JP2021197607A - Radio transmission device, base station, terminal device, mobile communication system, fixed wireless access system, radio transmission method, and program - Google Patents

Abstract

To suppress occurrence of a nonlinear distortion caused by an intermediate input power region in which a power gain partially decreased in a radio transmission device comprising a power amplifier including the intermediate input power region and having input/output characteristics.SOLUTION: A radio transmission device amplifies a transmission signal by a power amplifier including a nonlinear intermediate input power region in which a power gain partially decreased and having input/output characteristics. The radio transmission device comprises a power control unit which controls power of the transmission signal before power amplification so that power distribution of the transmission signal before amplification of power by the power amplifier becomes power distribution avoiding the nonlinear intermediate input power region.SELECTED DRAWING: Figure 1

Description

The present invention relates to radio transmission devices, base stations, terminal devices, mobile communication systems, fixed wireless access systems, and radio transmission methods and programs equipped with high-efficiency power amplifiers such as Doherty amplifiers.

Conventionally, a base station of a mobile communication system including a wireless transmission device using a high-efficiency Doherty amplifier is known (see Patent Document 1). The Doherty amplifier includes a power distributor that distributes the input signal, a main amplifier (also referred to as a "carrier amplifier") and a peak amplifier to which the signals distributed by the power distributor are input, respectively, and only the main amplifier at low output. At high output, both the main amplifier and the peak amplifier are operated at the same time.

Japanese Unexamined Patent Publication No. 2010-273018

In the above Doherty amplifier, the efficiency is generally maximized in the vicinity of the saturation region where the output power is saturated in the input / output power characteristics. Here, "efficiency" is the ratio of the output power of the amplified AC signal to the DC power input to the power amplifier. In the vicinity of the saturation region where this efficiency is maximized, the relationship between the input power and the output power becomes non-linear and exhibits non-linear characteristics. As a result, distortion and interference occur in the transmitted signal after power amplification, and the communication performance of wireless communication deteriorates.

As a technique for improving linearity without reducing efficiency in the vicinity of the saturation region, there is a kind of active linearization called "digital predistortion" (DPD).

However, even if active linearization is applied to improve the linearity near the saturation region, the low output operation mode that operates only the main amplifier and the high output operation mode that operates both the main amplifier and the peak amplifier at the same time. In the intermediate input power region where switching between be. In particular, non-linear distortion due to such input / output power characteristics including a non-linear intermediate input power region is more likely to occur as the efficiency of the power amplifier increases.

The wireless transmission device according to one aspect of the present invention is a wireless transmission device that amplifies a transmission signal by a power amplifier having input / output characteristics including a non-linear intermediate input power region in which the power gain is partially reduced. In this wireless transmission device, the power of the transmission signal before the power amplification is such that the power distribution of the transmission signal before the power amplification amplified by the power amplifier becomes the power distribution avoiding the non-linear intermediate input power region. It is provided with a power control unit for controlling.

In the wireless transmitter, the power amplifier has input / output characteristics including a linear low input power region, a non-linear intermediate input power region, and a linear high input power region, and the non-linear intermediate input power region. The avoided power distribution is such that the power portion of the power distribution of the transmission signal before the power amplification is larger than the first input power threshold located at the boundary between the low input power region and the intermediate input power region. The power distribution may be shifted to the high power side by the power width of the power region.

In the wireless transmitter, the power amplifier has input / output characteristics including a linear low input power region, a non-linear intermediate input power region, and a linear high input power region, and the non-linear intermediate input power region. The avoided power distribution is from the first input power threshold located at the boundary between the low input power region and the intermediate input power region after shifting the entire power distribution of the transmission signal before the power amplification to the low power side. The power distribution may be such that the large power portion is shifted to the high power side by the power width of the intermediate input power region.

In the wireless transmitter, the power amplifier has input / output characteristics including a linear low input power region, a non-linear intermediate input power region, and a linear high input power region, and the non-linear intermediate input power region. The avoided power distribution is larger than the first input power threshold located at the boundary between the low input power region and the intermediate input power region while maintaining the maximum power point of the power distribution of the transmitted signal before the power amplification. The power distribution may be such that the power portion is compressed to the high power side.

In the wireless transmitter, the power amplifier has input / output characteristics including a linear low input power region, a non-linear intermediate input power region, and a linear high input power region, and the non-linear intermediate input power region. The avoided power distribution is such that the power portion of the power distribution of the transmission signal before the power amplification is smaller than the second input power threshold located at the boundary between the intermediate input power region and the high input power region. The power distribution may be shifted to the low power side by the power width of the power region.

In the wireless transmission device, the power control unit inputs a digitally modulated signal generated based on transmission data, and the power distribution of the transmission signal before power amplification amplified by the power amplifier is a non-linear intermediate input. A DA converter that controls and outputs the digitally modulated signal so that the power distribution avoids the power region, and converts the digitally modulated signal output from the power control unit into an analog modulated signal, and a high-frequency carrier. Further, a carrier signal generation unit that generates a signal and a frequency conversion unit that converts the analog modulated signal output from the DA conversion unit into a high-frequency transmission signal after the carrier signal is input from the carrier signal generation unit. You may prepare.

In the wireless transmission device, a DA conversion unit that converts a digital modulation signal generated based on transmission data into an analog modulation signal, a carrier signal generation unit that generates a high-frequency carrier signal, and a carrier signal generation unit to the carrier. The power control unit further includes a frequency conversion unit for inputting a signal and converting the analog modulation signal output from the DA conversion unit into a high-frequency transmission signal, and the power control unit is a high-frequency transmission signal from the frequency conversion unit. Is input, and the high-frequency transmission signal is controlled and output so that the power distribution of the transmission signal before power amplification amplified by the power amplifier becomes a power distribution avoiding the non-linear intermediate input power region. You may.

In the wireless transmitter, the power amplifier may be a Doherty amplifier having input / output characteristics including the linear low input power region, the non-linear intermediate input power region, and the linear high input power region.

In the wireless transmission device, the power amplifier may be a high-efficiency power amplifier.

A base station of a mobile communication system or fixed wireless access (FWA) system according to another aspect of the present invention includes any of the above wireless transmission devices.

The terminal device of the mobile communication system or the fixed wireless access (FWA) system according to still another aspect of the present invention includes any of the above-mentioned wireless transmission devices.

The mobile communication system or fixed wireless access (FWA) system according to still another aspect of the present invention includes at least one of the base station and the terminal device.

A method according to still another aspect of the present invention is a power amplifier having input / output characteristics including an intermediate input power region in which a transmission signal generated by processing data to be transmitted is generated and the power gain is partially reduced. This is a wireless transmission method in which the power of a transmission signal is amplified and transmitted. In this wireless transmission method, the power of the transmission signal before the power amplification is such that the power distribution of the transmission signal before the power amplification amplified by the power amplifier becomes a power distribution avoiding the non-linear intermediate input power region. Including controlling.

A program according to still another aspect of the present invention uses a power amplifier having input / output characteristics including an intermediate input power region in which a transmission signal generated by processing data to be transmitted is generated and the power gain is partially reduced. A program executed by a computer or processor provided in a wireless transmission device that amplifies and transmits the power of a transmission signal. This program controls the power of the transmission signal before power amplification so that the power distribution of the transmission signal before power amplification amplified by the power amplifier becomes a power distribution avoiding the non-linear intermediate input power region. Includes program code to do.

According to the present invention, when the power amplifier that amplifies the transmission signal has input / output characteristics including an intermediate input power region in which the power gain is partially reduced, the occurrence of nonlinear distortion due to the intermediate input power region is generated. It can be suppressed.

The block diagram which shows one configuration example of the wireless transmission device which concerns on one Embodiment of this invention. The block diagram which shows an example of the Doherty amplifier which concerns on embodiment. The graph which shows an example of the efficiency and output of the Doherty amplifier which concerns on embodiment. The graph which shows an example of the power distribution of the input signal input to the Doherty amplifier which concerns on embodiment. The block diagram which shows an example (first power control example) of control of an amplifier input power in the power control part of the wireless transmission apparatus which concerns on embodiment. Explanatory drawing which shows an example of the relationship between the input / output characteristic of the Doherty amplifier in the 1st power control example, and the power distribution of an input signal after power control. An explanatory diagram showing an example of the relationship between the effective input / output characteristics of the Doherty amplifier and the power distribution of the output signal of the Doherty amplifier when the first power control example is implemented. FIG. 3 is a block diagram showing another example (second power control example) of controlling amplifier input power in the power control unit of the wireless transmission device according to the embodiment. Explanatory drawing which shows an example of the relationship between the input / output characteristic of the Doherty amplifier in the 2nd power control example, and the power distribution of an input signal after power control. Explanatory drawing which shows an example of the relationship between the effective input / output characteristic of a Doherty amplifier and the power distribution of an output signal of a Doherty amplifier when the second power control example is carried out. FIG. 3 is a block diagram showing still another example (third power control example) of control of amplifier input power in the power control unit of the wireless transmission device according to the embodiment. The explanatory view which shows an example of the relationship between the input / output characteristic of the Doherty amplifier and the power distribution of an input signal after power control in the 3rd power control example. An explanatory diagram showing an example of the relationship between the effective input / output characteristics of the Doherty amplifier and the power distribution of the output signal of the Doherty amplifier when the third power control example is implemented. FIG. 3 is a block diagram showing still another example (fourth power control example) of control of amplifier input power in the power control unit of the wireless transmission device according to the embodiment. An explanatory diagram showing an example of the relationship between the input / output characteristics of the Doherty amplifier and the power distribution of the input signal after power control in the fourth power control example. An explanatory diagram showing an example of the relationship between the effective input / output characteristics of the Doherty amplifier and the power distribution of the output signal of the Doherty amplifier when the fourth power control example is implemented. FIG. 3 is a block diagram showing a configuration example of a base station including a wireless transmitter (transmitter) including a Doherty amplifier according to an embodiment. (A) and (b) are graphs showing an example of the simulation result of the power distribution of the input signal and the output signal of the OFDM signal in each of the first power control example and the comparative example, respectively. (A) and (b) are graphs showing an example of the simulation result of the signal point arrangement of the OFDM signal after demodulation in each of the 1st power control example and the comparative example, respectively. (A) and (b) are graphs showing an example of the simulation result of the power distribution of the input signal and the output signal of the SC-FDMA signal in each of the first power control example and the comparative example, respectively. (A) and (b) are graphs showing an example of the simulation result of the signal point arrangement of the SC-FDMA signal after demodulation in each of the 1st power control example and the comparative example, respectively. (A) and (b) are graphs showing an example of the simulation result of the power distribution of the input signal and the output signal of the OFDM signal in the second power control example and the comparative example, respectively. (A) and (b) are graphs showing an example of the simulation result of the signal point arrangement of the OFDM signal after demodulation in each of the 2nd power control example and the comparative example, respectively. (A) and (b) are graphs showing an example of the simulation result of the power distribution of the input signal and the output signal of the SC-FDMA signal in the second power control example and the comparative example, respectively. (A) and (b) are graphs showing an example of the simulation result of the signal point arrangement of the SC-FDMA signal after demodulation in each of the 2nd power control example and the comparative example, respectively. (A) and (b) are graphs showing an example of the simulation result of the power distribution of the input signal and the output signal of the OFDM signal in the third power control example and the comparative example, respectively. (A) and (b) are graphs showing an example of the simulation result of the signal point arrangement of the OFDM signal after demodulation in each of the 3rd power control example and the comparative example, respectively. (A) and (b) are graphs showing an example of the simulation result of the power distribution of the input signal and the output signal of the SC-FDMA signal in each of the third power control example and the comparative example, respectively. (A) and (b) are graphs showing an example of the simulation result of the signal point arrangement of the SC-FDMA signal after demodulation in each of the 3rd power control example and the comparative example, respectively.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the configuration of the embodiment described below and the actions and effects obtained by the configuration are examples, and are not limited to the contents described below. Further, the wireless transmission device described in the following embodiment can be applied not only to a base station or terminal device of a mobile communication system, but also to a base station or terminal device of a fixed wireless access (FWA) system.

FIG. 1 is a block diagram showing a configuration example of a wireless transmission device 10 according to an embodiment of the present invention. In FIG. 1, the wireless transmission device 10 includes a power control unit 20, a power amplifier 30, and an antenna 40. The wireless transmission device 10 may include a transmission signal generation unit 50.

The power amplifier 30 is, for example, a Doherty amplifier illustrated later. The power amplifier 30 has an input / output characteristic including a non-linear intermediate input power region in which the power gain is partially reduced, and amplifies a transmission signal whose power is controlled by the power control unit 20. The transmission signal amplified by the power amplifier 30 is transmitted from the antenna 40.

In the power control unit 20, a transmission signal generated based on the transmission data by the transmission signal generation unit 50 is input, and the power distribution of the transmission signal before power amplification amplified by the power amplifier 30 is the non-linear intermediate input power. The power of the transmission signal before power amplification is controlled so that the power distribution avoids the region.

FIG. 2 is a block diagram showing an example of the configuration of the Doherty amplifier (power amplifier) 30 according to the present embodiment. The Doherty amplifier 30 is a high-efficiency power amplifier whose power efficiency in a low-distortion state in which the signal level of the input signal is relatively low and does not reach the saturation amplification state is higher than that of an amplifier according to another method. The Doherty amplifier 30 is particularly suitable for low distortion and high efficiency power amplification in a wide high frequency band (for example, microwave band or millimeter wave band of 100 MHz to 100 GHz), for example, mobile communication system or fixed wireless access (FWA) system. It can be applied to a wireless transmitter (transmitter) mounted on the wireless communication unit of the constituent base station.

Further, the Doherty amplifier 30 is a radio signal having a larger peak power than the average power, for example, a CDMA (Code Divisional Multiple Access) in a next-generation mobile communication system such as a third generation, a fourth generation, or a fifth generation. Back-off when power-amplifying a signal or a signal generated by a digital modulation method such as an OFDM (Oriental Frequency Division Multiple Access) or SC-FDMA (Single-Carrier Frequency Division Access) signal with a large point efficiency. Since it can be increased, it is suitable for a power amplifier of a transmitter mounted on a wireless communication device such as a base station (for example, eNodeB, gNodeB). The mobile communication system may include one or more wireless communication devices such as a base station (for example, eNodeB, gNodeB) using the Doherty amplifier 30 of the present embodiment as the power amplifier of the transmitter.

Further, the Doherty amplifier 30 power-amplifies a radio signal having a peak power higher than the average power, a CDMA signal in a fixed wireless access (FWA) system, and a signal generated by a digital modulation method such as an OFDM or SC-FDMA signal. It is also suitable for a power amplifier of a transmitter mounted on a wireless communication device such as a base station of a fixed wireless access (FWA) system because the efficiency can be improved at an operating point with a large backoff. The fixed wireless access (FWA) system may include one or more wireless communication devices such as a base station using the Doherty amplifier 30 of the present embodiment as the power amplifier of the transmitter.

Here, the "backoff" of the power amplifier is to operate the power amplifier with a power lower than the saturated output power Psat [dB] of the power amplifier as the maximum output power Pmax [dB] in the output power range. .. Further, the difference Psat-Pmax [dB] between the maximum output power Pmax [dB] and the saturated output power Psat [dB] of the power amplifier may be referred to as "backoff". This power difference Psat-Pmax [dB] is also referred to as "backoff margin", "backoff amount", or "backoff value". Further, the "efficiency" η of the power amplifier is the ratio of the output power P _{OUT of the amplified AC signal to the DC power P DC} input to the power amplifier, and is, for example, η = (P _OUT / P _DC ). It is represented by × 100 [%].

In FIG. 2, the Doherty amplifier 30 includes a first amplifier circuit 31, a second amplifier circuit 32, a power distributor 33, and an impedance conversion circuit 34.

The first amplifier circuit 31 includes a carrier amplifier 311, an input side circuit 312, and an output side circuit 313, and amplifies an input signal input from the outside. The carrier amplifier 311 is composed of, for example, a class A operation, a class AB operation or a class B operation amplifier in which the DC bias voltage is biased to a class A, class AB or class B operation reference point, and is mainly linear in input / output characteristics. In the region, the power of the whole waveform or the power of the half-cycle waveform of the input signal is amplified.

The input side circuit 312 is a circuit that adjusts the phase of the input signal with respect to the peak amplifier 321. Output circuit 313 has an impedance Z _{0 'for} adjusting the electrical length is constituted by transmission lines 1 (lambda / 4) of the quarter of the wavelength of the fundamental wave lambda, adjusting the output impedance of the carrier amplifier 311 It is a circuit to do.

The second amplifier circuit 32 is provided in parallel with the first amplifier circuit 31, includes a peak amplifier 321, an input side circuit 322, and an output side circuit 323, and the signal level (average power) of the input signal is higher than the threshold value. Amplifies the input signal when it is large. The peak amplifier 321 is composed of, for example, a class C operation amplifier in which the DC bias voltage is biased to a class C operating point, and in a region including a linear region and a non-linear region of input / output characteristics, only power near the peak of the input signal is supplied. Amplify.

The input side circuit 322 has the same impedance Z _{0 as the characteristic impedance Z 0} of the external load with respect to the fundamental wave of the input signal (output signal), and the electric length is 1/4 (λ / 4) of the wavelength λ of the fundamental wave. It is a circuit that adjusts the input impedance of the peak amplifier 321 and is composed of the transmission line of. The output side circuit 323 is a circuit that adjusts the phase of the output signal with respect to the carrier amplifier 311.

The Doherty amplifier 30 automatically switches between the low input amplification mode and the high input amplification mode according to the power level (instantaneous input power) of the input signal.

When the power level (instantaneous input power) of the input signal is low, the first amplifier circuit 31 is turned on and the second amplifier circuit 32 is turned off, so that the input signal is amplified only by the first amplifier circuit 31. Low input amplification mode. In the low input amplification mode, the carrier amplifier 311, for example, has a DC bias voltage biased to a class A, class AB, or class B operating reference point, so that amplification is performed regardless of the power level (instantaneous input power) of the input signal. And output the output signal. On the other hand, since the DC bias voltage of the peak amplifier 321 is biased to class C, when the power level (instantaneous input power) of the input signal is small, the peak amplifier 321 is in an off state, that is, the amplification operation is not performed and the amplification output is not generated. Further, since the DC power consumption of the peak amplifier 321 is 0 or sufficiently small, the efficiency of the Doherty amplifier 30 as a whole is high.

When the power level (instantaneous input power) of the input signal is high, both the first amplifier circuit 31 and the second amplifier circuit 32 are turned on, so that both the first amplifier circuit 31 and the second amplifier circuit 32 are in the ON state. The high input amplification mode is set in which the input signal is amplified. In the high input amplification mode, the peak amplifier 321 is turned on, the input signal to the peak amplifier 321 is amplified, and an output signal is generated. At this time, the output of the carrier amplifier 311 of the first amplifier circuit 31 and the output power of the peak amplifier 321 of the second amplifier circuit 32 are combined, and as a result, a power amplifier having a larger saturation power is configured.

The power distributor 33 is composed of, for example, a Wilkinson power distributor, distributes the power of the input signal at a predetermined distribution ratio, and supplies the input signal to each of the first amplifier circuit 31 and the second amplifier circuit 32.

The doherty amplifier 30 may be a symmetrical doherty amplifier or an asymmetrical doherty amplifier. The symmetrical Doherty amplifier is set so that the saturated output power of the carrier amplifier 311 and the saturated output power of the peak amplifier 321 are the same. On the other hand, the asymmetric type Doherty amplifier is set so that the saturated output power of the peak amplifier 321 is larger than the saturated output power of the carrier amplifier 311. For example, in a 1: 2 asymmetrical Doherty amplifier, the saturated output power of the peak amplifier 321 is set to "2" when the saturated output power of the carrier amplifier 311 is "1". In this asymmetric type Doherty amplifier, the power distribution ratio is input to the carrier amplifier 311 at "1", and the power distribution ratio is input to the peak amplifier 321 via the input side circuit 322 of the λ / 4 line. Will be done. In particular, the asymmetric Doherty amplifier can obtain a high efficiency η by power amplification at an operating point with a large backoff.

The impedance conversion circuit 34 outputs such that the output impedance at the synthesis point 35 of the output of the first amplifier circuit 31 and the output of the second amplifier circuit 32 and the load impedance connected to the Doherty amplifier 30 are impedance-matched. It has a function to convert impedance. This impedance matching is performed, for example, so that the relationship between the output impedance after conversion and the load impedance becomes a complex conjugate relationship. If impedance matching is not required, the impedance conversion circuit 34 may not be provided.

FIG. 3 is a graph showing an example of the efficiency and output of the Doherty amplifier 30 according to the embodiment. The curve C101 in FIG. 3 is an input / output characteristic indicating the output power Pout [dBm] with respect to the input power Pin [dBm] of the Doherty amplifier 30. The curve C102 is the efficiency of the Doherty amplifier 30, and is also called the drain efficiency when an FET is used in the amplifier, for example. The drain efficiency is the ratio of the output power P _{OUT of the amplified AC signal to the DC power P DC} supplied to the drain of the FET η = (P _OUT / P _DC ) × 100 [%].

As shown in the curve C101 of FIG. 3, the Doherty amplifier 30 has a linear low input power region P0 to P1 (inclination: a), a non-linear intermediate input power region P1 to P2, and a linear high input power region P2 to Pmax. It has input / output characteristics including (inclination: b (> a)). The intermediate input power regions P1 to P2 are regions in which a low output operation mode in which only the carrier amplifier 311 is operated and a high output operation mode in which both the carrier amplifier 311 and the peak amplifier 321 are operated at the same time are switched. The intermediate input power regions P1 to P2 of this input / output characteristic are non-linear parts in which the gain (power gain) of the output power Pout with respect to the input power Pin is partially reduced. When a transmission signal having power in the intermediate input power regions P1 to P2 is input to the Doherty amplifier 30 and power is amplified, non-linear distortion may occur in the output signal after power amplification.

Therefore, in the wireless transmission device 10 of the present embodiment, in order to suppress the generation of nonlinear distortion caused by the intermediate input power regions P1 to P2, the power distribution of the transmission signal before the power amplification amplified by the Doherty amplifier 30 is described above. A power control unit 20 for controlling the power of the transmission signal before power amplification (hereinafter, also referred to as “amplifier input power”) is provided so that the power distribution avoids the non-linear intermediate input power regions P1 to P2.

Hereinafter, a plurality of power control examples in which the function of controlling the amplifier input power in the power control unit 20 is realized by the digital signal processing circuit will be described. The function of the power control unit 20 may be configured to be realized by an analog signal processing circuit, or may be configured to realize software (program) that can be executed by a computer or a processor.

FIG. 4 is a graph showing an example of the power distribution of the transmission signal (hereinafter, also referred to as “input signal”) input to the Doherty amplifier 30 in the following power control example. FIG. 4 is an example in which the input signal input to the Doherty amplifier 30 is an OFDM signal generated by a baseband processing unit or the like of a base station. The horizontal axis of FIG. 4 is the input power Pin of the input signal (OFDM signal) input to the Doherty amplifier 30, and the vertical axis is the unit period (for example, 1 per unit time) counted for each input power Pin. It is the cumulative number of appearances per radio frame or multiple radio frames). (The same applies to FIGS. 6, 9, 12, 15, and simulation results described later).

[First power control example]
FIG. 5 is a block diagram showing an example (first power control example) of controlling the amplifier input power in the power control unit 20 of the wireless transmission device according to the embodiment. FIG. 6 is an explanatory diagram showing an example of the relationship between the input / output characteristics of the Doherty amplifier 30 and the power distribution of the input signal after power control in the first power control example. FIG. 7 is an explanatory diagram showing an example of the relationship between the effective input / output characteristics of the Doherty amplifier 30 and the power distribution of the output signal of the Doherty amplifier 30 when the first power control example is implemented. The horizontal axis of FIG. 7 is the power (hereinafter, also referred to as “output power”) Pout of the output signal (transmission signal) output from the Doherty amplifier 30, and the vertical axis is a predetermined value counted for each output power Pout. It is the cumulative number of occurrences per unit period (for example, per unit time, per radio frame, or per multiple radio frames) (the same applies to FIGS. 10, 13, 16 and simulation results described later).

In the first power control example, the input power is set so that the power distribution of the input signal before being amplified by the Doherty amplifier 30 is a power distribution avoiding the non-linear intermediate input power regions P1 to P2 shown in the lower figure of FIG. I'm in control. The power distribution avoiding the intermediate input power regions (P1 to P2) is the boundary between the linear low input power region (0 to P1) and the non-linear intermediate input power region (P1 to P2) in the power distribution of the input signal. It is a power distribution in which a power portion larger than the first input power threshold value (hereinafter referred to as “first threshold value”) P1 located in is shifted to the higher power side by the power width of the intermediate input power region (P1 to P2). ..

In FIG. 5, when an input signal is input to the power control unit 20, the power (input power) Pin of the input signal is calculated (S201), and the calculated input power Pin and the first threshold value P1 are compared (S202). ). When the input power Pin is larger than the first threshold P1, the new input power Pin'= (Pin-) is used to shift the input power Pin to the higher power side by the power width of the intermediate input power region (P1 to P2). P1) + P2 is calculated (S203), a complex signal is synthesized using the calculated new input power Pin'and the angle information (S204) acquired from the input signal (S205), and is output as a new input signal. On the other hand, in the comparison of S202, when the input power Pin is equal to or less than the first threshold value P1, the input signal input to the power control unit 20 is output as it is (S206).

When an input signal having the power distribution shown in the lower figure of FIG. 6 controlled by the power control unit 20 of FIG. 5 is input to the Doherty amplifier 30 having the input / output characteristics shown in the upper figure of FIG. 6, a non-linear intermediate input is input. The input signal amplified in the power region (P1 to P2) disappears or becomes extremely small, and as shown in the lower figure of FIG. 7, a non-linear distortion having almost the same profile as the power distribution of the input signal input to the power control unit 20. The output signal in which is suppressed is output from the Doherty amplifier 30. As a result, the occurrence of error vector amplitude (EVM) can be reduced. As shown in the upper figure of FIG. 7, the effective input / output characteristics of the Doherty amplifier 30 are such that the portion corresponding to the non-linear intermediate input power region P1 to P2 is suppressed and the linear low input power region (0 to P1) is suppressed. The characteristic includes a portion of the power gain (inclination: a) of the above and a portion of the power gain (inclination: b (> a)) in the linear high input power region (P2 to Pmax).

[Second power control example]
FIG. 8 is a block diagram showing another example (second power control example) of controlling the amplifier input power in the power control unit 20 of the wireless transmission device according to the embodiment. FIG. 9 is an explanatory diagram showing an example of the relationship between the input / output characteristics of the Doherty amplifier 30 and the power distribution of the input signal after power control in the second power control example. FIG. 10 is an explanatory diagram showing an example of the relationship between the effective input / output characteristics of the Doherty amplifier 30 and the power distribution of the output signal of the Doherty amplifier 30 when the second power control example is implemented.

In the second power control example, the input power is set so that the power distribution of the input signal before being amplified by the Doherty amplifier 30 is a power distribution avoiding the non-linear intermediate input power regions P1 to P2 shown in the lower figure of FIG. I'm in control. The power distribution avoiding this intermediate input power region (P1 to P2) shifts (backs off) the entire power distribution of the input signal to the low power side (P2-P1 minutes), and then linearly low input power region (P2-P1 minutes). The power portion larger than the first threshold P1 located at the boundary between 0 to P1) and the non-linear intermediate input power region (P1 to P2) is on the high power side by the power width of the intermediate input power region (P1 to P2). The power distribution is shifted to.

In FIG. 8, when an input signal is input to the power control unit 20, the power (input power) Pin of the input signal is calculated (S211), and the entire power distribution of the input signal is shifted to the low power side. The intermediate input power Pin'= Pin− (P2-P1) is calculated (S212), and the calculated intermediate input power Pin'is compared with the first threshold P1 (S213). When the intermediate input power Pin'is larger than the first threshold P1, the intermediate input power Pin' is newly shifted (backed off) to the higher power side by the power width of the intermediate input power region (P1 to P2). The input power Pin'' = (Pin'-P1) + P2 is calculated (S214), and the complex signal is synthesized using the calculated new input power Pin'' and the angle information (S215) acquired from the input signal (S214). S216), it is output as a new input signal. On the other hand, in the comparison of S213, when the intermediate input power Pin'is equal to or less than the first threshold value P1, the intermediate input power Pin'calculated in step 212 and the angle information (S218) acquired from the input signal are used. The complex signal is synthesized (S219) and output as a new input signal (S220).

When an input signal having the power distribution shown in the lower figure of FIG. 9 controlled by the power control unit 20 of FIG. 8 is input to the Doherty amplifier 30 having the input / output characteristics shown in the upper figure of FIG. 9, a non-linear intermediate input is input. The input signal amplified in the power region (P1 to P2) disappears or becomes extremely small, and as shown in the lower figure of FIG. 10, the non-linear distortion having almost the same profile as the power distribution of the input signal input to the power control unit 20. The output signal in which is suppressed is output from the Doherty amplifier 30. As a result, the occurrence of error vector amplitude (EVM) can be reduced. As shown in the upper figure of FIG. 10, the effective input / output characteristics of the Doherty amplifier 30 are such that the portion corresponding to the non-linear intermediate input power region P1 to P2 is suppressed and the linear low input power region (0 to P1) is suppressed. The characteristic includes a portion of the power gain (inclination: a) of the above and a portion of the power gain (inclination: b (> a)) in the linear high input power region (P2 to Pmax).

In particular, in the case of the second power control, as shown in the lower figure of FIG. 10, there is no overflow in which the power of the input signal exceeds the maximum power point (maximum allowable input power) Pmax, so that an error vector amplitude (EVM) is further generated. Can be reduced.

[Third power control example]
FIG. 11 is a block diagram showing still another example (third power control example) of controlling the amplifier input power in the power control unit 20 of the wireless transmission device according to the embodiment. FIG. 12 is an explanatory diagram showing an example of the relationship between the input / output characteristics of the Doherty amplifier 30 and the power distribution of the input signal after power control in the third power control example. FIG. 13 is an explanatory diagram showing an example of the relationship between the effective input / output characteristics of the Doherty amplifier 30 and the power distribution of the output signal of the Doherty amplifier 30 when the third power control example is implemented.

In the third power control example, the input power is set so that the power distribution of the input signal before being amplified by the Doherty amplifier 30 is a power distribution avoiding the non-linear intermediate input power regions P1 to P2 shown in the lower figure of FIG. I'm in control. The power distribution avoiding the intermediate input power regions (P1 to P2) is a linear low input power region (0 to P1) and a non-linear intermediate input power region while maintaining the maximum power point Pmax of the input signal power distribution. It is a power distribution in which a power portion larger than the first threshold P1 located at the boundary with (P1 to P2) is compressed to the high power side (P2 to Pmax).

In FIG. 11, when an input signal is input to the power control unit 20, the power (input power) Pin of the input signal is calculated (S221), and the calculated input power Pin and the first threshold P1 are compared (S222). ). When the input power Pin is larger than the first threshold P1, the power portion larger than the first threshold P1 is compressed to the high power side (P2 to Pmax) while maintaining the maximum power point Pmax of the power distribution of the input signal. In order to make the distribution, the new input power Pin'= (Pin-P1) × (Pmax-P2) / (Pmax-P1) + P2 is calculated (S223), and the calculated new input power Pin'and the input signal are obtained. A complex signal is synthesized (S225) using the angle information (S224), and is output as a new input signal. On the other hand, in the comparison of S222, when the input power Pin is equal to or less than the first threshold value P1, the input signal input to the power control unit 20 is output as it is (S226).

When an input signal having the power distribution shown in the lower figure of FIG. 12 controlled by the power control unit 20 of FIG. 11 is input to the Doherty amplifier 30 having the input / output characteristics shown in the upper figure of FIG. 12, a non-linear intermediate input is input. The input signal amplified in the power region (P1 to P2) disappears or becomes extremely small, and as shown in the lower figure of FIG. 13, a non-linear distortion having almost the same profile as the power distribution of the input signal input to the power control unit 20. The output signal in which is suppressed is output from the Doherty amplifier 30. As a result, the occurrence of error vector amplitude (EVM) can be reduced. As shown in the upper figure of FIG. 13, the effective input / output characteristics of the Doherty amplifier 30 are such that the portion corresponding to the non-linear intermediate input power region P1 to P2 is suppressed and the linear low input power region (0 to P1) is suppressed. The characteristic includes a portion of the power gain (inclination: a) of the above and a portion of the power gain (inclination: a) in the linear high input power region (P2 to Pmax).

In particular, in the case of the third power control, as shown in the upper figure of FIG. 13, the power gain (inclination: a) in the low input power region (0 to P1) and the power gain in the high input power region (P2 to Pmax). Since (inclination: a) is the same or almost the same, the entire Doherty amplifier 30 becomes a linear amplifier. Further, as shown in the lower figure of FIG. 13, since the power of the input signal does not overflow exceeding the maximum allowable input power Pmax, the occurrence of the error vector amplitude (EVM) can be further reduced.

[Fourth power control example]
FIG. 14 is a block diagram showing an example (fourth power control example) of controlling the amplifier input power in the power control unit 20 of the wireless transmission device according to the embodiment. FIG. 15 is an explanatory diagram showing an example of the relationship between the input / output characteristics of the Doherty amplifier 30 and the power distribution of the input signal after power control in the fourth power control example. FIG. 16 is an explanatory diagram showing an example of the relationship between the effective input / output characteristics of the Doherty amplifier 30 and the power distribution of the output signal of the Doherty amplifier 30 when the fourth power control example is implemented.

In the fourth power control example, the input power is set so that the power distribution of the input signal before being amplified by the Doherty amplifier 30 is a power distribution avoiding the non-linear intermediate input power regions P1 to P2 shown in the lower figure of FIG. I'm in control. The power distribution avoiding the intermediate input power region (P1 to P2) is the boundary between the non-linear intermediate input power region (P1 to P2) and the linear high input power region (P2 to Pmax) in the power distribution of the input signal. It is a power distribution in which the power portion smaller than the second input power threshold value (hereinafter referred to as “second threshold value”) P2 located in is shifted to the low power side by the power width of the intermediate input power region (P1 to P2). ..

In FIG. 14, when an input signal is input to the power control unit 20, the power (input power) Pin of the input signal is calculated (S231), and the calculated input power Pin and the second threshold value P2 are compared (S232). ). When the input power Pin is smaller than the second threshold P2, the new input power Pin'= Pin- (in order to shift the input power Pin to the lower power side by the power width of the intermediate input power region (P1 to P2)) P2-P1) is calculated (S233), a complex signal is synthesized (S235) using the calculated new input power Pin'and the angle information (S234) acquired from the input signal, and is output as a new input signal. .. On the other hand, in the comparison of S232, when the input power Pin is the second threshold value P2 or more, the input signal input to the power control unit 20 is output as it is (S236).

When an input signal having the power distribution shown in the lower figure of FIG. 15 controlled by the power control unit 20 of FIG. 14 is input to the Doherty amplifier 30 having the input / output characteristics shown in the upper figure of FIG. 15, a non-linear intermediate input is input. Non-linear distortion having almost the same profile as the power distribution of the input signal input to the power control unit 20 as shown in the lower figure of FIG. 16 as the input signal amplified in the power region (P1 to P2) disappears or becomes extremely small. The output signal in which is suppressed is output from the Doherty amplifier 30. As a result, the occurrence of error vector amplitude (EVM) can be reduced. As shown in the upper figure of FIG. 16, the effective input / output characteristics of the Doherty amplifier 30 are such that the portion corresponding to the non-linear intermediate input power region P1 to P2 is suppressed, and the linear low input power region (0 to P1) is suppressed. The characteristic includes a portion of the power gain (inclination: a) of the above and a portion of the power gain (inclination: b (> a)) in the linear high input power region (P2 to Pmax).

In particular, in the case of the fourth power control, as shown in the lower figure of FIG. 16, there is no overflow in which the power of the input signal exceeds the maximum power point (maximum allowable input power) Pmax, so that an error vector amplitude (EVM) is further generated. Can be reduced.

FIG. 17 is a block diagram showing a configuration example of a base station 60 of a mobile communication system including a wireless transmitter (transmitter) 10 including a Doherty amplifier 30 according to an embodiment.
In FIG. 17, the base station 60 includes an antenna 61, a radio unit 62, a data processing unit 63, a NW (network) communication unit 64, a control unit 65, and a storage unit 66. The antenna 61 is connected to the radio unit 62 via a transmission / reception duplexer (DUP: Duplexer) or the like.

The radio unit 62 has a receiver having a low noise high frequency amplifier and a frequency converter, and a transmitter (radio transmitter) having a transmission power amplifier and a frequency converter, and transmits and receives radio signals via the antenna 61. I do. The transmitter constituting the radio unit 62 includes the power control unit 20 described above and the Doherty amplifier 30 described above as a transmission power amplifier.

The data processing unit 63 performs demodulation and decoding processing of the received signal received from the wireless unit 62 to restore the received data, and encodes and modulates the transmission data to generate a transmission signal to generate the transmission signal 62. Or give it to. The power control unit 20 described above may be provided at the final stage of the data processing unit 63.

The NW communication unit 64 communicates with the core network of the mobile communication network via a predetermined interface, transmits the received data to the core network, and receives the data to be transmitted and the control information from the core network.

The control unit 65 controls the radio unit 62 and the data processing unit 63 based on the control information by executing the control program incorporated in advance. The storage unit 66 stores received data, transmission data, control programs, control information, and the like.

The base station 60 in FIG. 17 is a separate device for an RRH (remote radio head) having an antenna 61 and a radio unit 62, and a BBU (baseband unit) having a data processing unit 63 and a NW communication unit 64. RRH and BBU may be connected by a high-speed communication interface such as an optical fiber line.

Further, the above-mentioned wireless transmission device 10 may be applied to a transmitter that transmits an uplink signal in a terminal device that communicates with a base station of a mobile communication system. The mobile communication system may include at least one of the base station and the terminal device according to the present embodiment.

Further, the above-mentioned wireless transmission device 10 may be applied to a transmitter that transmits an uplink signal in a terminal device that communicates with a base station of a fixed wireless access (FWA) system. The fixed wireless access (FWA) system may include at least one of the base station and the terminal device according to the present embodiment.

Further, in the wireless transmitter (transmitter) 10 of the base station 60, the power control unit 20 has, for example, a digitally modulated signal (for example, an OFDM signal or an SC-FDMA signal) generated based on transmission data by a BBU or the like. The digitally modulated signal is controlled and output so that the power distribution of the transmitted signal before power amplification, which is input and amplified by the Doherty amplifier 30, is a power distribution avoiding the non-linear intermediate input power region. It may be configured. In this case, the wireless transmitter (transmitter) 10 has a DA conversion unit that converts a digital modulation signal output from the power control unit 20 into an analog modulation signal, a carrier signal generation unit that generates a high-frequency carrier signal, and a carrier. A frequency conversion unit may be provided, in which a carrier signal is input from the signal generation unit and the analog modulation signal output from the DA conversion unit is converted into a high-frequency transmission signal.

Further, the wireless transmitter (transmitter) 10 of the base station 60 converts a digitally modulated signal (for example, an OFDM signal or an SC-FDMA signal) generated based on transmission data by a BBU or the like into an analog modulated signal. A carrier signal generator that generates a high-frequency carrier signal, and a frequency converter that converts an analog modulated signal that is input from the carrier signal generator and output from the DA converter into a high-frequency transmission signal. You may prepare. In this case, the power control unit 20 receives a high frequency transmission signal from the frequency conversion unit, and the power distribution of the transmission signal before power amplification amplified by the Doherty amplifier 30 avoids the non-linear intermediate input power region. The high frequency transmission signal may be controlled and output so as to have a power distribution.

Next, with respect to the above-mentioned first power control example to third power control example, the power distribution and power of the input signal and the output signal when the digital modulation signal (OFDM signal or SC-FDMA signal) is power-amplified by the Doherty amplifier 30. The result of the computer simulation which evaluated the reproducibility of the signal point when demodulating the signal after amplification will be described. In the results of the following simulations, the results when the power control of this embodiment is not performed are also shown as comparative examples. Commercially available numerical analysis software (MATLAB (registered trademark) manufactured by MathWorks Inc.) was used for computer simulation, and the modulation method was 16QAM (Quadrature Amplitude Modulation).

18 (a) and 18 (b) are graphs showing an example of the simulation result of the power distribution of the input signal and the output signal of the OFDM signal in each of the first power control example and the comparative example described above, respectively. As shown in FIG. 18A, when the OFDM signal after controlling the power in the first power control example is input to the Doherty amplifier 30 and amplified, the OFDM signal in which the nonlinear distortion is suppressed can be output. .. On the other hand, as shown in FIG. 18B, the comparative example in which the OFDM signal is input to the Doherty amplifier 30 and amplified without power control corresponds to the above-mentioned nonlinear intermediate input power regions P1 to P2. Distortion occurs in the output voltage at the position.

19 (a) and 19 (b) are graphs showing an example of simulation results of signal point arrangement of the OFDM signal after demodulation in each of the first power control example and the comparative example described above, respectively. As shown in FIG. 19A, when the OFDM signal after controlling the power in the first power control example is input to the Doherty amplifier 30 and amplified, the fluctuation (variation) of the position of the signal point of the OFDM signal is small. .. On the other hand, as shown in FIG. 19B, in the comparative example in which the OFDM signal is input to the Doherty amplifier 30 and amplified without power control, the fluctuation (variation) of the position of the signal point of the OFDM signal is large. ..

20 (a) and 20 (b) are graphs showing an example of a simulation result of the power distribution of the input signal and the output signal of the SC-FDMA signal in each of the first power control example and the comparative example described above, respectively. As shown in FIG. 20A, when the SC-FDMA signal after power control in the first power control example is input to the Doherty amplifier 30 and amplified, the SC-FDMA signal with suppressed nonlinear distortion is output. can do. On the other hand, as shown in FIG. 20B, in the comparative example in which the SC-FDMA signal is input to the Doherty amplifier 30 and amplified without power control, the above-mentioned nonlinear intermediate input power regions P1 to P2 are used. Distortion occurs in the output voltage at the corresponding position.

21 (a) and 21 (b) are graphs showing an example of the simulation result of the signal point arrangement of the SC-FDMA signal after demodulation in each of the first power control example and the comparative example described above, respectively. As shown in FIG. 21 (a), when the SC-FDMA signal after power control in the first power control example is input to the Doherty amplifier 30 and amplified, the position of the signal point of the SC-FDMA signal changes ( Variation) is small. On the other hand, as shown in FIG. 21B, in the comparative example in which the SC-FDMA signal is input to the Doherty amplifier 30 and amplified without power control, the position of the signal point of the SC-FDMA signal fluctuates (). (Variation) is large.

22 (a) and 22 (b) are graphs showing an example of the simulation result of the power distribution of the input signal and the output signal of the OFDM signal in the second power control example and the comparative example described above, respectively. As shown in FIG. 22A, when the OFDM signal after controlling the power in the second power control example is input to the Doherty amplifier 30 and amplified, the OFDM signal in which the nonlinear distortion is suppressed can be output. .. On the other hand, as shown in FIG. 22B, the comparative example in which the OFDM signal is input to the Doherty amplifier 30 and amplified without power control corresponds to the above-mentioned nonlinear intermediate input power regions P1 to P2. Distortion occurs in the output voltage at the position.

23 (a) and 23 (b) are graphs showing an example of simulation results of signal point arrangement of the OFDM signal after demodulation in each of the above-mentioned second power control example and comparative example, respectively. As shown in FIG. 23A, when the OFDM signal after controlling the power in the second power control example is input to the Doherty amplifier 30 and amplified, the fluctuation (variation) of the position of the signal point of the OFDM signal is small. .. On the other hand, as shown in FIG. 23B, in the comparative example in which the OFDM signal is input to the Doherty amplifier 30 and amplified without power control, the fluctuation (variation) of the position of the signal point of the OFDM signal is large. ..

FIGS. 24 (a) and 24 (b) are graphs showing an example of the simulation results of the power distribution of the input signal and the output signal of the SC-FDMA signal in the second power control example and the comparative example described above, respectively. As shown in FIG. 24A, when the SC-FDMA signal after power control in the second power control example is input to the Doherty amplifier 30 and amplified, the SC-FDMA signal with suppressed nonlinear distortion is output. can do. On the other hand, as shown in FIG. 24B, in the comparative example in which the SC-FDMA signal is input to the Doherty amplifier 30 and amplified without power control, the above-mentioned nonlinear intermediate input power regions P1 to P2 are used. Distortion occurs in the output voltage at the corresponding position.

25 (a) and 25 (b) are graphs showing an example of simulation results of signal point arrangement of SC-FDMA signal after demodulation in each of the above-mentioned second power control example and comparative example, respectively. As shown in FIG. 25 (a), when the SC-FDMA signal after power control in the second power control example is input to the Doherty amplifier 30 and amplified, the position of the signal point of the SC-FDMA signal changes ( Variation) is small. On the other hand, as shown in FIG. 25B, in the comparative example in which the SC-FDMA signal is input to the Doherty amplifier 30 and amplified without power control, the position of the signal point of the SC-FDMA signal fluctuates (). (Variation) is large.

26 (a) and 26 (b) are graphs showing an example of a simulation result of the power distribution of the input signal and the output signal of the OFDM signal in each of the above-mentioned third power control example and comparative example, respectively. As shown in FIG. 26A, when the OFDM signal after controlling the power in the third power control example is input to the Doherty amplifier 30 and amplified, the OFDM signal in which the nonlinear distortion is suppressed can be output. .. On the other hand, as shown in FIG. 26B, the comparative example in which the OFDM signal is input to the Doherty amplifier 30 and amplified without power control corresponds to the above-mentioned nonlinear intermediate input power regions P1 to P2. Distortion occurs in the output voltage at the position.

27 (a) and 27 (b) are graphs showing an example of simulation results of signal point arrangement of the OFDM signal after demodulation in each of the above-mentioned third power control example and comparative example, respectively. As shown in FIG. 27 (a), when the OFDM signal after controlling the power in the third power control example is input to the Doherty amplifier 30 and amplified, the fluctuation (variation) of the position of the signal point of the OFDM signal is small. .. On the other hand, as shown in FIG. 27 (b), in the comparative example in which the OFDM signal is input to the Doherty amplifier 30 and amplified without power control, the fluctuation (variation) of the position of the signal point of the OFDM signal is large. ..

28 (a) and 28 (b) are graphs showing an example of the simulation result of the power distribution of the input signal and the output signal of the SC-FDMA signal in each of the above-mentioned third power control example and comparative example, respectively. As shown in FIG. 28A, when the SC-FDMA signal after power control in the third power control example is input to the Doherty amplifier 30 and amplified, the SC-FDMA signal with suppressed nonlinear distortion is output. can do. On the other hand, as shown in FIG. 28B, in the comparative example in which the SC-FDMA signal is input to the Doherty amplifier 30 and amplified without power control, the above-mentioned nonlinear intermediate input power regions P1 to P2 are used. Distortion occurs in the output voltage at the corresponding position.

FIGS. 29 (a) and 29 (b) are graphs showing an example of simulation results of signal point arrangement of SC-FDMA signal after demodulation in each of the above-mentioned third power control example and comparative example, respectively. As shown in FIG. 29 (a), when the SC-FDMA signal after power control in the third power control example is input to the Doherty amplifier 30 and amplified, the position of the signal point of the SC-FDMA signal changes ( Variation) is small. On the other hand, as shown in FIG. 29B, in the comparative example in which the SC-FDMA signal is input to the Doherty amplifier 30 and amplified without power control, the position of the signal point of the SC-FDMA signal fluctuates (). (Variation) is large.

As described above, according to the present embodiment, when the Doherty amplifier 30 that amplifies the transmission signal has input / output characteristics including an intermediate input power region in which the power gain is partially reduced, the nonlinear distortion caused by the intermediate input power region is obtained. Can be suppressed.

In addition, the processing process described in this specification and components such as a wireless transmission device, a wireless communication device, a base station, a terminal device, a mobile communication system, and a fixed wireless access (FWA) system shall be implemented by various means. Can be done. For example, these processes and components may be implemented in hardware, firmware, software, or a combination thereof.

Regarding hardware implementation, a processing unit used to realize the above steps and components in an entity (for example, various wireless communication devices, transmitters, Node Bs, terminals, UEs, hard disk drive devices, or optical disk drive devices). Means such as one or more application-specific ICs (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays, etc. (FPGA), processor, controller, microcontroller, microprocessor, electronic device, implemented in other electronic units, computers, or combinations thereof designed to perform the functions described herein. You may.

Further, for firmware and / or software implementation, means such as a processing unit used to realize the above components are programs (eg, procedures, functions, modules, instructions) that execute the functions described herein. , Etc.) may be implemented. In general, any computer / processor readable medium that clearly embodies the firmware and / or software code is a means such as a processing unit used to implement the steps and components described herein. May be used to implement. For example, the firmware and / or software code may be stored in memory and executed by a computer or processor, for example, in a control device. The memory may be mounted inside the computer or processor, or it may be mounted outside the processor. The firmware and / or software code may be, for example, a random access memory (RAM), a read-only memory (ROM), a non-volatile random access memory (NVRAM), a programmable read-only memory (PROM), or an electrically erasable PROM (EEPROM). ), Flash memory, floppy (registered trademark) discs, compact discs (CDs), digital versatile discs (DVDs), magnetic or optical data storage devices, etc. good. The code may be executed by one or more computers or processors, or the computers or processors may be made to perform functional embodiments described herein.

Further, the medium may be a non-temporary recording medium. Further, the code of the program may be read and executed by a computer, a processor, or another device or device machine, and the format thereof is not limited to a specific format. For example, the code of the program may be any of source code, object code, and binary code, or may be a mixture of two or more of these codes.

Also, the description of the embodiments disclosed herein is provided to allow one of ordinary skill in the art to manufacture or use the present disclosure. Various amendments to this disclosure will be readily apparent to those of skill in the art and the general principles defined herein are applicable to other variations without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not limited to the examples and designs described herein, but should be recognized in the broadest range consistent with the principles and novel features disclosed herein.

10: Wireless transmitter 20: Power control unit 30: Doherty amplifier (power amplifier)
40: Antenna 50: Transmission signal generation unit 60: Base station 61: Antenna 62: Radio unit 63: Data processing unit 64: NW communication unit 65: Control unit 66: Storage unit

Claims (17)

A wireless transmission device that amplifies a transmission signal by a power amplifier having input / output characteristics including a non-linear intermediate input power region in which the power gain is partially reduced.
A power control unit that controls the power of the transmission signal before power amplification so that the power distribution of the transmission signal before power amplification amplified by the power amplifier becomes a power distribution avoiding the non-linear intermediate input power region. A wireless transmitter characterized by being provided with. In the wireless transmission device of claim 1,
The power amplifier has input / output characteristics including a linear low input power region, the non-linear intermediate input power region, and a linear high input power region.
The power distribution avoiding the non-linear intermediate input power region is larger than the first input power threshold located at the boundary between the low input power region and the intermediate input power region in the power distribution of the transmission signal before the power amplification. A wireless transmission device characterized in that a large power portion is shifted to the high power side by the power width of the intermediate input power region. In the wireless transmission device of claim 1,
The power amplifier has input / output characteristics including a linear low input power region, the non-linear intermediate input power region, and a linear high input power region.
The power distribution avoiding the non-linear intermediate input power region is formed at the boundary between the low input power region and the intermediate input power region after shifting the entire power distribution of the transmitted signal before the power amplification to the low power side. A wireless transmission device characterized in that a power portion larger than a located first input power threshold is shifted to a higher power side by the power width of the intermediate input power region. In the wireless transmission device of claim 1,
The power amplifier has input / output characteristics including a linear low input power region, the non-linear intermediate input power region, and a linear high input power region.
The power distribution avoiding the non-linear intermediate input power region is located at the boundary between the low input power region and the intermediate input power region while maintaining the maximum power point of the power distribution of the transmitted signal before the power amplification. A wireless transmission device characterized in that the power distribution of a transmission signal before power amplification is changed so as to compress a power portion larger than the first input power threshold to the high power side. In the wireless transmission device of claim 1,
The power amplifier has input / output characteristics including a linear low input power region, the non-linear intermediate input power region, and a linear high input power region.
The power distribution avoiding the non-linear intermediate input power region is larger than the second input power threshold located at the boundary between the intermediate input power region and the high input power region in the power distribution of the transmission signal before the power amplification. A wireless transmission device characterized by having a power distribution in which a small power portion is shifted to the low power side by the power width of the intermediate input power region. In the wireless transmission device according to any one of claims 1 to 5.
In the power control unit, a digitally modulated signal generated based on transmission data is input, and the power distribution of the transmission signal before power amplification amplified by the power amplifier is a power avoiding the non-linear intermediate input power region. The digitally modulated signal is controlled and output so as to be distributed.
A DA conversion unit that converts the digital modulation signal output from the power control unit into an analog modulation signal, and a DA conversion unit.
A carrier signal generator that generates a high-frequency carrier signal,
A wireless transmission device further comprising a frequency conversion unit for inputting the carrier signal from the carrier signal generation unit and converting the analog modulated signal output from the DA conversion unit into a high-frequency transmission signal. In the wireless transmission device according to any one of claims 1 to 5.
A DA converter that converts a digitally modulated signal generated based on transmission data into an analog modulated signal, and
A carrier signal generator that generates a high-frequency carrier signal,
A frequency conversion unit for inputting the carrier signal from the carrier signal generation unit and converting the analog modulation signal output from the DA conversion unit into a high-frequency transmission signal is further provided.
In the power control unit, the high-frequency transmission signal is input from the frequency conversion unit, and the power distribution of the transmission signal before power amplification amplified by the power amplifier is a power distribution that avoids the non-linear intermediate input power region. A wireless transmission device characterized in that the high-frequency transmission signal is controlled and output so as to be. In the wireless transmission device according to any one of claims 1 to 7.
The power amplifier is a wireless transmission device having input / output characteristics including a linear low input power region, the non-linear intermediate input power region, and a linear high input power region. In the wireless transmission device according to any one of claims 1 to 8.
The power amplifier is a wireless transmission device characterized by being a high-efficiency power amplifier. A base station for mobile communication systems
A base station including the wireless transmission device according to any one of claims 1 to 9. A base station for fixed wireless access (FWA) systems
A base station including the wireless transmission device according to any one of claims 1 to 9. It is a terminal device for mobile communication systems.
A terminal device comprising the wireless transmission device according to any one of claims 1 to 9. It is a terminal device of fixed wireless access (FWA) system.
A terminal device comprising the wireless transmission device according to any one of claims 1 to 9. A mobile communication system comprising at least one of a base station according to claim 10 and a terminal device according to claim 12. A fixed wireless access system comprising at least one of a base station according to claim 11 and a terminal device according to claim 13. The transmission signal generated by processing the data to be transmitted is generated, and the power of the transmission signal is amplified and transmitted by a power amplifier having input / output characteristics including a non-linear intermediate input power region in which the power gain is partially reduced. It ’s a wireless transmission method.
It includes controlling the power of the transmission signal before power amplification so that the power distribution of the transmission signal before power amplification amplified by the power amplifier becomes a power distribution avoiding the non-linear intermediate input power region. A wireless transmission method characterized by that. The transmission signal generated by processing the data to be transmitted is generated, and the power of the transmission signal is amplified and transmitted by a power amplifier having input / output characteristics including a non-linear intermediate input power region in which the power gain is partially reduced. A program that runs on a computer or processor in a wireless transmitter.
A program for controlling the power of the transmission signal before power amplification so that the power distribution of the transmission signal before power amplification amplified by the power amplifier becomes a power distribution avoiding the non-linear intermediate input power region. A program characterized by containing code.

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