WO2012144104A1 - Wireless communication apparatus - Google Patents

Abstract

Provided is a wireless communication apparatus that can suppress the degradation of wireless transmission characteristics during a low-temperature interval, for example, at startup of apparatus. The wireless communication apparatus comprises: an amplifier unit for receiving and amplifying a transmitted signal that is to be transmitted to another apparatus; an attenuator unit that can attenuate the transmitted signal that is to be outputted to the amplifier unit; and a temperature detector unit for detecting the temperature. The attenuator unit attenuates the transmitted signal when the temperature detected by the temperature detector unit is lower than a predetermined value. Also provided is a wireless communication apparatus that can perform a control, for example, attenuation of a transmitted signal with a simple structure. This wireless communication apparatus comprises: a temperature detector unit for outputting a control voltage having a level corresponding to the temperature; a voltage selector unit for selecting either the control voltage outputted by the temperature detector unit or a predetermined voltage; and a wireless transmitter unit for transmitting a wireless signal to another apparatus and for controlling the electric power of the wireless signal on the basis of the voltage selected by the voltage selector unit.

Description

Wireless communication device

The present invention relates to a wireless communication device, and more particularly to a wireless communication device having a function of controlling the power of a transmission wireless signal.

(Background Technology 1)
In a wireless communication apparatus, there is a case where DPD (Digital Pre Distortion) for compensating distortion of a transmission amplifier or the like by correcting transmission data (for example, Lei Ding, “Digital predistortion of power amplifiers for wireless application”, Thesis, Georgia institute of Technology, 2004 (see Non-Patent Document 1).

In this case, in the wireless communication apparatus, for example, the branched transmission wireless signal is subjected to reception processing and converted into a baseband digital signal, thereby measuring the transmission wireless signal and performing distortion compensation based on the measurement result. .

(Background Technology 2)
On the other hand, there is a case where a wireless communication device is required to have a function of reducing the transmission power of a radio signal by a predetermined amount or more from normal time. For example, Non-Patent Document 2 ("WiMAX Forum Mobile RCT", pp.295-296, 2008.9) discloses a base station test method that uses the above function in a WiMAX (Worldwide Interoperability for Microwave Access) system.

Lei Ding, "Digital predistortion of power amplifiers for wireless application", Thesis, Georgia institute of Technology, 2004 "WiMAX Forum Mobile RCT", pp.295-296, 2008.9

(Problem 1)
In the wireless communication device, when the device is started up, the device temperature is low, so that the gain of the transmission amplifier becomes larger than that at room temperature, and the transmission power of the wireless signal may exceed the specified value. In particular, in a high power amplifier for transmitting a radio signal, the output power is large even at room temperature, and this problem becomes remarkable.

In addition, in a wireless communication device that employs DPD, there is a time lag between measurement of a transmission wireless signal and correction of transmission data. Therefore, when the device is started and the device temperature is rising, the device temperature at the time of measurement is increased. There is a high possibility that the apparatus temperature at the time of correction of transmission data is different.

As a result, although the device temperature has risen compared to the time of measurement at this time, distortion compensation is performed based on the results of measurement under past low temperature conditions, and distortion compensation is performed more than necessary. I will be broken. For this reason, much time is spent for convergence of the DPD processing, a state in which the wireless transmission characteristic is deteriorated occurs at the time of starting the apparatus, and the state continues for a long time.

However, Non-Patent Document 1 does not disclose a configuration for solving such a problem.
The present invention has been made to solve the above-described problems, and a first object thereof is to provide a wireless communication device capable of suppressing deterioration of wireless transmission characteristics at low temperatures such as when the device is started up. It is to be.

(Problem 2)
On the other hand, as a configuration for realizing the function in Background Art 2, a method of controlling amplitude information of transmission data that is a digital signal and a method of providing an attenuation circuit for attenuating a transmission signal that is an analog signal are conceivable. .
However, the former method complicates transmission data processing, and the latter method increases the circuit scale.

The present invention has been made to solve the above-described problems, and a second object of the present invention is to provide a wireless communication apparatus capable of performing control such as attenuation of a transmission signal with a simple configuration. is there.

(First means corresponding to the first purpose)
(1) In order to solve the above-described problem, a wireless communication apparatus according to an aspect of the present invention receives an amplifying unit for receiving a transmission signal to be transmitted to another apparatus and outputs the amplified signal to the amplifying part. An attenuation unit capable of attenuating the transmission signal; and a temperature detection unit for detecting a temperature. The attenuation unit transmits the transmission signal when the temperature detected by the temperature detection unit is lower than a predetermined value. Is attenuated.

With such a configuration, it is possible to prevent the output power of the amplifying unit from being saturated at a low temperature, so that it is possible to suppress deterioration in wireless transmission characteristics at a low temperature such as when the apparatus is started up.

(2) Preferably, the wireless communication apparatus further generates communication data to be transmitted to another apparatus, converts the generated communication data into an analog signal and outputs the analog data, and A radio transmission unit for converting the analog signal received from the transmission data processing unit into a radio signal and transmitting the radio signal to another device, wherein the radio transmission unit includes the attenuation unit, the amplification unit, and the amplification unit A branch circuit for branching and outputting the wireless signal amplified by the wireless communication device, wherein the wireless communication device further converts the wireless signal received from the branch circuit into a digital signal to measure the wireless signal. A transmission signal measuring unit for converting, and the transmission data processing unit corrects and corrects the communication data based on the digital signal converted by the transmission signal measuring unit. It converts the communication data into an analog signal and outputs.

In a wireless communication apparatus employing such a DPD, even if the apparatus temperature at the measurement timing differs from the apparatus temperature at the communication data correction timing due to an increase in the apparatus temperature, the convergence point of the distortion correction amount and the distortion correction after the DPD processing are performed. The difference from the quantity state can be reduced. That is, by reducing the time required for convergence of the DPD process at a low temperature such as immediately after the wireless communication device is activated, it is possible to prevent the state in which the wireless transmission characteristics are deteriorated from continuing for a long time from the activation of the device. it can. Furthermore, it is possible to prevent a state in which the wireless transmission characteristics are deteriorated from occurring when the apparatus is started up.

(3) Preferably, the attenuation unit does not attenuate the transmission signal when the temperature is higher than the predetermined value.
In this way, when a certain ambient temperature rises to a predetermined value or more, the output power of the amplifying unit can be appropriately set according to the rise in the device temperature by the configuration that allows the input signal to pass through without being attenuated. The wireless transmission characteristics can be kept good from the low temperature to the normal temperature.

(4) Preferably, the temperature detection unit outputs a control voltage having a level corresponding to the detected temperature, and the attenuation unit outputs the transmission signal based on the control voltage received from the temperature detection unit. The temperature detecting unit includes a voltage dividing circuit that outputs a voltage corresponding to the voltage dividing ratio, the voltage dividing ratio changes according to temperature, and a voltage follower for receiving the output voltage of the voltage dividing circuit. The attenuator receives the voltage received from the voltage follower as the control voltage, the voltage dividing circuit outputs a voltage obtained by dividing the supplied first voltage, and the voltage follower receives the first voltage. A second voltage whose level is lower than the voltage of 1 is supplied as the power supply voltage.
With such a configuration, the maximum value of the control voltage can be limited to a voltage lower in level than the voltage supplied to the voltage dividing circuit.

(5) Preferably, the attenuation unit can select a plurality of types of attenuation, and selects the attenuation based on the temperature detected by the temperature detection unit from the plurality of types of attenuation.
In this way, by adopting a configuration in which the attenuation amount can be set stepwise, the power of the input signal to the amplification unit can be flexibly set according to the difference in temperature at the time of starting the device depending on the installation environment of the device. Can do. That is, it is possible to further reliably suppress the deterioration of the wireless transmission characteristics at low temperatures.

(6) More preferably, the temperature detection unit outputs a control voltage having a level corresponding to the detected temperature, and the attenuation unit compares the control voltage with a first threshold voltage. A first comparator, a second comparator for comparing the control voltage and a second threshold voltage, and a third comparator for comparing the control voltage and a third threshold voltage. An attenuation amount is selected from the plurality of types of attenuation amounts based on the comparison result of the first comparator and the comparison result of the second comparator, and the first comparator and the second comparator are selected. Whether to attenuate the transmission signal is selected based on the comparison result of the third comparator regardless of the comparison result of the second comparator.
With such a configuration, it is possible to set the attenuation amount of the radio signal to the amplifier more flexibly.

The attenuating unit may be configured to include at least a first comparator and a second comparator in addition to the third comparator. That is, the attenuating unit transmits based on the comparison result of the third comparator regardless of the comparison result of the plurality of comparators including the first comparator and the second comparator other than the third comparator. Select whether to attenuate the signal.

(Second means corresponding to the second purpose)
(7) In order to solve the above problem, a wireless communication apparatus according to an aspect of the present invention outputs a temperature detection unit for outputting a control voltage having a level corresponding to a temperature, and is output from the temperature detection unit. A voltage selection unit for selecting one of the control voltage and a predetermined voltage, and a radio signal is transmitted to another device, and the power of the radio signal is controlled based on the voltage selected by the voltage selection unit And a wireless transmission unit.

The temperature detection unit and the wireless transmission unit correspond to, for example, a temperature compensation circuit for continuously and finely controlling the attenuation amount according to the temperature for each season. This temperature compensation circuit is used as a circuit for performing control for reducing the transmission power of the radio signal. Thereby, simplification of an apparatus structure can be achieved. Therefore, control such as attenuation of the transmission signal can be performed with a simple configuration. In addition, the configuration that controls the attenuation amount of the radio signal that is an analog signal enables a quick response to an attenuation instruction or the like.

(8) Preferably, the wireless transmission unit includes an attenuation circuit capable of attenuating a transmission signal to be transmitted to another device and changing an attenuation amount based on the voltage selected by the voltage selection unit.
Here, an amplifier having a variable gain may be used instead of the variable attenuation circuit, and the gain may be controlled according to the temperature. However, when the gain of the amplifier is controlled, it is difficult to optimize the characteristics of the wireless transmission unit. . On the other hand, in this wireless communication device, it is possible to stabilize the characteristics of the wireless transmission unit by using a variable attenuation circuit, and simplifying the device configuration by using this variable attenuation circuit. Can be achieved.

(9) More preferably, the attenuation circuit increases the amount of attenuation when the predetermined voltage is selected by the voltage selection unit compared to when the control voltage is selected.
With such a configuration, it is possible to provide a function of greatly attenuating a radio signal compared to normal operation.

(10) Preferably, the wireless communication device further includes a transmission data processing unit for generating communication data to be transmitted to another device, converting the generated communication data into an analog signal, and outputting the analog signal. The wireless transmission unit includes a branch circuit for converting the analog signal received from the transmission data processing unit into a wireless signal, transmitting the signal to another device, and branching and outputting the wireless signal, The wireless communication apparatus further includes a transmission signal measuring unit for converting the wireless signal received from the branch circuit into a digital signal in order to measure the wireless signal, and the transmission data processing unit includes the transmission signal The communication data is corrected based on the digital signal converted by the measurement unit, and the corrected communication data is converted into an analog signal and output.
Even in a wireless communication apparatus employing such a DPD, control such as attenuation of a transmission signal can be performed with a simple configuration.

(11) Preferably, the voltage selection unit selects the predetermined voltage when receiving an attenuation instruction for attenuating the radio signal.
With such a configuration, in particular, it is possible to perform control for attenuating a transmission signal with a simple configuration in accordance with an attenuation instruction from an upper network or the like.

(12) Preferably, the temperature detection unit outputs a voltage corresponding to the voltage dividing ratio, and receives the output voltage of the voltage dividing circuit that changes the voltage dividing ratio according to temperature and the voltage dividing circuit, and performs the wireless transmission. A voltage follower for outputting the control voltage to the unit, and the voltage selection unit outputs the predetermined voltage from the voltage follower to the wireless transmission unit by stopping the voltage supply to the voltage follower. .
With such a configuration, control such as attenuation of the transmission signal can be performed with a simple configuration without separately providing a circuit for generating a predetermined voltage.

(13) Preferably, the temperature detection unit outputs a voltage corresponding to the voltage dividing ratio, and receives the output voltage of the voltage dividing circuit in which the voltage dividing ratio changes according to the temperature and the wireless transmission upon receiving the output voltage of the voltage dividing circuit. A voltage follower for outputting the control voltage to the unit, and the voltage selection unit outputs the predetermined voltage from the voltage follower to the wireless transmission unit by stopping the voltage supply to the voltage dividing circuit. To do.
With such a configuration, control such as attenuation of the transmission signal can be performed with a simple configuration without separately providing a circuit for generating a predetermined voltage.

According to the present invention (first means), it is possible to suppress deterioration of radio transmission characteristics at a low temperature such as when the apparatus is started up.
According to the present invention (second means), control such as attenuation of a transmission signal can be performed with a simple configuration.

It is a figure which shows the structure of the radio | wireless communications system which concerns on the 1st Embodiment of this invention. It is a figure which shows the structure of the radio | wireless communication apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows the structure of the input power control part in the radio | wireless communication apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows the relationship between each threshold voltage of the attenuation amount determination circuit based on the 1st Embodiment of this invention, and temperature. It is a figure which shows the relationship between the input power and output power of a high power amplifier in the radio | wireless communication apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows notionally the DPD process performed when it is assumed that the radio | wireless communication apparatus which concerns on the 1st Embodiment of this invention is not provided with an input power control part. It is a figure which shows notionally the DPD process in the radio | wireless communication apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows the structure of the input power control part in the radio | wireless communication apparatus which concerns on the 2nd Embodiment of this invention. It is a figure which shows the equivalent circuit of the attenuation circuit in the radio | wireless communication apparatus which concerns on the 2nd Embodiment of this invention. It is a figure which shows an example of the attenuation characteristic with respect to the input voltage of the attenuation circuit in the radio | wireless communication apparatus which concerns on the 2nd Embodiment of this invention. It is a figure which shows an example of the attenuation characteristic with respect to the temperature of the attenuation circuit in the radio | wireless communication apparatus which concerns on the 2nd Embodiment of this invention. It is a figure which shows the structure of the modification of the input power control part in the radio | wireless communication apparatus which concerns on the 2nd Embodiment of this invention.

(First embodiment)
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

FIG. 1 is a diagram showing a configuration of a radio communication system according to an embodiment of the present invention.
With reference to FIG. 1, a wireless communication system 301 includes a wireless base station device (wireless communication device) 101 and a plurality of wireless terminal devices (wireless communication devices) 201.

The radio base station apparatus 101 generates communication data and transmits it to the radio terminal apparatus 201. This communication data includes data received from the upper network. Also, the radio base station apparatus 101 transmits all or part of the communication data received from the radio terminal apparatus 201 to the upper network.

Here, communication data generated in the radio base station apparatus 101 and the radio terminal apparatus 201 are subjected to various signal processing by the radio base station apparatus 101 and the radio terminal apparatus 201, respectively, and finally converted into radio signals. Then, the data is transmitted to the wireless terminal device 201 and the wireless base station device 101, respectively.

FIG. 2 is a diagram showing the configuration of the wireless communication apparatus according to the embodiment of the present invention.
Referring to FIG. 2, radio base station apparatus (radio communication apparatus) 101 includes transmission data processing unit 21, radio transmission unit 22, transmission signal measurement unit 24, and antenna 23. The transmission data processing unit 21 includes a communication data generation unit 1, a data correction unit 2, and a digital / analog converter (DAC) 3. The wireless transmission unit 22 includes a quadrature modulator 4, an input power control unit 5, a transmission amplification unit 25, a coupler (branch circuit) 8, and an oscillator 9.

The transmission amplifier 25 includes a driver amplifier 6 and a high power amplifier 7. The transmission signal measurement unit 24 includes a mixer 11, an LPF 12, an analog / digital converter (ADC) 13, a baseband conversion unit 14, and an oscillator 15. The signal processing unit 16 is, for example, a DSP (Digital Signal Processor), and executes at least the functions of the communication data generation unit 1, the data correction unit 2, and the baseband conversion unit 14.

The transmission data processing unit 21 generates communication data to be transmitted, converts the generated communication data into an analog signal, and outputs the analog signal.
The wireless transmission unit 22 converts the analog signal received from the transmission data processing unit 21 into a wireless signal and transmits the wireless signal to the wireless terminal device 201.
The transmission signal measurement unit 24 converts the radio signal received from the radio transmission unit 22 into an intermediate frequency (IF) signal in the intermediate frequency band, and converts the converted IF signal into a digital signal.

That is, the transmission signal measurement unit 24 uses the measurement local signal to reduce the frequency of the radio signal received from the coupler 8 in order to measure the transmission radio signal transmitted from the radio transmission unit 22 to the radio terminal device 201. Conversion to an IF signal having a center frequency fIF. Then, the transmission signal measuring unit 24 converts the converted IF signal into a digital signal.

More specifically, in the transmission data processing unit 21, the communication data generation unit 1 generates communication data including data received from, for example, an upper network, and an OFDM (OrthogonalgonFrequency Division Multiplex) scheme is generated for the generated communication data. Signal processing such as IFFT (Inverse Fast Fourier 等 Transform) is performed, and a digital signal after this signal processing is output to the data correction unit 2.

The digital / analog converter 3 converts the digital signal received from the communication data generation unit 1 via the data correction unit 2 into an analog signal and outputs the analog signal to the quadrature modulator 4.
The quadrature modulator 4 multiplies the baseband analog signal received from the digital / analog converter 3 and the local signal for transmission received from the oscillator 9, for example, to convert the analog signal received from the digital / analog converter 3 into, for example, The signal is orthogonally modulated to be converted into a radio signal, that is, an RF (Radio Frequency) band signal, and output to the input power control unit 5.

The input power control unit 5 adjusts the power of the radio signal received from the quadrature modulator 4 and outputs it to the transmission amplification unit 25. More specifically, the input power control unit 5 controls the level of the input signal of the transmission amplification unit 25 according to the ambient temperature.
The driver amplifier 6 amplifies the radio signal received from the input power control unit 5 and outputs it to the high power amplifier 7.
The high power amplifier 7 amplifies the radio signal received from the driver amplifier 6 and outputs it to the coupler 8. The gain of the high power amplifier 7 is larger than the gain of the driver amplifier 6.

The coupler 8 branches and outputs the radio signal received from the high power amplifier 7. One radio signal branched by the coupler 8 is transmitted to the radio terminal device 201 via the antenna 23. The other radio signal branched by the coupler 8 is output to the mixer 11 in the transmission signal measurement unit 24. Here, the coupling degree in the coupler 8 is set so that the power of the radio signal output from the coupler 8 to the mixer 11 is considerably smaller than the power of the radio signal output from the coupler 8 to the mixer 11.

The mixer 11 multiplies the radio signal received from the coupler 8 by the measurement local signal received from the oscillator 15 to frequency-convert the radio signal received from the coupler 8 into an IF signal having a center frequency fIF, and the low-pass filter 12. Output to.
The low-pass filter 12 outputs to the digital / analog converter 13 a signal obtained by attenuating a component having a predetermined frequency or higher among the frequency components of the IF signal received from the mixer 11.

The digital / analog converter 13 performs analog / digital conversion on the IF signal received from the low-pass filter 12 and outputs it to the baseband conversion unit 14 in the signal processing unit 16.
The baseband conversion unit 14 performs, for example, orthogonal demodulation on the IF band digital signal received from the digital / analog converter 13 to convert it into a baseband digital signal, and outputs the baseband digital signal to the data correction unit 2. This baseband digital signal indicates the measurement result of the transmission wireless signal output from the wireless transmission unit 22.

The data correction unit 2 corrects the communication data generated by the communication data generation unit 1 based on the digital signal received from the baseband conversion unit 14, and outputs it to the digital / analog converter 3. More specifically, the data correction unit 2 measures, for example, a component outside the modulation band of the transmission radio signal, that is, a side lobe from the measurement result of the transmission radio signal indicated by the digital signal received from the transmission signal measurement unit 24. The communication data is corrected so that the side lobe is below a predetermined level.

FIG. 3 is a diagram showing the configuration of the input power control unit in the wireless communication apparatus according to the embodiment of the present invention.
Referring to FIG. 3, input power control unit 5 includes a temperature detection unit 61 and an attenuation unit 62. The temperature detection unit 61 includes a thermistor 31, resistors 32 and 33, and an operational amplifier 34. The attenuation unit 62 includes an attenuation determination circuit 63 and a variable attenuator 64. The attenuation determination circuit 63 includes operational amplifiers 35 and 37 to 40, EXOR gates 41 to 46, and a switch 51. The operational amplifiers 37 to 40 are included in one IC (Integrated Circuit) 36. The variable attenuator 64 includes attenuation switching circuits 47-50.

The temperature detector 61 outputs a control voltage Vctrl having a level corresponding to the detected temperature.
The attenuation unit 62 can attenuate the radio signal output to the transmission amplification unit 25. That is, the attenuation unit 62 attenuates the radio signal received from the quadrature modulator 4 based on the control voltage Vctrl received from the temperature detection unit 61. For example, the attenuation unit 62 can select a plurality of types of attenuation, and selects the attenuation based on the temperature detected by the temperature detection unit 61 from the plurality of types of attenuation. The attenuating unit 62 can select whether the radio signal received from the quadrature modulator 4 is attenuated and output without being attenuated.

More specifically, in the temperature detection unit 61, the thermistor 31 has a first end connected to a node to which the power supply voltage Vcc is supplied, and a second end. Resistor 32 has a first end connected to the second end of the thermistor 31 and a second end connected to a node to which a ground voltage is supplied.

The operational amplifier 34 has a non-inverting input terminal connected to the second end of the thermistor 31 and the first end of the resistor 32, and an output terminal and an inverting input terminal connected to each other. Resistor 33 has a first end connected to the node supplied with power supply voltage Vcc, and a second end connected to the power supply input terminal of operational amplifier 34.

The temperature detection unit 61 uses, for example, a thermistor whose resistance value varies greatly with temperature. The thermistor 31 is disposed, for example, in the vicinity of the transmission amplifier 25 and detects the ambient temperature of the transmission amplifier 25.
Specifically, in the temperature detection unit 61, a thermistor 31 is used to configure a voltage dividing circuit, and by changing the voltage dividing ratio of the voltage dividing circuit according to a temperature change, the ambient temperature is converted into a voltage value, The control voltage Vctrl having the voltage value is output.

In the attenuation unit 62, the attenuation amount determination circuit 63 sets an attenuation amount corresponding to the current device temperature based on the control voltage Vctrl received from the temperature detection unit 61. In addition, the attenuation amount determination circuit 63 sets the attenuation amount to 0 dB when the apparatus temperature becomes equal to or higher than a predetermined value.
The variable attenuator 64 includes a plurality of attenuators connected in series, attenuates the input signal by the attenuation set by the attenuation determination circuit 63, and outputs the attenuated signal.

In the temperature detector 61, the thermistor 31 is, for example, an NTC (Negative Temperature Coefficient) thermistor, and has a characteristic that the resistance value decreases as the ambient temperature rises. The thermistor 31 may be a PTC (Positive Temperature Coefficient) thermistor whose resistance value increases as the ambient temperature rises. If a PTC thermistor is used, the thermistor 31 and the resistor 32 can be replaced. Good.

Thereby, the voltage dividing ratio of the voltage dividing circuit 30 constituted by the thermistor 31 and the resistor 32 changes according to the temperature. The voltage dividing circuit 30 outputs a divided voltage obtained by dividing the supplied power supply voltage Vcc.
The operational amplifier 34 operates as a voltage follower and outputs the divided voltage received from the voltage dividing circuit 30 as the control voltage Vctrl.

When the resistance value of the thermistor 31 is Rx and the resistance value of the resistor 32 is R, the control voltage Vctrl is expressed by the following equation.
Vctrl = (R / (R + Rx)) × Vcc
That is, when the ambient temperature of the thermistor 31 decreases, the resistance value Rx of the thermistor increases and the control voltage Vctrl decreases. On the other hand, when the ambient temperature of the thermistor 31 increases, the resistance value Rx of the thermistor decreases and the control voltage Vctrl increases.

Note that, for example, a resistor connected in parallel with the thermistor 31 may be provided in order to adjust the gradient of the divided voltage depending on the temperature.
In the temperature detection unit 61, a voltage follower is used as an output circuit for the control voltage Vctrl. Thereby, it is possible to prevent the divided voltage from being lowered due to the influence of the subsequent circuit of the voltage dividing circuit 30.

Further, a voltage lower than the power supply voltage Vcc is supplied to the voltage follower as the power supply voltage.
Specifically, since the voltage follower cannot output a voltage higher than its own power supply voltage, even if the power supply voltage Vcc is 5 V, for example, the resistance value of the resistor 33 is adjusted to adjust the power supply voltage of the voltage follower, for example. By setting the voltage to 3.3V, the maximum value of the control voltage Vctrl can be limited to 3.3V. That is, the maximum value of the control voltage Vctrl can be adjusted by adjusting the resistance value of the resistor 33.

In the attenuation determination circuit 63, the operational amplifier 35 compares the threshold voltage Vthc with the control voltage Vctrl. When the control voltage Vctrl is smaller than the threshold voltage Vthc, the operational amplifier 35 outputs a logic high level signal, and the control voltage Vctrl. When this is larger than the threshold voltage Vthc, a logic low level signal is output.

The operational amplifier 37 compares the threshold voltage Vth1 and the control voltage Vctrl. When the control voltage Vctrl is smaller than the threshold voltage Vth1, the operational amplifier 37 outputs a logic high level signal, and the control voltage Vctrl is higher than the threshold voltage Vth1. If the signal is larger, a logic low level signal is output.

The operational amplifier 38 compares the threshold voltage Vth2 and the control voltage Vctrl. When the control voltage Vctrl is smaller than the threshold voltage Vth2, the operational amplifier 38 outputs a logic high level signal, and the control voltage Vctrl is greater than the threshold voltage Vth2. If the signal is larger, a logic low level signal is output.

The operational amplifier 39 compares the threshold voltage Vth3 with the control voltage Vctrl. When the control voltage Vctrl is smaller than the threshold voltage Vth3, the operational amplifier 39 outputs a logic high level signal, and the control voltage Vctrl is greater than the threshold voltage Vth3. If the signal is larger, a logic low level signal is output.

The operational amplifier 40 compares the threshold voltage Vth4 and the control voltage Vctrl. When the control voltage Vctrl is smaller than the threshold voltage Vth4, the operational amplifier 40 outputs a logic high level signal, and the control voltage Vctrl is higher than the threshold voltage Vth4. If the signal is larger, a logic low level signal is output.

The switch 51 is connected between a node to which the power supply voltage Vcc is supplied and the power input terminal of the IC 36, and switches on and off based on a signal received from the operational amplifier 35. Specifically, the switch 51 is turned on when the signal received from the operational amplifier 35 is at a logic high level, and turned off when the signal is at a logic low level.

The EXOR gate 41 outputs a signal indicating an exclusive OR of the signal received from the operational amplifier 37 and the signal received from the operational amplifier 38.
The EXOR gate 42 outputs a signal indicating an exclusive OR of the signal received from the operational amplifier 37 and the signal received from the operational amplifier 39.
The EXOR gate 43 outputs a signal indicating an exclusive OR of the signal received from the operational amplifier 37 and the signal received from the operational amplifier 40.

EXOR gate 44 outputs a signal indicating an exclusive OR of the signal received from EXOR gate 41 and the signal received from EXOR gate 42.
EXOR gate 45 outputs a signal indicating an exclusive OR of the signal received from EXOR gate 41 and the signal received from EXOR gate 43.
EXOR gate 46 outputs a signal indicating an exclusive OR of the signal received from EXOR gate 44 and the signal received from EXOR gate 45.

In the variable attenuator 64, when the signal received from the operational amplifier 37 is at a logic high level, the attenuation switching circuit 47 attenuates and outputs the radio signal received from the quadrature modulator 4 by 8 dB, and when the signal is at a logic low level. Outputs the radio signal received from the quadrature modulator 4 without being attenuated.

When the signal received from the EXOR gate 41 is at a logic high level, the attenuation switching circuit 48 attenuates and outputs the radio signal received from the attenuation switching circuit 47 by 4 dB. When the signal is at a logic low level, the attenuation switching circuit 48 The radio signal received from 47 is output without being attenuated.

When the signal received from the EXOR gate 44 is at a logic high level, the attenuation switching circuit 49 attenuates and outputs the radio signal received from the attenuation switching circuit 48 by 2 dB. When the signal is at a logic low level, the attenuation switching circuit 49 The radio signal received from 48 is output without being attenuated.

The attenuation switching circuit 50 attenuates the radio signal received from the attenuation switching circuit 49 by 1 dB and outputs it to the driver amplifier 6 when the signal received from the EXOR gate 46 is at a logic high level, and outputs the signal to the driver amplifier 6 when the signal is at a logic low level. The radio signal received from the attenuation switching circuit 49 is output to the driver amplifier 6 without being attenuated.

FIG. 4 is a diagram showing a relationship between each threshold voltage and temperature of the attenuation determination circuit according to the embodiment of the present invention.
Referring to FIG. 4, in attenuation amount determination circuit 63, threshold voltages Vth1, Vth2, Vth3 and Vth4 correspond to control voltage Vctrl at temperatures t1, t2, t3 and t4, respectively. The temperatures t1, t2, t3 and t4 are, for example, −30 ° C., −20 ° C., −10 ° C. and 0 ° C. Further, the maximum value VLM of the control voltage Vctrl corresponds to the power supply voltage of the operational amplifier 34.

The attenuator 62 selects an attenuation amount from a plurality of types of attenuation amounts based on the comparison results of the operational amplifiers 37 to 40.
Specifically, when the temperature detected by the temperature detection unit 61 is lower than t1, logic high level signals are output from the operational amplifiers 37 to 40. Then, the attenuation switching circuit 47 receives the logic high level signal and attenuates the input signal by 8 dB, and the attenuation switching circuits 48 to 50 receive the logic low level signal and output the input signal without attenuation. That is, the attenuation amount of the variable attenuation circuit 64 is 8 dB.

When the temperature detected by the temperature detector 61 is higher than t1 and lower than t2, a logic low level signal is output from the operational amplifier 37, and a logic high level signal is output from the operational amplifiers 38 to 40. Then, the attenuation switching circuit 48 receives the logic high level signal and attenuates the input signal by 4 dB, and the attenuation switching circuits 47, 49 and 50 receive the logic low level signal and output the input signal without attenuation. . That is, the attenuation amount of the variable attenuation circuit 64 is 4 dB.

Further, when the temperature detected by the temperature detector 61 is higher than t2 and lower than t3, the operational amplifiers 37 and 38 output logic low level signals, and the operational amplifiers 39 and 40 output logic high level signals. Then, the attenuation switching circuit 49 receives the logic high level signal and attenuates the input signal by 2 dB, and the attenuation switching circuits 47, 48, and 50 receive the logic low level signal and output the input signal without attenuation. . That is, the attenuation amount of the variable attenuation circuit 64 is 2 dB.

Further, when the temperature detected by the temperature detector 61 is higher than t3 and lower than t4, a logic low level signal is output from the operational amplifiers 37 to 39, and a logic high level signal is output from the operational amplifier 40. Then, the attenuation switching circuit 50 receives the logic high level signal and attenuates the input signal by 1 dB, and the attenuation switching circuits 47 to 49 receive the logic low level signal and output the input signal without attenuation. That is, the attenuation amount of the variable attenuation circuit 64 is 1 dB.

Further, when the temperature detected by the temperature detector 61 is higher than t4, a logic low level signal is output from the operational amplifiers 37 to 40. Then, the attenuation switching circuits 47 to 50 receive the logic low level signal and output the input signal without attenuation. That is, the attenuation amount of the variable attenuation circuit 64 is 0 dB.

Further, the attenuating unit 62 selects whether or not to attenuate the transmission signal based on the comparison result of the operational amplifier 35 regardless of the comparison result of the operational amplifiers 37 to 40.

More specifically, the level of the threshold voltage Vthc received by the operational amplifier 35 can be changed. When the temperature detected by the temperature detector 61 becomes higher than the temperature tc corresponding to the threshold voltage Vthc, that is, when the control voltage Vctrl becomes higher than the threshold voltage Vthc, the operational amplifier 35 outputs a logic low level signal to the switch 51.

The switch 51 receives a logic low level signal from the operational amplifier 35 and is turned off. As a result, the power supply voltage Vcc is not supplied to the IC 36, and the output signals of the operational amplifiers 37 to 40 become a logic low level. As a result, the attenuation amount of the variable attenuation circuit 64 becomes 0 dB.

For example, consider a case where the threshold voltage Vthc is set to a level greater than the threshold voltage Vth3 and smaller than the threshold voltage Vth4 as shown in FIG. In this case, when the apparatus temperature rises after the attenuation amount determination circuit 63 sets the attenuation amount to 2 dB in a state where the apparatus temperature is increasing, the attenuation amount determination circuit 63 skips the setting of 1 dB and sets the attenuation amount to 0 dB. It is possible to control the amount of attenuation such as setting to.

The attenuation determination circuit 63 may be configured to perform a logical operation that can synthesize the attenuation in each attenuation switching circuit. Further, the attenuation amount in each attenuation switching circuit may be appropriately set according to the characteristics of the driver amplifier 6 and the high power amplifier 7. Further, the variable attenuation circuit 64 may have a configuration in which only one attenuation switching circuit is provided, or may have a configuration in which the attenuation amount can be set by two types of 0 dB and other attenuation amounts.

However, by adopting a configuration in which the amount of attenuation can be set stepwise like the variable attenuation circuit 64, the input signal to the transmission amplifying unit 25 can be changed according to the difference in the temperature at the time of starting the device depending on the installation environment of the device. Electric power can be set flexibly. Thereby, early convergence of the DPD processing can be achieved, and deterioration of the wireless transmission characteristics at a low temperature can be further reliably suppressed.

FIG. 5 is a diagram showing the relationship between the input power and the output power of the high power amplifier in the wireless communication apparatus according to the embodiment of the present invention.
Referring to FIG. 5, graph GA shows the output power of high power amplifier 7 at room temperature when wireless communication apparatus 101 is sufficiently warm. At room temperature, since the output power is saturated when the input power of the high power amplifier 7 is PA, the input power of the high power amplifier 7 is set to P1, for example, smaller than PA.

Graph GB shows the output power of the high power amplifier 7 at a low temperature immediately after the wireless communication device 101 is started. At low temperatures, the gain of the high power amplifier 7 is higher than that at room temperature, so that the output power is saturated when the input power of the high power amplifier 7 is PB smaller than PA and P1.

For this reason, when the input power of the high power amplifier 7 is set to P1 in the same way as at room temperature, the output power of the high power amplifier 7 is saturated. Further, the gain of the driver amplifier 6 also increases at a low temperature as compared with that at room temperature, so that the input power of the high power amplifier 7 becomes larger than that at room temperature.

Therefore, the attenuation unit 62 in the input power control unit 5 attenuates the transmission signal, that is, the radio signal received from the quadrature modulator 4 when the temperature detected by the temperature detection unit 61 is lower than a predetermined value.
That is, the input power control unit 5 performs control to lower the input power of the high power amplifier 7 at a low temperature. For example, the input power control unit 5 sets the input power of the high power amplifier 7 to P2 smaller than PB.
As a result, it is possible to prevent the output power of the high power amplifier 7 from being saturated at a low temperature, and thus it is possible to prevent deterioration of the radio transmission characteristics at a low temperature.

The attenuation unit 62 does not attenuate the transmission signal when the temperature is higher than the predetermined value.
That is, when the temperature of the wireless communication device 101 rises to some extent, the input power control unit 5 performs control to restore the input power of the high power amplifier 7 to the original. Specifically, the input power control unit 5 returns the setting of the input power of the high power amplifier 7 from P2 to P1.

Thereby, since the output power of the high power amplifier 7 can be appropriately set according to the rise of the device temperature, the wireless transmission characteristics can be kept good from the low temperature to the normal temperature.

FIG. 6 is a diagram conceptually illustrating a DPD process performed when it is assumed that the wireless communication apparatus according to the embodiment of the present invention does not include an input power control unit.
Referring to FIG. 6, the measurement timing of the transmission radio signal that is the source of performing DPD processing immediately after activation of radio communication apparatus 101 is t1, and the timing at which communication data is corrected by the DPD processing is t2.

As described above, in the wireless communication apparatus 101 adopting DPD, there is a time lag between the measurement of the transmission wireless signal and the correction of the communication data. When the wireless communication device 101 is activated, the device temperature rises with time, so the device temperature at the measurement timing t1 is different from the device temperature at the communication data correction timing t2.

For this reason, at the correction timing t2, the distortion compensation is performed on the basis of the result measured under the past low temperature conditions than the correction timing t2, although the apparatus temperature has increased compared to the measurement timing t1. Therefore, distortion compensation is performed more than necessary. Specifically, the state of the distortion correction amount after the DPD process exceeds the convergence point of the distortion correction amount by D1.

For this reason, when the wireless communication apparatus 101 does not include the input power control unit 5, a lot of time is spent for convergence of the DPD processing, and a state in which the wireless transmission characteristic is deteriorated occurs at the time of starting the apparatus. That state continues for a long time. For example, the level of the transmission radio signal leaking to the adjacent channel increases.

FIG. 7 is a diagram conceptually showing DPD processing in the wireless communication apparatus according to the embodiment of the present invention.
Referring to FIG. 7, in wireless communication apparatus 101, input power control unit 5 performs control to reduce the input power of power amplifier 7 at a low temperature immediately after wireless communication apparatus 101 is activated.

Thereby, the state of the distortion correction amount at the measurement timing t1 becomes closer to the convergence point than in the case shown in FIG. For this reason, even if the apparatus temperature at the measurement timing t1 differs from the apparatus temperature at the communication data correction timing t2 due to an increase in the apparatus temperature, the difference between the convergence point of the distortion correction amount and the state of the distortion correction amount after DPD processing is calculated. It can be suppressed to D2 smaller than D1.

That is, at a low temperature such as immediately after the wireless communication device 101 is started, the time required for convergence of the DPD processing can be shortened, and the state in which the wireless transmission characteristic is deteriorated can be prevented from continuing for a long time from the time of starting the device. Furthermore, it is possible to prevent a state in which the wireless transmission characteristic is deteriorated from occurring at the time of starting up the apparatus.

By the way, in the wireless communication device, when the device is started up, the device temperature is low, so that the gain of the transmission amplifier becomes larger than that at room temperature, and the transmission power of the wireless signal may exceed the specified value.
On the other hand, in the radio communication apparatus according to the embodiment of the present invention, the attenuation unit 62 can attenuate the transmission signal output to the transmission amplification unit 25, and the temperature detected by the temperature detection unit 61 is predetermined. If it is lower than the value, the transmission signal is attenuated. Specifically, the value of the attenuator provided in the previous stage of the transmission amplification unit 25 is automatically switched according to the ambient temperature.

With such a configuration, it is possible to prevent the output power of the transmission amplification unit 25 from being saturated at a low temperature, so that it is possible to suppress deterioration in wireless transmission characteristics at a low temperature such as when the apparatus is started up.

In the wireless communication apparatus according to the embodiment of the present invention, the transmission data processing unit 21 generates communication data to be transmitted to another apparatus, converts the generated communication data into an analog signal, and outputs the analog signal. The wireless transmission unit 22 converts the analog signal received from the transmission data processing unit 21 into a wireless signal and transmits it to another device. The coupler 8 branches and outputs the radio signal amplified by the transmission amplifier 25. The transmission signal measurement unit 24 converts the radio signal received from the coupler 8 into a digital signal in order to measure the radio signal. The transmission data processing unit 21 corrects the communication data based on the digital signal converted by the transmission signal measurement unit 24, converts the corrected communication data into an analog signal, and outputs the analog signal.

In a wireless communication apparatus employing such a DPD, even if the apparatus temperature at the measurement timing differs from the apparatus temperature at the communication data correction timing due to an increase in the apparatus temperature, the convergence point of the distortion correction amount and the distortion correction after the DPD processing are performed. The difference from the quantity state can be reduced. That is, by reducing the time required for convergence of the DPD process at a low temperature such as immediately after the wireless communication device is activated, it is possible to prevent the state in which the wireless transmission characteristics are deteriorated from continuing for a long time from the activation of the device. it can. Furthermore, it is possible to prevent a state in which the wireless transmission characteristics are deteriorated from occurring when the apparatus is started up.

In the wireless communication apparatus according to the embodiment of the present invention, attenuation unit 62 does not attenuate the transmission signal when the temperature is higher than the predetermined value.
As described above, when the ambient temperature rises to a predetermined value or higher, the output power of the transmission amplifying unit 25 can be appropriately set according to the rise of the device temperature by the configuration in which the input signal is passed through without being attenuated. The wireless transmission characteristics can be kept good from low temperature to normal temperature.

In the wireless communication apparatus according to the embodiment of the present invention, in the temperature detection unit 61, the voltage dividing circuit 30 outputs a voltage corresponding to the voltage dividing ratio, and the voltage dividing ratio changes according to the temperature. The voltage follower receives the output voltage of the voltage dividing circuit 30. Attenuating unit 62 receives the voltage received from the voltage follower as control voltage Vctrl. The voltage dividing circuit 30 outputs a voltage obtained by dividing the supplied power supply voltage Vcc. A voltage lower than the power supply voltage Vcc is supplied to the voltage follower as the power supply voltage.

With such a configuration, the maximum value of the control voltage Vctrl can be limited to a voltage having a level lower than the voltage supplied to the voltage dividing circuit 30.

Further, in the wireless communication apparatus according to the embodiment of the present invention, the attenuation unit 62 can select a plurality of types of attenuation, and the temperature detected by the temperature detection unit 61 is selected from the plurality of types of attenuation. Select the amount of attenuation based on this.

In this way, by adopting a configuration in which the attenuation amount can be set stepwise, the power of the input signal to the transmission amplifier 25 can be flexibly set according to the difference in the temperature at the time of starting the device depending on the installation environment of the device. can do. That is, it is possible to further reliably suppress the deterioration of the wireless transmission characteristics at low temperatures.

In the wireless communication apparatus according to the embodiment of the present invention, the attenuation unit 62 selects an attenuation amount from a plurality of types of attenuation amounts based on the comparison results of the operational amplifiers 37 to 40. The attenuating unit 62 selects whether or not to attenuate the radio signal received from the coupler 8 based on the comparison result of the operational amplifier 35, regardless of the comparison result of the operational amplifiers 37 to 40.

With such a configuration, the attenuation amount of the radio signal to the transmission amplifier 25 can be set more flexibly.

In the wireless communication device according to the embodiment of the present invention, the attenuation amount of the attenuation unit 62 can be set to 0 dB. However, it may not be set to 0 dB. That is, the attenuation unit 62 may be configured to be able to set the attenuation amount large when the temperature is low and to set the attenuation amount small when the temperature is high.

In the wireless communication apparatus according to the embodiment of the present invention, the attenuating unit 62 is configured to control the power of the wireless signal received from the quadrature modulator 4, but is not limited thereto. The power control target may be a baseband signal or an IF signal.

Further, although the wireless communication apparatus according to the embodiment of the present invention is configured to perform DPD processing, the present invention is not limited to this. Even in a configuration that does not perform DPD processing, it is possible to suppress the distortion of the output signal of the high power amplifier 7 and reduce the spurious of the transmission radio signal at a low temperature such as immediately after the wireless communication device 101 is activated. It is done. That is, it is possible to prevent the state in which the wireless transmission characteristics are deteriorated from continuing for a long time from the time of starting the apparatus, and it is also possible to prevent the state in which the wireless transmission characteristics are deteriorated from occurring at the time of starting the apparatus. .

In the wireless communication device according to the embodiment of the present invention, the power supply voltage of the operational amplifier 34 is made lower than the power supply voltage Vcc by adjusting the resistance value of the resistor 33, and the maximum value of the control voltage Vctrl is limited. However, the present invention is not limited to this. By setting the threshold voltage Vthc of the operational amplifier 35 to be larger than the threshold voltage Vth4 and smaller than the power supply voltage Vcc, an equivalent function can be realized. In this case, the resistor 33 is unnecessary.

In the wireless communication device according to the embodiment of the present invention, the digital / analog converter 13 is configured to perform IF sampling. However, the present invention is not limited to this. A configuration in which the transmission radio signal is down-converted to a baseband signal in the preceding circuit of the digital / analog converter 13 and the digital / analog converter 13 samples the baseband signal may be employed.

In the embodiment of the present invention, the example in which the wireless base station apparatus 101 suppresses the deterioration of the wireless transmission characteristics at the low temperature has been described. However, the present invention is applicable to other wireless communication apparatuses such as the wireless terminal apparatus 201. Applicable.
In addition, the wireless communication apparatus according to the embodiment of the present invention can be applied to various wireless communication systems such as the TDD system and the FDD system.

In addition, it should be thought that the said embodiment is an illustration and restrictive at no points. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

(Second Embodiment)
FIG. 8 is a diagram showing a configuration of the input power control unit in the wireless communication apparatus according to the embodiment of the present invention. The overall configuration shown in FIGS. 1 and 2 is the same as that of the first embodiment, and thus the description thereof is omitted here.

Referring to FIG. 8, input power control unit 5 includes a temperature detection unit 151, a voltage selection unit 152, an attenuation circuit 153, and capacitors 147 and 148. The temperature detection unit 151 includes a thermistor 131, a resistor 132, and an operational amplifier 134. Voltage selection unit 152 includes a switch 135 and an OR gate 136. The attenuation circuit 153 includes PIN (p-intrinsic-n) diodes 137 to 140, resistors 141 to 144, capacitors 145, 146, and 149, and a resistor 150.

The temperature detection unit 151 outputs a control voltage Vctrl having a level corresponding to the temperature. More specifically, in the temperature detection unit 151, the thermistor 131 has a first end connected to a node to which the power supply voltage Vcc is supplied, and a second end. Resistor 132 has a first end connected to the second end of the thermistor 131 and a second end connected to a node to which a ground voltage is supplied.

The operational amplifier 134 has a non-inverting input terminal connected to the second end of the thermistor 131 and the first end of the resistor 132, and an output terminal and an inverting input terminal connected to each other.
The temperature detection unit 151 uses, for example, a thermistor whose resistance value changes greatly with respect to temperature. Specifically, the temperature detection unit 151 configures a voltage dividing circuit using the thermistor 131, changes the voltage dividing ratio of the voltage dividing circuit according to a temperature change, converts the ambient temperature into a voltage value, The control voltage Vctrl having the voltage value is output.

More specifically, in the temperature detector 151, the thermistor 131 is an NTC (Negative Temperature Coefficient) thermistor, for example, and has a characteristic that the resistance value decreases as the ambient temperature increases. The thermistor 131 may be a PTC (Positive Temperature Coefficient) thermistor whose resistance value increases as the ambient temperature rises. If a PTC thermistor is used, the thermistor 131 and the resistor 132 may be replaced. Good.

Thereby, the voltage dividing ratio of the voltage dividing circuit 130 constituted by the thermistor 131 and the resistor 132 changes according to the temperature. The voltage dividing circuit 130 outputs a divided voltage obtained by dividing the supplied power supply voltage Vcc.
The operational amplifier 134 operates as a voltage follower, and outputs the divided voltage received from the voltage dividing circuit 130 as the control voltage Vctrl.

When the resistance value of the thermistor 131 is Rx and the resistance value of the resistor 132 is R, the control voltage Vctrl is expressed by the following equation.
Vctrl = (R / (R + Rx)) × Vcc
That is, when the ambient temperature of the thermistor 131 decreases, the resistance value Rx of the thermistor increases and the control voltage Vctrl decreases. On the other hand, when the ambient temperature of the thermistor 131 increases, the resistance value Rx of the thermistor decreases and the control voltage Vctrl increases.

In order to adjust the gradient of the divided voltage depending on the temperature, for example, a resistor connected in parallel with the thermistor 131 may be provided.
The temperature detector 151 uses a voltage follower as an output circuit for the control voltage Vctrl. Thereby, it is possible to prevent the divided voltage from being lowered due to the influence of the subsequent circuit of the voltage dividing circuit 130.

The attenuation circuit 153 can attenuate a transmission signal to be transmitted to another device and change the attenuation amount based on the voltage selected by the voltage selection unit 152. More specifically, the attenuation circuit 153 attenuates the radio signal received from the quadrature modulator 4 via the capacitor 147 and outputs the attenuated signal to the driver amplifier 6 via the capacitor 148. The attenuation amount of attenuation circuit 153 changes based on control voltage Vctrl received from temperature detection unit 151.

In the attenuation circuit 153, the PIN diode 138 has an anode connected to the resistor 150 and a cathode connected to the capacitor 147. PIN diode 139 has an anode connected to resistor 150 and a cathode connected to capacitor 148. PIN diode 137 has a cathode connected to the cathode of PIN diode 138 and an anode. PIN diode 140 has a cathode connected to the cathode of PIN diode 139 and an anode.

The resistor 142 has a first end connected to the anode of the PIN diode 137 and a second end connected to a node supplied with the voltage V +. Resistor 143 has a first end connected to the anode of PIN diode 140 and a second end connected to a node to which voltage V + is supplied. Capacitor 145 has a first end connected to the first end of resistor 142 and a second end connected to a node to which a ground voltage is supplied. Capacitor 146 has a first end connected to the first end of resistor 143, and a second end connected to a node supplied with the ground voltage.

The resistor 141 has a first end connected to the cathode of the PIN diode 138 and a second end connected to a node to which a ground voltage is supplied. Resistor 144 has a first end connected to the cathode of PIN diode 139 and a second end connected to a node to which a ground voltage is supplied.

FIG. 9 is a diagram showing an equivalent circuit of the attenuation circuit in the wireless communication apparatus according to the embodiment of the present invention.
Referring to FIG. 9, this equivalent circuit includes variable resistors RV1-RV3 and resistors R1, R2. That is, the attenuation circuit 153 includes a π-type attenuator, and each PIN diode corresponds to the variable resistors RV1 to RV3.

The variable resistor RV1 has a first end connected to the output end of the quadrature modulator 4 via the capacitor 147, and a second end connected to the input end of the driver amplifier 6 via the capacitor 148. Each of resistor R1 and variable resistor RV2 has a first end connected to the first end of variable resistor RV1, and a second end connected to a node to which a ground voltage is supplied. Each of resistor R2 and variable resistor RV3 has a first end connected to the second end of variable resistor RV1, and a second end connected to a node to which a ground voltage is supplied.

FIG. 10 is a diagram illustrating an example of the attenuation characteristic with respect to the input voltage of the attenuation circuit in the wireless communication apparatus according to the embodiment of the present invention.
Referring to FIG. 10, in attenuation circuit 153, when control voltage Vctrl, which is an input voltage, increases, the PIN diode decreases in resistance value and functions as a variable resistor.

In normal operation, a certain level of voltage is applied to the attenuation circuit 153 as the control voltage Vctrl, and the attenuation circuit 153 operates as a variable attenuator.
That is, when the device temperature is high and the level of the control voltage Vctrl is large, the resistance values of the PIN diodes 138 and 139 are decreased, and the resistance values of the PIN diodes 137 and 140 are increased, so that the attenuation amount of the attenuation circuit 153 is increased. Get smaller.

On the other hand, when the device temperature is low and the level of the control voltage Vctrl is small, the resistance values of the PIN diodes 138 and 139 are increased, and the resistance values of the PIN diodes 137 and 140 are decreased, so that the attenuation amount of the attenuation circuit 153 is reduced. growing.

As described above, the radio base station apparatus 101 can continuously control the power of the input signal to the transmission amplifying unit 25 by continuously controlling the control voltage Vctrl applied to the PIN diode according to the temperature. The output power of the transmission amplifier 25 can be appropriately controlled according to the device temperature.

Next, the operation when the wireless communication apparatus according to the embodiment of the present invention performs control to attenuate the transmission signal will be described.
Referring to FIG. 8 again, voltage selection unit 152 selects one of control voltage Vctrl output from temperature detection unit 151 and a predetermined voltage. For example, the voltage selection unit 152 selects a predetermined voltage when receiving an attenuation instruction for attenuating the wireless transmission signal.

The wireless transmission unit 22 controls the power of a wireless signal to be transmitted to another device based on the voltage selected by the voltage selection unit 152.
Specifically, the voltage selection unit 152 outputs a predetermined voltage from the voltage follower to the attenuation circuit 153 by stopping the voltage supply to the voltage follower in the temperature detection unit 151.

More specifically, the control unit 161 receives an attenuation instruction from the upper network and outputs a logic high level signal to the OR gate 136.
The temperature sensor 162 detects the temperature in the wireless communication apparatus 101 and outputs a logic high level signal to the OR gate 136 when a temperature abnormality occurs.
OR gate 136 outputs a signal indicating the logical sum of the signal received from control unit 161 and the signal received from temperature sensor 162.

Switch 135 is connected between a node to which power supply voltage Vcc is supplied and the power input terminal of operational amplifier 134, and switches on and off based on a signal received from OR gate 136. Specifically, the switch 135 is turned off when the signal received from the OR gate 136 is at a logic high level, and turned on when the signal is at a logic low level. That is, when a logic high level signal is output from the control unit 161 or the temperature sensor 162, the power supply to the operational amplifier 134 is stopped by turning off the switch 135.

When power supply to the operational amplifier 134 is stopped, the operational amplifier 134 outputs a ground voltage, for example. This ground voltage corresponds to the predetermined voltage.
The attenuation circuit 153 increases the amount of attenuation when the predetermined voltage is selected by the voltage selection unit 152 compared to when the control voltage Vctrl is selected. Specifically, when receiving the ground voltage from the operational amplifier 134, the attenuation circuit 153 has the maximum attenuation, for example, 10 dB or more.

FIG. 11 is a diagram illustrating an example of attenuation characteristics with respect to temperature of the attenuation circuit in the wireless communication apparatus according to the embodiment of the present invention.
Referring to FIG. 11, during normal operation, voltage selection unit 152 selects control voltage Vctrl indicating the temperature detection result by temperature detection unit 151 and outputs the control voltage Vctrl from temperature detection unit 151 to attenuation circuit 153. In this case, the attenuation amount of the attenuation circuit 153 is continuously reduced as the temperature rises (graph G1).

On the other hand, the voltage selection unit 152 selects the ground voltage by stopping the power supply to the operational amplifier 134 when receiving an attenuation instruction from the upper network or when any abnormality occurs in the wireless communication apparatus 101, and selects the ground voltage. The signal is output from the detection unit 151 to the attenuation circuit 153. In this case, the attenuation amount of the attenuation circuit 153 becomes the maximum regardless of the apparatus temperature (graph G2).

FIG. 12 is a diagram showing a configuration of a modified example of the input power control unit in the wireless communication apparatus according to the embodiment of the present invention.
Referring to FIG. 12, in this modification, voltage selection unit 152 stops the voltage supply to voltage dividing circuit 130 in temperature detection unit 151, so that voltage follower in temperature detection unit 151 is supplied to attenuation circuit 153. Output voltage.

More specifically, switch 135 is connected between a node supplied with power supply voltage Vcc and thermistor 131 and switches on and off based on a signal received from OR gate 136. Specifically, the switch 135 is turned off when the signal received from the OR gate 136 is at a logic high level, and turned on when the signal is at a logic low level. That is, when a logic high level signal is output from the control unit 161 or the temperature sensor 162, the switch 135 is turned off to supply power to the voltage dividing circuit 130 including the thermistor 131 and the resistor 132. Stopped.

When the power supply to the voltage dividing circuit 130 is stopped, the operational amplifier 134 outputs a ground voltage, for example.
When the attenuation circuit 153 receives the ground voltage from the operational amplifier 134, the attenuation amount becomes maximum, for example, 10 dB or more.

By the way, as a configuration for realizing the function of reducing the transmission power of a radio signal by a predetermined amount or more from the normal time, a method for controlling amplitude information of transmission data that is a digital signal and a transmission signal that is an analog signal are attenuated. A method of providing an attenuation circuit for this purpose is conceivable. However, the former method complicates transmission data processing, and the latter method increases the circuit scale.

In addition, as an example of a method for controlling amplitude information of transmission data that is a digital signal, in a configuration in which the amplitude of digital I and Q signals is reduced, DPD processing for adjusting the amplitude of I and Q signals becomes complicated. End up.

On the other hand, in the wireless communication device according to the embodiment of the present invention, the temperature detection unit 151 outputs a control voltage Vctrl having a level corresponding to the temperature. The voltage selection unit 152 selects either the control voltage Vctrl output from the temperature detection unit 151 or a predetermined voltage. Then, the wireless transmission unit 22 transmits a wireless signal to another device, and controls the power of the wireless signal based on the voltage selected by the voltage selection unit 152.

The temperature detection unit 151 and the attenuation circuit 153 are temperature compensation circuits for continuously finely controlling the attenuation amount according to the temperature for each season, for example. In the wireless communication apparatus according to the embodiment of the present invention, this temperature compensation circuit is used as a circuit for performing control for reducing the transmission power of the wireless signal. Thereby, simplification of an apparatus structure can be achieved.

Therefore, in the wireless communication apparatus according to the embodiment of the present invention, control such as attenuation of a transmission signal can be performed with a simple configuration.
In addition, the configuration that controls the attenuation amount of the radio signal that is an analog signal enables a quick response to an attenuation instruction or the like.

In the wireless communication apparatus according to the embodiment of the present invention, the attenuation circuit 153 can attenuate the transmission signal to be transmitted to another apparatus and change the attenuation based on the voltage selected by the voltage selection unit 152. It is.

Here, an amplifier having a variable gain may be used instead of the variable attenuation circuit, and the gain may be controlled according to the temperature. However, when the gain of the amplifier is controlled, it is difficult to optimize the characteristics of the wireless transmission unit. . On the other hand, in the wireless communication apparatus according to the embodiment of the present invention, the configuration using the variable attenuation circuit can stabilize the characteristics in the wireless transmission unit, and can utilize this variable attenuation circuit. As a result, the apparatus configuration can be simplified.

In the wireless communication apparatus according to the embodiment of the present invention, the attenuation circuit 153 increases the attenuation when the predetermined voltage is selected by the voltage selection unit 152 as compared with the case where the control voltage Vctrl is selected. To do.
With such a configuration, it is possible to provide a function of greatly attenuating a radio signal compared to normal operation.

In the wireless communication apparatus according to the embodiment of the present invention, the transmission data processing unit 21 generates communication data to be transmitted to another apparatus, converts the generated communication data into an analog signal, and outputs the analog signal. The wireless transmission unit 22 includes a coupler 8 that converts the analog signal received from the transmission data processing unit 21 into a wireless signal, transmits the signal to another device, and branches and outputs the wireless signal. The transmission signal measurement unit 24 converts the radio signal received from the coupler 8 into a digital signal in order to measure the radio signal. The transmission data processing unit 21 corrects the communication data based on the digital signal converted by the transmission signal measurement unit 24, converts the corrected communication data into an analog signal, and outputs the analog signal.
Even in a wireless communication apparatus employing such a DPD, control such as attenuation of a transmission signal can be performed with a simple configuration.

Further, in the wireless communication apparatus according to the embodiment of the present invention, voltage selection unit 152 selects a predetermined voltage when receiving an attenuation instruction for attenuating a wireless signal.
With such a configuration, in particular, it is possible to perform control for attenuating a transmission signal with a simple configuration in accordance with an attenuation instruction from an upper network or the like.

In the wireless communication apparatus according to the embodiment of the present invention, voltage selection unit 152 outputs a predetermined voltage from voltage follower to attenuation circuit 153 by stopping the voltage supply to the voltage follower.
With such a configuration, control such as attenuation of the transmission signal can be performed with a simple configuration without separately providing a circuit for generating a predetermined voltage.

Further, in the wireless communication apparatus according to the embodiment of the present invention, voltage selection section 152 outputs a predetermined voltage from voltage follower to attenuation circuit 153 by stopping voltage supply to voltage dividing circuit 130.
With such a configuration, control such as attenuation of the transmission signal can be performed with a simple configuration without separately providing a circuit for generating a predetermined voltage.

In the wireless communication apparatus according to the embodiment of the present invention, the voltage selection unit 152 is configured to select either the control voltage Vctrl output from the temperature detection unit 151 or the ground voltage. However, the present invention is not limited to this. The voltage is not limited to the ground voltage, and may be any voltage that increases the attenuation amount of the attenuation circuit 153.

In addition, although the circuit using the PIN diode is illustrated as the variable attenuation circuit 153 in the wireless communication apparatus according to the embodiment of the present invention, any circuit may be used as long as the input signal can be attenuated. .

Further, although the wireless communication apparatus according to the embodiment of the present invention is configured to perform DPD processing, the present invention is not limited to this. A configuration in which DPD processing is not performed may be used.
In the wireless communication apparatus according to the embodiment of the present invention, the power of the wireless signal output from the quadrature modulator 4 is controlled based on an attenuation instruction or the like. However, the present invention is not limited to this. . The power control target may be a baseband signal or an IF signal.

In the wireless communication device according to the embodiment of the present invention, the digital / analog converter 13 is configured to perform IF sampling. However, the present invention is not limited to this. A configuration in which the transmission radio signal is down-converted to a baseband signal in the preceding circuit of the digital / analog converter 13 and the digital / analog converter 13 samples the baseband signal may be employed.

In the embodiment of the present invention, the example in which the configuration for performing the control for attenuating the transmission signal in the radio base station apparatus 101 is simplified has been described. However, the present invention is not limited to the radio terminal apparatus 201 or the like. The present invention can also be applied to a wireless communication device.
In addition, the wireless communication apparatus according to the embodiment of the present invention can be applied to various wireless communication systems such as the TDD system and the FDD system.

In addition, it should be thought that the said embodiment is an illustration and restrictive at no points. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 Communication Data Generation Unit 2 Data Correction Unit 3 Digital / Analog Converter (DAC)
4 Quadrature modulator 5 Input power controller 6 Driver amplifier 7 High power amplifier 8 Coupler (branch circuit)
9 Oscillator 11 Mixer 12 LPF
13 Analog / Digital Converter (ADC)
DESCRIPTION OF SYMBOLS 14 Baseband conversion part 15 Oscillator 16 Signal processing part 21 Transmission data processing part 22 Wireless transmission part 23 Antenna 24 Transmission signal measurement part 25 Transmission amplification part 31 Thermistor 32, 33 Resistance 34, 35, 37-40 Operational amplifier 41-46 EXOR gate 47 to 50 Attenuation switching circuit 51 Switch 61 Temperature detection unit 62 Attenuation unit 63 Attenuation amount determination circuit 64 Variable attenuator 131 Thermistor 132 Resistance 134 Operational amplifier 135 Switch 136 OR gate 147 to 149 Capacitor 151 Temperature detection unit 152 Voltage selection unit 153 Attenuation circuit 101 wireless base station device (wireless communication device)
201 wireless terminal device (wireless communication device)
301 Wireless communication system RV1 to RV3 Variable resistance R1, R2 resistance

Claims (13)

An amplification unit for receiving and amplifying a transmission signal to be transmitted to another device;
An attenuation unit capable of attenuating the transmission signal output to the amplification unit;
A temperature detection unit for detecting the temperature,
The attenuation unit attenuates the transmission signal when the temperature detected by the temperature detection unit is lower than a predetermined value. The wireless communication device further includes:
A transmission data processing unit for generating communication data to be transmitted to another device, converting the generated communication data into an analog signal and outputting the analog data;
A wireless transmission unit for converting the analog signal received from the transmission data processing unit into a wireless signal and transmitting it to another device;
The wireless transmission unit includes a branch circuit for branching and outputting the wireless signal amplified by the attenuation unit, the amplification unit, and the amplification unit,
The wireless communication device further includes:
In order to measure the radio signal, a transmission signal measuring unit for converting the radio signal received from the branch circuit into a digital signal,
The wireless transmission according to claim 1, wherein the transmission data processing unit corrects the communication data based on the digital signal converted by the transmission signal measurement unit, converts the corrected communication data into an analog signal, and outputs the analog signal. Communication device. 3. The wireless communication apparatus according to claim 1, wherein the attenuation unit does not attenuate the transmission signal when the temperature is higher than the predetermined value. The temperature detection unit outputs a control voltage having a level corresponding to the detected temperature,
The attenuation unit attenuates the transmission signal based on the control voltage received from the temperature detection unit,
The temperature detector is
A voltage dividing circuit that outputs a voltage according to the voltage dividing ratio and changes the voltage dividing ratio according to temperature;
A voltage follower for receiving the output voltage of the voltage dividing circuit,
The attenuation unit receives a voltage received from the voltage follower as the control voltage,
The voltage dividing circuit outputs a voltage obtained by dividing the supplied first voltage,
4. The wireless communication apparatus according to claim 1, wherein a second voltage lower than the first voltage is supplied to the voltage follower as a power supply voltage. 5. The said attenuation | damping part can select multiple types of attenuation amount, The attenuation amount is selected based on the temperature detected by the said temperature detection part from the said multiple types of attenuation amount. 5. The wireless communication device according to any one of 4 above. The temperature detection unit outputs a control voltage having a level corresponding to the detected temperature,
The attenuation part is
A first comparator for comparing the control voltage with a first threshold voltage;
A second comparator for comparing the control voltage with a second threshold voltage;
A third comparator for comparing the control voltage with a third threshold voltage;
Based on the comparison result of the first comparator and the comparison result of the second comparator, an attenuation amount is selected from the plurality of types of attenuation amounts, and the first comparator and the second comparator 6. The wireless communication apparatus according to claim 5, wherein whether to attenuate the transmission signal is selected based on a comparison result of the third comparator regardless of a comparison result of the comparator. A temperature detector for outputting a control voltage having a level corresponding to the temperature;
A voltage selection unit for selecting one of the control voltage output from the temperature detection unit and a predetermined voltage;
A wireless communication apparatus comprising: a wireless transmission unit configured to transmit a wireless signal to another device and control power of the wireless signal based on a voltage selected by the voltage selection unit. The wireless transmitter is
The radio communication apparatus according to claim 7, further comprising an attenuation circuit that attenuates a transmission signal to be transmitted to another apparatus and can change an attenuation amount based on the voltage selected by the voltage selection unit. The attenuation circuit is
The radio communication device according to claim 8, wherein when the predetermined voltage is selected by the voltage selection unit, the attenuation amount is increased as compared with a case where the control voltage is selected. The wireless communication device further includes:
A communication data to be transmitted to another device is generated, a transmission data processing unit for converting the generated communication data into an analog signal and outputting it,
The wireless transmission unit includes the branch circuit for converting the analog signal received from the transmission data processing unit into a wireless signal and transmitting it to another device, and branching and outputting the wireless signal,
The wireless communication device further includes:
In order to measure the radio signal, a transmission signal measuring unit for converting the radio signal received from the branch circuit into a digital signal,
The transmission data processing unit corrects the communication data based on the digital signal converted by the transmission signal measurement unit, converts the corrected communication data into an analog signal, and outputs the analog signal. The wireless communication device according to any one of the above. The wireless communication apparatus according to any one of claims 7 to 10, wherein the voltage selection unit selects the predetermined voltage when receiving an attenuation instruction for attenuating the wireless signal. The temperature detector is
A voltage dividing circuit that outputs a voltage according to the voltage dividing ratio and changes the voltage dividing ratio according to temperature;
A voltage follower for receiving the output voltage of the voltage dividing circuit and outputting the control voltage to the wireless transmission unit;
The said voltage selection part outputs the said predetermined voltage to the said radio | wireless transmission part from the said voltage follower by stopping the voltage supply to the said voltage follower, The Claim 1 any one of Claim 11 Wireless communication device. The temperature detector is
A voltage dividing circuit that outputs a voltage according to the voltage dividing ratio and changes the voltage dividing ratio according to temperature;
A voltage follower for receiving the output voltage of the voltage dividing circuit and outputting the control voltage to the wireless transmission unit;
The said voltage selection part outputs the said predetermined voltage to the said radio | wireless transmission part from the said voltage follower by stopping the voltage supply to the said voltage dividing circuit, The Claim 1 any one of Claim 11 Wireless communication device.

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