the best. Accordingly, since the matching control is performed in consideration of both power matching and noise matching, the reception sensitivity can be optimized.

  Note that the RF matching circuit shown in FIG. 2 is an example. For example, as shown in FIGS. 4A to 4E, RF matching is performed by combining one or more capacitors and one or more inductors in series or in parallel. A circuit may be assembled. Even in such a configuration, the control voltages V, V1, and V2 are applied to the varactors 1022 from the control circuit 111, thereby changing the capacitance and changing the impedance of the RF matching circuit.

  Further, the RF matching circuit sweeps the capacitance value by switching a plurality of weighted capacitors C1023 of the RF matching circuit using the switch 1024 as shown in FIG. 5, and the control circuit 211 performs peak search of the LQI output. The structure to perform may be sufficient. That is, the control circuit 211 may change the RF matching constant of the RF matching circuit by performing control to switch the switch 1024 connected to each of the plurality of capacitors 1023. The control circuit 211 can set each switch ON / OFF with the peak of the LQI output being monitored as the best point of reception sensitivity.

  In addition, although FIG. 5 demonstrated the structure which switches the several capacitor installed in parallel with weighting, the control circuit 211 may be the structure which switches the several inductor weighted and installed in parallel.

(Embodiment 2)
The radio communication apparatus according to the second embodiment is characterized in that matching is performed using a bit error rate or a packet error rate obtained after demodulation. Hereinafter, it demonstrates using drawing. However, part of the description already given in Embodiment 1 is omitted for the sake of clarification of the invention.

  FIG. 6 is a block diagram showing a configuration of radio communication apparatus 200 according to the second embodiment. The wireless communication apparatus 200 includes an antenna 101, an RF matching circuit 102, an LNA 103, a mixer 104, a filter 105, a VGA 106, an ADC 107, a DEM 108, an RSSI calculation circuit 109, an error rate measurement unit 210, and a control. Circuit 111.

  The error rate measurement unit 210 monitors data that has been demodulated and decoded by the DEM 108, and measures BER (Bit Error Rate) or PER (Packet Error rate). As shown in FIG. 7, BER and PER each depend on the signal-to-noise ratio (S / N). Therefore, BER or PER is a quality index that reflects the received signal strength and noise, and S / N can be calculated backward by measuring the BER or PER. The error rate measurement unit 210 outputs the measured BER or PER to the control circuit 211.

  The monitor unit 1112 of the control circuit 111 monitors the BER or PER output from the error rate measuring unit 210 for each control voltage that the control voltage changing unit 1111 sweeps. The control voltage determination unit 1113 determines the control voltage to a voltage value that has the best BER or PER within the swept voltage range as a result of monitoring in the monitor unit 1112. Whether to use BER or PER as the information to be fed back may be used depending on the radio communication system using the radio communication apparatus.

  Thus, in this embodiment, BER or PER is measured, and the matching constant of the RF matching circuit is controlled based on the BER or PER. Even in such a configuration, since BER or PER is a quality index reflecting both signal (received signal strength) and noise, BER or PER is monitored by changing the control voltage, and BER or PER is optimal. The reception sensitivity can be optimized by setting the control voltage with a value.

  In the above description, the error rate measurement unit 210 measures the BER or PER and feeds back the BER or PER to the control circuit 211. However, the present invention is not limited to this. For example, the error rate measurement unit 210 may be configured to obtain S / N by measuring BER or PER and feed back the S / N to the control circuit 211. The control circuit 211 may sweep the control voltage and set the voltage having the best S / N as the control voltage. Since S / N is also a quality index reflecting both signal and noise, reception sensitivity can be optimized even with such a configuration.

  Note that the method of obtaining the S / N in the error rate measuring unit 210 is not limited to the method of obtaining based on BER or PER, and may be obtained using other methods. For example, the error rate measurement unit 210 obtains a signal based on RSSI in a frame in which a signal is transmitted, obtains noise on the basis of RSSI in a frame in which no signal is transmitted, and obtains an S / N by combining these. Feedback to the control circuit 111.

  Further, the error rate measuring unit 210 may be configured to measure the error rate of the received signal in the error correction processing performed by the DEM 108 and feed back to the control circuit 111 as a quality index reflecting noise.

(Embodiment 3)
The wireless communication apparatus according to the third embodiment is characterized by performing two-stage matching control, that is, matching control using RSSI in which noise is not reflected and matching control using a quality index in which noise is reflected. Hereinafter, it demonstrates using drawing. However, part of the description of Embodiment 1 or 2 is omitted for the sake of clarity.

  FIG. 8 is a block diagram of the configuration of the wireless communication apparatus 300 according to the third embodiment. The wireless communication apparatus 300 includes an antenna 101, an RF matching circuit 102, an LNA 103, a mixer 104, a filter 105, a VGA 106, an ADC 107, a DEM 108, an RSSI calculation circuit 109, an error rate measurement unit 210, and a control. A circuit 311.

  The RSSI calculation circuit 109 obtains RSSI based on the received signal after amplification output from the VGA 106 and outputs the RSSI to the control circuit 311.

  The control voltage changing unit 1111 of the control circuit 311 roughly sweeps the control voltage output to the RF matching circuit 102 according to the control from the control voltage determining unit 3113 as the first-stage sweep. The monitor unit 3112 monitors the RSSI value input from the RSSI calculation circuit 109 and outputs the monitoring result to the control voltage determination unit 3113. The control voltage determination unit 3113 determines the voltage position and sweep width of the second-stage sweep in the control voltage change unit 1111 based on the monitoring result input from the monitor unit 3112, and instructs the control voltage change unit 1111. The control voltage changing unit 1111 sweeps the control voltage within the range instructed by the control voltage determining unit 3113 as the second-stage sweep.

  The monitor unit 3112 monitors BER or PER input from the error rate measuring unit 210 instead of RSSI during the second sweep in the control voltage changing unit 1111 according to the control from the control voltage determining unit 1113. The monitor unit 3112 outputs the monitoring result to the control voltage determination unit 3113. The control voltage determination unit 3113 controls the voltage value with the best BER or PER within the sweep range as a result of the monitoring in the monitor unit 3112. Set as voltage.

  As described above, in the third embodiment, a rough range for performing RF matching is specified based on RSSI, and then final adjustment is performed using BER or PER, that is, the control voltage applied to the varactor, that is, The matching constant of the RF matching circuit is determined.

  Since BER and PER are values obtained by performing a demodulation process and a decoding process in DEM 108 and then monitoring a predetermined number of samples bit string by error rate measurement unit 210, before BER or PER is obtained in comparison with RSSI. It takes a long time. In particular, in order to obtain the optimum matching constant using PER, it is necessary to obtain PER after obtaining a certain amount of packets, which requires a considerable amount of time. Therefore, it is not preferable to determine the matching constant by monitoring the BER and PER by sweeping an unnecessarily wide range of voltages by the control voltage changing unit 1111 in the control circuit 111.

  Here, there is a certain correlation between the optimum control voltage value Vr obtained based on RSSI and the optimum control voltage value Vp obtained based on BER or PER, although there is a deviation. Therefore, Vr is specified by the first-stage sweep using RSSI, the second-stage control voltage is swept within a predetermined range around Vr, and BER or PER is monitored to obtain Vp. As a typical control voltage.

  That is, the control circuit determines a second range in which the matching constant is changed based on the received signal strength of the received signal when the matching constant is changed in the first range, and the matching is performed in the second range. Control is performed to set the matching constant based on the quality index value reflecting the noise when the constant is changed.

  By adopting such a configuration, it is possible to limit the peak search range based on BER and PER as compared with the case where the voltage is swept in a wide range based only on BER and PER and the control voltage is obtained. Matching control can be performed so that the optimum reception sensitivity can be obtained quickly.

  In the above description, the configuration in which RSSI is monitored as the voltage sweep at the first stage has been described. However, the present invention is not limited to this. A peak search is performed using a quality index that does not reflect noise obtained before the demodulation process, a rough decision is made about the control voltage (RF matching constant), and it is obtained after the demodulation process in the voltage sweep of the second stage. The configuration may be such that BER or PER is monitored and a control voltage (RF matching constant) to be finally set is determined.

  In the above description, the configuration for monitoring BER or PER in the voltage sweep at the second stage has been described. However, the present invention is not limited to this. Other forms can be used as long as the quality index reflects noise obtained after demodulation processing, and for example, a configuration in which LQI or SNR is monitored can be adopted.

  Note that the voltage sweep performed in the first stage is performed to specify the voltage sweep range in the second stage, so it does not matter even if the accuracy is not so high. Therefore, the control voltage determination unit 3113 may instruct the control voltage change unit 1111 to perform the first-stage sweep with a plurality of discrete voltage values. The control voltage determining unit 3113 is centered on the voltage value when the value is the best among the BER or PER values obtained by the monitor unit 3112 based on the plurality of control voltages applied by the control voltage changing unit 1111. The sweep range of the second stage may be determined. However, it is preferable that the voltage sweep range of the first stage is wider than the voltage sweep range of the second stage.

In the above description, the voltage sweep of the first stage is performed over a relatively wide range of voltages to monitor RSSI and the like, and after determining the voltage sweep range of the second stage, the BER or PER is monitored and finally controlled. Although the case of determining the voltage has been described, the present invention is not limited to this. The time required to obtain the quality index related to the received signal strength that does not include noise, such as RSSI, that is obtained before demodulation, and each quality index that reflects noise such as BER and PER, is expressed by the following equation (1). Have
(1) RSSI <LQI ≦ BER <PER

  Therefore, the first stage voltage sweep is performed to monitor the BER, the second stage voltage sweep range is obtained, the second stage voltage sweep is performed within the range, and the PER is monitored. The final control voltage may be determined. In addition, LQI is monitored by the first-stage voltage sweep, the second-stage voltage sweep range is obtained, and the second-stage voltage sweep is performed within the range to monitor BER and PER. It is also good.

  Also, RSSI is monitored by the first voltage sweep, BER is monitored by the second voltage sweep of the narrower voltage range, and PER is monitored by the third voltage sweep of the narrower voltage range. Thus, the final control voltage may be determined. With this configuration, it is possible to obtain an optimum control voltage in a shorter time and perform impedance matching.

  In the above description, the RSSI is monitored by the first-stage voltage sweep and the second-stage voltage sweep range is obtained. However, the present invention is not limited to this. Usually, RSSI may be monitored, impedance matching may be performed based on RSSI, and impedance matching may be performed using a quality index including noise such as LQI at predetermined intervals measured by a timer or the like. In addition, when a peak search is performed using LQI in the normal state, the control voltage is determined to control the matching constant of the RF matching circuit, and the coding rate of the error correction code is set to be low by adaptive modulation, the BER May be switched to control the matching constant of the RF matching circuit by determining the control voltage by performing a peak search. As described above, the control circuit performs the first control for temporarily setting the matching constant based on the received signal strength of the received signal, and sets the matching constant based on the value of the quality index reflecting the noise. It is good also as a structure which performs control of 2.

  Also, when the reception strength is good, such as when the mobile station device is in the vicinity of the radio base station device, the RSSI is monitored and a peak search is performed to obtain a control voltage, while the reception strength falls below a predetermined reference value. In this case, impedance matching may be performed using a quality index including noise such as LQI. When the reception strength is high, BER satisfying the standard can be achieved even by impedance matching using RSSI. On the other hand, when the reception strength is lower than a predetermined reference value, such as a cell edge, a peak using a quality index including noise is used.・ By performing search, determining the control voltage and performing impedance matching, it is possible to perform optimum operation as a whole.

(Embodiment 4)
The wireless communication apparatus according to the present embodiment stores a management table in which a relationship between a control voltage value and a VTF (Voltage, temperature, Frequency) is recorded in advance. This will be described below with reference to the drawings. However, a part of the description already given in the first to third embodiments will be omitted.

  FIG. 9 is a block diagram of the configuration of the wireless communication apparatus 400 according to the fourth embodiment. The wireless communication apparatus 400 includes an antenna 101, an RF matching circuit 102, an LNA (Low Noise Amplifier) 103, a mixer 104, a filter 105, a VGA (Variable Gain Amplifier) 106, an ADC (Analog Digital Converter) 107, , A DEM (Demodulator) 108, a control circuit 411, a supply voltage measurement unit 412, a temperature measurement unit 413, and a use frequency band determination unit 414. The control circuit 411 includes a management table recording unit 4111 and a control voltage determination unit 4113.

  The supply voltage measurement unit 412 measures the supply voltage supplied to the system from a battery or the like. The supply voltage measurement unit 412 notifies the control voltage determination unit 4113 of the measured supply voltage value as supply voltage information.

  The temperature measurement unit 413 measures the temperature of its own device. Specifically, the temperature measurement unit 413 includes a semiconductor temperature sensor and the like, and measures using the temperature around the matching circuit 102. Note that when the matching circuit 102 is incorporated in an LSI in a subsequent stage, the temperature measurement unit 413 may measure the temperature of the LSI. The RF matching circuits 102 to DEM 108 are mounted on a single LSI, and a temperature measuring unit 413 such as a semiconductor temperature sensor can also be mounted on the LSI. The temperature measurement unit 413 notifies the control voltage determination unit 4113 of temperature information regarding the measured temperature.

  The used frequency band determining unit 414 determines a frequency band, that is, a channel, to be used in wireless communication performed with the wireless communication base station. Normally, in a radio communication system, a radio base station apparatus performs channel scheduling management, and a channel is allocated to a mobile station apparatus that performs radio communication. The used frequency band determination unit 414 receives the control information demodulated by the DEM 108 and notifies the control voltage determination unit 4113 of the frequency band information related to the frequency band used for radio reception. In addition, the used frequency band determination unit 414 notifies the transmission unit (not shown) of frequency band information related to the frequency band used for wireless transmission.

  Next, the control circuit 411 will be described.

  The management table storage unit 4111 is, for example, a ROM (Read Only Memory) provided in the control circuit 411. The management table storage unit 4111 is voltage information about the supplied voltage, temperature information about the temperature, and frequency about the frequency band (channel) used for reception. A management table in which correspondences between information and control voltages are summarized is stored.

  FIG. 10 shows an example of the management table. As shown in FIG. 10, in the management table, control voltages corresponding to supply voltage, temperature, and frequency band are described.

  Based on the supply voltage information, temperature information, and frequency band information input from the above-described supply voltage measurement unit 412, temperature measurement unit 413, and use frequency band determination unit 414, the control voltage determination unit 4113 is a management table described later. The value of the control voltage applied to the RF matching circuit is determined with reference to FIG. Specifically, the control voltage determination unit 4113 reads the management table from the management table storage unit 4111, and the control voltage value described in association with the input supply voltage information, temperature information, and frequency band information portions. Is determined as the value of the control voltage applied to the RF matching circuit.

  As described above, in this embodiment, the control circuit refers to the management table, obtains an appropriate voltage value even when the supply voltage, temperature, and use frequency change, and applies the control voltage to the RF matching circuit. Since the matching constant is controlled, good reception sensitivity can be realized.

  In the above description, the supply voltage, temperature, and frequency band are described in association with the value of the control voltage applied to the varactor of the RF matching circuit, but the present invention is not limited to this. The supply voltage, temperature, and frequency band may be described in association with the matching constant of the RF matching circuit. The control circuit refers to the management table based on the supply voltage information, the temperature information, and the frequency band information input from the supply voltage measurement unit 412, the temperature measurement unit 413, and the use frequency band determination unit 414, respectively. And the RF matching circuit may be controlled so that the impedance indicated by the matching constant is obtained.

  As shown in FIG. 11, the control voltage determination unit 4113 may be configured to determine a search range for performing a peak search based on the input frequency information, temperature information, and supply voltage value. As shown in FIG. 12, in the configuration, the management table stored in the management table storage unit 4111 is described with the supply voltage value, temperature, operating frequency band, and peak search range associated with each other.

  The control voltage determination unit 4113 refers to the management table stored in the management table storage unit 411, and supplies the supply voltage value and temperature input from the supply voltage measurement unit 412, the temperature measurement unit 413, and the use frequency band determination unit 414, respectively. A peak search range is obtained based on the information and the frequency band information. The control voltage determining unit 4113 instructs the control voltage changing unit 1111 to change the control voltage within the obtained peak search range. The monitor unit 1112 monitors a quality index such as LQI while sweeping the control voltage within the range instructed by the control voltage changing unit 1111 and notifies the control voltage determining unit 5113 of the peak position. The control voltage determination unit 5113 determines the voltage value at the peak position as the control voltage value, and instructs the control voltage change unit 1111. With such a configuration, the voltage range in which peak search is performed can be appropriately selected according to the usage state of the terminal, so that optimum reception sensitivity can be realized quickly.

  Also in this configuration, the management table may have a configuration in which a sweep range of matching constants corresponding to the supply voltage, temperature, and frequency is written. The control voltage determination unit 4113 may refer to the management table, obtain a matching constant sweep range based on the input supply voltage information, temperature information, and frequency information, and perform control to change the matching constant within the range.

  Needless to say, the quality index to be monitored is not limited to LQI, and the above-described quality index including noise can be monitored.

  10 and 12, the case where the control voltage value or the peak search range corresponding to three parameters of the supply voltage, the temperature, and the use frequency band is described has been described. However, the present invention is not limited to this. At least one of supply voltage, temperature, and operating frequency band is associated, and the control voltage determination unit inputs information on the parameters described in the management table and refers to the management table to control voltage value or peak search The structure which calculates | requires a range may be sufficient.

  As described above in each embodiment, the present invention addresses the problem that RF matching is shifted due to variations in PVTF (Process, Voltage, Temperature, Frequency) and reception sensitivity is deteriorated in a reception system circuit of a wireless communication device. Power matching and noise matching. Therefore, the present invention can obtain the best receiving sensitivity in consideration of both the received signal and noise as compared with the case where matching processing is performed using RSSI.

  Note that the present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the present invention. For example, as shown in FIG. 13, a configuration may be adopted in which a VTF fluctuation monitoring unit 520 is newly provided. The VTF fluctuation monitoring unit 520 inputs a supply voltage value, temperature information, and frequency band information, and monitors these values. The VTF fluctuation monitoring unit 520 controls the control voltage determination unit 1113 to control if there is a fluctuation exceeding a predetermined reference value compared with the supply voltage value, temperature, and frequency band at the time of the current control voltage setting as a result of monitoring. It may be instructed to reset the voltage. With such a configuration, it is possible to reduce the occurrence of processing for determining a control voltage by performing an unnecessary peak search. When the control voltage determination unit 1113 receives an instruction to reset the control voltage from the VTF fluctuation monitoring unit 520, the control voltage determination unit 1113 may perform a peak search again and reset the value of the control voltage.

  In this case, the VTF fluctuation monitoring unit 520 obtains the peak search range by referring to the management table shown in FIG. 12, and notifies the control voltage determination unit 1113 of the peak search range together with the control voltage resetting instruction. It is good also as composition to do.

  Further, the VTF fluctuation monitoring unit 520 may instruct the resetting of the control voltage when any one of the supply voltage value, the temperature information, and the frequency band information fluctuates more than a predetermined reference value. The control voltage resetting instruction may be issued when the sum of the fluctuations of the values fluctuates more than a predetermined reference value.

  That is, the VTF fluctuation monitoring unit 520 monitors at least one of a supply voltage value, a temperature at a predetermined position of the own device, or a use frequency band used for reception, and the value of the supply voltage or the temperature of the own device. Alternatively, when it is detected that a variation of a predetermined reference value or more has occurred in any item or a plurality of items in the used frequency band used for the reception, the control circuit 511 is notified that the variation has occurred. . Upon receiving the notification, the control circuit 511 resets a matching constant for impedance matching performed by the matching unit based on the quality index reflecting the noise. With such a configuration, when a shift in reception sensitivity is assumed, readjustment can be performed appropriately and good reception sensitivity can be maintained.

  Further, the management table of FIG. 10 or FIG. 12 summarizes voltage information (supply voltage value) relating to the supplied voltage, temperature information relating to temperature, and frequency band information relating to the frequency band used for reception and corresponding control voltage values. However, the present invention is not limited to this. In the management table, matching constants corresponding to at least one of voltage information, temperature information, and frequency band information may be collected. The control circuit acquires a corresponding matching constant based on any of voltage information, temperature information, and frequency band information input with reference to the management table, and controls the RF matching circuit to be the matching constant. May be.

  The block diagram of the wireless communication apparatus described in each embodiment has been described by taking only the reception system circuit. Needless to say, each wireless communication apparatus includes a transmission system circuit. The transmission system circuit includes a modulator, a DA converter, a mixer, a filter, an amplifier, and the like.

  In the above description, the wireless communication apparatus having the wireless transmission / reception function has been described. However, the present invention is not limited to this, and the wireless reception apparatus having the wireless reception function described in each of the above embodiments is naturally applicable. be able to.

  Further, the RF matching circuit and various control circuits described above can be incorporated into one chip and manufactured as a matching control circuit.

DESCRIPTION OF SYMBOLS 100 Wireless communication apparatus 101 Antenna 102 RF matching circuit 103 LNA (low noise amplifier)
104 mixer 105 filter 106 VGA (variable gain amplifier) 108 DEM (demodulator)
109 RSSI Calculation Circuit 110 LQI Calculation Circuit 111 Control Circuit 200 Wireless Communication Device 210 Error Rate Measurement Unit 211 Control Circuit 300 Wireless Communication Device 311 Control Circuit 400 Wireless Communication Device 411 Control Circuit 412 Supply Voltage Measurement Unit 413 Temperature Measurement Unit 414 Use Frequency Band Determination unit 511 Control circuit 520 VTF fluctuation monitoring unit 1021 Inductor 1022 Variable capacitance capacitor 1023 Capacitor 1024 Switch 1111 Control voltage change unit 1112 Monitor unit 1113 Control voltage determination unit 3112 Monitor unit 3113 Control voltage determination unit 4111 Management table storage unit 4113 Control voltage determination 5113 Control voltage determination unit

Claims (13)

Matching means for performing impedance matching on the received signal received by the antenna;
Quality index calculation means for calculating a quality index reflecting noise of the received signal subjected to the impedance matching;
Control means for controlling a matching constant of impedance matching performed by the matching means based on the quality index reflecting the noise;
A wireless communication apparatus comprising: The quality index calculating means calculates a link quality index (LQI) as a quality index reflecting the noise based on a received signal strength and a noise strength of the received signal;
The wireless communication apparatus according to claim 1. The quality index calculating means calculates a signal-to-noise ratio (SNR) as a quality index reflecting the noise based on a received signal strength and a noise strength of the received signal;
The wireless communication apparatus according to claim 1. Further comprising demodulation means for demodulating the received signal subjected to the impedance matching;
The quality index calculation means calculates a bit error rate (BER) or a packet error rate (PER) as a quality index reflecting the noise based on the demodulated received signal.
The wireless communication apparatus according to claim 1. The control means performs control to set the matching constant to a value where the value of the quality index reflecting the noise is the best within a range in which the matching constant is changed.
The wireless communication apparatus according to any one of claims 1 to 4. The matching means includes an inductor and a capacitor whose capacity can be changed,
The control means controls the matching constant by changing a capacitance of the capacitor by applying a control voltage according to a value of a quality index reflecting the noise to the capacitor.
The wireless communication apparatus according to any one of claims 1 to 5. The control means determines a second range for changing the matching constant based on the received signal strength of the received signal when the matching constant is changed in the first range, and the matching is performed in the second range. Performing control to set the matching constant based on the value of the quality index reflecting the noise when the constant is changed,
The wireless communication apparatus according to claim 6. Storage means for storing a management table in which at least one information of voltage information related to a supplied voltage, temperature information related to temperature, and frequency band information related to a frequency band used for reception is associated with a control voltage value;
The control means inputs at least one information of voltage information about a supplied voltage, temperature information about a temperature, and frequency band information about a frequency band used for reception, and applies to the capacitor with reference to the management table Determine the value of the control voltage,
The wireless communication apparatus according to claim 6. A management table in which at least one of voltage information related to a supplied voltage, temperature information related to temperature, and frequency band information related to a frequency band used for reception is associated with a sweep range of a control voltage applied to the capacitor is stored. And further storing means for
The control means inputs at least one information of voltage information related to a supplied voltage, temperature information related to temperature, and frequency band information related to a frequency band used for reception, and in a range obtained by referring to the management table. The wireless communication apparatus according to claim 6, wherein control is performed to set the matching constant based on a value of a quality index that reflects the noise when a value of a control voltage applied to the capacitor is changed. The control means performs first control for temporarily setting the matching constant based on the received signal strength of the received signal, and sets the matching constant based on a quality index value reflecting the noise. Control
The wireless communication apparatus according to any one of claims 1 to 6. Monitoring means for monitoring at least one of a supply voltage value, a temperature at a predetermined position of the device itself, or a used frequency band used for reception;
The monitoring means has detected that a fluctuation of a predetermined reference value or more has occurred in any item or a plurality of items of the supply voltage value, the temperature of the device itself, or the use frequency band used for the reception. The control means is notified that the change has occurred,
The control means receives the notification and resets a matching constant of impedance matching performed by the matching means based on a quality index reflecting the noise.
The wireless communication apparatus according to any one of claims 1 to 6. Matching means for performing impedance matching on the input received signal;
Control means for controlling a matching constant of impedance matching performed by the matching means based on a quality index reflecting noise of the received signal subjected to the impedance matching;
A matching control circuit comprising: Impedance matching is performed on the input received signal.
Calculating a quality index reflecting the noise of the received signal subjected to the impedance matching;
Controlling a matching constant of the impedance matching based on a quality index reflecting the noise;
Matching control method.

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