WO2024069304A1 - Appareil et procédé de génération d'une mesure evm pour une transmission mimo - Google Patents

Appareil et procédé de génération d'une mesure evm pour une transmission mimo Download PDF

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Publication number
WO2024069304A1
WO2024069304A1 PCT/IB2023/059163 IB2023059163W WO2024069304A1 WO 2024069304 A1 WO2024069304 A1 WO 2024069304A1 IB 2023059163 W IB2023059163 W IB 2023059163W WO 2024069304 A1 WO2024069304 A1 WO 2024069304A1
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WIPO (PCT)
Prior art keywords
evm
layer
matrix
transmission
combining gain
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PCT/IB2023/059163
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English (en)
Inventor
Colin Frank
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Lenovo (Singapore) Pte. Ltd.
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Publication of WO2024069304A1 publication Critical patent/WO2024069304A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/0413—MIMO systems
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/0008—Modulated-carrier systems arrangements for allowing a transmitter or receiver to use more than one type of modulation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/18—Phase-modulated carrier systems, i.e. using phase-shift keying
    • H04L27/22—Demodulator circuits; Receiver circuits
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/32—Carrier systems characterised by combinations of two or more of the types covered by groups H04L27/02, H04L27/10, H04L27/18 or H04L27/26
    • H04L27/34—Amplitude- and phase-modulated carrier systems, e.g. quadrature-amplitude modulated carrier systems
    • H04L27/38—Demodulator circuits; Receiver circuits
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/0001—Arrangements for dividing the transmission path
    • H04L5/0014—Three-dimensional division
    • H04L5/0023—Time-frequency-space
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0048—Allocation of pilot signals, i.e. of signals known to the receiver
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/2601—Multicarrier modulation systems
    • H04L27/2602—Signal structure

Definitions

  • the present disclosure is directed to an apparatus and method of communication on a wireless network. More particularly, the present disclosure is directed to generating an Error Vector Magnitude (EVM) for a Multiple-Input Multiple-Output (MIMO) transmission.
  • EVM Error Vector Magnitude
  • MIMO Multiple-Input Multiple-Output
  • wireless communication devices such as User Equipments (UEs)
  • UEs User Equipments
  • EVM is a measure of modulation accuracy, or how well the power amplifier in a UE is transmitting information, represented by the varying phase and amplitude of a Radio-Frequency (RF) signal.
  • RF Radio-Frequency
  • the UE may send a transmission signal, such as a multi-layer transmission, to a test equipment.
  • the test equipment calculates a transmitter EVM for multi-layer transmission.
  • the UE may transmit to a base station and the base station calculates a transmitter EVM for multi-layer transmission.
  • FIG.1 is an example block diagram of a system according to a possible embodiment
  • FIG.2 is an example block diagram illustrating a communication arrangement for determining an EVM of a transmitter according to a possible embodiment
  • FIG.3 is an example flowchart of a method of operation of a device according to a possible embodiment
  • FIG.4 is an example flowchart of a method of operation of a device according to a possible embodiment
  • Docket No: SMM920220160-WO-PCT
  • FIG.5 is an example block diagram of an apparatus according to a possible embodiment
  • FIG.6 is an example illustration of a relationship between EVM and MPR according to a possible embodiment
  • FIG.7 is an example flowchart of a method in a device according to a possible embodiment
  • FIG.8 is an example flowchart of a method in a device according to a possible embodiment.
  • Embodiments provide a method and apparatus for communicating on a wireless network. Embodiments can also provide for generating an EVM for a MIMO transmission. Embodiments can also provide a method for defining EVM for multi-antenna multi-layer transmission using a conductive measurement, such as a measurement of a conductively received transmission. [0013] According to a possible embodiment, a multiple-layer transmission can be conductively received with each layer having a modulation type. Layers can be separated from the multiple-layer transmission by using a matrix MIMO receiver having matrix coefficients. An EVM can be measured for at least one layer for the separated layers.
  • An increase in an allowed Maximum Power Reduction (MPR) can be determined for the modulation type for the at least one layer.
  • the measured EVM for the at least one layer can be increased by a function of an allowed MPR increase for the modulation type.
  • a multiple-layer transmission can be conductively received with each layer having a modulation type. Layers can be separated from the multiple-layer transmission by using a matrix MIMO receiver having matrix coefficients. An EVM can be measured for at least one layer of the separated layers. A maximum combining gain of the MIMO receiver can be determined for each layer based on the receiver matrix coefficients. An adjusted EVM can be generated by multiplying the measured EVM by a fraction of a square root of the maximum combining gain.
  • FIG.1 is an example block diagram of a system 100 according to a possible embodiment.
  • the system 100 can include a UE 110, at least one network entity 120 and 125, and a network 130.
  • the UE 110 can be a wireless wide area network device, a user device, a wireless terminal, a portable wireless communication device, a smartphone, a cellular Docket No: SMM920220160-WO-PCT telephone, a flip phone, a personal digital assistant, a smartwatch, a personal computer, a tablet computer, a laptop computer, a selective call receiver, an IoT device, or any other user device that is capable of sending and receiving communication signals on a wireless network.
  • the at least one network entity 120 and 125 can be a wireless wide area network base station, can be a NodeB, can be an eNB, can be a gNB, such as a 5G NodeB, can be an unlicensed network base station, can be an access point, can be a base station controller, can be a network controller, can be a transmit-receive point, can be a different type of network entity from the other network entity, and/or can be any other network entity that can provide wireless access between a UE and a network.
  • the network 130 can include any type of network that is capable of sending and receiving wireless communication signals.
  • the network 130 can include a wireless communication network, a cellular telephone network, a TDMA-based network, a CDMA-based network, an OFDMA-based network, an LTE network, a NR network, a 3GPP- based network, a 5G network, a satellite communications network, a high-altitude platform network, the Internet, and/or other communications networks.
  • the UE 110 can communicate with the network 130 via at least one network entity 120.
  • the UE 110 can send and receive control signals on a control channel and user data signals on a data channel.
  • the Error Vector Magnitude is a measure of the difference between the reference waveform and the measured waveform. This difference is called the error vector.
  • the measured waveform is corrected by the sample timing offset and RF frequency offset. Then the carrier leakage shall be removed from the measured waveform before calculating the EVM.
  • the measured waveform is further equalized using the channel estimates subjected to an EVM equalizer spectrum flatness requirement.
  • the EVM result is defined after the front-end FFT and IDFT as the square root of the ratio of the mean error vector power to the mean reference power expressed as a percentage.
  • the EVM result is defined after the front-end FFT as the square root of the ratio of the mean error vector power to the mean reference power expressed as a percentage.
  • the basic EVM measurement interval in the time domain is one preamble sequence for the PRACH and one slot for PUCCH and PUSCH in the time domain.
  • the EVM measurement interval is reduced by any symbols that contain an allowable power transient in the measurement interval.
  • FIG.2 is an example block diagram illustrating a communication arrangement 200 for determining an EVM of a transmitter according to a possible embodiment.
  • the arrangement 200 can include a UE 210, such as the UE 110, and an evaluator 230.
  • the UE 210 can include a transmitter 212 and a plurality of antenna connectors 222, 224, 226, and 228.
  • the evaluator 23 can include a MIMO receiver 232, an analyzer 234, and a plurality of connectors 242, 244, 246, and 248.
  • a plurality of transmitter antennas, such as Tx antennas, may or may not be connected to antenna connectors and arranged into one or more antenna ports when the UE 210 is connected to the evaluator 230.
  • Each antenna port can include multiple antennas with an antenna connector for each antenna.
  • the transmitter 212 can generate a multiple- layer transmission signal for MIMO and transmit the multiple-layer transmission signal to the evaluator 230.
  • Docket No: SMM920220160-WO-PCT [0023]
  • the evaluator 230 can calculate an EVM of the transmitter 212.
  • the evaluator 230 can be test equipment, can be located at the network entity 120, and/or can be a part of the UE 110.
  • the 212 may be an embodiment of the network entity 120, where the evaluator 220 can be an embodiment of test equipment another network entity.
  • the evaluator 230 can measure the multiple-layer transmission signal using a MIMO receiver 232 and can calculate an EVM of the transmitter 212 using the analyzer 234 according to the below descriptions.
  • a connector 242, 244, 246, or 248 can conductively receive a multiple-layer transmission with each layer having a modulation type. Conductively receiving can include receiving the transmission directly from least one antenna connector 222, 224, 226, or 228.
  • Modulation types can include DFT-s-OFDM, DFT-s-OFDM Pi/2 BPSK, DFT-s-OFDM QPSK, DFT-s- OFDM 16 QAM, DFT-s-OFDM 64 QAM, DFT-s-OFDM 256 QAM, CP-OFDM, CP-OFDM QPSK, CP-OFDM 16 QAM, CP-OFDM 64 QAM, CP-OFDM 256 QAM, and other modulation types.
  • the receiver 232 can separate the multiple-layer transmission by using a matrix MIMO receiver having matrix coefficients.
  • the analyzer 234 can measure an EVM for at least one layer of the separated multiple-layer transmission.
  • the analyzer 234 can determine a maximum combining gain of the MIMO receiver for each layer based on the receiver matrix coefficients.
  • the analyzer 234 can generate an adjusted EVM by multiplying the measured EVM by a fraction of a square root of the maximum combining gain. [0026]
  • the analyzer 234 can compare the adjusted EVM to an EVM threshold predefined for the modulation type of at least one layer.
  • the MIMO receiver 232 can be a zero-forcing MIMO receiver.
  • the MIMO receiver 232 can be a linear unbiased MMSE MIMO receiver.
  • the MIMO receiver 232 can be a pseudo-inverse MIMO receiver. Separating the layers can include separating the layers prior to EVM measurement.
  • the maximum combining gain can be determined for a particular layer based on a fraction of a pre-set maximum combining gain, a MIMO receiver matrix of the MIMO receiver, and a matrix of a transmission channel.
  • the connector 242, 244, 246, or 248 can conductively receive a multiple-layer transmission with each layer having a modulation type. Conductively receiving can include receiving the transmission directly from at least one antenna connector 222, 224, 226, or 228.
  • the receiver 232 can separate layers from the multiple-layer transmission by using a matrix MIMO receiver having matrix coefficients.
  • the analyzer 234 can measure an EVM for at least one layer for the separated layers. The analyzer 234 can determine an increase in an allowed MPR for the modulation type for the at least one layer. The analyzer 234 can increase the measured EVM for the at least one layer by a function of an allowed MPR increase for the modulation type.
  • the EVM measurement can be increased based on a product of the EVM measurement, a scalar, and an amount of increase of an allowed MPR.
  • the increase in the allowed MPR can be pre-set according to the modulation type.
  • the increase in the allowed MPR can also be based on a number of antennas used for transmission. The number of antennas can be greater than one. According to a possible embodiment, the allowed MPR can be based on four or more antennas.
  • the analyzer 234 can compare the increased EVM measurement to an allowed EVM to determine whether an allowed EVM requirement is satisfied.
  • the allowed EVM can be different for at least two different modulation types.
  • FIG.3 is an example flowchart 300 of a method of operation of a device, such as the UE 110, the network entity 120, the analyzer 230 or another, device according to a possible embodiment.
  • the method can include conductively receiving a multiple-layer transmission with each layer having a modulation type.
  • the multiple-layer transmission can be generated at one device and measured using another device. Alternatively, multiple-layer transmission can be generated and measured by a single device. Docket No: SMM920220160-WO-PCT [0033]
  • the method can include separating layers from the multiple-layer transmission by using a matrix MIMO receiver having matrix coefficients.
  • the MIMO receiver can separate the layers of a multi-layer transmission to allow demodulation of signals, such as by inverting the channel.
  • the MIMO receiver can be different for each frequency.
  • the MIMO receiver can operate on a different Resource Element (RE) at a time, but multiple REs can use the same receiver.
  • RE Resource Element
  • MIMO receiver coefficients can be coefficients of a matrix receiver that is predefined.
  • the receiver can be a zero-forcing MIMO receiver, a linear unbiased MMSE MIMO receiver, a pseudo-inverse receiver, a MIMO receiver, or other receiver. Values of the matrix can be used to define the receiver.
  • Separating the layers can include separating the layers prior to EVM measurement.
  • the method can include measuring an EVM for at least one layer of the separated layers. EVM can be measured for each layer. Each layer can have the same or different modulation type from at least one other layer.
  • a layer can be a sequence of modulated symbols transmitted from one or more antennas. If multiple layers are transmitted, then each layer is transmitted using a different set of antenna combining coefficients.
  • Two different layers can be two different sequences of modulated symbols. They may or may not be independently modulated. Multiple layers can be transmitted in good signal conditions and they can increase the bandwidth of the channel.
  • the method can include determining a maximum combining gain of the MIMO receiver for each layer based on the receiver matrix coefficients.
  • the combining gain can be an improvement in signal-to-noise ratio that results when a signal is received from multiple transmit antennas and the transmitter noise on each of these antennas is independent. When the transmitter noise is correlated, the improvement in signal-to-noise ratio can be reduced. There may be no combining gain with worst-case correlation of the transmitter noise.
  • the maximum combining gain can be determined for a particular layer based on a fraction of a pre-set maximum combining gain, a MIMO receiver matrix of the MIMO receiver, and a matrix of a transmission channel.
  • the receiver matrix A can separate layers of a received signal.
  • the matrix H can be a channel upon which a transmission is received.
  • the value for f can be any real-valued scalar chosen in an interval (0, 1], can be a predetermined value, such as set in a standard, and/or can otherwise be determined. For example, a value of one (1) can be used.
  • the method can include generating an adjusted EVM by multiplying the measured EVM by a fraction of a square root of the maximum combining gain. The fraction can be one (1). The multiplying of the measured EVM by a fraction of a square root of the maximum combining gain can remove at least some of the maximum combining gain from the conductive EVM measurement.
  • the method can further include comparing the adjusted EVM to an EVM threshold predefined for the modulation type of at least one layer.
  • FIG.4 is an example flowchart 400 of a method of operation of a device, such as the UE 110, the network entity 120, the analyzer 230, or another device, according to a possible embodiment.
  • the method can include conductively receiving a multiple-layer transmission with each layer having a modulation type.
  • Conductively receiving can include receiving the transmission directly from at least one antenna connector.
  • a device can be physically connected to the antenna connectors to take the measurement.
  • measurements can be taken at a plurality of antenna connectors. If directional couplers are used during receiving and measurement, then it may not be necessary to increase the EVM.
  • the method can include separating layers from the multiple-layer transmission by using a matrix MIMO receiver having matrix coefficients.
  • the method can include measuring an EVM for at least one layer for the separated layers.
  • the method can include determining an increase in an allowed MPR for the modulation type for the at least one layer.
  • the allowed MPR can be set according to each modulation type and the allowed MPR can be determined to be the set MPR for the particular modulation type.
  • the allowed MPR can be an allowed additional-MPR (A-MPR) or a regular allowed MPR.
  • the method can include increasing the measured EVM for the at least one layer by a function of an allowed MPR increase for the modulation type.
  • the increase in the allowed MPR can be pre-set according to the modulation type.
  • the increase in the allowed Docket No: SMM920220160-WO-PCT MPR can be based on a number of antennas used for transmission. For example, the number of antennas can be greater than one, such as at least four antennas.
  • the EVM measurement can be adjusted in accordance with an MPR increase allowed for a type of modulation for a transmission.
  • the EVM measurement can be increased based on a product of the EVM measurement, a scalar, and an amount of increase of an allowed MPR.
  • the EVM measurement can be increased based on [0043] where EVMconductive is the EVM measurement of the conductively received transmission, f is a scalar in an interval [0,1], ⁇ MPR is an amount of increase of an allowed MPR in dB, and EVM increased is the increased EVM measurement.
  • the method can include comparing the increased EVM measurement to an allowed EVM to determine whether an allowed EVM requirement is satisfied.
  • the allowed EVM can be different for at least two different modulation types.
  • a network entity such as a base station, transmission and reception point, mobility management entity, or other network entity, can perform reciprocal operations of a UE.
  • the network entity can transmit signals received by the UE and can receive signals transmitted by the UE.
  • the network entity can also process and operate on sent and received signals.
  • FIG.5 is an example block diagram of an apparatus 500, such as the UE 110, the network entity 120, or any other wireless communication device disclosed herein, according to a possible embodiment. At least some parts of the apparatus 500 can also be in the evaluator 230.
  • the apparatus 500 can include a housing 510, a controller 520 coupled to the housing 510, audio input and output circuitry 530 coupled to the controller 520, a display 540 coupled to the controller 520, a memory 550 coupled to the controller 520, a user interface 560 coupled to the controller 520, a transceiver 570 coupled to the controller 520, at least one antenna port 575, such as an array of multiple antennas, coupled to the transceiver 570, and a network interface 580 coupled to the controller 520.
  • the apparatus 500 may not necessarily Docket No: SMM920220160-WO-PCT include all of the illustrated elements for different embodiments of the present disclosure. The apparatus 500 can perform the methods described in all the embodiments.
  • the display 540 can be a viewfinder, an LCD, an LED display, an OLED display, a plasma display, a projection display, a touch screen, or any other device that displays information.
  • the transceiver 570 can be one or more transceivers that can include a transmitter and/or a receiver.
  • the audio input and output circuitry 530 can include a microphone, a speaker, a transducer, or any other audio input and output circuitry.
  • the user interface 560 can include a keypad, a keyboard, buttons, a touch pad, a joystick, a touch screen display, another additional display, or any other device useful for providing an interface between a user and an electronic device.
  • the network interface 580 can be a USB port, an Ethernet port, an infrared transmitter/receiver, an IEEE 1394 port, a wireless transceiver, a WLAN transceiver, or any other interface that can connect an apparatus to a network, device, and/or computer and that can transmit and receive data communication signals.
  • the memory 550 can include a RAM, a ROM, an EPROM, an optical memory, a solid-state memory, a flash memory, a removable memory, a hard drive, a cache, or any other memory that can be coupled to an apparatus.
  • the apparatus 500 or the controller 520 may implement any operating system, such as Microsoft Windows®, UNIX®, LINUX®, Android TM , or any other operating system.
  • Apparatus operation software may be written in any programming language, such as C, C++, Java, or Visual Basic, for example. Apparatus software may also run on an application framework, such as, for example, a Java® framework, a .NET® framework, or any other application framework.
  • the software and/or the operating system may be stored in the memory 550, elsewhere on the apparatus 500, in cloud storage, and/or anywhere else that can store software and/or an operating system.
  • coding for operations can be implemented as firmware programmed into ROM.
  • the apparatus 500 or the controller 520 may also use hardware to implement disclosed operations.
  • the controller 520 may be any programmable processor.
  • the controller 520 may perform some or all of the disclosed operations.
  • At least some operations can be performed using cloud computing and the controller 520 may perform other operations. At least some operations can also be performed computer executable instructions executed by at least one computer processor. Disclosed embodiments may also be implemented on a general-purpose or a special purpose computer, a programmed microprocessor or microprocessor, peripheral integrated circuit elements, an application-specific integrated circuit or other integrated circuits, hardware/electronic logic circuits, such as a discrete element circuit, a programmable Docket No: SMM920220160-WO-PCT logic device, such as a programmable logic array, field programmable gate-array, or the like. In general, the controller 520 may be any controller or processor device or devices capable of operating an apparatus and implementing the disclosed embodiments.
  • the apparatus 500 can perform the methods and operations of the disclosed embodiments.
  • the transceiver 570 can transmit and receive signals, including data signals and control signals that can include respective data and control information.
  • the controller 520 can generate and process the transmitted and received signals and information.
  • the controller 520 can generate a multiple-layer transmission with each layer having a modulation type.
  • the transceiver 570 can transmit the generated multiple-layer transmission signal through multiple antennas.
  • Transmission of the generated multiple-layer transmission can be based on layers separated from a previous multiple-layer transmission by using a matrix MIMO receiver having matrix coefficients. Transmission of the generated multiple-layer transmission can also be based on an EVM measurement for at least one layer of the separated layers. [0052] Transmission of the generated multiple-layer transmission can also be based on a maximum combining gain of the MIMO receiver determined for each layer based on the receiver matrix coefficients.
  • the MIMO receiver can be a zero-forcing MIMO receiver, a linear unbiased MMSE MIMO receiver, a pseudo-inverse MIMO receiver, or other MIMO receiver.
  • the maximum combining gain can be determined for a particular layer based on a fraction of a pre-set maximum combining gain, a MIMO receiver matrix of the MIMO receiver, and a matrix of a transmission channel.
  • Transmission of the generated multiple-layer transmission can also be based on an adjusted EVM generated by multiplying the measured EVM by a fraction of a square root of the maximum combining gain.
  • Transmission of the generated multiple-layer transmission can also be based on a comparison of the adjusted EVM to an EVM threshold predefined for the modulation type of at least one layer.
  • the adjusted EVM can be compared to an EVM threshold predefined for the modulation type of at least one layer.
  • the controller 520 can generate a multiple-layer transmission with each layer having a modulation type.
  • the transceiver 570 can transmit. the generated multiple-layer transmission signal through multiple antennas.
  • Transmission of the generated multiple-layer transmission Docket No: SMM920220160-WO-PCT can be based on layers separated from a previous multiple-layer transmission of the modulation type by using a matrix MIMO receiver having matrix coefficients. Transmission of the generated multiple-layer transmission can also be based on a measured EVM for at least one layer for the separated layers.
  • Transmission of the generated multiple-layer transmission can also be based on a determined increase in an allowed MPR for the modulation type for the at least one layer
  • Transmission of the generated multiple-layer transmission can also be based on an increase of the measured EVM for the at least one layer by a function of an allowed MPR increase for the modulation type.
  • the EVM measurement can be increased based on a product of the EVM measurement, a scalar, and an amount of increase of an allowed MPR.
  • the increase in the allowed MPR can be based on a number of antennas used for transmission.
  • Transmission of the generated multiple-layer transmission can also be based on a comparison of the increased EVM measurement to an allowed EVM to determine whether the allowed EVM requirement is satisfied.
  • At least some embodiments can provide an EVM definition for conductive MIMO testing.
  • RF requirements enhancement for NR frequency range 1 can include, specifying the UE RF requirements to support 4Tx including 4x4 UL MIMO.
  • At least some embodiments can provide how EVM requirements can be applied for 4x4 UL MIMO.
  • At least some embodiments can provide error vector magnitude (EVM) for 4x4 UL MIMO.
  • EVM error vector magnitude
  • An EVM can be a metric to quantify the combination of all signal impairments in a system.
  • TS Technical Specification
  • the EVM for closed-loop spatial multiplexing can be further defined as follows: For UE with two transmit antenna connectors in closed-loop spatial multiplexing scheme, specified EVM requirements apply per layer.
  • a layer can be a transmission stream and each layer/stream can be a sequence of modulated symbols.
  • Each layer/stream can be transmitted using a different weighted combination of antenna elements.
  • the number of streams/layers should be less than or equal to the number of transmit antennas.
  • At least some embodiments can provide details of how the per-layer EVM is defined. For consistency with the 2 Tx case, the EVM requirement for 4x4 UL MIMO can be defined on a per-layer basis also.
  • the precoding matrix for 4x4 UL can be Docket No: SMM920220160-WO-PCT [0061] It is possible the EVM can be defined per connector since there is a one-to-one mapping between layers and antenna connectors for this case. However, a per-connector EVM definition may not work in the case of one-, two-, or three-layer transmission from four antenna ports since each layer will be transmitted from a combination of antennas if full power is to be achieved.
  • the antenna connector can be where the antenna connects to the transmitter and/or receiver.
  • the antenna connector can also be the point at which test equipment connects for conductive measurements. For Frequency Range 1 (FR1), most tests are conductive and are made using the antenna connectors.
  • FR1 Frequency Range 1
  • the term 2 Tx can indicate two transmission antennas.
  • N Tx can indicate N transmit antennas.
  • 4x4 Uplink (UL) MIMO requires four transmit antennas and four receive antennas. Both the number of transmit antennas and the number of receive antennas should be greater than or equal to the number of layers. For example, a 3-layer transmission can use 4 transmit antenna and 5 receive antennas.
  • a per-layer EVM definition is used for 4 Tx, then a MIMO receiver can be defined to separate the layers before EVM is measured. For the two transmit antenna case, the linear zero-forcing receiver, the linear unbiased MIMO receiver, or other relevant receiver can be used.
  • a rank-2 transmission can be a transmission with two layers.
  • a rank-N transmission can be a transmission with N layers.
  • Conductive measurements can be made by having test equipment connect to the antenna connectors. Radiated tests or measurements can be made by measuring signals radiated by the device and not through a connector.
  • the combining gain for the i-th layer can be as large as the ratio [0070]
  • This maximum combining gain represents the maximum increase of the layer signal- to-noise ratio that can result if the conducted transmitter noise is independent while the radiated transmitter noise has worst-case correlation due to antenna coupling.
  • ⁇ ⁇ is an estimate of the channel and ⁇ ⁇ is either reference symbols or demodulated data.
  • the maximum combining gain for the i-th layer is given by [0072] In order to avoid underestimating the radiated EVM with a conductive measurement, the maximum combining gain can be removed from the EVM measurement.
  • it may be better to scale the conductive EVM measurement by a fraction f of the maximum combining gain so that ⁇ ⁇ ⁇ ⁇ ′ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ , where f is in the interval (0, 1].
  • At least two unbiased linear receivers can be used to separate the layers, and these are the unbiased linear Minimum Mean-Squared Error (MMSE) receiver and the pseudo-inverse receiver.
  • MMSE Minimum Mean-Squared Error
  • the maximum combining gain for the i-th layer is given by Docket No: SMM920220160-WO-PCT [0081]
  • the linear unbiased MMSE receiver can be used.
  • a MMSE,U can denote a linear unbiased MMSE MIMO receiver, which can be a matrix.
  • At least some embodiments can provide EVM adjustment using an allowed increase of MPR/Additional MPR (A-MPR) for multi-antenna transmission ports.
  • A-MPR MPR/Additional MPR
  • MPR multi-antenna transmission
  • These increased values are typically based on PA measurements taken using conductive measurements but with coupling between the PA’s introduced using directional couplers in order to emulate the coupling that occurs between antennas with limited isolation.
  • An example of the increased MPR can be seen in Table 6.2.2-2 and 6.2D.2-1 below. It can Docket No: SMM920220160-WO-PCT be observed that for CP-OFDM 64 QAM, the dual Tx MPR is 4.5 dB while the single antenna MPR is 3.5 dB. For CP-OFDM 256 QAM, the dual Tx MPR is 8.0 dB while the single antenna MPR is 6.5 dB. Thus, for CP-OFDM 64 QAM, MPR is increased by 1.0 dB while for 256 QAM MPR is increased by 1.5 dB. Table 6.2.2-2 MPR for power class 2 (single antenna transmission)
  • FIG.6 is an example illustration 600 of a relationship between EVM and MPR according to a possible embodiment. From this illustration, it can be observed that as the MPR is increased by 1 dB, the EVM is decreased by approximately ⁇ 2. This relationship can be expressed as where ⁇ ⁇ ⁇ 1 and ⁇ ⁇ ⁇ 2 are the EVM values before and after the power reduction by ⁇ ⁇ ⁇ ⁇ . From this relationship, the relationship between the conducted EVM measurement and the radiated EVM measurement can be expressed as where ⁇ ⁇ ⁇ ⁇ is the increased MPR allowed for dual Tx for the given modulation type.
  • At least some embodiments can define the EVM for 4 Tx transmission on a per layer basis. At least some embodiments can, for full-rank transmission, measure the conductive EVM using a zero-forcing MIMO receiver. At least some embodiments can, for less than full-rank transmission, measure the conductive EVM using a pseudo-inverse receiver.
  • FIG.7 is an example flowchart 700 of a method in a device, such as the UE 110, according to a possible embodiment.
  • the method can include generating a multiple- layer transmission with each layer having a modulation type.
  • the method can include transmitting the generated multiple-layer transmission signal through multiple antennas.
  • the transmission of the generated multiple-layer transmission can be based on layers separated from a previous multiple-layer transmission by using a matrix MIMO receiver having matrix coefficients.
  • the transmission of the generated multiple-layer transmission can also be based on an EVM measurement for at least one layer of the separated layers.
  • the transmission of the generated multiple-layer transmission can also be based on a maximum combining gain of the MIMO receiver determined for each layer based on the receiver matrix coefficients.
  • the maximum combining gain can determined for a particular layer based on a fraction of a pre-set maximum combining gain, a MIMO receiver matrix of the MIMO receiver, and a matrix of a transmission channel.
  • the MIMO receiver can be a zero-forcing MIMO receiver, a linear unbiased MMSE MIMO receiver, a pseudo-inverse MIMO receiver, or other MIMO receiver.
  • the transmission of the generated multiple-layer transmission can also be based on an adjusted EVM generated by multiplying the measured EVM by a fraction of a square root of the maximum combining gain.
  • the transmission of the generated multiple-layer transmission can also be based on a comparison of the adjusted EVM to an EVM threshold predefined for the modulation type of at least one layer.
  • the method can include other operations discussed above.
  • FIG.8 is an example flowchart 800 of a method in a device, such as the UE 110, according to a possible embodiment.
  • the method can include generating a multiple- layer transmission with each layer having a modulation type.
  • the method can include transmitting the generated multiple-layer transmission signal through multiple antennas.
  • Transmission of the generated multiple-layer transmission can be based on layers separated from a previous multiple-layer transmission of the modulation type by using a matrix MIMO receiver having matrix coefficients.
  • Transmission of the generated multiple- Docket No: SMM920220160-WO-PCT layer transmission can also be based on a measured EVM for at least one layer for the separated layers.
  • Transmission of the generated multiple-layer transmission can also be based on a determined increase in an allowed MPR for the modulation type for the at least one layer.
  • Transmission of the generated multiple-layer transmission can also be based on an increase of the measured EVM for the at least one layer by a function of an allowed MPR increase for the modulation type.
  • the transmission of the generated multiple- layer transmission can be based on the previously separated layers, the measured EVM, the determined increase in the allowed MPR, and the increase of the EVM measurement by the device satisfying a requirement that is tested using these parameters.
  • the method can include other operations discussed above.
  • Embodiments above can further be based on the following descriptions.
  • UEs can have multiple antennas. The number or antennas at each end, such as at the UE and at the base station, should be at least equal to the number of layers.
  • a UE or base station may compute its own EVM, but generally this can be done at test equipment.
  • test equipment can be connected to at least one antenna connector to take measurements. Contrary to conductive measurements, radiated measurements can be taken without the test equipment connecting to the antenna connectors, such as by measuring the radiated fields outside the device.
  • the EVM measurement is a requirement on the quality of the transmitted signal. The larger the EVM, the worse the signal-to-noise ratio at the receiver.
  • the UE transmits a transmission of the modulation type with the required EVM for the modulation type and with the required power level. The required power level can be based on MPR.
  • the allowed MPR can be increased for multiple Tx, such as multiple transmit antennas.
  • a table can provide the allowed MPR for four transmit antennas (4 Tx).
  • the tables above disclosure show 1 Tx and 2 Tx.
  • MPR should reflect antenna impairments.
  • these impairments may not be seen when conductively measuring, such as when taking measurements of a conductively received transmission.
  • the impairments can be artificially added, not measured, when testing using conductive measurements.
  • a coupler can be inserted between the output of one PA and the output of another other PA to reflect the impairment based on assumptions that coupling will occur.
  • the coupling may not be known when doing conductive instead of radiated measurements. Thus, the coupling can be approximated or based on an assumption.
  • Embodiments can adjust a conductive measurement, or what it is compared to, in order to account for antenna coupling.
  • the measurement or what it is compared to can be adjusted for impairments that are not seen when performing conductive measuring. This can be done based on a fraction of combining gain, a fraction the MPR, and or other adjustments. For example, if more MPR is allowed, conductive measurements can be penalized to reflect the need for increased MPR.
  • the EVM can also be increased based on expected degradation that may or may not occur.
  • the degradation can be based on the transmitter noise becoming correlated due to antenna coupling and causing loss of combining gain in the receiver. It can also be based on reverse intermodulation due to antenna coupling or other degradation factors.
  • the adjusted EVM can be less than a specified required EVM value, which can be a percent based on the modulation type being used.
  • a UE can be tested for each constellation type of 16 QAM, 64 QAM, QPSK, and/or other constellation type.
  • the UE can increase MPR, such as lower its power, to meet an EVM requirement.
  • the max power required to transmit QPSK can be higher than 64 QAM.
  • the MPR can be optional, so as much power can be used for QAM as QPSK for transmission when using a good transmitter.
  • the UE can transmit to meet the EVM requirement.
  • the UE can be set for the EVM requirement before retail sale, but it may also be allowed to calibrate itself.
  • the EVM requirement can be a function of the modulation type.
  • the formula that is defined for maximum combining name can be applied for a zero- forcing receiver for 4-layer transmission, for the pseudo-inverse receiver for the case that the number of layers is less than 4, and for other receiver types such as the linear unbiased MMSE receiver.
  • any component that performs an action, function, process, calculation, configuration, determination, and other operations can be configured to perform the operations.
  • Appendix Maximum Transmitter Noise Variance with Correlated Transmitter Noise.
  • any device on which resides a finite state machine capable of Docket No: SMM920220160-WO-PCT implementing the flowcharts shown in the figures may be used to implement the processor functions of this disclosure.
  • At least some embodiments can improve operation of the disclosed devices.
  • this disclosure has been described with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art.
  • various components of the embodiments may be interchanged, added, or substituted in the other embodiments.
  • all of the elements of each figure are not necessary for operation of the disclosed embodiments.
  • one of ordinary skill in the art of the disclosed embodiments would be enabled to make and use the teachings of the disclosure by simply employing the elements of the independent claims.

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  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Radio Transmission System (AREA)

Abstract

Selon l'invention, une transmission à couches multiples peut être reçue de manière conductrice (310), chaque couche présentant un type de modulation. Les couches peuvent être séparées (320) de la transmission à couches multiples en utilisant un récepteur MIMO matriciel présentant des coefficients de matrice. Une mesure EVM peut être mesurée (330) pour au moins une couche des couches séparées. Un gain de combinaison maximal du récepteur MIMO peut être déterminé (340) pour chaque couche sur la base des coefficients de matrice de récepteur. Une mesure EVM ajustée peut être générée (350) en multipliant la mesure EVM mesurée par une fraction d'une racine carrée du gain de combinaison maximal.
PCT/IB2023/059163 2022-09-29 2023-09-15 Appareil et procédé de génération d'une mesure evm pour une transmission mimo WO2024069304A1 (fr)

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Publication number Priority date Publication date Assignee Title
WO2021229546A1 (fr) * 2020-05-15 2021-11-18 Lenovo (Singapore) Pte. Ltd. Détermination d'une qualité de signal à l'aide d'une amplitude de vecteur d'erreur

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2021229546A1 (fr) * 2020-05-15 2021-11-18 Lenovo (Singapore) Pte. Ltd. Détermination d'une qualité de signal à l'aide d'une amplitude de vecteur d'erreur

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
QUALCOMM INCORPORATED: "Tx EVM requirement for 4 layer MIMO with MMSE-IRC receiver", vol. RAN WG4, no. SAN JOSE DEL CABO, MEXICO; 20160411 - 20160415, 1 April 2016 (2016-04-01), XP051083764, Retrieved from the Internet <URL:http://www.3gpp.org/ftp/tsg_ran/WG4_Radio/TSGR4_78Bis/Docs/> [retrieved on 20160401] *

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