JP2007335995A - Radio signal transmitter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radio signal transmitter capable of suppressing deterioration in characteristics caused by variations in the temperature of a power amplifier appropriately, when a radio signal to be transmitted is a burst signal. <P>SOLUTION: A sum-of-power calculator 110 calculates the sum of power of the burst signal transmitted from a burst signal generator 101 within fixed time starting from current time. A temperature variation estimator 104 estimates the temperature variation value of the power amplifier 103 based on the calculated sum of power. A temperature corrector 106 calculates a current temperature correction value in the power amplifier 103, based on the temperature variation estimation value estimated by the temperature variation estimator 104. A control unit 105 uses the current temperature correction value to correct the detection temperature of the power amplifier 103 detected by a temperature sensor 107. A distortion/power control circuit 102 refers to the control table of the control unit 105, and corrects variations in the distortion and output power characteristics of the burst signal following the variations in temperature of the power amplifier 103 based on a detection temperature correction value. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a radio signal transmission apparatus in a radio signal transmission system such as mobile communication or a wireless LAN, and more particularly to a radio signal transmission apparatus that amplifies and transmits a burst signal transmitted by a frame or a packet.

  In the future, the transmission band of wireless signals such as mobile communication (cellular) communication and wireless LAN will increase from several hundred kHz to several tens of MHz, and data communication and video transmission services other than voice communication will be available. Along with this, the power consumption of the power amplifier (PA: Power-Amplifier) of the portable terminal increases, and as a result, the reduction of battery life and heat generation become major issues.

  On the other hand, the transmission power of a mobile terminal is required to have a wide dynamic range of about 70 dB to 90 dB in order to transmit a high-quality signal with little distortion and noise. However, since the amount of heat generated by the power amplifier changes according to the magnitude of each transmission power, the mobile terminal changes in operating temperature, which causes the transmission power to fluctuate or the distortion characteristics to deteriorate. . Therefore, various techniques for suppressing fluctuations in transmission power due to temperature fluctuations of the mobile terminal have been disclosed (see, for example, Patent Document 1).

  FIG. 4 is a block diagram illustrating a temperature compensation method for transmission power in a conventional radio signal transmission apparatus. In FIG. 4, the power detection unit 17 detects the output power of the power amplifier (PA) 3, and the gain control unit 18 is based on the detection result information from the power detection unit 17 and the transmission power information of the transmission power information unit 8. And if there is an error in both, a feedback signal is transmitted to the variable gain amplifier 16 so that the error becomes zero. In addition, a temperature sensor 7 is installed so as to reduce the influence of a temperature rise due to a change in environmental temperature or heat generated in the power amplifier (PA) 3. That is, the gain control unit 18 performs temperature correction based on the temperature information from the temperature sensor 7 so as to vary the signal transmitted to the variable gain amplifier 16 according to the temperature fluctuation. This makes it possible to compensate for fluctuations in output power due to temperature fluctuations in the power amplifier (PA) 3.

  Next, in order to suppress the heat generation of the portable terminal, there is a high efficiency as a problem required for the wireless signal transmission device. As one method for modulating or amplifying a transmission signal with high efficiency, a polar modulation method is generally used (see, for example, Patent Document 2).

FIG. 5 is a basic configuration diagram of a polar modulation circuit in a conventional radio signal transmission apparatus. In FIG. 5, a polar coordinate converter 11 decomposes baseband signals I (t) and Q (t) to be transmitted into a signal having an amplitude component r (t) and a signal having a phase component φ (t). Then, the signal of the amplitude component r (t) passes through the amplitude amplifier 12 and then is input to the power supply terminal of the power amplifier (PA) 3 at the final stage to perform power supply voltage modulation. On the other hand, the signal of the phase component φ (t) is generated by the phase modulator 13 after generating an RF (Radio Frequency) phase modulation signal (cos (2πf _C t + φ (t)), which is the center frequency f _C of the carrier (carrier wave). , The signal of the amplitude component r (t) and the signal of the phase component (cos (2πf _C t + φ (t)) are multiplied by the input to the power amplifier (PA) 3 in the final stage. ) 3 can generate and output a high-power radio signal (r · cos (2πf _C t + φ (t)).

  In such a polar modulation method, the power amplifier (PA) 3 can be switched in the saturation region, so that very efficient amplification can be performed. In addition, the polar modulation system generally has a function of compensating for distortion characteristic deterioration. As a distortion compensation method using polar modulation, there are a feedback (FB) method and a predistortion method. The predistortion method has a correction table corresponding to temperature and output power, and distortion compensation is performed when a polar coordinate digital signal is generated.

Therefore, FIG. 5 shows a configuration of a distortion compensation circuit using a predistortion method in a polar modulation circuit. In FIG. 5, the control unit 5 causes the music coordinate converter 11 to perform the polar modulation as described above based on the desired power value determined by the transmission power information of the transmission power information unit 8. In addition, the control unit 5 has a distortion correction table corresponding to the signal level, and an operation of applying predistortion (distortion correction) to the polar coordinate converter 11 based on information of the distortion correction table. Is going. As a result, distortion characteristics generated in amplitude modulation and phase modulation can be compensated. Furthermore, since the strain characteristic of the polar coordinate converter 11 has temperature dependence, the control unit 5 can compensate the temperature dependence of the strain characteristic based on the temperature information from the temperature sensor 7.
Japanese National Patent Publication No. 11-505380 JP-T-2004-501527

  However, the temperature compensation method using the temperature sensor in the conventional wireless signal transmission apparatus cannot perform temperature compensation when the temperature change of the power amplifier (PA) is fast because the response speed of the temperature sensor is slow. There is a case. In particular, this is expected to be a big issue in next-generation mobile communications. The reason will be described below.

  Data transmission in the second and third generation mobile communication systems is a circuit switching system. However, in the next generation mobile communication, the ratio of data communication other than voice communication increases, and equipment costs are mainly reduced. With the progress of IP (Internet-Protocol), the packet switching method becomes mainstream. That is, transmission signals in next-generation mobile communication are a collection of burst signals in units of time called frames or packets. A burst signal is a signal transmitted discontinuously on the time axis.

  On the other hand, in the next generation mobile communication, the power consumption of the power amplifier (PA) is increased in the time zone when there is no packet to be transmitted because the transmission rate of mobile terminals and the use service are required to reduce the power consumption. It seems that a so-called battery saving technique is required to turn off the power. Therefore, ON / OFF control of the power supply of the power amplifier (PA) is continuously repeated on the order of 0.1 msec to several msec, and the temperature fluctuation of the power amplifier (PA) increases accordingly. It will be. However, in the temperature compensation method using the temperature sensor in the conventional wireless signal transmission device, the temperature sensor and the power amplifier (PA) are separated from each other, and the response speed of the temperature sensor is low. PA) cannot be accurately compensated for temperature.

  The present invention has been made in view of the above points, and provides a radio signal transmission device capable of appropriately suppressing characteristic deterioration caused by temperature fluctuations of a power amplifier when a radio signal to be transmitted is a burst signal. For the purpose.

  When a burst signal transmitted by a frame or a packet is amplified and transmitted by a power amplifier, the radio signal transmission device of the present invention has a function of setting the drive current of the power amplifier to a standby current or less if no burst signal exists. A wireless signal transmission device having a power sum calculation means for calculating a power sum of burst signals transmitted within a certain time from the past to the present, and a power sum calculation result calculated by the power sum calculation means The temperature correction value calculating means for calculating the current temperature correction value of the power amplifier, the temperature detection means for detecting the temperature of the power amplifier, and the temperature detection means using the temperature correction value calculated by the temperature correction value calculation means Detection temperature correction means for correcting the detected temperature detected by the sensor, and a detected temperature correction value corrected by the detection temperature correction means, according to the temperature fluctuation of the power amplifier. It adopts a configuration and a characteristic variation correction means for correcting the variation of the characteristics of the burst signal.

  According to such a configuration, when the power sum calculation means calculates the power sum of the burst signals transmitted within a certain time period from the past to the present, the temperature correction value calculation means is based on the calculation result of the power sum. To calculate the current temperature correction value of the power amplifier. Then, the detected temperature correction means corrects the detected temperature of the power amplifier detected by the temperature detection means based on the calculated temperature correction value. As a result, the characteristic fluctuation correction unit appropriately corrects the characteristic fluctuation of the burst signal accompanying the temperature fluctuation of the power amplifier based on the correction value of the detected temperature. That is, according to the radio signal transmitting apparatus of the present invention, it is possible to estimate the temperature rise of the current power amplifier from the history of the current flowing in the power amplifier in the past and accurately compensate for the characteristic deterioration due to the temperature fluctuation.

  Note that the characteristic of the burst signal corrected by the characteristic variation correcting means is the distortion characteristic or output power characteristic of the radio signal transmitted from the power amplifier. Therefore, according to the radio signal transmitting apparatus of the present invention, the temperature compensation of the distortion compensation circuit and the temperature compensation of the output power can be reliably performed. The power sum calculation means calculates the power sum of the burst signal from the sum of the products of the length of the burst signal and the average power of the burst signal. Therefore, since the power sum can be calculated by simple digital signal processing, the temperature fluctuation can be estimated at a high speed and the temperature fluctuation estimation process can be simplified.

  In the radio signal transmitting apparatus of the present invention, the power amplifier can amplify the power of the burst signal by a switching operation in the saturation region. Furthermore, the power amplifier can also be applied to an amplifier using a polar modulation system that performs modulation by decomposing a burst signal into an amplitude component and a phase component. As a result, highly efficient power amplification can be performed. In particular, the feedforward polar modulation system is often premised on a distortion compensation function according to temperature. However, by adding a power amplifier to the digital processing unit of the polar signal generator, the distortion compensation function of the present invention is provided. Can be easily realized. Compared with the quadrature modulation method, the polar modulation method, which is a switching operation, has less distortion characteristics other than temperature fluctuations and power fluctuation deterioration factors during high-speed ON / OFF operation of the power amplifier. And output power characteristics become more stable.

  In the radio signal transmission device of the present invention, a switch for turning off the drive current flowing through the power amplifier may be provided when there is no burst signal to be transmitted. With this configuration, the power consumption of the power amplifier can be further reduced.

  According to the present invention, a radio signal to be transmitted is a burst signal, and a radio having a battery saving function for turning on / off the power of the power amplifier (PA) in order to suppress power consumption of the power amplifier (PA). In the signal transmission device, by estimating the temperature fluctuation due to self-heating of the power amplifier (PA), it is possible to appropriately suppress the distortion characteristic and the characteristic deterioration of the power characteristic due to the temperature fluctuation at high speed.

  Furthermore, even if the transmission rate of wireless communication becomes higher and packet transmission becomes mainstream in the future, the power amplifier battery is turned off in the mobile terminal by turning off the power amplifier when there is no packet signal to be transmitted. Consumption can be further reduced. Therefore, according to the radio signal transmitting apparatus of the present invention, it can be applied to an energy-saving next-generation mobile terminal.

<Summary of invention>
A radio signal transmission apparatus according to the present invention is a radio signal transmission apparatus having a function of setting a drive current of a power amplifier to a standby current (non-operation current) or less or zero when there is no burst signal to be transmitted. When a burst signal is amplified and transmitted by an amplifier, the current temperature rise of the power amplifier is estimated from the history of currents that flowed in the power amplifier in the past, and the power characteristics and distortion of the power amplifier are estimated based on the estimated temperature rise value. Temperature compensation for characteristics is performed. As a result, it is possible to accurately and rapidly compensate for deterioration of power characteristics and distortion characteristics due to temperature fluctuations of the power amplifier. In other words, it is possible to correct the distortion characteristics by estimating the current temperature rise from the past current history and performing temperature compensation of the distortion compensation circuit, or by estimating the current temperature rise from the past current history and power control By performing the above, it is possible to perform temperature compensation of the output power characteristics.

  As a specific method for estimating the temperature rise, the power sum of the burst signal is calculated from the sum of the products of the length of the burst signal received in the past and the average power of the burst signal. Then, the current temperature value of the power amplifier is estimated from the calculated power sum. As a result, the temperature fluctuation of the power amplifier can be estimated at a high speed, so that the temperature compensation of the distortion characteristics and the temperature compensation of the output power characteristics can be performed at high speed and easily. Such temperature compensation of the power amplifier based on the estimation of the temperature rise can be performed by any power amplifier of a polar modulation system or an orthogonal modulation system.

  Hereinafter, several embodiments of a radio signal transmitting apparatus according to the present invention will be described in detail with reference to the drawings. In the drawings used in the embodiments, the same components are denoted by the same reference numerals, and redundant description is omitted as much as possible.

<Embodiment 1>
FIG. 1 is a block diagram showing a configuration of a radio signal transmission apparatus according to Embodiment 1 of the present invention. This radio signal transmission apparatus is configured to perform power amplification by an orthogonal modulation method. First, the configuration of the wireless signal transmission device shown in FIG. 1 will be described. 1 includes a burst signal generator 101, a distortion / power control circuit 102, a power amplifier (PA) 103, a temperature fluctuation estimation unit 104, a control unit 105, a temperature correction unit 106, a temperature sensor 107, transmission power. The information unit 108, the switch 109, and the power sum calculation unit 110 are included.

  The burst signal generator 101 has a function of generating a burst signal in which signals are intermittent in time. The distortion / power control circuit (characteristic fluctuation correction means) 102 performs distortion characteristic control or power control of the burst signal accompanying the temperature fluctuation of the power amplifier (PA) 103 based on the detected temperature correction value corrected by the control unit 105. It has a function to correct characteristic fluctuations. The power amplifier (PA) 103 has a function of performing power amplification of the burst signal.

  The temperature fluctuation estimation unit 104 has a function of calculating a value of a current flowing from the burst signal to the power amplifier (PA) 103 and estimating a temperature rise of the power amplifier (PA) 103. The control unit (detected temperature correction means) 105 has a function of correcting the detected temperature detected by the temperature sensor 107 using the temperature correction value calculated by the temperature correction unit 106 while referring to the control table owned by itself. I have. The temperature correction unit (temperature correction value calculation means) 106 uses the estimated temperature rise value of the power amplifier (PA) 103 estimated by the temperature fluctuation estimation unit 104 based on the calculation result of the power sum calculated by the power sum calculation unit 110. Temperature correction function.

  The temperature sensor 107 has a function of measuring the temperature of the power amplifier (PA) 103. The transmission power information unit 108 has a function of transmitting transmission power information held by itself to the temperature fluctuation estimation unit 104 and the control unit 105. The switch 109 has a function of turning on / off the power of the power amplifier (PA) 103. The power sum calculation unit (power sum calculation means) 110 has a function of calculating the power sum of burst signals transmitted within a certain period of time from the past to the present, and transmitting the calculation result to the temperature fluctuation estimation unit 104. I have.

  Next, the operation of this radio signal transmitting apparatus will be described. The burst signal generated by the burst signal generator 101 is input to the distortion / power control circuit 102 to perform distortion characteristic control or power control. As a result, it is possible to compensate for distortion characteristics degradation at a predetermined transmission power and operating temperature, or to compensate for temperature fluctuations of the transmission power. The burst signal subjected to distortion characteristic deterioration compensation and transmission power temperature variation compensation in this way is amplified to a desired level by the power amplifier 103 and output.

  When the distortion characteristic control of the burst signal is performed, the distortion / power control circuit 102 functions as a circuit having a predistortion function. On the other hand, when power control of the burst signal is performed, the distortion / power control circuit 102 functions as a variable gain amplifier, for example. Such a distortion / power control circuit 102 controls distortion characteristics or power characteristics based on transmission power information held by the transmission power information section 108 and control table information held by the control section 105. The control table of the control unit 105 stores optimal control signals corresponding to each temperature based on information from the temperature sensor 107 that detects the operating temperature. As a result, it is possible to suppress deterioration due to temperature fluctuations of the distortion characteristics and power characteristics.

  In addition, while there is no burst signal to be transmitted, the power amplifier (PA) 103 turns off the driving current of the power amplifier (PA) 103 or sets it to a very small standby current, so that a wireless signal transmission device (for example, A battery saving function for reducing power consumption of the portable terminal) can be realized. The switch 109 can also turn on / off the power of the power amplifier (PA) 103 based on a signal from the burst signal generator 101. At this time, since it takes time until the operation of the power amplifier (PA) 103 is stabilized immediately after the power supply NO, a slight current (standby current) is allowed to flow without turning off the power of the power amplifier (PA) 103. In some cases, it may be more effective.

  As in the GSM (Global-System-for-Mobile-Communication) modulation method, the power amplifier (PA) 103 performs a switching operation with a constant amplitude of the transmission signal, and the distortion of the power amplifier (PA) 103 immediately after the power is turned on. When the deterioration of the characteristics and the amplitude characteristics can be ignored, the power supply and current when the power amplifier (PA) 103 is OFF may be completely turned OFF. In such a case, the power of the power amplifier (PA) 103 may be turned off by the switch 109.

  Further, in the present embodiment, the addition of the temperature fluctuation estimation unit 104 and the temperature correction unit 106 is a novel point compared to the prior art. Details of these functions will be described below.

  The temperature fluctuation estimation unit 104 calculates a current flowing through the power amplifier (PA) 103 from the burst signal. Thereby, since the self-heating amount in the power amplifier (PA) 103 is known, it is possible to estimate the temperature rise of the power amplifier (PA) 103. FIG. 2 is a burst signal that flows from the burst signal generator 101 shown in FIG. 1, where the horizontal axis indicates time and the vertical axis indicates the power value of the burst signal.

  As shown in FIG. 2, the burst signal is composed of data in units called frames or packets. Note that the frequency of occurrence of frames or packets is generally random. Therefore, when the transmitted frame or packet is dense, the power consumption of the power amplifier (PA) 103 increases within a certain time, and when there is not much frame or packet to be transmitted, within a certain time. The power consumption of the power amplifier (PA) 103 is reduced. Therefore, the temperature of the power amplifier (PA) 103 varies randomly according to the frequency of occurrence of burst signal frames (or packets).

  By utilizing the above, the temperature fluctuation of the power amplifier (PA) 103 can be estimated as follows. That is, the power sum calculation unit 110 obtains the total power of burst signals transmitted in the past for a certain time T from the current time shown in FIG. Here, a certain time T is a time constant related to the rate at which the heat generated by the power amplifier (PA) 103 diffuses, and the burst signal generated at this time T causes a local temperature increase due to the self-heating. It becomes. The value of the time T varies depending on the heat dissipation state of the power amplifier (PA) 103, and may be several milliseconds to several seconds, for example. In order for the power sum calculation unit 110 to obtain the total power of the burst signal, a method of electrically detecting power from the generated burst signal may be used. However, as a simpler method, digital signal processing is performed. Therefore, there is a method for obtaining the total power.

  Hereinafter, a method in which the power sum calculation unit 110 obtains the total power by performing digital signal processing will be described. The portable terminal holds information on the number of frames past T time from the current time and the transmission power information of each frame as known values. In addition, since the generation of the burst signal is often realized by an inexpensive high-speed digital processing circuit, the power sum calculation unit 110 receives information about the sum of each frame within the time T from the burst signal generator 101 and its transmission power. Is obtained as digital signal information, and the value is stored in the memory of the control unit 105.

  Note that the length of the burst signal, that is, the frame length is generally about 0.1 to several milliseconds, so temperature fluctuations occur on the order of milliseconds, but the temperature using a conventional temperature sensor In the measurement, since the distance between the power amplifier (PA) 103 and the temperature sensor 107 is long, such a fast temperature fluctuation cannot be measured accurately.

  Information on the total power calculated by the power sum calculation unit 110 as described above is immediately transmitted to the temperature fluctuation estimation unit 104. Then, the temperature fluctuation estimation unit 104 calculates the estimated temperature rise value of the power amplifier (PA) 103 based on the total power information received from the power sum calculation unit 110, and sends this estimated temperature rise value to the temperature correction unit 106. Send. Thus, the temperature correction unit 106 performs temperature correction based on the estimated temperature rise value on the detected temperature of the power amplifier (PA) 103 detected by the temperature sensor 107. As a result, it is possible to compensate for the effect of temperature fluctuations with a fast time constant due to self-heating of the power amplifier (PA) 103.

  That is, in order to realize the wireless signal transmission device of the present invention, the power sum calculation unit 110 that calculates the power sum of burst signals transmitted within a certain time from the past to the present, and the power sum calculation unit 110 include Based on the calculation result of the calculated power sum, a temperature correction unit 106 that calculates the current temperature correction value of the power amplifier (PA) 103, a temperature sensor 107 that detects the temperature of the power amplifier (PA) 103, and temperature correction The controller 105 corrects the detected temperature detected by the temperature sensor 107 using the temperature correction value calculated by the unit 106, and the temperature of the power amplifier (PA) 103 based on the detected temperature correction value corrected by the controller 105. It is necessary to provide a distortion / power control circuit 102 that corrects fluctuations in the characteristics of the burst signal due to fluctuations.

  The burst signal characteristics are distortion characteristics and output power characteristics of a radio signal transmitted from the power amplifier (PA) 103. Further, the power sum calculation unit 110 calculates the power sum of the burst signal from the total sum of the products of the length of the burst signal and the average power of the burst signal. Furthermore, the wireless signal transmission device can also include a switch 109 that turns off the drive current of the power amplifier (PA) 103 when there is no burst signal to be transmitted.

  According to the configuration as described above, the power sum calculation unit 110 calculates the power sum of the burst signal transmitted from the burst signal generator 101 within a certain time from the current time. Then, the temperature correction unit 106 calculates the current temperature correction value of the power amplifier (PA) 103 based on the calculation result of the power sum calculated by the power sum calculation unit 110. The control unit 105 corrects the detected temperature of the power amplifier (PA) 103 detected by the temperature sensor 107 using the temperature correction value calculated by the temperature correction unit 106. Further, the distortion / power control circuit 102 refers to the control table of the control unit 105, and based on the corrected detected temperature correction value, the distortion characteristics and power characteristics of the burst signal accompanying the temperature fluctuation of the power amplifier (PA) 103 are determined. Compensate for fluctuations.

<Embodiment 2>
FIG. 3 is a block configuration diagram of the radio signal transmitting apparatus according to the second embodiment of the present invention when the power amplifier is a polar modulation system. First, the configuration of the wireless signal transmission device shown in FIG. 3 will be described. The radio signal transmission apparatus includes a burst signal generator 101, a polar coordinate converter 111, an amplitude amplifier 112, a phase modulator 113, a power amplifier (PA) 103, a power sum calculation unit 110, a temperature fluctuation estimation unit 104, a control unit 105, a temperature The correction unit 106, the temperature sensor 107, and the transmission power information unit 108 are configured.

  The burst signal generator 101 has a function of inputting a transmission data signal and generating a burst signal. The polar coordinate converter 111 has a function of generating a polar modulation signal from a burst signal. The amplitude amplifier 112 has a function of amplifying the amplitude component signal decomposed by the polar coordinate converter 111. The phase modulator 113 has a function of generating an RF (Radio Frequency) phase modulation signal from the phase component signal decomposed by the polar coordinate converter 111. The power amplifier (PA) 103 has a function of performing power amplification of the phase component signal using the amplitude component signal as a power source.

  The power sum calculation unit 110 calculates the power sum of the burst signal transmitted within a certain time period from the past to the present based on the current value of the burst signal flowing from the burst signal generator 101 to the power amplifier (PA) 103. The calculation result is transmitted to the temperature fluctuation estimation unit 104. The temperature fluctuation estimation unit 104 estimates the temperature rise value of the power amplifier (PA) 103 based on the power sum information received from the power sum calculation unit 110 and transmits the temperature rise value information to the temperature correction unit 106. It has a function.

  The control unit 105 has a function of correcting the detected temperature detected by the temperature sensor 107 using the temperature correction value calculated by the temperature correction unit 106 while referring to the control table owned by itself. The temperature correction unit 106 has a function of performing temperature correction using the estimated temperature rise value of the power amplifier (PA) 103 estimated by the temperature fluctuation estimation unit 104 based on the power sum calculation result calculated by the power sum calculation unit 110. I have. The temperature sensor 107 has a function of measuring the temperature of the power amplifier (PA) 103. The transmission power information unit 108 has a function of transmitting transmission power information held by itself to the temperature fluctuation estimation unit 104 and the control unit 105.

  Since the configuration of polar modulation in the radio signal transmission device shown in FIG. 3 is a predistortion type like the configuration of polar modulation in the conventional radio signal transmission device shown in FIG. 5, a control unit having a distortion compensation table. 105 and the temperature sensor 107 already exist. Therefore, the radio signal transmission device of FIG. 3 applied to the second embodiment only needs to add only the power sum calculation unit 110, the temperature fluctuation estimation unit 104, and the temperature correction unit 106 to the conventional configuration. .

Next, an operation of normal polar modulation performed by the radio signal transmission device of FIG. 3 will be schematically described. When the burst signal generator 101 generates a burst signal and transmits the baseband signals I (t) and Q (t) to the polar coordinate converter 111, the polar coordinate converter 111 receives the received baseband signals I (t) and Q (t). (T) is decomposed into a signal having an amplitude component r (t) and a signal having a phase component φ (t). Then, the signal of the amplitude component r (t) passes through the amplitude amplifier 112 and is then input to the power supply terminal of the power amplifier (PA) 103 at the final stage to perform power supply voltage modulation. On the other hand, the signal of the phase component φ (t) is generated by the phase modulator 113 after generating an RF (Radio Frequency) phase modulation signal (cos (2πf _C t + φ (t)) that is the center frequency f _C of the carrier (carrier wave). , The signal of the amplitude component r (t) is multiplied by the signal of the phase component (cos (2πf _C t + φ (t)) by being input to the power amplifier (PA) 103 in the final stage. ) 103 can generate and output a high-power radio signal (r · cos (2πf _C t + φ (t)).

  As for the operation of the temperature compensation circuit, the power sum calculation unit 110 uses the burst signal of the burst signal generator 101 for a certain time from the current time in the same manner as in the first embodiment described above. The total power of the burst signal transmitted in time is calculated, and the temperature fluctuation estimation unit 104 determines the power based on the total power information from the power sum calculation unit 110 and the transmission power information acquired from the transmission power information unit 108. The instantaneous temperature fluctuation of the amplifier (PA) 103 is estimated. Then, the temperature correction unit 106 corrects the estimated temperature fluctuation value of the power amplifier (PA) 103 using the estimated temperature fluctuation value acquired from the temperature fluctuation estimation unit 104. As a result, the control unit 105 can compensate for the influence of the temperature fluctuation of the fast time constant due to the self-heating of the power amplifier (PA) 103 using the estimated correction value of the temperature fluctuation. That is, based on the detected temperature correction value, it is possible to correct fluctuations in burst signal characteristics (that is, distortion characteristics and power characteristics) due to temperature fluctuations in the power amplifier (PA) 103.

  In the quadrature modulation power amplifier according to the first embodiment of FIG. 1, a switch 109 needs to be newly provided in order to turn on / off the power amplifier (PA) 103 in accordance with the presence / absence of a burst signal. However, in the case of the polar modulation type power amplifier in the second embodiment of FIG. 3, if the amplitude of the burst signal to be transmitted is zero, the power source of the power amplifier (PA) 103 is necessarily automatically turned on. Since it is turned off, a switch for controlling the power amplifier (PA) 103 to be turned on / off is not necessary.

  Further, in the polar modulation method of FIG. 3, the power amplifier (PA) 103 performs power amplification of the burst signal by switching operation, so that the power amplifier (PA) 103 has the same structure as the orthogonal modulation method shown in FIG. It is rare that the characteristics become unstable immediately after turning on. Therefore, there is an advantage that battery saving control can be performed to obtain stable distortion characteristics and power characteristics.

  As described above, in the radio signal transmission apparatus having a battery saving function for turning on / off the power of the power amplifier in order to suppress the power consumption of the power amplifier, the radio signal to be transmitted is a burst signal. Distortion characteristics and output power characteristics fluctuate due to temperature fluctuations caused by self-heating. However, in the wireless signal transmission device of the present invention, the temperature rise of the power amplifier is estimated from the sum of the powers of the past burst signals, and the distortion characteristics and the output power characteristics are corrected, so that the distortion characteristics caused by the temperature fluctuations. And deterioration of output power characteristics can be appropriately suppressed.

  According to the radio signal transmitting apparatus of the present invention, temperature correction can be easily realized by estimating the temperature change due to self-heating of the power amplifier, and thus can be effectively used for the next generation mobile terminal.

1 is a block diagram showing a configuration of a radio signal transmission apparatus according to Embodiment 1 of the present invention. Burst signal flowing from the burst signal generator shown in FIG. Block configuration diagram of the radio signal transmission apparatus according to the second embodiment of the present invention when the power amplifier is a polar modulation system Block diagram showing a temperature compensation method of transmission power in a conventional radio signal transmission apparatus Basic configuration diagram of a polar modulation circuit in a conventional radio signal transmitter

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Burst signal generator 102 Distortion / power control circuit 103 Power amplifier (PA)
DESCRIPTION OF SYMBOLS 104 Temperature fluctuation estimation part 105 Control part 106 Temperature correction part 107 Temperature sensor 108 Transmission power information part 109 Switch 110 Power sum calculation part 111 Polar coordinate converter 112 Amplitude signal amplifier 113 Phase modulator

Claims (7)

When a burst signal transmitted by a frame or a packet is amplified and transmitted by a power amplifier, if the burst signal does not exist, the wireless signal transmission device has a function of setting the drive current of the power amplifier to a standby current or less. And
Power sum calculation means for calculating the power sum of burst signals transmitted within a certain period of time from the past to the present;
A temperature correction value calculating means for calculating a current temperature correction value of the power amplifier based on the calculation result of the power sum calculated by the power sum calculating means;
Temperature detecting means for detecting the temperature of the power amplifier;
Detection temperature correction means for correcting the detected temperature detected by the temperature detection means using the temperature correction value calculated by the temperature correction value calculation means;
A radio signal transmitting apparatus comprising: a characteristic fluctuation correcting unit that corrects fluctuations in characteristics of the burst signal due to temperature fluctuations of the power amplifier based on the detected temperature correction value corrected by the detected temperature correcting means. .   The radio signal transmission apparatus according to claim 1, wherein the characteristic of the burst signal is a distortion characteristic of a radio signal transmitted from the power amplifier.   The radio signal transmitting apparatus according to claim 1, wherein the characteristic of the burst signal is an output power characteristic of a radio signal transmitted from the power amplifier.   The power sum calculation means calculates the power sum of the burst signal from the sum of products of the length of the burst signal and the average power of the burst signal. The radio signal transmitting device according to item.   5. The radio signal transmission apparatus according to claim 1, wherein the power amplifier performs a switching operation to perform power amplification of the burst signal. 6.   6. The radio signal transmission device according to claim 1, wherein the power amplifier is an amplifier using a polar modulation method.   The wireless signal transmission device according to claim 1, further comprising a switch that turns off a current flowing through the power amplifier when there is no burst signal to be transmitted. .

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