KR101145830B1 - Power output unit with an interference suppress system filter unit and pre-distorter for mobile telecommunication equipments - Google Patents

Abstract

The present invention outputs the output of the driving amplifier having a high adjacent channel leakage equipment so as to be separated from other frequency bands, by inputting a non-linear output of the power amplifier as a feedback signal and inputting a signal inverted distorted magnitude and phase, The present invention provides an output terminal of a mobile communication device to which a predistortion device and an interference suppression system filter module capable of refining distortion to maintain linearity at an output terminal of a mobile communication system are applied.

The technical configuration includes a driving amplifier receiving an RF analog frequency signal received through an antenna or a plurality of antennas and converting the RF analog frequency signal into a frequency signal having a constant gain and power; Passing or stopping the frequency signal input through the driving amplifier, increasing the adjacent channel leakage equipment (ACLR) by compensating and removing interference signals and ripples except the frequency band passed or blocked, and a constant gain and An interference suppression system filter module converting the frequency signal into power; A power amplifier for amplifying the power of the frequency signal output from the interference suppression system filter module, converting the RF signal into a RF analog frequency signal having a predetermined power and gain and outputting the radiation through an antenna; A frequency signal output from the interference suppression system filter module and the power amplifier is input, and the intermodulation distortion (IMD) generated by the power amplifier is sensed and distorted to cancel the distortion to linearize the output signal of the power amplifier. And a predistortion device.

Description

OUTPUT UNIT WITH AN INTERFERENCE SUPPRESS SYSTEM FILTER UNIT AND PRE-DISTORTER FOR MOBILE TELECOMMUNICATION EQUIPMENTS}

The present invention relates to an output stage of a mobile communication device, and in particular, to maximize the characteristics of adjacent channel leakage facilities so as to have high separation from other frequency bands, and to have a linearity by receiving an output as a feedback signal to remove nonlinearity of a power amplifier. The present invention relates to an output terminal of a mobile communication device to which a predistortion device and an interference suppression system filter unit are applied.

In general, a transmitter (TX) of a mobile communication device converts a transmission signal including data into a high frequency signal, amplifies the signal with appropriate power, and transmits the signal without interference from other frequencies. After filtering and receiving only desired frequency bands among noise and interference signals, amplifying weak signals while minimizing noise to generate usable sizes, and lowering the frequency of the converted high frequency signals to recover actual signals.

Here, the transmitter should send out the proper end stage power enough to receive the signal at the receiving end, and should not emit components other than the frequency to be transmitted, and should be able to export without interference when using multiple frequency channels. .

In addition, since the receiver must amplify the weak signal transmitted from the transmitter, a multi-stage amplification stage is required, and in order to suppress various noise and interference signals in the air as much as possible, and to select the desired channel accurately when using multiple frequency channels, And it should prevent or filter out various frequency components from outside.

In other words, since the atmosphere is a medium in which various frequency signals are emitted and traveled, electromagnetic waves have a lot of noise and are attenuated by various elements in the atmosphere. (W)) and gain (Gain, dB) should be sent.

Here, the output power efficiency of the base station and the repeater, which are mobile communication devices, is very low at about 10%, which means that 200W of power is required to obtain 20W of RF signal output. The remaining 200W-20W = 180W means that it is converted to heat and released into the atmosphere by the heat release device.

In addition, the heat dissipation device uses a heat sink and a heat sink such as a fan or air conditioner, and the heat sink and heat sink occupy 30% of the total weight and volume of the mobile communication device, so that the efficiency of the output stage is increased. With the economics of the power supply, the weight and volume of the mobile communication device can be reduced.

On the other hand, the power efficiency of the output terminal of the mobile communication device is low because the characteristics of the communication signal must meet the Adjacent Channel Leakage Power Ratio (ACLR), which does not affect other channels or frequencies.

Here, referring to FIG. 1, the adjacent channel leakage facility is an index indicating a linearity of a power amplifier (PA), and in WCDMA, a standard specification indicating a linearity of a power amplifier. The difference in power is expressed in dBc, and the result is the same as that of the adjacent channel leakage facility (ACPR).

FIG. 2 is a diagram schematically illustrating output stages of a base station and a repeater according to the prior art, and FIG. 3 is a graph showing the output spectral density of a single channel output of the communication apparatus according to the prior art. As shown in FIGS. 2 and 3, an input signal of a power amplifier (PA) is amplified by a driving amplifier (DA) in front of it.

The power value of the input signal of the power amplifier, which is the output of the driving amplifier, is about 0 to 10 dBm, and the gain of the output signal of the power amplifier is about 30 dB to 50 dB.

The efficiency of the power amplifier increases as it approaches the saturation point, which is the highest value the power amplifier can afford. In this case, the power amplifier enters the nonlinear characteristic region, so the characteristic of the output signal is high in spectrum. Due to growth, the adjacent channel leakage equipment is distorted.

Therefore, in order to minimize such damage, the efficiency is lowered to operate the power amplifier in a region where linearity is ensured.

In this case, the characteristics of the output signal including adjacent channel leakage facilities are directly influenced by the characteristics of the input signal as well as the characteristics of the power amplifier. The above description is based on the assumption that the characteristics of the input signal are the same.

In addition, the characteristics of the transistor constituting the power amplifier is between 25% to 35% higher than the above-mentioned efficiency, and when designed under optimal conditions, the efficiency of the transistor can be obtained up to 50% or more. The gain is approximately 8 dB to 20 dB.

On the other hand, the output characteristics of the existing mobile communication device is determined by the difference between the signal size in the desired band and the noise out of the band, it may be represented by the isolation (Isolation) characteristics, and recently referred to as the adjacent channel leakage facilities. In the following description, it is assumed that the adjacent channel leakage facility is a concept including the isolation.

In order to increase the output efficiency of the mobile communication device, the gain must be increased. The amplification in the device does not only amplify a signal within a desired band, but also amplifies noise outside a desired band. The better the leakage ratio characteristic, the larger the gain can be amplified, and thus the desired output can be obtained.

Referring to FIG. 2, the total gain of the power amplifier, which is the last output terminal of the mobile communication device, is designed to be 30 dB to 50 dB. In this case, even though the characteristic (ACLR) of the input signal of the power amplifier is relatively good, as described above, the power amplifier ( In PA, both signal and noise are amplified from 30dB to 50dB, resulting in distortion in the ACLR characteristics of the last output signal. To compensate for this, power amplifiers must be designed to operate in areas of low efficiency, that is, in the area of linearity.

In order to solve this problem, Korean Laid-Open Patent Publication No. 2005-0010596 discloses a predistortion apparatus of a mobile communication system, which will be described with reference to FIG. 4.

FIG. 4 is a block diagram illustrating a predistortion apparatus of a mobile communication system according to the Korean Laid-Open Patent, and includes a predistortion apparatus for pre-distortion at a baseband stage that is a front end of an intermediate frequency modulator. The power amplified output signal is input to a predistorter and configured to correct distortion.

As shown in FIG. 4, the predistorter 100 and the power amplifier 200 are configured, among which the power amplifier 200 includes an intermediate frequency amplifier for modulating an input signal and an intermediate frequency thereof. A high frequency amplifier stage for band-passing a signal and high-frequency modulation, and a power amplifier stage for band-passing the high-frequency signal and high-power modulation.

The predistorter 100 receives the baseband signal and converts the baseband signal into a digital signal, and digitally converts the AD-converted baseband signals Ii and Qi using a predetermined predistortion algorithm. DSP 102 for distortion processing, De-Converter 103 for converting the pre-distorted signal through the DSP 102 to an analog signal and output to the intermediate frequency amplifier stage, and the signal output from the power amplifier 200 Detects and inversely modulates the radio frequency signal into a high frequency inverse modulator 104 and an intermediate frequency inverse modulator 105 for inversely modulating the high frequency signal inversely modulated by the high frequency inverse modulator 104 into an intermediate frequency signal. The AID converter 106 converts the inversely modulated intermediate frequency signal through the intermediate frequency inverse modulator 105 into a digital baseband signal (Io, Qo) and outputs it to the DPS 102 so that it can be corrected when predistorted. ) To configure.

However, the efficiency of the output stage using the predistorter according to the prior art is known to be about 15% to 20% in the case of WCDMA, and the improvement of the efficiency is desirable. However, the higher the efficiency of the output stage, the more various advantages are applied. Since one technique can be derived, the present invention applies a configuration in which the interference suppression system filter unit is further added to the predistortion apparatus of the mobile communication system according to the prior art, so that the linearization of the predistortion apparatus and the interference suppression system filter unit are applied. By inducing synergy effect due to the increase of adjacent channel facilities, we want to obtain higher output stage efficiency than when each method is applied.

The present invention has been made to achieve the above object, in order to eliminate the nonlinearity of the power amplifier, by receiving the output of the power amplifier as a feedback signal by combining a frequency signal having a different type of nonlinearity, An object of the present invention is to provide an output terminal of a mobile communication device to which a predistortion device and an interference suppression system filter-unit which can remove nonlinearity are applied.

Another object of the present invention is to maximize the characteristics of the adjacent channel leakage facility so that the frequency signal inputted to the power amplifier is different from other frequency bands, and also maximizes the gain of the driving amplifier DA and the last power amplifier PA. It is desirable to provide an output stage of a mobile communication device to which a predistortion device and an interference suppression system filter-unit are applied which can have the same effect as operating in a linear region even if the power amplifier is operated in a nonlinear region.

Another object of the present invention is to increase the power efficiency so that most of the input power is not converted to heat, and accordingly to remove and minimize the heat sink and the heat sink to reduce the size and weight of the device including the base station and the repeater mobile communication device The present invention provides an output terminal of a mobile communication device to which a predistortion device and an interference suppression system filter-unit which can achieve a miniaturization of the device are applied.

 In order to achieve the above object, the present invention provides a drive amplifier for receiving an RF analog frequency signal received through an antenna or a plurality of antennas and converts the signal into a frequency signal having a constant gain (Gain) and power (Power); Passing or stopping the frequency signal input through the driving amplifier, increasing the adjacent channel leakage equipment (ACLR) by compensating and removing interference signals and ripples except the frequency band passed or blocked, and a constant gain and An interference suppression system filter module converting the frequency signal into power; A power amplifier for amplifying the power of the frequency signal output from the interference suppression system filter module, converting the RF signal into a RF analog frequency signal having a predetermined power and gain and outputting the radiation through an antenna; A frequency signal output from the interference suppression system filter module and the power amplifier is input, and the intermodulation distortion (IMD) generated by the power amplifier is sensed and distorted to cancel the distortion to linearize the output signal of the power amplifier. Predistortion device is included.

The predistortion device may be connected in parallel with the interference suppression system filter module between the interference suppression system filter module and the power amplifier.

The predistortion device may further include a coupler for extracting a part of a signal output from the interference suppression system filter module.

In addition, the output stage further includes a coupler (Coupler) for distributing and outputting the power of the interference suppression system filter module to the predistortion device and the coupler between the interference suppression system filter module, the predistortion device and the combiner. It is characterized by including.

The predistortion device may include: a first A / D converter for converting an analog frequency signal output from the interference suppression system filter module into a digital; CFR (Crest Factor Reduction) for reducing the peak-to-average power ratio of the digital frequency signal output from the first A / D converter; A second A / D converter receiving an analog frequency signal, which is an output of the power amplifier, as a feedback signal and converting the digital signal into a digital signal; A digital pre-distortion (DPD) for receiving a digital frequency signal output from the second A / D converter and distorting the phase so that the phase is inverted with the magnitude of the distortion generated by the power amplifier; A D / A converter converting the frequency signal output from the DPD to analog; A first mixer for increasing the frequency of the signal output from the D / A converter; A second mixer for lowering a frequency signal input to the second A / D converter; A local oscillator for each frequency input to the first mixer and the second mixer; And a coupler for receiving the output of the power amplifier as a feedback signal in the second A / D converter.

In addition, the gain of the power amplifier is within the range that can produce a linear output in the region having a linearity and / or non-linearity because the adjacent channel leakage equipment of the signal output from the interference suppression system filter module is high. do.

The gain of the driving amplifier may have a gain obtained by subtracting the sum of the gain of the power amplifier, the gain or the loss of the interference suppression system filter module from the total gain of the output stage.

In addition, the interference suppression system-filter unit includes one or more interference suppression system filter module for passing and blocking a frequency signal of a predetermined band, and amplifies the frequency signal passed; And a compensation circuit for stopping and compensating a ripple band generated by the filter module that compensates for the interference signal.

The one or more interference suppression system filter modules may include two or more series-connected filters having the same characteristics to pass and block frequency signals of a predetermined band; It characterized in that it comprises an LNA provided to compensate for the insertion loss generated according to the stop band in the filter.

In addition, the filter is characterized in that it is formed of any one of a dielectric or metal cavity (Metal Cavity) or DR-metal cavity or stripline.

In addition, the filter may be made of a combination of dielectric or metal cavities or dielectric resonance-metal cavities or striplines.

In this case, the LNA has a gain according to the insertion loss and is connected in series with the filter to compensate for the insertion loss generated in the filter.

The compensation circuit may include a filter that suppresses an amplitude equal to the size of the ripple in the frequency band in which the ripple is generated to compensate for the ripple generated in the interference suppression system filter module.

Preferably, the filter is characterized in that the band stop filter (BSF) to block the amplitude as much as the size of the ripple frequency band and the ripple generated.

At this time, the filter is characterized in that the directional filter (Directional Filter) to block the amplitude as much as the size of the ripple generated frequency band and ripple.

In addition, the power amplifier is characterized by consisting of a power transistor (Power Transistor) consisting of a MOSFET or gallium nitride (GaN).

In addition, the output terminal of the mobile communication device further comprises a low noise amplifier for amplifying the RF signal received by the antenna or a plurality of antennas in front of the driving amplifier.

As described above, the present invention having the above-described configuration receives a nonlinear output signal of a power amplifier, which is a nonlinear element, as a feedback signal, and distorts the input signal in advance, thereby obtaining an output signal having linearity by canceling the nonlinear output signals. As the linearity is increased and the characteristics of adjacent channel leakage facilities are improved by the interference suppression system filter unit, the separation can be increased so that there is no noise and interference with other bands, and the adjacent channel characteristic ratio is not considered in the driving amplifier. Gain can be increased without gain, so even if the power amplifier operates in the linear or nonlinear region, it can have the same effect as operating in the linear region, increasing the efficiency of the power supplied to the power amplifier versus the output power, thereby reducing the power lost to heat. To increase power efficiency By deleting and minimizing the heat dissipation device and the heat sink, the size and volume of the mobile communication device can be miniaturized.

Hereinafter, with reference to the accompanying drawings, an embodiment according to the present invention will be described in detail.

5 is a diagram illustrating an output terminal of a mobile communication device to which a predistortion device and an interference suppression system filter module according to the present invention are applied. As shown in FIG. 5, the output terminal of the mobile communication device to which the predistortion device and the interference suppression system filter module according to the present invention are applied is a driving amplifier (DA) 10 and an interference suppression system filter unit (ISS FU: Interference Supperess System Filter). Unit 30), predistorter 20, combiner 40, and power amplifier 50.

Here, since the driving amplifier 10 does not satisfy both the gain and power efficiency in the power amplifier 50, a high gain in the front end to drive the power amplifier 50 is obtained. ) To compensate for the gain of the power amplifier 50.

The gain of the drive amplifier 10 in the present invention is designed to be 60dB to 70dB, provided for gain compensation rather than power efficiency, to supply an input signal of sufficient magnitude required for the power amplifier 50.

In addition, since the power amplifier 50 must transmit a high power to a signal to be radiated to the air through the antenna ANT at the output terminal, if the high power is compensated by the power amplifier 50, the high gain is the drive amplifier ( 10) to compensate.

In addition, the interference suppression system filter unit (ISS FU) 30 according to the present invention is characterized by low insertion loss in the operating frequency band, excellent skirt, ripple and isolation characteristics, and at the same time small in volume and weight and light in weight.

Referring to FIG. 8, the interference suppression system filter unit 30 includes one or more interference suppression system filter modules (ISS FM) 31 and a compensation circuit 33.

Here, when two or more filters are connected in series, the skirt and isolation characteristics of two or more filter combinations are more than doubled when compared to one, but another important characteristic of the filter combination is insertion loss and ripple. The property is more than doubled.

Therefore, the present invention first combines a low noise amplifier (LNA) with one or more filters to compensate for insertion loss and to obtain the total gain required by the filter module.

Here, Insertion Loss is one of the important characteristics of the filter, which means that the signal loses power as it passes through the filter.If S21 is less than 0 dB in the pass band, all input power is not output. In other words, it means that a loss of power has occurred. In other words, as much as S21 falls from 0 dB, the insertion loss is referred to as dB.

In this case, the number of LNAs is determined by the gain characteristics required by the filter module, and the LNA is the first filter of the interference suppression system filter module (ISS FM: 31) to reduce the noise figure, which is also one of the important characteristics. It is preferable to mount at the front end, but it may be deleted.

The above-described interference suppression system filter module (ISS FM: 31) can be designed to be used in a high output mobile communication device having a skirt, adjacent channel leakage facilities and gains sufficiently, which is 100 watt or more, which is an interference noise outside the signal band. Signal) can be sufficiently suppressed.

Here, the ripple increases according to the number of BPFs. Accordingly, since the damage of the ripple characteristic occurs by a multiple of the number of the combined BPFs, the total ripple characteristic of the filter module is sufficiently compensated.

The BPF according to the present invention can use all kinds of filters, and depending on the implementation type, a concentrated element, a transmission line, a microstrip or a stripline, a ceramic, or Dielectric or waveguide, Surface Acoustic Wave (SAW), MEMS, LTCC, FBAR and the like may be used.

Here, the lumped element is a device which can be made by soldering lead or SMD L and C elements to the PCB, and in the case of several GHz or more, a microstrip or stripline that can be implemented in consideration of coupling, resonance, and multiple impedance connection is used. .

In addition, the ceramic or the dielectric is a structural filter using the resonance according to the wavelength, it is made by using a high dielectric dielectric ceramic to reduce the electrical wavelength of the signal, to implement a smaller filter.

In addition, the waveguide is a case of directly using the resonance phenomenon, there is a Cavity method using a metal block or a ceramic method to insert a dielectric, SAW is used in the filter of portable equipment, such as mobile communication terminal pursuing small size, light weight, thin do.

In addition, a compensation circuit 33 is provided to compensate for the ripple between the two interference suppression system filter modules (ISS FM: 31), where the ripple is the highest and lowest of the insertion loss in the signal passband. The difference is obtained by measuring S21, usually expressed in dB.

Therefore, in order to perform the above-described compensation, the compensation circuit 30 uses a band stop filter (BSF) as much as the band in which the ripple exists to compensate for the ripple.

In other words, by using the BSF, the ripple is prevented from passing by the existing frequency band, thereby compensating for the ripple.

Alternatively, a compensation filter 33 includes a directional filter, which is configured to separate and combine a transmission frequency band and a reception frequency band when the transmission line is a 2-wire type, and separates only the band where the ripple exists. And inhibit.

Then, the rest of the interference suppression system filter module (ISS FM: 31) is preferably further provided at the rear end of the compensation circuit 33, the configuration and operation of the remaining interference suppression system filter module (ISS FM: 31) Since it is the same as the interference suppression system filter module (ISS FM: 31) mentioned above, the description thereof will be omitted.

Through the above-described interference suppression system filter unit (ISS FU, 30), adjacent channel leakage equipment has been refined at least -80 dB or more, and a signal of 30 dBm amplified by a plurality of LNAs is input to the predistorter 20 and the combiner 40. do.

First, when the frequency signal is output from the interference suppression system filter unit 30 and directly through the combiner 40 to the power amplifier 50, the distortion level of the power amplifier 50 is determined by the predistorter 20. In response to the feedback signal, the phase of the frequency signal having the same magnitude as the distortion is inverted and output to the combiner 40.

In this case, the combiner 40 combines the distortion signal output from the interference suppression system filter unit 30 and the distortion signal inverted by the predistortion device 20, and thus the distortion signal and the inverted distortion signal. Is combined in the combiner 40 so that a signal that is not distorted, that is, a linear frequency signal, may be output from the power amplifier 50.

Accordingly, the predistortion device 20 detects the degree of distortion of the signal output from the power amplifier 50 as a feedback signal, and inverts the phase of the frequency having the same magnitude as that of the distortion to pre-distortion the signal. This eliminates nonlinearities at the output stage.

Lastly, the power amplifiers PA and 50 raise adjacent channel leakage facilities so that the interference suppression system filter unit 30 has a high degree of separation from the other frequency bands, and, once again, the power amplifier 50 in the predistorter 20. Since the distortion is preliminarily removed in order to remove the nonlinearity of the power amplifier, the power amplifier 50 may have a high adjacent channel leakage characteristic and output a linear characteristic while operating in a nonlinear region, thereby maximizing efficiency. .

That is, the interference suppression system filter unit 30 primarily improves the characteristics of adjacent channel leakage equipment to increase the separation from other channel frequencies, and secondly pre-distorts the linearity of the predistortion device 20. Therefore, due to the synergistic effect of the interference suppression system filter unit 30 and the predistortion device 20 is made to maximize the efficiency.

At this time, the power amplifier 50 is designed to have a gain between 8dB and 20dB.

In addition, even if the power amplifier 50 amplifies the power in the nonlinear region, the interference suppression system filter unit 30 according to the present invention improves the characteristics of the adjacent channel leakage equipment, and the distortion level of the predistortion device 20 is increased. Since the frequency signal inverted in phase with the feedback signal is combined with the frequency signal output from the interference suppression system filter unit 30, it has a linear output and satisfies all power, gain and efficiency. It is a feature of the present invention that can be.

Therefore, the present invention has a high efficiency and is configured so that the power of most input signals is not radiated to heat, minimizing the configuration of the heat dissipation device and the heat sink, thereby miniaturizing the mobile communication device, can reduce the waste of power By adding a predistortion device, feedback control may be performed so as to remove in advance nonlinear distortion that may be generated at the output stage.

6 is a view for explaining the concept of a predistortion apparatus according to the present invention. As shown in FIG. 6, the predistortion device 20 receives the output of the power amplifier 50 as a feedback signal, and receives the input signal of the power amplifier 50 as a distortion signal opposite to the original output signal (eg, A device that compensates in real time to produce a signal having the same amplitude and phase 180 degrees (degrees difference), thereby improving the characteristics of the output signal and consequently increasing the efficiency of the output stage.

6, when the output of the power amplifier PA 50 is distorted, the distorted signal opposite to the distorted frequency can be linearized in the pre-distorter 20. Combine to create offset.

That is, when a deliberately made nonlinearity opposite to the power amplifier 50 is inputted, the nonlinearity is summed to have linearity. Even if the power amplifier 50 operates in the nonlinearity region, it is the same as operating in the linearity region. Can have an effect.

In addition, the digital pre-distortion of the predistortion device 20 is one of methods of removing inter-modulation distortion of the output of the mobile communication device, and the predistortion device 20 according to the present invention. Is defined as a device that performs digital predistortion.

Here, inter-modulation is caused by a nonlinear element (for example, a power amplifier 50 composed of transistors) included in an active circuit existing in a system, and is a signal component not present at the input but appearing at the output. Nonlinearity of the device causes nonlinear outputs with harmonics to be output.

Accordingly, in the present invention, the predistortion device 20 is refined by two kinds of other methods that can have a linear characteristic to the high frequency separation of the interference suppression system filter unit 30 by eliminating harmonic components and nonlinearities. It is characterized by providing an output stage for outputting a signal having two levels of output efficiency.

7 is a diagram illustrating in detail the predistortion apparatus according to the present invention. As shown in FIG. 7, the predistorter 20 may include a first A / D converter 21, a crest factor reduction (CFR) 22, a digital pre-distortion 23, a coupler 24, and a coupler 24. , A first mixer 25, a second A / D converter 26, a D / A converter 27, a local oscillator 28, and a second mixer 29.

Here, the first converter 21 converts an analog frequency signal having a high adjacent channel leakage device output from the interference suppression system filter unit 30 into digital, and the converted frequency signal is inputted to the CFR 22 to be peak-to-average. It reduces the power to average ratio and is input to the DPD (Digital Pre-Distorter) 23.

On the other hand, the frequency signal output from the indirect suppression system filter unit 30 is input to the power amplifier 50 via the combiner 40, the coupler 24 to the feedback signal to remove the non-linearity of the power amplifier 50 Received through the first mixer 25 to output the frequency down by the local oscillator (LO: Local Oscillator, 28).

Then, it is input to the second A / D converter 26 to convert the analog frequency signal into a digital frequency signal, which is input to the DPD 23.

In short, the DPD 23 receives the reference frequency signal output from the interference suppression system filter unit 30 and the actual frequency signal output from the power amplifier 50, and converts the actual frequency signal on the basis of the reference frequency signal. The input signal is used to determine the degree of distortion and to output a nonlinear signal for removing the distortion of the real frequency signal.

Finally, the pre-distorted frequency signal for removing the distorted signal is converted into an analog frequency signal via the D / A converter 27, and the frequency is adjusted in the second mixer 29 according to the frequency of the local oscillator 28. After raising, it is output to the combiner 40.

In this case, since the opposite distortion signal is combined at the combiner 40 by the amount of distortion, the nonlinearity shown at the output of the power amplifier 50 is eliminated, thus eliminating the nonlinearity of the power amplifier 50, and thus the interference. Since the suppression system filter unit 30 can output a frequency signal having a high degree of separation from other frequency bands, the efficiency can be maximized.

The predistortion device 20 according to the present invention should be used with a chip that performs the CFR 22, and it can be seen from the published data that the output stage efficiency can be obtained up to 20% in the case of WCDMA.

Here, the DPD 23 and the CFR 22 include a Texas Instruments (TI) company, an Opticron company, and a PMC company, a Canadian company, which use the device of the company, and the basic DPD 23. The description is described in detail in "RF and Microwave Circuit Design for Wireless Communications", by LELarson, Chapter 4, Artech House (1996), and a detailed description thereof will be omitted.

9 is a graph comparing signals input to a driving amplifier according to the present invention and a driving amplifier according to the prior art. As shown in Figure 9, (a) is a signal input to the drive amplifier in the prior art, (b) is a signal input to the drive amplifier according to the present invention.

(A) shows the shape and size of the full-band WIBRO signal, and shows an input signal input to the driving amplifier DA, which is a first amplified signal by the LNA.

(B) shows the shape and size of the full-band WIBRO signal, and shows an input signal input to the driving amplifier DA 10, which is a first amplified signal by the LNA.

10 is a graph illustrating a signal output from a driving amplifier according to the present invention. As shown in FIG. 10, since the output of the driving amplifier 10 according to the present invention is input to the interference suppression system filter unit 30 to compensate for the characteristics of the adjacent channel leakage facility, the characteristics of the adjacent channel leakage facility are Not so important, only the size of the output.

On the other hand, the driving amplifier DA according to the prior art should have at least -50 dB of adjacent channel leakage facilities and be separated from other frequency bands when all characteristics including adjacent channel leakage facilities are amplified through the last power amplifier PA. .

Accordingly, when looking at the adjacent channel leakage equipment (ACLR), it can be seen that the characteristics deteriorate from -32.364 dB to -20.460 dB in FIG. 9, which increases the gain of the driving amplifier 10 and improves the characteristics of the adjacent channel leakage equipment (ACLR). It is not considered, and even if it is not separated from other channels, the interference suppression system filter unit 30 will compensate for adjacent channel leakage equipment (ACLR) and will be purified to be separated from other channels. 10) only needs to compensate for the gain.

In addition, the magnitude of the signal passed through the driving amplifier 10 is 34.4 dBm, which is large enough to compensate for the loss of the signal (about 5 dB) generated while purifying the signal in the interference suppression system filter unit 30 of the next stage. to be.

Therefore, the driving amplifier 10 according to the present invention is input to the interference suppression system filter unit 30 to output a signal while compensating the gain of about 60dB to 70dB to correspond to the efficiency of the entire output stage.

11 is a graph comparing signals input to a power amplifier according to the present invention and a power amplifier according to the prior art. As shown in Figure 11, (a) is a signal input to the power amplifier (PA) according to the prior art, (b) is a power amplifier (PA, via the interference suppression system filter unit 30 according to the present invention) 50) is input signal.

That is, (a) is a signal output from the drive amplifier (DA) because the interference suppression system filter unit 30 according to the present invention is not present, (b) is the drive amplifier 10 and the power amplifier 50 Since the interference suppression system filter unit 30 is included therebetween, it is an output signal passed through the interference suppression system filter unit 30.

In (A), the adjacent channel leakage equipment is -42.549dB, and (B) shows that the adjacent channel leakage equipment is -75.971dB.

That is, the interference suppression system filter unit 30 according to the present invention can be seen that the -75.971dB is purified about the signal separation with other channels is increased.

In addition, (b), the size of the signal output from the interference suppression system filter unit 30 is 31dBm, the adjacent channel leakage equipment, as mentioned above, the noise removal and separation with other frequency bands of about -75.971dB It can be seen that a signal having excellent characteristics is outputted due to a high value.

12 is a graph comparing signals output from a power amplifier according to the present invention and a power amplifier according to the prior art. As shown in FIG. 12, (a) is an output signal of the power amplifier PA according to the prior art, and (b) is an output signal of the power amplifier 50 according to the present invention.

(A) In the form of a full-band WIBRO output signal of 43.38 dBm (20 W) size, the efficiency of the power amplifier (PA) in this case is about 50%, but the adjacent channel leakage of this signal is -29.205 dB. It can be seen that it does not satisfy -37dB, the pass characteristic specified in the WIBRO specification.

The reason is that even if the characteristics of the signal input to the power amplifier PA are excellent, since the gain of the power amplifier PA is 30 dB to 50 dB, the signal outside the frequency is also amplified to 30 dB to 50 dB with the signal within the frequency.

Therefore, when the mobile communication device is provided with an output terminal according to the prior art, the efficiency is significantly lowered due to the nonlinearity of the power amplifier and the characteristics of the adjacent channel leakage facility.

On the other hand, in (B), it is 43.08dBm (20W) full-band WIBRO output signal, and the characteristics of adjacent channel leakage equipment is -38.414dB, satisfying WIBRO specification and increasing power efficiency by 50%.

That is, according to the present invention, the interference suppression system filter unit 30 improves the characteristics of the adjacent channel leakage equipment, so that the separation can be increased so that there is no noise and interference with other bands, and the adjacent channel characteristic ratio in the driving amplifier 10 is improved. Since the gain can be increased without taking into consideration, the efficiency of the power amplifier 50 can be the same as that of the linear region even if the power amplifier 50 operates in the nonlinear region, thereby increasing the efficiency of the power to the output power supplied to the power amplifier 50. In addition, the power loss is minimized to increase power efficiency, and at the same time, the size and volume of the mobile communication device can be minimized by eliminating and minimizing the heat dissipation device and the heat sink.

Input signal (dBm) Drive amplifier
Output signal (dBm) Power amplifier
Output signal (W) efficiency(%) Adjacent channel leak facilities (dBc) EVM (%) -32.2 26.1 10 28.12 -41.5 2.6 -31.0 27.5 15 40.58 -38.7 4.13 -28.8 28.8 20 49.60 -38.4 7.1

Input signal (dBm) Drive amplifier
Output signal (dBm) Power amplifier
Output signal (W) efficiency(%) Adjacent channel leak facilities (dBc) EVM (%) -33.2 24.2 10 30.27 -39 2.1 -31.9 26.4 15 42.86 -38.4 3.7 -30.6 27.3 20 53.71 -37.1 5.55

Table 1 and Table 2 show measured values when the output terminal according to the present invention is applied to the mobile communication equipment of the full-band WIBRO.

The efficiency of the output stage increases as the output increases, and when the output of the power amplifier used in the experiment is 20W, the efficiency is about 50%.

Here, Table 1 and Table 2 are both measured values of WIBRO, and experiments using two different types of output stages, but show similar efficiency.

On the other hand, when the output stage according to the present invention is applied to WCDMA, the efficiency is estimated to be about 25%, because of the switching process between the receiver and the transmitter of WIBRO or WIMAX.

13 is a schematic block diagram of a WIBRO repeater with an output stage according to the present invention. As shown in Fig. 13, first, data received from one of two antennas is amplified by a low noise amplifier (LNA).

The reason is that since the power received at the RF receiver has a very low power level due to the effects of attenuation and noise, the signal is already received including a lot of noise from the outside, so minimizing the noise is a priority.

Then, when the gain taking into account the insertion loss of the interference suppression system filter unit 30 and the like through the drive amplifier 10 according to the present invention, that is, insertion loss of the interference suppression system filter unit 30 occurs, the driving amplifier ( The signal is amplified in consideration of the gain for compensation in 10) because the interference suppression system filter unit 30 purifies characteristics of adjacent channel leakage facilities and the like.

Therefore, the signal amplified with sufficient gain from the driving amplifier 10 is input to the interference suppression system filter unit 30 to increase the separation with other frequencies and noises and to improve the characteristics of adjacent channel leakage facilities.

In addition, a signal having higher characteristics and gain of adjacent channel leakage equipment is input to the power amplifier 50, and the output of the power amplifier 50 is input to the predistorter 20 as a feedback signal, thereby providing nonlinearity. If there is an output signal having a waveform, an opposite waveform having nonlinearity is output to the combiner 40 so as to be input to the power amplifier 50 in order to remove it.

Therefore, the power amplifier 50 outputs a signal with high efficiency while having the same effect as operating in the linear region without having to operate in the nonlinear region to give a large gain as in the prior art, and at the same time, frequency signals in the nonlinear region. Even though the predistortion device 20 receives it as a feedback signal and removes it, it is made to maximize both gain, power, and efficiency by satisfying both the adjacent channel leakage facilities and the linearity characteristics.

That is, even if the power amplifier 50 operates primarily in the nonlinear region, since the interference suppression system filter module 30 according to the present invention improves adjacent channel leakage facilities, which are separated from other frequency bands, the power amplifier is improved. Even if 50 operates in the nonlinear region, the same efficiency as in the linear region can be obtained. Secondly, the frequency signal operated in the nonlinear region is inputted as a feedback signal, and the distorted frequency signal is output to the combiner 40. This allows the linearization of the output signal, increased efficiency, and the ability to output at full power.

Therefore, since the present invention increases the efficiency of the power amplifier 50 as a result, it is possible to reduce the rate of loss of input power to heat, thereby reducing the power consumption, and to minimize the configuration of the heat dissipation device and the heat sink. The volume and weight of the mobile communication device equipped with the output stage of the present invention can be miniaturized, and the characteristics of the adjacent channel equipment meet the WIBRO standard, so that it is possible to receive purified and clean signals, and has a linear frequency. The signal can be output for maximum efficiency.

In addition, since the signal received by the antenna on the opposite side is processed in the same manner as the above-mentioned process will be omitted.

Finally, the output terminal according to the present invention may be applied to all output terminals including the driving amplifier and the power amplifier at the output terminal of the mobile communication device.

14 is a view showing a filter of the interference suppression filter unit of the output stage according to the present invention. As shown in FIG. 14, a filter applied to the present invention is generated as shown in (b).

First, as shown in (a), one filter is formed by combining a plurality of resonators in series, and all five resonators are formed as DR cavity resonators, and in (b), one resonator is made of metal. It can be seen that the cavity is a cavity cavity (Metal Cavity Resonator), the remaining four resonators are formed of a DR cavity cavity (DR Cavity Resonator).

Here, in the case of (b), the spurious characteristic can be greatly improved without significantly damaging the insertion loss, but the spurious characteristic is unnecessary harmonics and harmonics generated in addition to the frequency desired by the radio transmitter. Refers to the signal component of.

In addition, spurious copying or unnecessary copying of unwanted harmonics and low-harmonic signal components into the space is called a spurious copy and is limited to a certain limit or less because it interferes with other communication.

Therefore, a metal cavity resonator made of metal both outside and inside of the resonator and a DR cavity resonator made of a metal outside and inside of the dielectric are connected in series to improve spurious characteristics, and a compensation circuit does not need to be connected in series. Ripple is adjustable below 2dB.

However, when strict ripple characteristics are required, it is desirable to connect a compensation circuit.

In the above described exemplary embodiments of the present invention by way of example, the scope of the present invention is not limited only to this specific embodiment, and those skilled in the art within the scope of the claims of the present invention Changes may be made as appropriate.

1 is a graph for explaining the concept of adjacent channel leak facilities.

2 is a schematic illustration of the output stages of a base station and repeater according to the prior art;

3 is a graph illustrating the output spectral density of a single channel output of a communication device according to the prior art.

Figure 4 is a block diagram showing a predistortion apparatus of the mobile communication system according to the prior art.

5 is a diagram illustrating an output terminal of a mobile communication device to which a predistortion device and an interference suppression system filter unit according to the present invention are applied.

6 is a conceptual diagram illustrating the concept of a predistortion device according to the present invention.

Figure 7 illustrates in detail the predistortion device according to the present invention.

8 is a detailed view of an interference suppression system filter unit according to the present invention;

9 is a graph comparing signals input to a driving amplifier according to the present invention and a driving amplifier according to the prior art.

10 is a graph showing a signal output from a drive amplifier according to the present invention.

11 is a graph comparing signals input to a power amplifier according to the present invention and a power amplifier according to the prior art.

12 is a graph comparing signals output from a power amplifier according to the present invention and a power amplifier according to the prior art.

Figure 13 is a schematic block diagram of a WIBRO repeater with an output stage in accordance with the present invention.

14 is a view showing a filter of the interference suppression filter unit of the output stage according to the present invention.

<Brief description of reference numerals for the main parts of the drawings>

10: drive amplifier 20: predistortion device

21: first A / D converter 22: CFR

23: DPD 24: Coupler

25: first mixer 26: second A / D converter

27: D / A converter 28: Local oscillator

29: second mixer 30: interference suppression filter unit

31: interference suppression filter module 31a: LNA

31b: band pass filter 33: compensation circuit

40: combiner 50: power amplifier

Claims (16)

A driving amplifier which receives an RF analog frequency signal received through an antenna or a plurality of antennas and converts the RF analog frequency signal into a frequency signal having a predetermined gain and power; Passing or stopping the frequency signal input through the driving amplifier, increasing the adjacent channel leakage equipment (ACLR) by compensating and removing interference signals and ripples except the frequency band passed or blocked, and a constant gain and An interference suppression system-filter unit for converting into a frequency signal having power; A power amplifier for amplifying the power of the frequency signal output from the interference suppression system-filter unit, converting it into an RF analog frequency signal having a predetermined power and gain, and outputting the radiation through an antenna; Linearizes the output signal of the power amplifier by canceling the distortion by receiving a frequency signal output from the interference suppression system-filter unit and the power amplifier, and detecting and pre-distorting the intermodulation distortion (IMD) generated by the power amplifier. Predistortion Predistortion device and interference suppression system comprising a-output unit of the mobile communication device to which the filter unit is applied. The method according to claim 1, The output stage is an interference suppression system-filter unit A combiner for summing the power of the interference suppression system-filter unit and the predistortion device between the power amplifier and the interference suppression system-filter unit and predistortion device; Predistortion device and interference suppression system characterized in that it further comprises a filter-output unit of the mobile communication device to which the filter unit is applied. The method according to claim 2, The predistortion device Coupler (Coupler) for extracting a part of the signal output from the interference suppression system-filter unit Predistortion device and interference suppression system characterized in that it further comprises a filter-output unit of the mobile communication device to which the filter unit is applied. The method of claim 3, The predistortion device A first A / D converter for converting an analog frequency signal output from the interference suppression system filter unit into digital; CFR (Crest Factor Reduction) for reducing the peak-to-average power ratio of the digital frequency signal output from the first A / D converter; A second A / D converter receiving an analog frequency signal, which is an output of the power amplifier, as a feedback signal and converting the digital signal into a digital signal; A digital pre-distortion (DPD) for receiving a digital frequency signal output from the second A / D converter and distorting the phase so that the phase is inverted with the magnitude of the distortion generated by the power amplifier; A D / A converter converting the frequency signal output from the DPD to analog; A first mixer for increasing the frequency of the signal output from the D / A converter; A second mixer for lowering a frequency signal input to the second A / D converter; A local oscillator for each frequency input to the first mixer and the second mixer; Coupler for receiving the output of the power amplifier as a feedback signal in the second A / D converter Predistortion device and interference suppression system, characterized in that it comprises an output terminal of the mobile communication device to which the filter unit is applied. The method according to claim 1, The gain of the power amplifier is less than 20dB within a range capable of producing a linear output in a region having linearity and / or a nonlinearity because the adjacent channel leakage equipment of the signal output from the interference suppression system filter unit is high. Predistortion device and interference suppression system. The method according to claim 5, The gain of the drive amplifier has a gain obtained by subtracting the sum of the gain of the power amplifier and the gain or loss of the interference suppression system-filter unit from the total gain of the output stage. Output terminal of mobile communication device to which unit is applied. The method according to claim 1, The interference suppression system-filter unit At least one interference suppression system filter module configured to pass and stop a frequency signal of a predetermined band and amplify the passed frequency signal; Compensation circuit for stopping and compensating the ripple band generated in the filter module that compensated the interference signal Predistortion device and interference suppression system, characterized in that it comprises an output terminal of the mobile communication device to which the filter unit is applied. The method of claim 7, The one or more interference suppression system filter module Two or more series-connected filters having the same characteristics to pass and stop a frequency band signal; LNA provided to compensate for insertion loss caused by the stop band in the filter Predistortion device and interference suppression system, characterized in that it comprises an output terminal of the mobile communication device to which the filter unit is applied. The method according to claim 8, And the filter is formed of any one of a dielectric or a metal cavity or a DR-metal cavity or a stripline. The output end of the mobile communication device to which the predistortion device and the interference suppression system filter unit are applied. The method according to claim 8, And said filter comprises a combination of a dielectric or metal cavity or a dielectric resonant-metal cavity or stripline. The method according to claim 8, And the LNA has a gain according to insertion loss so as to compensate for insertion loss generated in the filter, and is connected in series with the filter, and an output terminal of the mobile communication device to which the predistortion device and the interference suppression system filter unit are applied. The method according to claim 8, The compensation circuit is a predistortion device and interference suppression system filter, characterized in that for the compensation of the ripple generated in the interference suppression system filter module to suppress the amplitude as much as the ripple magnitude in the frequency band where the ripple occurs Output terminal of mobile communication device to which unit is applied. The method according to claim 12, And the filter is a band stop filter (BSF) that prevents the amplitude of the ripple-generated frequency band and the amplitude of the ripple. The output stage of the mobile communication device to which the predistortion device and the interference suppression system filter unit are applied. The method according to claim 12, And said filter is a directional filter for blocking amplitude as much as the frequency band and ripple where said ripple is generated, and an output end of a mobile communication device to which a predistortion device and an interference suppression system filter unit are applied. The method according to claim 1, The power amplifier is an output terminal of a mobile communication device to which the predistortion device and the interference suppression system filter unit are characterized in that the power transistor (Power Transistor) consisting of a MOSFET or gallium nitride (GaN). The method according to claim 1, The output stage Low noise amplifier to amplify the RF signal received by the antenna or a plurality of antennas in front of the drive amplifier An output terminal of the predistortion device and the interference suppression system-filter unit is applied, further comprising a.

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