Device and method for adjusting supply voltage for optimizing efficiency of power amplifier

Abstract

Disclosed are a device and method for adjusting a supply voltage for optimizing the efficiency of a power amplifier. The device for adjusting a supply voltage for optimizing the efficiency of a power amplifier according to an embodiment of the present application comprises: a signal analysis unit for acquiring output level information about an output signal of a communication device through analysis of an input signal of the communication device provided with a power amplifier; and a voltage adjustment unit for adjusting a supply voltage of the power amplifier on the basis of the output level information.

Description

Supply voltage regulating device and method for optimizing the efficiency of a power amplifier

[0001] The present invention relates to a supply voltage regulating device and method for optimizing the efficiency of a power amplifier.

[0002] As mobile communication systems transition to the Orthogonal Frequency Division Multiplexing (OFDM) modulation method and data throughput increases significantly in 5G, the Peak-to-Average Power Ratio (PAPR) value has increased, and improving the efficiency of power amplifiers, which account for most of the power consumption of mobile communication systems, is a very important core technology.

[0003] In this regard, envelope tracking (ET)-based power amplifiers can improve efficiency while maintaining linearity and possess excellent power efficiency characteristics in broadband communication systems. PAMs for terminals using this ET technology exhibit an Adjacent Channel Leakage Ratio (ACLR) performance of approximately -35 dBc, whereas power amplifiers for base stations require higher ACLR performance compared to terminals.

[0004] In particular, power amplifiers using ET technology have difficulty achieving high ACLR, so power amplifiers for base stations supporting ET technology also need to research broadband high-performance Digital Pre-Distortion (DPD) technology. Accordingly, it can be said that for power amplifiers for base stations supporting ET technology, an integrated design linked with the digital modem technology of the base station RU (Radio Unit) is essential to implement high-performance DPD technology and ET technology.

[0005] In addition, 5G mobile communication RF signals have the characteristics of having a continuously changing amplitude over time and being wideband, and due to these signal characteristics, Peak to Average Ratio (PAR) and linearity must be considered, but linearity may degrade when the signal operates close to the saturation region of the FET, which is a key component of the power amplifier.

[0006] Therefore, the average power of the amplifier must operate back-off from the saturation region, which consequently leads to a decrease in power efficiency. To solve this problem, an ET circuit operates by sampling the RF signal at the input to detect the envelope, passing it through a broadband envelope amplifier, and inputting it to the drain terminal of the amplifier's terminal FET. In other words, ET technology is a technique that can improve the efficiency of the amplifier by changing the applied voltage at the FET's drain terminal in accordance with the level of the input signal.

[0007] Meanwhile, current 5G power amplifiers for terminals employ the aforementioned ET technology to optimize amplifier operation by adjusting the power supply in real-time according to the input signal magnitude, as a technique to improve amplifier efficiency. Although this ET technology is a core technology for enhancing power efficiency by adding a Supply Modulator to the power amplifier to regulate its power supply and accurately supplying power suitable for the signal magnitude in real-time, terminal power amplifiers have a maximum output of 23-26 dBm and operate on Li-Ion batteries, with the supply output range of the Supply Modulator being within 5V. In contrast, base station power amplifiers generate very high-output RF signals compared to terminal power amplifiers, and the V of the power amplifier CCSince the power supply voltage also operates in a high operating range of about 24V to 50V, there is a need to develop a supply modulator capable of outputting a high voltage of about 28V or higher, targeting power amplifiers for base stations.

[0008] Furthermore, there are currently no products released for base station power amplifiers utilizing Envelope Tracking (ET) technology. While various products are being released in the global market as Envelope Tracking technology has recently been widely adopted in terminal power amplifiers, there are no products related to supply modulator technology for implementing Envelope Tracking in Korea, and only power amplifier modules with Average Power Tracking (APT) technology applied have been developed to a limited extent.

[0009] In particular, supply modulators required to implement envelope tracking functionality are currently supplied exclusively by global companies, necessitating domestic development. Furthermore, since integration with modems is critical for achieving high efficiency through envelope tracking technology, joint development linked with base station equipment is required, in addition to the development of power amplifier modules.

[0010] The technology forming the background of this invention is disclosed in Korean Registered Patent Publication No. 10-1931150.

[0011] The present invention aims to solve the problems of the aforementioned conventional technology by providing a supply voltage adjustment device and method that achieve efficiency optimization of a power amplifier by applying an algorithm that pre-controls the power supply voltage of a power amplifier (PA) to match the output characteristics of the power amplifier through power tracking, and an ET (Envelope Tracking) technology using instantaneous power-based envelope data.

[0012] However, the technical problems that the embodiments of the present invention aim to solve are not limited to the technical problems described above, and other technical problems may exist.

[0013] As a technical means for achieving the above-mentioned technical problem, a supply voltage adjustment device for optimizing the efficiency of a power amplifier according to one embodiment of the present invention may include a signal analysis unit that obtains output level information of an output signal of a communication device equipped with a power amplifier through analysis of an input signal of the communication device, and a voltage adjustment unit that adjusts the supply voltage of the power amplifier based on the output level information.

[0014] In addition, the signal analysis unit can predict the output level information for the output signal scheduled to be output through the communication device by analyzing the frequency domain input signal of the communication device.

[0015] In addition, the voltage adjustment unit can adjust the supply voltage of the power amplifier by selectively applying an envelope tracking method or a section-by-section control method depending on whether the output level information is above a preset threshold level.

[0016] In addition, the signal analysis unit can obtain output level information for each of the output signals distinguished based on preset interval units.

[0017] In addition, the voltage adjustment unit may adjust the supply voltage by applying the envelope tracking method in correspondence with the high-output section, which is an output signal section where the output level information is scheduled to be above the threshold level.

[0018] In addition, the voltage adjustment unit can adjust the supply voltage by applying the section-by-section control method in correspondence with the output signal section preceding the high-output section.

[0019] Additionally, the voltage adjustment unit may include an envelope tracking (ET) unit that applies the envelope tracking method to a high-power section in a subframe unit where the output level information is above the threshold level, and an average power tracking (APT) unit that applies the section-by-section control method that determines the supply voltage using the average power of the low-power section in a low-power section in a subframe unit where the output level information is below the threshold level.

[0020] In addition, the average power tracking unit can vary the supply voltage within the CP (Cyclic Prefix) section of the low-power section.

[0021] Additionally, the voltage adjustment unit may include an envelope tracking (ET) unit that applies the envelope tracking method to a high-power section in symbol units where the output level information is above the threshold level, and a symbol power tracking (SPT) unit that applies the section-by-section control method that determines the supply voltage using the average power of the low-power section in a low-power section in symbol units where the output level information is below the threshold level.

[0022] In addition, the symbol power tracking unit can pre-adjust the supply voltage applied to the section immediately preceding the high-power section among the low-power sections upward by considering the output level information predicted for the high-power section and a preset voltage variable range.

[0023] In addition, the symbol power tracking unit can vary the supply voltage within the CP (Cyclic Prefix) section of the low-power section.

[0024] Meanwhile, a supply voltage adjustment method for optimizing the efficiency of a power amplifier according to one embodiment of the present invention may include: (a) obtaining output level information of an output signal of a communication device by analyzing an input signal of a communication device equipped with a power amplifier; and (b) adjusting the supply voltage of the power amplifier based on the output level information.

[0025] In addition, the above step (a) can predict the output level information for the output signal scheduled to be output through the communication device by analyzing the frequency domain input signal of the communication device.

[0026] In addition, step (b) above may adjust the supply voltage of the power amplifier by selectively applying an envelope tracking method or a segment-by-segment control method depending on whether the output level information is above a preset threshold level.

[0027] Additionally, the above step (b) may include (b1) a step of applying the envelope tracking method to a high-power section in a subframe unit where the output level information is above the threshold level, and (b2) a step of determining the supply voltage using the average power of the low-power section in a subframe unit where the output level information is below the threshold level.

[0028] Additionally, the above step (b) may include (b1') a step of applying the envelope tracking method to a high-power section in symbol units where the output level information is above the threshold level, and (b2') a step of determining the supply voltage using the average power of the low-power section in symbol units where the output level information is below the threshold level.

[0029] In addition, the above step (b2') can pre-adjust the supply voltage applied to the section immediately preceding the high-power section among the low-power sections by considering the output level information predicted for the high-power section and a preset voltage variable range.

[0030] The means for solving the problem described above are merely exemplary and should not be interpreted as intended to limit the present invention. In addition to the exemplary embodiments described above, additional embodiments may exist in the drawings and the detailed description of the invention.

[0031]

[0032] According to the means for solving the problem of the present invention described above, a supply voltage adjustment device and method can be provided to achieve efficiency optimization of a power amplifier by applying an algorithm that pre-controls the power supply voltage of a power amplifier (PA) to match the output characteristics of the power amplifier through power tracking, and an ET (Envelope Tracking) technology using instantaneous power-based envelope data.

[0033] According to the solution to the problem of the present invention described above, power efficiency can be improved compared to existing base station equipment through a power amplifier applying envelope tracking technology and a radio unit (RU) supporting envelope tracking technology.

[0034] According to the means for solving the problem of the present invention described above, high supply conversion efficiency can be provided even for high-bandwidth signals.

[0035] However, the effects obtainable from this invention are not limited to those described above, and other effects may exist.

[0036]

[0037] FIG. 1 is a schematic diagram of an open LAN-based communication system comprising a communication device having a supply voltage adjustment device for optimizing the efficiency of a power amplifier according to one embodiment of the present invention.

[0038] FIG. 2 is a diagram showing a comparison between the operation of a supply modulator of a conventional power amplifier and a supply voltage adjustment method according to a supply voltage adjustment device for optimizing the efficiency of a power amplifier disclosed herein.

[0039] FIG. 3a is a conceptual diagram showing a detailed circuit of a communication device having a supply voltage adjustment device for optimizing the efficiency of a power amplifier according to one embodiment of the present invention.

[0040] FIG. 3b is a detailed circuit diagram of a supply voltage regulator for optimizing the efficiency of a power amplifier according to one embodiment of the present invention.

[0041] FIG. 4 is a conceptual diagram illustrating a process for adjusting the supply voltage of a power amplifier by selectively applying an envelope tracking method or a section-by-section control method according to the first embodiment of the present invention.

[0042] FIG. 5 is a conceptual diagram illustrating a process for adjusting the supply voltage of a power amplifier by selectively applying an envelope tracking method or a section-by-section control method according to the second embodiment of the present invention.

[0043] Figure 6 is a conceptual diagram showing the radio frame structure.

[0044] FIG. 7 is a schematic diagram of a supply voltage adjustment device for optimizing the efficiency of a power amplifier according to one embodiment of the present invention.

[0045] FIG. 8 is a detailed configuration diagram of a voltage adjustment unit of a supply voltage adjustment device for optimizing the efficiency of a power amplifier according to one embodiment of the present invention.

[0046] FIG. 9 is an operation flowchart of a supply voltage adjustment method for optimizing the efficiency of a power amplifier according to one embodiment of the present invention.

[0047] FIG. 10 is a detailed operation flowchart for the selective application process of an envelope tracking method or a segment-by-segment control method according to the first embodiment of the present invention.

[0048] FIG. 11 is a detailed operation flowchart for the selective application process of an envelope tracking method or a segment-by-segment control method according to the second embodiment of the present invention.

[0049] Embodiments of the present invention are described below with reference to the attached drawings to enable those skilled in the art to easily implement the invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein. Furthermore, in order to clearly explain the present invention in the drawings, parts unrelated to the explanation have been omitted, and similar parts throughout the specification are denoted by similar reference numerals.

[0050] Throughout this specification, when a part is described as being "connected" to another part, this includes not only cases where they are "directly connected," but also cases where they are "electrically connected" or "indirectly connected" with other elements interposed between them.

[0051] Throughout the entire specification, when a component is described as being located "on," "on top," "on top," "under," "on bottom," or "on bottom" of another component, this includes not only cases where the component is in contact with the other component but also cases where another component exists between the two components.

[0052] Throughout this specification, when a part is described as "comprising" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0053] The present invention relates to a supply voltage regulating device and method for optimizing the efficiency of a power amplifier.

[0054] FIG. 1 is a schematic diagram of an open LAN-based communication system comprising a communication device having a supply voltage adjustment device for optimizing the efficiency of a power amplifier according to one embodiment of the present invention.

[0055] Referring to FIG. 1, an open RAN-based communication system (1000) according to one embodiment of the present invention may include an O-RU (O-RAN Distributed Unit; 10), an O-DU (O-RAN Radio Unit; 20), and an antenna module (30). In addition, the supply voltage adjustment device (100) for optimizing the efficiency of the power amplifier disclosed herein (hereinafter referred to as the 'supply voltage adjustment device (100)') may be provided for the O-RU (10), which is a communication device forming the open RAN-based communication system (1000), but is not limited thereto. According to an embodiment of the present invention, the supply voltage adjustment device (100) may be widely applied to various types of communication devices (equipment), such as base station devices and repeater devices.

[0056] In an O-RAN (Open-Radio Access Network), the physical layer is functionally separated, and the O-DU (20) included in the Open-RAN-based communication system (1000) may be responsible for the High PHY, which is option 7, and the O-RU (10) may be responsible for the Low PHY, which is option 8, and these O-RU (10) and O-DU (20) may be connected to each other via a fronthaul interface.

[0057] The communication device (10), O-DU (20), and antenna module (30) can communicate with each other through a network (not shown). The network (not shown) refers to a connection structure that enables information exchange between each node, such as terminals and servers. Examples of such a network (not shown) include, but are not limited to, a 3GPP (3rd Generation Partnership Project) network, an LTE (Long Term Evolution) network, a 5G network, a WIMAX (World Interoperability for Microwave Access) network, the Internet, a LAN (Local Area Network), a Wireless LAN (Wireless Local Area Network), a WAN (Wide Area Network), a PAN (Personal Area Network), a Wi-Fi network, a Bluetooth network, a satellite broadcasting network, an analog broadcasting network, and a DMB (Digital Multimedia Broadcasting) network.

[0058] In addition, a user terminal (not shown) equipped to mutually transmit and receive data (signals) with a communication device (10) may be, for example, a smartphone, a smartpad, a tablet PC, and any type of wireless communication device such as a PCS (Personal Communication System), GSM (Global System for Mobile communication), PDC (Personal Digital Cellular), PHS (Personal Handyphone System), PDA (Personal Digital Assistant), IMT (International Mobile Telecommunication)-2000, CDMA (Code Division Multiple Access)-2000, W-CDMA (W-Code Division Multiple Access), or Wibro (Wireless Broadband Internet) terminal.

[0059] Additionally, referring to FIG. 1, the open RAN-based communication system (1000) disclosed herein may be designed to build a broadband (e.g., 4.7 GHz level) base station system by applying envelope tracking technology and low-loss packaging matching technology to a high-power power amplifier (1) for a Sub-6 GHz band Massive MIMO base station, for example.

[0060] For example, the open RAN-based communication system (1000) disclosed herein may be equipped with a supply modulator (11) having a 3dB bandwidth of 130MHz and a high efficiency of 80% or more so as to be able to track the envelope of an RF signal having a bandwidth of 100MHz of 5G NR.

[0061] In addition, the open RAN-based communication system (1000) disclosed herein may be a broadband 300MHz-supported 4T4R specialized network base station system that adjusts the supply voltage of a power amplifier (1) by applying an envelope tracking (ET) method and a segment control (APT / SPT) method.

[0062] Specifically, referring to FIG. 1, the fronthole connection between the O-RU (10) and the O-DU (20) can be configured as eCPRI based on wired communication means such as optical fiber. Additionally, the lower PHY layer of the O-RU (10) can be implemented using an FPGA (Field Programmable Gate Array), and may be a layer that performs Fast Fourier Transform (FFT) / Inverse Fast Fourier Transform (IFFT) functions, Cyclic Prefix (CP) addition and removal functions, PRACH (Physical Random Access Channel) filtering functions, digital beamforming functions, etc.

[0063] Additionally, the digital front end (DFE) of the O-RU (10) may be a component that performs DUC (Digital Up-Conversion), DDC (Digital Down-Conversion), CFR (Crest Factor Reduction), DPD (Digital Pre-Distortion), ET (Envelope Tracking), etc., and the RF front end (RF FE) may be a component that includes an array antenna, a bandpass filter, PA (Power Amplifier), LNA (Low Noise Amplifier), DAC (Digital-to-Analog Converter), ADC (Analog-to-Digital Converter), etc.

[0064] FIG. 2 is a diagram showing a comparison between the operation of a supply modulator of a conventional power amplifier and a supply voltage adjustment method according to a supply voltage adjustment device for optimizing the efficiency of a power amplifier disclosed herein.

[0065] Specifically, FIG. 2(a) shows a method of applying a supply voltage to a conventional power amplifier, and FIG. 2(b) shows a method of adjusting the supply voltage for optimizing the efficiency of a power amplifier disclosed herein.

[0066] Referring to FIG. 2, the supply voltage adjustment device (100) disclosed herein applies a power modulation technique that can simultaneously obtain linearity and efficiency by controlling the supply voltage of a power amplifier (1) to match the output level (power) of an output signal. Specifically, by applying ET and APT / SPT techniques using a supply modulator (11), the supply voltage of the power amplifier (1) is increased at high output power to ensure linearity of the power amplifier (1), and conversely, the supply voltage is lowered at low output power so that an unnecessarily high power voltage is not supplied, thereby improving the efficiency of the power amplifier (1).

[0067] In this regard, existing power amplifiers for base stations are the base station's V CC Although it was developed to deliver optimal performance under fixed supply voltage conditions of 28V or higher, power amplifiers with ET technology have a characteristic where the supply voltage supplied by the supply modulator changes, and the supply voltage changes significantly from the high voltage of 28V or higher used conventionally to as little as 5V.

[0068] Meanwhile, such changes in supply voltage can change the RF characteristics of the power amplifier and affect various performance indicators related to the power amplifier (e.g., gain, AM-AM, AM-PM, efficiency, etc.). Therefore, the core structure of the power amplifier (1) to support such supply power control technology needs to be designed to maintain high-performance output characteristics by taking into account these changes in supply voltage.

[0069] Below, the specific functions and operations of the supply voltage adjustment device (100) will be described in detail.

[0070] FIG. 3a is a conceptual diagram showing a detailed circuit of a communication device having a supply voltage adjustment device for optimizing the efficiency of a power amplifier according to one embodiment of the present invention.

[0071] Referring to FIG. 3a, the supply voltage adjustment device (100) can be divided into an FPGA part (10a), an analog conversion part (10b), and an RF part (10c).

[0072] Specifically, the FPGA part (10a) receives and processes a frequency domain input signal (A) of the communication device (10), and this input signal (A) is a frequency domain signal prior to the IFFT, and the supply voltage adjustment device (100) can analyze it to predict in advance the output characteristics of the power amplifier (1) of the RF part (10c) to be described later.

[0073] Meanwhile, the FPGA part (10a) can perform IFFT operations, CP insertion, and windowing processing on the input signal (A), and after processing the signal primarily through a pre-linear distortion compensation filter and a channel filter, perform DPD (Digital Pre-Distortion) processing. In addition, the FPGA part (10a) can extract amplitude information of the signal using the CORDIC (COordinate Rotation Digital Computer) algorithm and generate envelope shaping information based on this to optimize the supply voltage of the power amplifier (1) in advance.

[0074] Additionally, the analog conversion part (10b) may be equipped with a DAC that converts digital signals processed in the FPGA part (10a) into analog signals, and an ADC that converts feedback signals from the RF part (10c) into digital signals.

[0075] Additionally, the RF part (10c) is a circuit part responsible for amplifying and transmitting the actual RF signal, and the supply voltage (V) for the power amplifier (1) through the supply modulator (11) bott The power amplifier (1) can adjust the ) and, under the adjusted supply voltage, amplify the RF signal and transmit it through the antenna.

[0076] In particular, the supply voltage adjustment device (100) disclosed herein has the advantage of enabling efficient power amplification by pre-analyzing the frequency domain input signal (A) in the FPGA part (10a) to predict the power level of the output signal and pre-optimizing the supply voltage of the power amplifier (1) based on this. That is, the supply voltage adjustment device (100) can optimize the efficiency of the power amplifier (1) by pre-identifying the section requiring high output through the analysis of the input signal (A), applying an envelope tracking method to the corresponding section, and applying a section-by-section control method to the low output section.

[0077] FIG. 3b is a detailed circuit diagram of a supply voltage regulator for optimizing the efficiency of a power amplifier according to one embodiment of the present invention.

[0078] Referring to FIG. 3b, the supply voltage adjustment device (100) disclosed herein is mounted as a sub-module of a communication device (10) and may be configured to adjust the supply voltage applied to the power amplifier (1) through a supply modulator (11) of the power amplifier (1) provided in the communication device (10).

[0079] Meanwhile, according to one embodiment of the present invention, the ‘DPD’ block among the submodules of the supply voltage adjustment device (100) shown in FIG. 3b can operate to compensate for AM (Amplitude Modulation) and PM (Phase Modulation) errors of the power amplifier (1) that receives a voltage changing by envelope tracking.

[0080] In this regard, the open RAN-based communication system (1000) disclosed herein can be implemented by combining envelope tracking (ET) technology and digital pre-distortion (DPD) technology.

[0081] In particular, the supply modulator (11) is equipped with a Symbol Power Tracking (SPT) function to support a wideband of 300 MHz or more, and according to an embodiment of the present invention, a delay reduction technique using a pre-distortion compensation circuit may also be applied.

[0082] In this regard, in conventional power amplifiers, the supply voltage is fixed and AM-AM and AM-PM distortion characteristics occur consistently, so signal distortion is compensated by applying digital pre-distortion using a look-up table, but when power modulation technology such as ET or APT / SPT is applied to the power amplifier (1), the RF characteristics of the power amplifier (1) may change.

[0083] In other words, as the AM-AM and AM-PM signal distortion characteristics in the power amplifier change according to the change in supply voltage, the existing DPD technology alone cannot compensate for the signal distortion of the power amplifier with applied ET technology. Therefore, in the case of the power amplifier (1) with applied ET technology, a DPD algorithm that reflects the change in RF characteristics according to the VCC level must be applied to apply digital pre-distortion, and the change in characteristics appearing in the RF output according to the frequency characteristics according to the envelope bandwidth of VCC must be detected and an inverse distortion signal generated so that the output signal of the power amplifier can be linearized.

[0084] In consideration of this, the open RAN-based communication system (1000) disclosed herein can be newly developed and applied by combining the ET-DPD algorithm for ET with conventional memory DPD and closed-loop DPD technologies.

[0085] Meanwhile, since DPD involves additional processing steps in the signal path to correct non-linear signal distortion, combining it with ET can increase the overall complexity of the system and cause more delays due to the interaction between the two systems. To effectively combine ET and DPD, specialized algorithms are required that take into account the interaction between the two systems. While ET improves the efficiency of PA, it can simultaneously lead to additional power consumption due to the complex calculations of DPD; consequently, heat generation and power consumption are important considerations in system design.

[0086] Additionally, the 'Pad out Delay' block among the submodules of the supply voltage regulator (100) shown in FIG. 3b can operate to compensate for timing mismatches between the ET path and the signal path and within the signal path.

[0087] In this regard, compensation for the group delay between the RF Path and the output VCC Path of the supply modulator IC must be provided. Since ET is a technology that improves efficiency by adjusting the VCC power supply voltage of the power amplifier to match the level of the envelope signal of the RF input signal, if the delay between the envelope power supplied by the supply modulator and the RF input signal is not compensated and becomes misaligned, the ET performance will be significantly degraded.

[0088] To ensure ET performance, the group delay compensation technique between the RF path of the power amplifier and the output (VCC) path of the supply modulator IC is very important. The delay on both paths is inversely proportional to the bandwidth of the RF signal, and since the envelope signal changes faster as the RF signal bandwidth widens, a delay alignment circuit with more precise resolution needs to be implemented on the modem side.

[0089] Generally, for LTE transmission signals with an RF bandwidth of 20 MHz, it was sufficient to perform path delay compensation within 1 nsec, but for 5G NR signals of 100 MHz, very precise delay compensation within 200 psec is required, so for 5G ET, delay compensation technology between the VCC path and the RF path is required, and this must be able to operate together with a pre-distortion compensation circuit.

[0090] In addition, the supply voltage adjustment device (100) can obtain output level information of the output signal of the communication device (100) equipped with a power amplifier (1).

[0091] Specifically, the supply voltage adjustment device (100) can obtain output level information for an output signal scheduled to be output through the communication device (100) in advance through analysis of the frequency domain input signal of the communication device (100).

[0092] The spectrum of the envelope of a wireless communication signal has a bandwidth that is approximately 2.5 to 3 times wider than the bandwidth of the I / Q signal. For example, the I / Q baseband signal of a signal having an RF spectrum of 100 MHz of 5G NR can have a bandwidth of 50 MHz, and the envelope signal has a bandwidth of 125 MHz (2.5 times 50 MHz). As the bandwidth increases, it is very difficult to maintain high efficiency, and the open RAN-based communication system (1000) disclosed herein is designed to achieve a high level of supply conversion efficiency (e.g., 80% or more) even with high bandwidth signals.

[0093] According to one embodiment of the present invention, the supply modulator (11) may be designed to support a 3-dB bandwidth of up to 130 MHz or more to track the envelope of a 5G NR 100 MHz signal.

[0094] Specifically, in the case of the supply modulator (11), a large voltage change cannot be applied in a single CP section at the operating speed of the existing IC, and to solve this, the I / Q data in the frequency domain of the IFFT stage is acquired in symbol units and the voltage can be increased step by step in advance.

[0095] To implement an ET signal generator, amplitude information in symbol units is required, and, for example, amplitude information can be extracted using the CORDIC algorithm.

[0096] In summary, the open RAN-based communication system (1000) disclosed herein can extract information on the symbol unit average power from the I / Q data extracted from the IFFT stage, raise the voltage in advance, and transmit a signal to the supply modulator (11) IC to control the voltage in sampling units using the instantaneous power obtained from the CORDIC algorithm.

[0097] In other words, the average power in the frequency domain can be obtained in advance, and using this, the supply voltage adjustment device (100) disclosed herein can apply an envelope tracking method that supplies power to the power amplifier (1) according to the magnitude of the envelope of the 5G transmission signal in an instantaneous power, i.e., Sample By Sample, at a point where the output of the power amplifier (1) is relatively high.

[0098] Thus, ET is a method of dynamically adjusting the supply voltage of the power amplifier (1) to match the envelope of the signal, which means that the operating point of the power amplifier (1) is constantly changing, which can make the linearization process of the DPD algorithm more complex. Since DPD is optimized at a constant operating point, it must effectively track and adapt to the operating point that changes due to ET.

[0099] Additionally, the supply voltage adjustment device (100) can adjust the supply voltage of the power amplifier (1) by selectively applying an envelope tracking method or a section-by-section control method depending on whether the acquired output level information is above a preset threshold level.

[0100] FIG. 4 is a conceptual diagram illustrating a process for adjusting the supply voltage of a power amplifier by selectively applying an envelope tracking method or a section-by-section control method according to the first embodiment of the present invention.

[0101] Referring to FIG. 4, the supply voltage adjustment device (100) according to the first embodiment of the present invention can apply an envelope tracking method to a high-output section in a subframe unit where the output level information is above a threshold level.

[0102] For example, the 'Subframe 2' section shown in FIG. 4 is a high-power section where the output level information expected (calculated) for that section is above a threshold level, and it indicates that the supply voltage of the power amplifier (1) changes in real time according to the magnitude of the envelope through an envelope tracking method using instantaneous power.

[0103] In addition, according to the first embodiment of the present invention, the supply voltage adjustment device (100) can determine the supply voltage of the power amplifier (1) using the average power of the low output section in a subframe unit for a low output section in which the output level information is below a threshold level.

[0104] For example, the 'Subframe 1' and 'Subframe 3' sections shown in FIG. 4 are low-power sections where the output level information expected (calculated) for the corresponding section is below a threshold level, and the supply voltage of the power amplifier (1) is applied consistently within the corresponding subframe section to correspond to the average power calculated for the corresponding subframe section rather than the instantaneous power.

[0105] FIG. 5 is a conceptual diagram illustrating a process for adjusting the supply voltage of a power amplifier by selectively applying an envelope tracking method or a section-by-section control method according to the second embodiment of the present invention.

[0106] Referring to FIG. 5, the supply voltage adjustment device (100) according to the second embodiment of the present invention can apply an envelope tracking method to a high-output section in the symbol unit where the output level information is above a threshold level.

[0107] For example, the 'Symbol 3' and 'Symbol 5' sections shown in FIG. 5 are high-power sections where the output level information expected (calculated) for the corresponding section is above a threshold level, and the supply voltage of the power amplifier (1) varies in real time according to the magnitude of the envelope through an envelope tracking method using instantaneous power.

[0108] In addition, according to the second embodiment of the present invention, the supply voltage adjustment device (100) can determine the supply voltage of the power amplifier (1) using the average power of the low output section for a low output section in units of Symbols where the output level information is below a threshold level.

[0109] For example, the 'Symbol 1', 'Symbol 2', 'Symbol 4', and 'Symbol 6' sections shown in FIG. 5 are low-power sections where the output level information expected (calculated) for the corresponding section is below a threshold level, and the supply voltage of the power amplifier (1) is applied consistently within the corresponding symbol section to correspond to the average power calculated for the corresponding symbol section rather than the instantaneous power.

[0110] Specifically, according to one embodiment of the present invention, the supply voltage adjustment device (100) can pre-adjust the supply voltage applied to the immediate preceding section of the high-output section among the low-output sections where the output level information is below a threshold level by considering the output level information predicted for the high-output section and a preset voltage variable range.

[0111] In this regard, referring to the 'Symbol 1' and 'Symbol 2' sections of FIG. 5, it is expected (calculated) that an output level above a threshold level is required in the 'Symbol 3' section following the 'Symbol 2' section. Considering the voltage variation range of the supply modulator (11), it may be difficult to provide a high supply voltage corresponding to the output level in real time in the high-output section, the 'Symbol 3' section. Therefore, by supplying a supply voltage relatively higher than the supply voltage corresponding to the average power predicted (calculated) for the corresponding symbol section in the 'Symbol 2' section preceding the high-output section, the supply voltage of the power amplifier (1) is adjusted upward in advance, thereby making it possible to adjust the supply voltage upward to a level that matches the voltage variation range of the supply modulator (11) in the subsequent high-output section.

[0112] Meanwhile, as illustrated in FIG. 5, when a high-power section is scheduled, the method of preemptively raising the supply voltage of the power amplifier (1) using two or more low-power sections can be commonly applied not only to the SPT-based section-by-section control method according to the second embodiment of the present invention, but also to the APT-based section-by-section control method according to the first embodiment of the present invention described through FIG. 4, by raising the supply voltage stepwise through two or more low-power sections in subframe units.

[0113] In addition, according to one embodiment of the present invention, the range in which the supply voltage is raised in a low-power section preceding a high-power section may be varied according to the specifications or standards of the supply modulator (11) (e.g., voltage variable range, etc.). For example, the supply voltage adjustment device (100) may operate such that the number of low-power sections in which a preemptive supply voltage increase is applied preceding the high-power section increases as the voltage variable range of the supply modulator (11) becomes smaller.

[0114] Figure 6 is a conceptual diagram showing the radio frame structure.

[0115] Referring to FIG. 6, the supply voltage adjustment device (100) can vary the supply voltage to match the supply voltage determined for a corresponding section (in other words, a subframe unit section or a symbol unit section) by using a CP (Cyclic Prefix) section among the sections forming the radio frame when applying a section-by-section control method based on APT or SPT.

[0116] In this regard, the frame structure applied in 5G can not only allocate uplink and downlink signals per symbol but also adjust TX power per symbol. As the Modulation Code Scheme (MCS) level increases from 256-QAM to 1024-QAM, the symbol EVM becomes more important.

[0117] In order to control the TX power per symbol, it is necessary to reduce the voltage switching time for the supply voltage of the power amplifier (1) from the existing 20 usec to about 1 to 5 usec, and for this purpose, Symbol Power Tracking (SPT) technology may be applied.

[0118] Currently, ET technology is primarily used to amplify the efficiency of power amplifiers in mobile devices, and new algorithms are required for its use in power amplifiers for base stations. ET signal generators for base stations must handle a larger power range and a wider frequency band than those for terminals, and therefore must meet higher power and thermal management requirements.

[0119] In OFDM systems, Cyclic Prefix (CP) is used to avoid Inter-Symbol Interference (ISI), a phenomenon in which the signal of one symbol overlaps with the signal of the next symbol and causes interference. The power supply conversion between APT and SPT must be performed during the CP period.

[0120] The duration of the CP interval is determined by Numerology. When Numerology is "0" (SubCarrierSpaceing=15Khz), the CP is 4.66 usec, and when Numerology is "1" (SubCarrierSpaceing=30Khz), the CP is reduced to 2.33 usec.

[0121] In this regard, the supply voltage adjustment device (100) according to one embodiment of the present invention may, for example, use "1" as the numerology. That is, the voltage of the SPT must be converted in the CP section of 2.33 µs, but since the voltage conversion speed of the supply modulator (11) is at the level of 4 usec per 1 V, the voltage cannot be rapidly changed from 5 V to 28 V in the CP section. To solve this, the supply voltage adjustment device (100) disclosed herein may apply a pre-staged power modulation (Pre-Staged APT / SPT) method that converts the power supply (in other words, the supply voltage of the power amplifier (1)) in stages in advance in the CP section.

[0122] Unlike conventional 4G, the Reference Signal (RS) of 5G is not output broadly across the entire band but is transmitted only for a limited time within a very restricted bandwidth (7.2 MHz). This means that the signal output is very low when there is no traffic. Therefore, efficiency and linearity must be precisely managed using APT and SPT in periods of low signal output, while ET is operated for control during high output periods; however, the DPD and ET must operate in a manner that prevents mutual interference. In other words, the key is to control the Supply Modulator by constantly monitoring signal traffic based on the 5G signal's Radio Frame, a capability that is only possible at base stations such as O-RUs.

[0123] FIG. 7 is a schematic diagram of a supply voltage adjustment device for optimizing the efficiency of a power amplifier according to one embodiment of the present invention.

[0124] Referring to FIG. 7, the supply voltage adjustment device (100) may include a signal analysis unit (110) and a voltage adjustment unit (120).

[0125] The signal analysis unit (110) can obtain output level information of the output signal of the communication device (100) equipped with a power amplifier (1).

[0126] Specifically, the signal analysis unit (110) can obtain output level information for an output signal scheduled to be output through the communication device (100) in advance by analyzing the frequency domain input signal of the communication device (100).

[0127] The voltage adjustment unit (120) can adjust the supply voltage of the power amplifier (1) by selectively applying an envelope tracking method or a section-by-section control method depending on whether the acquired output level information is above a preset threshold level.

[0128] FIG. 8 is a detailed configuration diagram of a voltage adjustment unit of a supply voltage adjustment device for optimizing the efficiency of a power amplifier according to one embodiment of the present invention.

[0129] Referring to FIG. 8, the voltage adjustment unit (120) may include an envelope tracking unit (121), an average power tracking unit (122), and a symbol power tracking unit (123).

[0130] According to the first embodiment of the present invention, the envelope tracking unit (121) can apply an envelope tracking method to a high-output section in subframe units where the output level information is above a threshold level.

[0131] In addition, according to the first embodiment of the present invention, the average power tracking unit (122) can determine the supply voltage of the power amplifier (1) using the average power of the low-power section in a subframe unit for a low-power section where the output level information is below a threshold level.

[0132] According to the second embodiment of the present invention, the envelope tracking unit (121) can apply an envelope tracking method to a high-output section in the symbol unit where the output level information is above a threshold level.

[0133] In addition, according to the second embodiment of the present invention, the symbol power tracking unit (123) can determine the supply voltage of the power amplifier (1) using the average power of the low-power section for a low-power section in units of Symbols where the output level information is below a threshold level.

[0134] Specifically, according to one embodiment of the present invention, the symbol power tracking unit (123) can pre-adjust the supply voltage applied to the immediate preceding section of the high-power section among the low-power sections where the output level information is below the threshold level by considering the output level information predicted for the high-power section and the preset voltage variable range.

[0135] Meanwhile, regarding the core structure design of the power amplifier (1), a passive component embedded high frequency low loss package process technology is required, and in particular, the mobile communication band of 3 GHz or lower has various bands densely arranged in a narrow frequency range, so the band is supported using a SAW (Surface Acoustic Wave) filter and a BAW (Bulk Acoustic Wave) filter.

[0136] 5G mobile communication supports a significantly wider band compared to the existing LTE mobile communication bandwidth, with the n77 (3.3~4.2GHz), n78 (3.3~3.8GHz), and n79 (4.4~5.0GHz) bands corresponding to Sub-6GHz. Therefore, it is impossible to support this band using SAW filters or BAW filters. In other words, there are limitations to bandwidth support with existing filter technology, so a high-frequency, low-loss package process technology with embedded passive components is required to overcome this. In this regard, according to one embodiment of the present invention, the core structure of the power amplifier (1) can minimize signal loss and increase the efficiency of the entire system by using an Integrated Passive Device (IPD) method that directly integrates passive components such as capacitors and inductors onto a substrate.

[0137] Below, based on the details described above, we will briefly examine the operation flow of the present invention.

[0138] FIG. 9 is an operation flowchart of a supply voltage adjustment method for optimizing the efficiency of a power amplifier according to one embodiment of the present invention.

[0139] The supply voltage adjustment method for optimizing the efficiency of the power amplifier illustrated in FIG. 9 can be performed by the supply voltage adjustment device (100) described above. Therefore, even if the details are omitted below, the description of the supply voltage adjustment device (100) can be equally applied to the description of the supply voltage adjustment method for optimizing the efficiency of the power amplifier.

[0140] Referring to FIG. 9, in step S11, the signal analysis unit (110) can obtain output level information of the output signal of the communication device (100) having (a) a power amplifier (1).

[0141] Specifically, in step S11, the signal analysis unit (110) can obtain in advance output level information for an output signal scheduled to be output through the communication device (100) by analyzing the frequency domain input signal of the communication device (100).

[0142] Next, in step S12, the voltage adjustment unit (120) can adjust the supply voltage of the power amplifier (1) by selectively applying an envelope tracking method or a section-by-section control method depending on whether (b) the acquired output level information is above a preset threshold level.

[0143] In the description above, steps S11 to S12 may be further divided into additional steps or combined into fewer steps according to an embodiment of the present invention. Additionally, some steps may be omitted as necessary, and the order between steps may be changed.

[0144] FIG. 10 is a detailed operation flowchart for the selective application process of an envelope tracking method or a segment-by-segment control method according to the first embodiment of the present invention.

[0145] The selective application process of the envelope tracking method or the section-by-section control method illustrated in FIG. 10 can be performed by the supply voltage adjustment device (100) described above. Therefore, even if the details are omitted below, the description of the supply voltage adjustment device (100) can be applied equally to the description of FIG. 10.

[0146] Referring to FIG. 10, in step S121, the envelope tracking unit (121) can apply an envelope tracking method to a high-output section in a subframe unit where (b1) output level information is above a threshold level.

[0147] Next, in step S122, the average power tracking unit (122) can determine the supply voltage of the power amplifier (1) using the average power of the low-power section in a subframe unit of (b2) output level information that is below a threshold level.

[0148] In the description above, steps S121 to S122 may be further divided into additional steps or combined into fewer steps according to an embodiment of the present invention. Additionally, some steps may be omitted as necessary, and the order of the steps may be changed.

[0149] FIG. 11 is a detailed operation flowchart for the selective application process of an envelope tracking method or a segment-by-segment control method according to the second embodiment of the present invention.

[0150] The selective application process of the envelope tracking method or the section-by-section control method illustrated in FIG. 11 can be performed by the supply voltage adjustment device (100) described above. Therefore, even if the details are omitted below, the description of the supply voltage adjustment device (100) can be applied equally to the description of FIG. 11.

[0151] Referring to FIG. 11, in step S121', the envelope tracking unit (121) can apply an envelope tracking method to a high-output section of a symbol unit where the output level information (b1)' is above a threshold level.

[0152] Next, in step S122', the symbol power tracking unit (123) can determine the supply voltage of the power amplifier (1) using the average power of the low-power section for the low-power section of the symbol unit (b2)' output level information that is below the threshold level.

[0153] Specifically, in step S122', the symbol power tracking unit (123) can pre-adjust the supply voltage applied to the immediate preceding section of the high-power section among the low-power sections where the output level information is below the threshold level, by considering the output level information predicted for the high-power section and the preset voltage variable range.

[0154] In the foregoing description, steps S121' through S122' may be further subdivided into additional steps or combined into fewer steps, depending on the embodiment of the present invention. Additionally, some steps may be omitted as necessary, and the order between steps may be changed.

[0155] A supply voltage adjustment method for optimizing the efficiency of a power amplifier according to one embodiment of the present invention may be implemented in the form of program instructions that can be executed through various computer means and recorded on a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, etc., either individually or in combination. The program instructions recorded on the medium may be those specifically designed and configured for the present invention, or may be those known and available to those skilled in the art of computer software. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tapes; optical recording media such as CD-ROMs and DVDs; magneto-optical media such as floptical disks; and hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, and flash memory. Examples of program instructions include machine code, such as that generated by a compiler, as well as high-level language code that can be executed by a computer using an interpreter, etc. The above-described hardware device may be configured to operate as one or more software modules to perform the operation of the present invention, and vice versa.

[0156] In addition, the supply voltage adjustment method for optimizing the efficiency of the aforementioned power amplifier can also be implemented in the form of a computer program or application executed by a computer and stored on a recording medium.

[0157] Meanwhile, the open RAN-based communication system (1000) disclosed in this invention can be equipped with a high-efficiency power amplifier (1) with envelope tracking technology applied in the Sub-6GHz band, and can contribute to the promotion of new domestic and international commercialization by configuring a broadband high-efficiency 5G Massive MIMO base station radio unit and a distributed unit tailored to the needs of the client company.

[0158] If high-efficiency power amplifier technology is applied using envelope tracking technology, it is expected that the electrical energy consumed by mobile communication base station infrastructure can be reduced and carbon neutrality can be achieved.

[0159] The foregoing description of the present invention is for illustrative purposes only, and those skilled in the art will understand that other specific forms can be easily modified without altering the technical concept or essential features of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. For example, each component described as a single unit may be implemented in a distributed manner, and components described as distributed may likewise be implemented in a combined form.

[0160] The scope of the present invention is defined by the claims set forth below rather than by the detailed description above, and all modifications or variations derived from the meaning and scope of the claims and the concept of equivalents thereof should be interpreted as being included within the scope of the present invention.

[0161] [Explanation of the symbol]

[0162] 10: Communication device, O-RU

[0163] 100: Supply voltage regulator for power amplifier efficiency optimization

[0164] 110: Signal Analysis Unit

[0165] 120: Voltage regulator

[0166] 121: Envelope Tracking Section

[0167] 122: Average Power Tracking Unit

[0168] 123: Symbol Power Trace Section

[0169] 1: Power amplifier

[0170] 11: Supply Modulator

[0171] 20: O-DU

[0172] 30: Antenna module

[0173] 1000: Open RAN-based communication system

Claims

1. In a supply voltage regulator for optimizing the efficiency of a power amplifier, A signal analysis unit that obtains output level information of an output signal of a communication device by analyzing an input signal of a communication device equipped with a power amplifier; and A voltage adjustment unit that adjusts the supply voltage of the power amplifier based on the above output level information, A supply voltage regulating device including 2. In Paragraph 1, The above signal analysis unit is, A supply voltage regulating device that predicts output level information for the output signal scheduled to be output through the communication device by analyzing the frequency domain input signal of the communication device.

3. In Paragraph 2, The above voltage adjustment unit is, A supply voltage adjustment device that adjusts the supply voltage of the power amplifier by selectively applying an envelope tracking method or a segment-by-segment control method depending on whether the output level information is above a preset threshold level.

4. In Paragraph 3, The above signal analysis unit is, The method involves obtaining output level information for each of the above output signals, which are distinguished based on preset interval units. The above voltage adjustment unit is, A supply voltage adjustment device that adjusts the supply voltage by applying the envelope tracking method in correspondence with a high-output section, which is an output signal section scheduled to be above the threshold level, for the output level information.

5. In Paragraph 4, The above voltage adjustment unit is, A supply voltage adjustment device that adjusts the supply voltage by applying the section-specific control method in response to an output signal section preceding the high-output section.

6. In Paragraph 3, The above voltage adjustment unit is, An envelope tracking (ET) unit that applies the envelope tracking method to high-output sections in subframe units where the output level information is above the threshold level; and An Average Power Tracking (APT) unit that applies the section-by-section control method to determine the supply voltage using the average power of the low-power section for low-power sections in subframe units where the output level information is below the threshold level, A supply voltage regulating device that includes 7. In Paragraph 6, The above average power tracking unit is, A supply voltage adjustment device that varies the supply voltage within the CP (Cyclic Prefix) section of the above low-power section.

8. In Paragraph 3, The above voltage adjustment unit is, An envelope tracking (ET) unit that applies the envelope tracking method to a high-output section in symbol units where the output level information is above the threshold level; and A Symbol Power Tracking (SPT) unit that applies the section-by-section control method to determine the supply voltage using the average power of the low-power section for a low-power section in symbol units where the output level information is below the threshold level, A supply voltage regulating device that includes 9. In Paragraph 8, The above symbol power tracking unit is, A supply voltage adjustment device that pre-adjusts the supply voltage applied to the immediate preceding section of the high-power section among the low-power sections by considering the output level information predicted for the high-power section and a preset voltage variable range.

10. In Paragraph 8, The above symbol power tracking unit is, A supply voltage adjustment device that varies the supply voltage within the CP (Cyclic Prefix) section of the above low-power section.

11. A method for adjusting the supply voltage to optimize the efficiency of a power amplifier, (a) a step of obtaining output level information of an output signal of a communication device by analyzing an input signal of a communication device equipped with a power amplifier; and (b) a step of adjusting the supply voltage of the power amplifier based on the output level information above, A supply voltage adjustment method including 12. In Paragraph 11, The above step (a) is, A supply voltage adjustment method that predicts output level information for the output signal scheduled to be output through the communication device by analyzing the frequency domain input signal of the communication device.

13. In Paragraph 12, The above step (b) is, A supply voltage adjustment method that adjusts the supply voltage of the power amplifier by selectively applying an envelope tracking method or a segment-by-segment control method depending on whether the output level information is above a preset threshold level.

14. In Paragraph 13, The above step (b) is, (b1) A step of applying the envelope tracking method to a high-output section in subframe units where the output level information is above the threshold level; and (b2) A step of determining the supply voltage using the average power of the low-power section for a low-power section in a subframe unit where the output level information is less than the threshold level, A supply voltage adjustment method that includes 15. In Paragraph 13, The above step (b) is, (b1') A step of applying the envelope tracking method to a high-output section in symbol units where the output level information is above the threshold level; and (b2') A step of determining the supply voltage using the average power of the low-power section for a low-power section in symbol units where the output level information is below the threshold level, A supply voltage adjustment method that includes 16. In Paragraph 15, The above (b2') step is, A supply voltage adjustment method in which the supply voltage applied to the immediate preceding section of the high-power section among the low-power sections is adjusted upward in advance by considering the output level information predicted for the high-power section and a preset voltage variable range.

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