JP2008187308A - Radio communication equipment, mobile communication terminal, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve the efficiency and power saving of transmission power control. <P>SOLUTION: A frequency control part 254 tunes the resonance frequency of an antenna to a frequency associated with a channel to be switched in response to a channel switching request from a base station. The frequency control part 254 adjusts the resonance frequency of an antenna with the reception of the increase/decrease request of a transmission power from a base station by an increase/decrease request reception part 253 as a trigger. In receiving the decrease request of a transmission power from the base station after the resonance frequency of an antenna is adjusted, a transmission output control part 255 decreases a transmission output by a power amplification part 244. Also, when the increase or decrease in the transmission power is continuously requested after the resonance frequency of the antenna is adjusted, a frequency control part 254 shifts the resonance frequency of the antenna according to the request, and when the shifted frequency exceeds a preset range, the frequency control part 254 shifts the resonance frequency of the antenna to an opposite direction. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a radio communication device, a mobile communication terminal, and a program, and more particularly, to a radio communication device, a mobile communication terminal, and a program suitable for performing transmission power control.

In mobile communications such as cellular phones, multiplexing is performed for efficient communication by a large number of users. As a method for this, multiple users' signals are multiplexed on one frequency by modulation / demodulation using spreading codes. The CDMA (Code Division Multiple Access) method is widely adopted. In the CDMA system, since a plurality of mobile communication terminals use a carrier wave of one frequency, interference occurs if there is a difference in radio wave intensity from a plurality of mobile communication terminals with different distances from the base station. (So-called perspective problem). In order to solve such a near-far problem, in CDMA mobile communication, transmission power control (TPC) is performed so that the radio wave intensity from each mobile communication terminal to the base station is equalized. (For example, patent document 1).
Japanese Patent No. 2776632

  In the case of transmission power control in mobile communication, the transmission power of the mobile communication terminal is increased or decreased in response to a request from the base station, so that it is necessary in the mobile communication terminal to obtain sufficient transmission power that can meet the request. Become. Here, if the radiation gain of the antenna in the mobile communication terminal is increased, the transmission power efficiency can be improved. Therefore, it is desirable that a sufficient antenna gain can be maintained. In order to improve antenna gain, it is effective to increase the size of the antenna. However, in mobile communication terminals that are becoming smaller and more multifunctional, it is not realistic to increase the size of the antenna due to design and mounting restrictions.

  For this reason, antennas tend to be miniaturized in many mobile communication terminals, but the smaller the antenna, the narrower the bandwidth. Here, as shown in FIG. 10, the magnitude of the antenna gain changes in a parabolic shape within the band, so that the parabola indicating the antenna gain becomes steeper as the antenna bandwidth becomes narrower. Therefore, when the required bandwidth is the same, the gain reduction of the small antenna (see FIG. 10B) is larger near the end of the bandwidth than the large antenna (see FIG. 10A). In other words, if the antenna can resonate at a frequency (a parabolic peak) at which the maximum antenna gain can be obtained, transmission can be performed most efficiently. However, at a frequency far from such a frequency (resonance frequency), a large antenna can be transmitted. Thus, sufficient antenna gain cannot be obtained. Due to such characteristics, when a small antenna is used, the antenna gain is not sufficient unless the antenna is near the resonance frequency, and transmission power efficiency is greatly reduced if the antenna is deviated from the resonance frequency.

  Therefore, when using such a narrow-band small antenna, in order to achieve good transmission power efficiency, it is desirable to always transmit and receive at a resonance frequency that maximizes the antenna gain. However, since the transmission frequency and the reception frequency are different for each channel, when the channel is switched, it may deviate from the resonance frequency of the antenna. In addition, even in the same channel, the resonant frequency of the antenna may change as a dielectric such as a human body or metal moves closer to or away from the antenna, so that a high antenna gain can be maintained stably. It is difficult.

  Thus, in a mobile communication terminal that requires the use of a small antenna, the transmission power efficiency may decrease due to fluctuations in the resonance frequency, so that the necessary transmission power can be obtained by adjusting the transmission output with a power amplifier or the like. I am doing so. However, since the operation using the amplifier involves power consumption, it is not preferable for power saving of the mobile communication terminal. Further, the waveform may be distorted by amplification, and transmission quality may be reduced. Therefore, it is desirable to limit the output adjustment by the amplifier to the minimum necessary.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a wireless communication device, a mobile communication terminal, and a program that realize optimization of transmission power efficiency and power saving.

In order to achieve the above object, a wireless communication apparatus according to the first aspect of the present invention provides:
In a wireless communication device that controls transmission power in response to an external request,
In response to an external transmission power control request, an antenna control means is provided for controlling the antenna so that the resonance frequency at which the gain of the antenna used for transmission is maximized is tuned to the transmission frequency.
It is characterized by that.

The wireless communication device is
Channel switching means for receiving a channel switching request from the outside and switching the channel;
It is desirable to further comprise control information storage means for storing frequency information for each channel, in this case,
The antenna control means, when the channel switching means receives an external channel switching request, based on the frequency information stored in the control information storage means, the resonance frequency to the requested channel frequency It is desirable to synchronize.

In the above wireless communication device,
The antenna control means includes
When either increase or decrease in transmission power is continuously requested from the outside, the resonance frequency of the antenna is shifted according to the request, and when the resonance frequency after the shift exceeds a preset range, It is desirable to shift the resonant frequency of the antenna in the opposite direction.

The wireless communication device is
A transmission amplifying means for amplifying the transmission output may be further provided.
Preferably, the antenna control means further comprises output control means for reducing the output of the transmission amplifying means when a reduction in transmission power is requested from the outside after controlling the resonance frequency of the antenna.

In the above wireless communication device,
The antenna control means preferably further includes a tuning circuit that changes a resonance frequency of the antenna according to an input voltage.
The resonant frequency of the antenna can be controlled by controlling the input voltage to the tuning circuit.

Also,
The control information storage means preferably stores control voltage information indicating an input voltage value to the tuning circuit for tuning the antenna to a frequency indicated by the frequency information in association with the frequency information. ,in this case,
The antenna control means can control the resonance frequency of the antenna by applying a voltage based on the control voltage information stored in the control information storage means to the tuning circuit.

  The wireless communication device can be a mobile communication terminal.

In order to achieve the above object, a mobile communication terminal according to the second aspect of the present invention provides:
In a mobile communication terminal equipped with an antenna whose resonance frequency can be changed by voltage control and controlling transmission power in response to a request from a base station,
Control information storage means for storing the frequency of the channel for communication and the control information indicating the control voltage for tuning the resonant frequency of the antenna to the frequency of the channel in association with each other;
In response to a channel switching request from the base station, channel switching means for switching a channel for communication;
Based on the control voltage indicated by the control information in response to the transmission power increase / decrease request when the transmission power increase / decrease request is received from the base station during communication at the channel frequency switched by the channel switching means. Antenna control means for performing voltage control to adjust the resonance frequency so as to maximize the gain of the antenna;
After adjusting the resonance frequency by the antenna control means, when receiving a transmission power reduction request from the base station, amplification control means for reducing the transmission output by the amplifier,
After the adjustment of the resonance frequency by the antenna control means, when either increase or decrease of transmission power is continuously requested from the base station, the resonance frequency of the antenna is shifted and shifted according to the request. Shift control means for shifting the resonance frequency in the reverse direction when the resonance frequency exceeds a preset range;
It is characterized by providing.

In order to achieve the above object, a program according to the third aspect of the present invention is:
In a computer that controls a mobile communication terminal that performs transmission power control in response to a request from a base station,
In response to a channel switching request from the base station, based on information indicating the frequency of each channel stored in the storage device, the function of tuning the antenna to the frequency of the requested channel;
A function of adjusting the resonance frequency so that the gain of the antenna is maximized in response to the increase / decrease request triggered by receiving the increase / decrease request for transmission power control from the base station;
After adjusting the resonance frequency, when receiving a request to reduce transmission power from the base station, a function to reduce the transmission output by the amplifier,
When either increase or decrease in transmission power is continuously requested from the base station after adjusting the resonance frequency, the resonance frequency is shifted according to the request, and the shifted resonance frequency is preset. When exceeding the range, the function of shifting the resonance frequency in the reverse direction;
A program characterized by realizing.

  According to the present invention, the antenna is controlled so that the gain of the antenna is maximized, so that transmission power efficiency during transmission power control can be improved.

  Hereinafter, embodiments according to the present invention will be described with reference to the drawings. In the present embodiment, a case where the wireless communication apparatus according to the present invention is realized by a mobile communication terminal will be described below as an example. The mobile communication terminal according to the present embodiment is a wireless communication device that functions as a mobile station in a mobile communication service such as a mobile phone, for example, and performs wireless communication with a base station installed by a communication carrier. Make voice calls and data communications with mobile communication terminals.

  In addition, the mobile communication terminal according to the present embodiment adopts a CDMA (Code Division Multiple Access) system as a multiplexing system, and a near-far problem (proximity problem) that occurs in communication by the CDMA system. In order to solve this problem, it is assumed that transmission power control (TPC) is performed. This transmission power control is performed in order to equalize the difference in radio field intensity caused by the difference in the distances of a plurality of mobile communication terminals that communicate with one base station, and the received power from each mobile communication terminal. Is measured by the base station, and the transmission power of each mobile communication terminal is controlled according to the measurement result.

  In this case, the base station requests each mobile communication terminal to increase / decrease the transmission power of the mobile communication terminal in units of a predetermined step (for example, ± 1/2 dBm, ± 1 dBm, etc.). The transmission power is increased or decreased in response to a request from the station. Such an increase / decrease request is transmitted to each mobile communication terminal, for example, at intervals of about 0.5 milliseconds to 1.5 milliseconds.

  In the mobile communication terminal 1 according to the present embodiment, full-duplex communication is realized by FDD (Frequency Division Duplex) using different frequencies for transmission (uplink) and reception (downlink). It shall be. In each transmission / reception, a plurality of channels are used to communicate with the base station.For example, in the case of a handover for changing the base station that communicates with movement, the channel according to the request from the base station is set. Switch to communicate.

  A configuration of such a mobile communication terminal according to the present embodiment is shown in FIG. FIG. 1 is a block diagram schematically showing the configuration of the mobile communication terminal 1 according to the present embodiment. As shown in the figure, the mobile communication terminal 1 includes an operation control unit 100, a wireless communication unit 200, a storage unit 300, an operation unit 400, a display unit 500, a voice processing unit 600, and the like.

  The operation control unit 100 includes a control unit 110, a power supply unit 120, and the like, and controls the entire operation of the mobile communication terminal 1.

  The control unit 110 includes, for example, a logic circuit such as a CPU (Central Processing Unit), a storage device such as a RAM (Random Access Memory), and the like, and executes an operation program stored in the storage unit 300. By doing so, each part of the mobile communication terminal 1 is controlled.

  The power supply unit 120 includes, for example, a power supply circuit, a rectifier circuit, and the like, adjusts power obtained from a power supply such as a battery, and supplies the power to each unit of the mobile communication terminal 1. In the present embodiment, the voltage and the like are adjusted by the operation of the power supply unit 120 and supplied to each unit.

  The radio communication unit 200 performs an operation when the mobile communication terminal 1 performs radio communication with a base station, and has a configuration as shown in FIG. 2, for example. FIG. 2 is a block diagram illustrating a configuration of the wireless communication unit 200. As illustrated, the wireless communication unit 200 includes an antenna 201, an antenna control unit 210, an antenna sharing unit 220, a reception unit 230, a transmission unit 240, a communication control unit 250, and the like.

  The antenna 201 is an antenna that transmits and receives radio waves when the mobile communication terminal 1 wirelessly communicates with a base station. For example, a PIFA (Planar Inverted-F Antenna) board mounted on an internal substrate of the mobile communication terminal 1 is used. A built-in antenna such as a reverse inverted F antenna). Since it is mounted as a built-in antenna, the antenna 201 according to the present embodiment is a relatively small antenna, and has a narrow band characteristic as shown in FIG.

  The antenna control unit 210 performs operations for antenna matching and changing the resonance frequency of the antenna 201, and includes a matching circuit 211, a tuning circuit 212, and the like. A circuit configuration example of the matching circuit 211 and the tuning circuit 212 is shown in FIG.

  As shown in the figure, the matching circuit 211 is, for example, a matching circuit using a lumped constant circuit configured by combining an inductance L and a capacitor C. The matching circuit 211 matches the intrinsic impedance of the antenna 201 and the characteristic impedance of the feeder line. Optimize radiation efficiency.

  The tuning circuit 212 is for adjusting the frequency (antenna frequency) to which the antenna 201 is tuned, and is configured to be incorporated in the circuit of the matching circuit 211 as shown in the figure. In the tuning circuit 212, a diode (variable capacitance diode) whose capacitance changes with voltage, such as a varicap diode or a varistor, is configured on the power supply line of the antenna 201, and the tuning circuit 212 corresponds to the input voltage from the power supply unit 120. The frequency with which the antenna 201 is tuned is changed by changing the capacitance. In the present embodiment, it is assumed that the tuning circuit 212 has a circuit configuration in which the frequency at which the antenna 201 is tuned increases as the input voltage increases. In the present embodiment, the “resonance frequency” that is the frequency at which the gain of the antenna 201 is maximized is controlled (adjusted) by the operation of the tuning circuit 212.

  Returning to FIG. 2, another configuration of the wireless communication unit 200 will be described.

  The antenna sharing unit 220 is a so-called duplexer, and includes a filter, a branch circuit, or the like corresponding to each of transmission and reception, and shares the antenna 201 for transmission / reception operations with different frequencies. That is, by the operation of the antenna sharing unit 220, a signal received by the antenna 201 is supplied to the reception unit 230, and a transmission signal generated by the transmission unit 240 is supplied to the antenna 201 via the antenna control unit 210.

  The receiving unit 230 performs a receiving operation of the mobile communication terminal 1, and includes a high frequency processing unit 231, an intermediate frequency processing unit 232, a filter unit 233, a demodulation unit 234, and the like as shown in FIG. .

  The high frequency processing unit 231 includes, for example, a low noise amplifier circuit, a high frequency amplifier circuit, and the like, and amplifies the received high frequency signal.

  The intermediate frequency processing unit 232 includes, for example, a local oscillation circuit, a frequency conversion circuit, an intermediate frequency amplification circuit, and the like, and converts the high frequency signal input from the high frequency processing unit 231 to a predetermined intermediate frequency.

  The filter unit 233 includes, for example, a SAW (Surface Acoustic Wave) filter and attenuates unnecessary signal waves included in the converted intermediate frequency signal.

  The demodulation unit 234 is configured by a demodulation circuit (for example, an orthogonal demodulation circuit) that demodulates a signal modulated by the base station, and extracts a signal wave by removing a carrier wave from the modulated signal and supplies the signal wave to the communication control unit 250. To do.

  Next, the transmission unit 240 will be described. The transmission unit 240 performs a transmission operation of the mobile communication terminal 1, and as shown in FIG. 2, a carrier wave oscillation unit 241, a modulation amplification unit 242, a filter unit 243, a power amplification unit 244, a stabilization unit 245, Etc.

  The carrier wave oscillator 241 includes, for example, a TCXO (Temperature Compensated X'tal (crystal) Oscillator), a VCO (Voltage Controlled Oscillator), a PLL (Phase Locked Loop) synthesizer, and the like. A carrier wave to be transmitted at a predetermined frequency is generated.

  The modulation amplification unit 242 includes, for example, a modulation circuit such as a quadrature modulation circuit, a GCA (Gain Control Amplifier), and the like. The carrier wave generated by the carrier wave oscillation unit 241 is a signal wave indicating an audio signal or a data signal. Modulate to generate a transmission signal.

  The filter unit 243 includes, for example, a filter such as a BPF (Band Pass Filter) or an LPF (Low Pass Filter), and the transmission signal generated by the modulation amplification unit 242 has a desired bandwidth. In addition to filtering, noise components are removed.

  The power amplifying unit 244 is a transmission power amplifier that includes, for example, an RF power module including an amplifier circuit, a bias circuit, and the like, and increases or decreases the transmission output (transmission power) of the generated transmission signal.

  The stabilization unit 245 includes, for example, an isolator and restricts the output from the power amplification unit 244 in one direction, thereby preventing an unnecessary reflected wave from being input to the power amplification unit 244 and power amplification. The operation of the unit 244 is stabilized.

  Next, the communication control unit 250 will be described. The communication control unit 250 includes, for example, a processor such as a DSP (Digital Signal Processor), a communication control circuit, an ADC (Analog-Digital Converter), a DAC (Digital-Analog Converter), and the like. This is a so-called baseband chip configured to control the communication operation of the wireless communication unit 200 in cooperation with the operation control unit 100.

  In the present embodiment, transmission power control and frequency control of the mobile communication terminal 1 are performed by the control operation of the communication control unit 250. FIG. 4 shows a functional configuration for realizing the function performed by the communication control unit 250 during such operation. As illustrated, the communication control unit 250 functions as a reception control unit 251, a channel switching unit 252, an increase / decrease request reception unit 253, a frequency control unit 254, a transmission output control unit 255, a transmission control unit 256, and the like.

  The reception control unit 251 controls the operation of the reception unit 230, and supplies the demodulated voice signal and data signal to the control unit 110, thereby realizing a voice call and data communication reception operation.

  When the signal demodulated by the receiving unit 230 is a channel switching request from the base station, the channel switching unit 252 controls the receiving unit 230 and the transmitting unit 240 to perform a control operation necessary for channel switching. .

  The increase / decrease request receiving unit 253 performs an operation of controlling the transmission power when the signal demodulated by the receiving unit 230 is a transmission power increase / decrease request from the base station.

  The frequency control unit 254 controls the power supply unit 120 according to an instruction from the channel switching unit 252 or the increase / decrease request receiving unit 253, and controls the resonance frequency of the antenna 201 by controlling the input voltage to the tuning circuit 212 ( adjust. That is, the resonance frequency at which the gain of the antenna 201 is maximized is tuned to the transmission / reception frequency according to channel switching or transmission power control requested from the base station. In this case, control is performed so that the resonance frequency of the antenna 201 becomes the transmission frequency by determining the input voltage to the tuning circuit 212 based on control information stored in the storage unit 300 described later.

  The transmission output control unit 255 controls the power amplification unit 244 so that the transmission power requested by the transmission power control is obtained based on the input from the increase / decrease request reception unit 253 or the like.

  The transmission control unit 256 controls the carrier wave oscillating unit 241 and the modulation amplification unit 242 to generate a carrier wave of a requested frequency, and modulates the carrier wave with a signal wave such as an audio signal or a data signal input from the control unit 110. By doing so, transmission operation of voice call and data communication is realized.

  In the present embodiment, each functional configuration illustrated in FIG. 4 is realized by the communication control unit 250 executing, for example, a program stored in a ROM (Read Only Memory) or the like. When such a software operation can be implemented, each of the functional configurations described above is not performed by the control unit 110 that controls the entire mobile communication terminal 1, but by the communication control unit 250 prepared for controlling the wireless communication unit 200. Some or all may be realized. Alternatively, some or all of these functional configurations may be realized by hardware such as an ASIC (Application Specific Integrated Circuit).

  Returning to FIG. 1, another configuration of the mobile communication terminal 1 will be described.

  The storage unit 300 includes a storage device such as a flash memory or a ROM, and stores programs and data necessary for the operation of the mobile communication terminal 1. As shown in FIG. 1, storage areas such as a program storage unit 310 and a control information storage unit 320 are prepared in the storage unit 300.

  The program storage unit 310 is a storage area for storing operation programs executed by the control unit 110 and the communication control unit 250. In the present embodiment, the control unit 110 and the communication control unit 250 execute a program stored in the program storage unit 310, thereby realizing a functional configuration as illustrated in FIG.

  The control information storage unit 320 is a storage area for storing control information that is referred to when the frequency control unit 254 controls the input voltage to the tuning circuit 212. An example of the control information stored in the control information storage unit 320 is shown in FIG. As shown in the figure, the control information storage 320 records a channel number used for transmission by the transmitter 240 and a control voltage corresponding to the transmission frequency (resonance frequency) of the channel.

  This control voltage indicates a voltage value to be input to the tuning circuit 212 according to the channel. As described above, the tuning circuit 212 configured by a variable capacitance diode such as a varicap diode can change the frequency of the antenna 201 in accordance with the input voltage, and thus operates the antenna 201 at the frequency of each channel. A control voltage indicating a voltage value to be applied to the tuning circuit 212 is stored in the control information storage unit 320 as control information referred to during frequency control.

  The operation unit 400 includes, for example, a cross cursor key, an alphanumeric key for inputting numbers and characters, a key for designating a function, and the like, and is operated by a user of the mobile communication terminal 1. . The operation unit 400 generates an input signal corresponding to the operation of these keys and inputs the input signal to the operation control unit 100.

  The display unit 500 is a display panel configured by, for example, a liquid crystal display (LCD) or the like, and displays and outputs various screens corresponding to each function of the mobile communication terminal 1.

  The voice processing unit 600 includes, for example, a codec circuit that performs voice processing, and performs voice processing related to voice calls. That is, the received voice data is converted into an analog signal and output from the speaker 610, and the transmitted voice input from the microphone 620 is converted into digital data for transmission.

  The above is the configuration of the mobile communication terminal 1 according to the present embodiment, but each of the above configurations is a configuration necessary for realizing the present invention, and other configurations and additional functions necessary as the mobile communication terminal. Etc. shall be provided as necessary.

  The operation of the mobile communication terminal 1 configured as described above will be described below. As described above, the mobile communication terminal 1 according to the present embodiment performs channel switching and transmission power control in response to a request from the base station. In the present embodiment, operations performed by the mobile communication terminal 1 in these scenes will be described below.

(Embodiment 1)
First, an operation example of the mobile communication terminal 1 in a channel switching scene will be described as a first embodiment. Here, the “channel switching process” executed by the communication control unit 250 at the time of channel switching will be described with reference to the flowchart shown in FIG. This channel switching process is started when the channel switching unit 252 receives a channel switching request transmitted from a base station communicating with the mobile communication terminal 1. In the present embodiment, channel switching for the transmission channel of the mobile communication terminal 1 will be described.

  When the channel switching unit 252 receives the channel switching request, it notifies the requested channel number to the frequency control unit 254 and the transmission control unit 256 to instruct the switching of the transmission channel. In this case, the transmission control unit 256 recognizes the transmission frequency corresponding to the notified channel number by referring to the control information in the control information storage unit 320, and sets the carrier oscillation unit 241 to oscillate the carrier wave of that frequency. Control.

  The frequency control unit 254 also refers to the control information in the control information storage unit 320 and acquires the voltage value of the control voltage corresponding to the requested channel number (step S101). The frequency control unit 254 instructs the power supply unit 120 so that the input voltage to the tuning circuit 212 becomes the voltage value of the acquired control voltage (step S102). In this case, the power supply unit 120 adjusts and applies the input voltage to the tuning circuit 212 to a voltage instructed by the frequency control unit 254. In this case, the antenna 201 is tuned to the frequency of the requested channel by changing the capacitance of the variable capacitance diode constituting the tuning circuit 212.

  That is, in response to a channel switching request from the base station, channel switching is performed by setting the frequency of the carrier wave or the frequency at which the antenna 201 is tuned to the frequency of the channel. When channel switching is performed in this way, transmission power control according to a transmission power control request from the base station is performed. In other words, since the transmission power increase / decrease request is transmitted from the base station at intervals of about 0.5 milliseconds to 1.5 milliseconds as described above, the increase / decrease request receiving unit 253 performs the tuning operation of the antenna 201. The transmission output control unit 255 performs transmission power control according to the received increase / decrease request.

  Here, when the increase / decrease request received from the base station is a request for increasing the transmission power (hereinafter referred to as “up request”) (step S103: Yes), the transmission output control unit 255 first sets the power amplifier. The power amplifying unit 244 is controlled to increase the output to meet the request (step S104). As described above, the base station requesting transmission power control requests increase / decrease in a predetermined step such as ± 1/2 dBm or ± 1 dBm, for example. In step S104, the output is increased according to the requested increment. I will do it.

  Therefore, when it is necessary to further increase the transmission power of the mobile communication terminal 1, the base station sequentially transmits an up request (step S105: No). In this case, the transmission output control unit 255 increases the output of the power amplification unit 244 step by step each time an up request is received (step S104).

  In this way, when the output of the power amplifying unit 244 is gradually increased as required, the transmission output satisfies the reception level desired by the base station. Since the base station performs transmission power control by requesting the mobile communication terminal 1 to increase / decrease finely, when the requested transmission output is reached, a request to reduce transmission power (hereinafter referred to as “down”) Request ") (step S105: Yes).

  The increase / decrease request reception unit 253 that has received the down request instructs the frequency control unit 254 to finely adjust the resonance frequency of the antenna 201 in order to reduce the power consumption of the power amplification unit 244. Here, under a favorable communication environment, if the antenna 201 is tuned to the transmission frequency, a required gain is theoretically obtained (that is, resonance frequency≈transmission frequency). For this reason, in the situation where the antenna 201 is tuned to the frequency of the channel at the time of channel switching, it is considered that the antenna gain necessary for transmission on the channel is obtained, but the resonance frequency at which the antenna gain becomes maximum is For example, it varies depending on the approaching state of a dielectric (such as a human body or metal). Therefore, under the actual usage environment, a situation occurs in which the transmission frequency does not match the resonance frequency. In such a case, if the resonance frequency of the antenna 201 can be finely adjusted and tuned to the transmission frequency at that time, the maximum antenna gain can be obtained, and even if the output of the power amplifying unit 244 is lowered accordingly. The same transmission power can be obtained.

  Here, since the resonance frequency of the antenna 201 changes depending on the input voltage to the tuning circuit 212, the frequency control unit 254 instructed to finely adjust the resonance frequency performs voltage adjustment to finely adjust the resonance frequency. To instruct. In this case, it is unclear whether the resonance frequency is higher or lower than the current transmission frequency, so at the first fine adjustment, the resonance frequency is shifted in one of the predefined directions. To see the change in transmission power.

  In the present embodiment, the first fine adjustment is shifted to the high frequency side (step S106). Here, if the characteristic of the tuning circuit 212 is that the frequency at which the antenna is tuned increases as the input voltage increases, the power supply unit 120 is instructed to output a voltage higher than the current voltage value. The amount of change in the voltage to be adjusted at this time is such that the resonance frequency of the antenna 201 is changed within a range not tuned to the frequency of the other channel, and is adjusted in units of 0.01 V, for example. By such voltage adjustment, for example, the resonance frequency is finely adjusted by a change amount of 0.1 MHz unit. Here, the frequency control unit 254 instructs the power supply unit 120 to slightly increase the input voltage to the tuning circuit 212, thereby finely adjusting the resonance frequency of the antenna 201 to the high frequency side.

  When the resonance frequency of the antenna 201 is finely adjusted in this way, it can be determined whether or not the adjusted resonance frequency has approached the transmission frequency based on the increase / decrease request received immediately after that. That is, if an up request is received after fine adjustment (step S107: Yes), the transmission output is reduced by fine adjustment. That is, there is a high possibility that the transmission frequency has been separated. Since the resonance frequency is shifted to the high frequency side in the first fine adjustment, there is a possibility that the resonance frequency is on the high frequency side than the transmission frequency (that is, the frequency of the current channel). Therefore, the frequency control unit 254 instructs the power supply unit 120 to perform voltage adjustment for shifting the resonance frequency in the direction opposite to the initial fine adjustment. In this case, if the voltage value is adjusted to be slightly lower than the control voltage associated with the current channel, the resonance frequency of the antenna 201 can be finely adjusted to a frequency lower than the channel frequency (step S108).

  If a down request is received after such fine adjustment (step S109: Yes or step S107: No), the transmission power is increased by fine adjustment of the resonance frequency. This means that the resonant frequency of the antenna 201 after fine adjustment is tuned to the transmission frequency. In this case, the transmission output control unit 255 controls the power amplification unit 244 in accordance with the down request to reduce the output (step S110). That is, since the antenna gain is improved by tuning the antenna 201 to the transmission frequency, the transmission power efficiency is increased, so that the required transmission power can be obtained even if the output of the power amplifier 244 is lowered. Here, the output reduction of the power amplifying unit 244, which is a power amplifier, causes a reduction in power consumption. Therefore, the power consumption of the mobile communication terminal 1 can be reduced by tuning the antenna 201 to the transmission frequency at that time by a simple operation of adjusting the voltage of the tuning circuit 212.

  On the other hand, if the up request is received even after the second fine adjustment (step S109: No), there is a high possibility that the initial resonance frequency is the tuned transmission frequency (that is, the current channel frequency). The frequency control unit 254 instructs the power supply unit 120 to output a voltage having a channel frequency (that is, a control voltage associated with the channel) (step S111). In this case, for example, there is a possibility that a relatively high transmission power is required because the distance to the base station is long, and in order to output with the requested transmission power, amplification by the power amplifier 244 is also required. . Therefore, in such a case, the output of the power amplifying unit 244 is not reduced.

  If the increase / decrease request received immediately after channel switching is a down request (step S103: No), the output of the power amplifying unit 244 may be lowered according to the down request (step S110).

  The above is the operation of the mobile communication terminal 1 at the time of channel switching. As described above, when the mobile communication terminal 1 switches the channel according to a request from the base station, even if a small antenna having a narrow band characteristic is used by tuning the antenna 201 to the frequency of the channel, Necessary antenna gain can be obtained. When transmission power up is required from this state, after responding to the request by increasing the output of the power amplifying unit 244, tuning to the transmission frequency is attempted by finely adjusting the resonance frequency of the antenna 201. If the frequency that is not the same as the channel frequency is the resonance frequency, an antenna gain higher than the initial antenna gain can be obtained by tuning to the transmission frequency by fine adjustment. If the antenna gain is improved, the output of the power amplifying unit 244 can be lowered accordingly, so that power saving can be achieved while performing transmission with the requested transmission power.

(Embodiment 2)
In the first embodiment, the operation when the channel switching is requested from the base station has been described. However, transmission power control is performed even when there is no channel switching. In the present embodiment, an operation of transmission power control performed by the mobile communication terminal 1 when such a channel switching request is not accompanied will be described.

  As described above, an increase / decrease request is periodically transmitted from the base station communicating with the mobile communication terminal 1. In the present embodiment, an operation performed by the mobile communication terminal 1 when a transmission power increase request is received will be described. In this case, the communication control unit 250 executes “transmission power control processing” when receiving the up request. This transmission power control process will be described below with reference to the flowchart shown in FIG.

  In executing this process, for example, a dielectric such as a human body or metal is used in the mobile communication terminal from the state where the resonance frequency is tuned to the transmission frequency (see FIGS. 8A and 9A). It is assumed that the resonance frequency changes by approaching 1 (antenna 201) and the resonance frequency of the antenna 201 deviates from the transmission frequency (see FIGS. 8B and 9B). Then, it is assumed that the antenna gain is reduced because the resonance frequency is not synchronized with the transmission frequency, and an up request is transmitted from the base station due to the reduction in transmission power efficiency.

  When the process is started, the increase / decrease request receiving unit 253 that has received the up request instructs the frequency control unit 254 to adjust the resonance frequency. Here, when a dielectric such as a human body or metal approaches the antenna 201, the resonance frequency usually decreases. Therefore, the frequency control unit 254 performs control so that the lowered resonance frequency is shifted to the high frequency side so as to be synchronized with the transmission frequency.

  In this case, the frequency control unit 254 instructs the power supply unit 120 to adjust the voltage input to the tuning circuit 212 so that the resonance frequency of the antenna 201 is shifted to the high frequency side. Here, for example, the current resonance frequency is increased in units of a predetermined step (for example, 0.1 MHz). Therefore, the frequency control unit 254 sets a voltage value for increasing the frequency for the step based on the control information stored in the control information storage unit 320 (step S201), and sets the voltage of the voltage value to the power supply unit 120. Instructs tuning circuit 212 to apply.

  The power supply unit 120 increases the voltage value applied to the tuning circuit 212 in response to an instruction from the frequency control unit 254. As a result, the resonance frequency of the antenna 201 is increased by one step (step S202). In this case, the frequency control unit 254 stores control information as a frequency difference (hereinafter referred to as “frequency difference information”), which is a frequency width shifted so as to tune the resonance frequency changed due to the approach of the dielectric to the transmission frequency. The data is recorded in the unit 320 (step S203).

  In this way, the resonance frequency of the antenna 201 is adjusted in response to an up request from the base station, and tuning to the transmission frequency is attempted. However, since it is unknown how much the frequency deviates from the original resonance frequency, it may not be synchronized with the transmission frequency even if the frequency is increased by one step. In such a case, the base station transmits a further up request. As described above, when the up request is received even after the initial adjustment of the resonance frequency (step S204: Yes), the frequency control unit 254 further increases the frequency by one step.

  Here, in the present embodiment, it is assumed that the adjustment range of the resonance frequency in the case where the up requests are continuous in this way is defined in advance. This adjustment range is set as a limit value (hereinafter referred to as “adjustment limit information”) indicating a predetermined frequency band (for example, ± 1 MHz, etc.) centered on the frequency of the currently transmitting channel, for example, It is assumed that it is stored in advance in the control information storage unit 320 or the like.

  The frequency control unit 254 refers to the frequency difference information recorded in the control information storage unit 320 in step S203, and calculates a frequency that is further increased by one step from the current resonance frequency, and the resonance frequency that has been changed due to the approach of the dielectric or the like. It is determined whether or not the frequency width exceeds the range indicated by the adjustment restriction information (step S205).

  Here, if the resonance frequency after further adjustment is within the set adjustment range (step S205: No), the frequency control unit 254 further increases the frequency based on the control information in the control information storage unit 320. A voltage value that increases the frequency for one step is set, and the power supply unit 120 is instructed to adjust the voltage value (step S201). Thereby, the resonance frequency of the antenna 201 is further increased by one step (step S202).

  In this way, if it is within the adjustment range defined in advance, the resonance frequency of the antenna 201 is increased step by step in response to a plurality of continuous up requests from the base station.

  As described above, in the present embodiment, transmission power control is performed according to a decrease in the resonance frequency caused by a dielectric body such as a human body or metal approaching the antenna 201. Such a decrease in the resonance frequency due to the approach of the dielectric may be restored when the approach state changes due to, for example, a change in the posture of the user. Therefore, if the resonance frequency is increased indefinitely in response to an up request from the base station, there is a possibility that the transmission frequency is significantly shifted when the resonance frequency is restored. Therefore, in the present embodiment, a range in which tuning can be achieved quickly even when the resonance frequency is restored is set as an adjustment range, and the resonance frequency is adjusted within the range.

  Therefore, when the adjusted resonance frequency exceeds the adjustment range (step S205: Yes), the frequency control unit 254 performs control to shift the resonance frequency in the reverse direction (that is, the high frequency direction) without further increasing the frequency. (Step S206). In this case, the frequency control unit 254 instructs the power supply unit 120 to have a voltage value lower than the current input voltage to the tuning circuit 212, whereby the input voltage to the tuning circuit 212 decreases, and the antenna The resonance frequency of 201 shifts to the low frequency side.

  When the control for shifting the resonance frequency in the reverse direction is performed in this way, the frequency control unit 254 notifies the transmission output control unit 255 to that effect. In this case, since the increase request from the base station could not be met only by adjusting the resonance frequency, the transmission output control unit 255 amplifies the transmission power by instructing the power amplification unit 244 to increase the output. Thus, transmission with the requested transmission power is performed (step S207).

  On the other hand, when the transmission frequency is tuned by adjusting the resonance frequency within the adjustment range (see FIG. 8C and FIG. 9C), a down request is received from the base station (step S204: No). ). That is, if the second and subsequent increase / decrease requests are down requests, the increase / decrease request reception unit 253 instructs the transmission output control unit 255 to reduce the output of the power amplification unit 244. In this case, the transmission output control unit 255 controls the power amplification unit 244 to reduce the output (step S208).

  By the operation as described above, tuning to the transmission frequency is attempted according to the decrease in the resonance frequency caused by the approach of the dielectric, so that it is possible to prevent the communication quality from being lowered when a human body or metal approaches. In this case, the adjustment range (restriction) of the resonance frequency is defined, and when the frequency adjustment within this range is not tuned to the transmission frequency, the resonance frequency is shifted in the reverse direction. Even when the value changes (returns), synchronization can be achieved quickly. Further, the output of the power amplifying unit 244, which is a power amplifier, is increased only when the resonance frequency cannot be tuned within the adjustment range. When the transmission frequency can be tuned within the adjustment range, the power amplifying unit 244 corresponding to the improved antenna gain is obtained. Therefore, efficient transmission power control and power saving can be achieved.

  As described above, by applying the present invention as in the above embodiments, it is possible to improve transmission power efficiency and save power in a wireless communication apparatus such as a mobile communication terminal that performs transmission power control. . In other words, it is possible to always obtain the maximum antenna gain by tuning the resonance frequency that changes under various conditions to the transmission frequency as needed. In a communication terminal or the like, it is possible to optimize transmission power efficiency while ensuring a degree of freedom in design and implementation.

  Such an antenna tuning operation is performed by adjusting the input voltage to a tuning circuit composed of a variable capacitance diode or the like based on control information defined in advance. The frequency can be adjusted, and even a mobile communication terminal or the like that requires downsizing and high-density mounting can be easily realized.

  In addition, since the antenna gain is improved by tuning to the transmission frequency, the output of a transmission amplifier such as a power amplifier can be lowered, so that the power consumption of the entire device can be reduced while appropriately responding to the transmission power control request from the base station. This can reduce power consumption. In addition, since the amplification by the transmission amplifier is performed only when the transmission frequency cannot be tuned or the increase in the transmission power is required even when tuned, the amplification of the transmission amplifier can be suppressed to the minimum necessary, Inconveniences such as waveform distortion accompanying amplification can be reduced.

  The said embodiment is an example and the application range of this invention is not restricted to this. That is, various applications are possible, and all embodiments are included in the scope of the present invention.

  In the above-described embodiment, as a scene for adjusting the resonance frequency, a case where there is a channel switching request from the base station and a case where there is a transmission power increase request from the base station due to the proximity of the dielectric are illustrated. However, the trigger for performing the operation to tune the resonance frequency to the transmission frequency at that time is not limited to these, and for example, the operation may be triggered by the activation of the device or the reception of a request to reduce the transmission power. Also good.

  In the above embodiment, the resonance frequency is controlled so as to be tuned to the transmission frequency by controlling the input voltage to the tuning circuit composed of a variable capacitance diode such as a varicap diode. As long as the antenna can be controlled so as to be maximized, the antenna control method and the configuration therefor are arbitrary.

  Further, in the above embodiment, in preparation for recovery of the resonance frequency when the dielectric is released from the approaching state, the resonance frequency is shifted in the reverse direction when the transmission frequency cannot be tuned within the preset adjustment range. However, if the resonance frequency after recovery can be tuned to the transmission frequency in a short time, the method for that is arbitrary. For example, the control voltage corresponding to the initial resonance frequency is stored, and when the increase / decrease request is reversed after a significant frequency shift, the stored control voltage is output, so that the resonance frequency after restoration is transmitted as the transmission frequency. It may operate to be close to

  In the above embodiment, the case where the present invention is applied to a mobile communication terminal is illustrated. However, as long as transmission power is controlled in response to an external request, the present invention is not limited to a mobile communication terminal. The present invention can be applied to a wireless communication apparatus.

  In addition, the mobile communication terminal according to the present invention can be provided as having the configurations and functions exemplified in the above embodiments in advance, and for example, a program for realizing the functional configuration shown in FIG. By applying the above, it is possible to cause an existing mobile communication terminal to function as the mobile communication terminal according to the present invention. Such a program distribution method is arbitrary. For example, the program can be distributed by being stored in a storage medium such as a CD-ROM or a memory card, or can be distributed via a communication medium such as the Internet. By applying (installing) the distributed program to a target device and causing a computer (a processor such as a CPU) to control the device to execute the program, the communication control unit 250 (control unit 110) and A similar configuration and operation can be realized.

It is a block diagram which shows the structure of the mobile communication terminal concerning embodiment of this invention. It is a block diagram which shows the structure of the radio | wireless communication part shown in FIG. It is a figure which shows the circuit structural example of the antenna control part shown in FIG. It is a functional block diagram which shows the function structure implement | achieved by the communication control part shown in FIG. It is a figure which shows the example of the control information stored in the control information storage part shown in FIG. It is a flowchart for demonstrating the "channel switching process" concerning Embodiment 1 of this invention. It is a flowchart for demonstrating the "transmission power control process" concerning Embodiment 2 of this invention. FIG. 8 is a diagram for explaining the operation in the transmission power control process shown in FIG. 7, wherein (a) shows the relationship between the antenna frequency and the antenna gain when the antenna resonance frequency is tuned to the transmission frequency; Shows the relationship between the antenna frequency and the antenna gain when the resonance frequency is changed, and (c) shows the relationship between the antenna frequency and the antenna gain when the resonance frequency of the antenna is shifted and tuned to the transmission frequency. FIG. 8 is a diagram for explaining the operation in the transmission power control process shown in FIG. 7, where (a) shows the relationship between the resonance frequency and the control voltage when the antenna resonance frequency is tuned to the transmission frequency; Shows the relationship between the resonance frequency and the control voltage when the resonance frequency is changed, and (c) shows the relationship between the resonance frequency and the control voltage when the resonance frequency of the antenna is shifted and tuned to the transmission frequency. It is a figure for demonstrating the difference in the characteristic by antenna size, (a) shows the characteristic of a large antenna, (b) shows the characteristic of a small antenna.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Mobile communication terminal, 100 ... Operation control part, 110 ... Control part, 120 ... Power supply part, 200 ... Wireless communication part, 201 ... Antenna, 210 ... Antenna control part, 211 ... Matching circuit, 212 ... Tuning circuit, 220 ... antenna sharing part, 230 ... receiving part, 231 ... high frequency processing part, 232 ... intermediate frequency processing part, 233 ... filter part, 234 ... demodulation part, 240 ... transmission part, 241 ... carrier wave oscillation part, 242 ... modulation amplification part, 243 ... Filter unit, 244 ... Power amplification unit, 245 ... Stabilization unit, 250 ... Communication control unit, 251 ... Reception control unit, 252 ... Channel switching unit, 253 ... Increase / decrease request receiving unit, 254 ... Frequency control unit, 255 ... Transmission output control section, 256 ... Transmission control section, 300 ... Storage section, 310 ... Program storage section, 320 ... Control information storage section, 400 ... Operation section, 500 ... Display section, 600 Audio processing unit, 610 ... speaker, 620 ... microphone, C ... Capacitor, L ... inductance, D ... Diode (variable capacitance diode), R ... resistance

Claims (9)

In a wireless communication device that controls transmission power in response to an external request,
In response to an external transmission power control request, an antenna control means is provided for controlling the antenna so that the resonance frequency at which the gain of the antenna used for transmission is maximized is tuned to the transmission frequency.
A wireless communication apparatus. Channel switching means for receiving a channel switching request from the outside and switching the channel;
Control information storage means for storing frequency information for each channel, and
The antenna control means, when the channel switching means receives an external channel switching request, based on the frequency information stored in the control information storage means, the resonance frequency to the requested channel frequency Tune the
The wireless communication apparatus according to claim 1. The antenna control means includes
When either increase or decrease in transmission power is continuously requested from the outside, the resonance frequency of the antenna is shifted according to the request, and when the resonance frequency after the shift exceeds a preset range, Shifting the resonant frequency of the antenna in the opposite direction;
The wireless communication apparatus according to claim 1, wherein the wireless communication apparatus is a wireless communication apparatus. A transmission amplifying means for amplifying the transmission output;
After the antenna control means controls the resonance frequency of the antenna, it further comprises output control means for reducing the output of the transmission amplification means when a decrease in transmission power is requested from the outside.
The wireless communication device according to claim 1, wherein the wireless communication device is a wireless communication device. The antenna control means further includes a tuning circuit that changes a resonance frequency of the antenna according to an input voltage,
Controlling the resonant frequency of the antenna by controlling the input voltage to the tuning circuit;
The wireless communication device according to claim 1, wherein the wireless communication device is a wireless communication device. The antenna control means further includes a tuning circuit that changes a resonance frequency of the antenna according to an input voltage,
The control information storage means stores control voltage information indicating an input voltage value to the tuning circuit for tuning the antenna to a frequency indicated by the frequency information in association with the frequency information,
The antenna control means controls a resonance frequency of the antenna by applying a voltage based on the control voltage information stored in the control information storage means to the tuning circuit;
The wireless communication device according to claim 2, wherein the wireless communication device is a wireless communication device. The wireless communication device is a mobile communication terminal.
The wireless communication apparatus according to claim 1, wherein the wireless communication apparatus is a wireless communication apparatus. In a mobile communication terminal equipped with an antenna whose resonance frequency can be changed by voltage control and controlling transmission power in response to a request from a base station,
Control information storage means for storing the frequency of the channel for communication and the control information indicating the control voltage for tuning the resonant frequency of the antenna to the frequency of the channel in association with each other;
In response to a channel switching request from the base station, channel switching means for switching a channel for communication;
Based on the control voltage indicated by the control information in response to the transmission power increase / decrease request when the transmission power increase / decrease request is received from the base station during communication at the channel frequency switched by the channel switching means. Antenna control means for performing voltage control to adjust the resonance frequency so as to maximize the gain of the antenna;
After adjusting the resonance frequency by the antenna control means, when receiving a transmission power reduction request from the base station, amplification control means for reducing the transmission output by the amplifier,
After the adjustment of the resonance frequency by the antenna control means, when either increase or decrease of transmission power is continuously requested from the base station, the resonance frequency of the antenna is shifted and shifted according to the request. Shift control means for shifting the resonance frequency in the reverse direction when the resonance frequency exceeds a preset range;
A mobile communication terminal comprising: In a computer that controls a mobile communication terminal that performs transmission power control in response to a request from a base station,
In response to a channel switching request from the base station, based on information indicating the frequency of each channel stored in the storage device, the function of tuning the antenna to the frequency of the requested channel;
A function of adjusting the resonance frequency so that the gain of the antenna is maximized in response to the increase / decrease request triggered by receiving the increase / decrease request for transmission power control from the base station;
After adjusting the resonance frequency, when receiving a request to reduce transmission power from the base station, a function to reduce the transmission output by the amplifier,
When either increase or decrease in transmission power is continuously requested from the base station after adjusting the resonance frequency, the resonance frequency is shifted according to the request, and the shifted resonance frequency is preset. When exceeding the range, the function of shifting the resonance frequency in the reverse direction;
A program characterized by realizing.

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