92 results about "Error vector magnitude" patented technology

An adaptable, generalized digital predistortion system that can increase the accuracy of the distortion applied to a power amplifier input signal is disclosed. Further, the digital predistortion system can be implemented using a reduced circuit area by reducing a number of coefficients used by the models applied to generate the distortion compensation signal. Further, the system can implement an improved digital predistortion adaptation engine that can improve one or more of the following metrics of a complete radio frequency (RF) analog front-end radio signal chain: error vector magnitude (EVM), adjacent channel leakage ratio (ACLR), spectrum emission mask (SEM), and power consumption of the circuits and systems. An example of circuits and systems is a radio frequency power amplifier (PA).

The invention provides an EVM (Error Vector Magnitude) detection method, a communication device and network equipment, which are applied to the field of wireless communication. The method comprises the steps that a first unit receives first information from a network manager and sends second information to a second unit according to the first information in an EVM detection period, the second information comprises EVM detection data and time domain information of the EVM detection data, and the time domain information is used for indicating the position of the EVM detection data in a wireless frame; the first unit receives an EVM detection result from the second unit, the EVM detection result comprises an EVM value of at least one node in the second unit and the number of sampling points of the EVM detection data, and the EVM value of any node in the at least one node is determined according to the EVM detection data collected at the node. Based on the method, the EVM value of the radio frequency system can be obtained at a low cost.

A system and method for determining an error vector magnitude (EVM) of a polarized transmission from a device-under-test (DUT). A first signal transmitted by the DUT is received via a horizontally polarized receiver antenna, and a second signal transmitted by the DUT is received via a vertically polarized receiver antenna. The second signal is coherent with the first signal. The EVM is calculated based at least in part on the first signal and the second signal and a reference signal.

The invention relates to the field of error vector magnitude calculation, in particular to a novel low-complexity error vector magnitude calculation method, which is used for simplifying EVM calculation of QAM (Quadrature Amplitude Modulation) of different orders, so that a redundant process generated in a judgment process during conventional calculation can be reduced, the processing speed is increased, and the processing efficiency is improved. The technical scheme comprises: determining a modulation type of a signal; performing normalization processing according to the modulation type of the signal; folding and translating the normalized signal; and judging whether the constellation image is equal to QPSK modulation or not, if so, calculating a signal EVM after folding transformation by adopting a calculation mode of a QPSK unit circle, otherwise, continuing to repeat folding and translation operations. The method is suitable for error vector magnitude calculation.

The present application relates to a soft peak clipping method and device for suppressing peak-to-average ratio (PAR) for OFDM, and relates to the field of signal processing technology. The method comprises: calculating the envelope amplitude value of the in-phase and quadrature signals based on the in-phase and quadrature components of the in-phase and quadrature signals obtained by OFDM modulation; calculating the envelope amplitude value of the in-phase and quadrature signals after peak clipping based on a preset peak clipping function and the envelope amplitude value of the in-phase and quadrature signals; wherein the peak clipping function is determined by a peak clipping threshold and a basic function, the peak clipping threshold is determined by the PAR, and the basic function includes any one of a Rapp model function, a Logistic function, and an inverse tangent function; and reducing the in-phase and quadrature components based on the envelope amplitude values ​​of the in-phase and quadrature signals before and after peak clipping. The present application can ensure that the OFDM signal after peak clipping meets the requirements of the spectrum emission template, while ensuring that the error vector amplitude performance meets the requirements.

Voltage ripple reduction in a power management circuit is disclosed. The power management circuit includes a power amplifier circuit configured to amplify a radio frequency (RF) signal based on a modulated voltage and an envelope tracking integrated circuit (ETIC) configured to provide the modulated voltage to the power amplifier circuit via a conductive path. Notably, an output impedance presenting at an input of the power amplifier circuit can interact with a modulated load current in the power amplifier circuit to create a voltage ripple in the modulated voltage to potentially cause an undesirable error in the RF signal. In this regard, a notch circuit is provided, preferably in the ETIC, to reduce the voltage ripple within a modulation bandwidth of the RF signal. As a result, it is possible to minimize the undesirable error, such as root-mean-square (RMS) error vector magnitude (EVM), within the modulation bandwidth of the RF signal.

The present invention discloses a method and device for demodulating and analyzing large Doppler frequency shift (OTFS) satellite communications, belonging to the field of satellite communications. The device includes a data acquisition unit, an IQ imbalance calculation unit, an amplitude error calculation unit, a continuous phase signal generation unit, a convolution detection frame header determination unit, two guard slot removal units, two receive reference signal acquisition units, a sampling phase error acquisition unit, two theoretical demodulation reference signal generation units, a channel model extraction unit, a Doppler frequency error calculation unit, a Doppler frequency error elimination unit, a phase error calculation unit, a Doppler phase error elimination unit, a channel estimation unit, an interpolation and smoothing unit, a channel error elimination unit, a Wigner transform unit, a symplectic finite Fourier transform unit, a digital modulation and demodulation unit, and an error vector magnitude (EVM) calculation unit. The present invention can achieve high-precision demodulation and analysis of large Doppler frequency shift (OTFS) orthogonal time-frequency-space modulation (6G) satellite communication signals.

The invention discloses an interference detection method and a related device, and is applied to the technical field of communication, and the method comprises the steps: obtaining a plurality of to-be-demodulated data signal segments in a time slot; determining a modulation mode corresponding to the data signal segment; for each to-be-demodulated data signal segment, determining an error vector amplitude corresponding to the data signal segment based on an ideal constellation diagram corresponding to the modulation mode; determining a reference error vector amplitude based on the error vector amplitude of each data signal segment; and if the data signal segment satisfies a set condition, determining that interference data exist in the data signal segment, the data signal segment satisfying the set condition comprises that a difference value between an error vector amplitude of the data signal segment and a reference error vector amplitude is greater than a set threshold. According to the scheme, the situation that data signals with interference data cannot be detected can be reduced, and the accuracy of interference detection is improved.

The invention discloses a radio frequency signal demodulation method and device. The method comprises the following steps: receiving an OFDM (Orthogonal Frequency Division Multiplexing)-based radio frequency signal comprising a plurality of subcarriers, each subcarrier time slot comprising a column of pilot signals; performing conversion processing on the radio frequency signal to obtain a frequency domain signal corresponding to each subcarrier, the frequency domain signal comprising a plurality of OFDM symbols; for each frequency domain signal, primary frequency offset compensation is carried out on each OFDM symbol in the frequency domain signal based on the pilot signal, and for a far-end OFDM symbol whose distance from the position of the pilot signal exceeds a preset distance, secondary frequency offset compensation is carried out on the far-end OFDM symbol based on the distribution state of each constellation point mapped to the constellation diagram; and recovering each frequency domain signal subjected to frequency offset compensation into original bit data. According to the method and the device, the technical problem that the error vector amplitude of a remote symbol demodulation result is relatively large when only a single-column pilot signal is configured in a subcarrier time slot in a traditional demodulation scheme is solved.

The application provides a method for controlling uplink throughput of a UAV satellite base station and the UAV satellite base station, and belongs to the technical field of communication. In the method for controlling uplink throughput of the UAV satellite base station, the UAV satellite base station analyzes modulation capability information sent by a UE, obtains a first modulation order and a second modulation order supported by the UE in different communication frequency bands, and combines a target communication frequency band currently located by the UE and a power switching type of the UE to perform optimized scheduling on a subsequent second uplink subframe, so that stable signal quality and throughput are maintained when the transmission power of the UE changes, the reduction of the throughput caused by the unstable error vector magnitude when the power switching is determined is effectively alleviated, the overall performance of the communication system is improved, and the waste of spectrum resources is reduced.

This disclosure provides systems, methods and apparatuses for demodulating multiple-input multiple-output (MIMO) transmissions using iterative demodulation of spatially separated streams. A user equipment (UE) transmits a request for precoder information for iterative demodulation of spatially separated streams. The UE receives, from a network entity, an indication of a latest slot from which a precoder was evaluated. The UE may perform iterative demodulation with a number of iterations based on the latest slot from which the precoder was evaluated. The number of iterations may be based on a mapping of a gap length between the latest slot from which the precoder was evaluated and a current slot to a number of iterations for the iterative demodulation to satisfy an error vector magnitude threshold.

An access node receives, from user equipment (UE), first channel state information (CSI) 506 associated with a channel between the access node and the UE, and sends, to the UE, a calibration reference signal configuration 510. The access node receives, from the UE via the channel, based on the calibration reference signal configuration, one or more calibration reference signals 512 and determines second CSI associated with the channel 514 based on the one or more calibration reference signals. The access node determines, based on the first CSI and the second CSI, assistance data for waveform correction 516 and sends, to the UE, the assistance data 518. The UE adjusts one or more transmission parameters 520 based on the assistance data. The access node may also adjust one or more reception parameters 522 based on the assistance data. One or more of the calibration reference signals may violate an allowed adjacent channel leakage ratio and / or an allowed error vector magnitude associated with the channel.

The present invention belongs to the field of Internet of Things communications technology and discloses a narrowband Internet of Things single-carrier uplink phase rotation compensation method, device, and medium, comprising: step 1, receiving an uplink time domain signal and extracting protocol-defined phase rotation parameters; step 2, generating a time domain compensation waveform based on the phase rotation parameters; step 3, performing a conjugate multiplication operation on the received signal to complete the signal's time domain derotation; step 4, inputting the derotated time domain signal into a narrowband Internet of Things optimized phase-locked loop module for phase synchronization and demodulation to obtain a demodulation result; and step 5, observing the modulus length of the final symbol based on the demodulation result. If the modulus length is uneven, the amplitude parameter used in generating the compensation waveform in step 2 is flexibly adjusted to ensure that the modulus length of the final demodulated symbol is as uniform as possible. Compared with traditional solutions, the present invention significantly reduces the bit error rate, significantly optimizes the error vector amplitude, and reduces processing latency.

An apparatus includes a receiver configured to receive data, and circuitry configured to receive one or more symbols based at least on the data, determine, using the one or more symbols, an error vector magnitude (EVM) value, identify a quadrature amplitude modulation (QAM) size, determine, using the EVM value and the QAM size, a signal-to-noise (SNR) value, and adjust, based at least on the SNR value, a transmission rate of a transmitter.

The present disclosure relates to an error vector magnitude detector for a wireless transmitter. An amplifier of a transmitter includes an input that receives an input signal and generates an amplified signal at an output. A digital power meter coupled to the input of the amplifier generates an estimated amplified signal and determines a peak power and an average power of the estimated amplified signal. An output power detector coupled to the output of the amplifier determines a peak power and an average power of the amplified signal. A controller coupled to the digital power meter and the output power detector determines an estimated crest factor based on the peak power and the average power of the estimated amplified signal, determines an amplified crest factor based on the peak power and the average power of the amplified signal, and determines an error vector magnitude based on the estimated crest factor and the amplified crest factor. The controller, which is also coupled to the amplifier, then adjusts operation of the amplifier based on the error vector magnitude.

An adaptable, multistage, multi-rate digital predistortion system that can increase the accuracy of the distortion applied to a power amplifier input signal is disclosed. Further, the digital predistortion system can be implemented using a reduced circuit area by reducing a number of coefficients used by the models applied to generate the distortion compensation signal. Further, the system can implement an improved digital predistortion adaptation engine that improves an adjacent channel leakage ratio of the digital predistortion system. Moreover, the system can compensate for non-linear impairments due to analog / RF circuits and systems and improve at least the following metrics: Error vector magnitude (EVM), adjacent channel leakage ratio (ACLR), spectrum emission mask (SEM), and power consumption of the circuits and systems. An example of circuits and systems is radio frequency power amplifier (RF PA).

An electronic device may include wireless circuitry with a baseband processor, a digital transmitter, a digital-to-analog-converter (DAC), and an antenna. The baseband processor may produce baseband signals. The digital transmitter may generate self-interference-compensated signals based on the baseband signals. The DAC may generate radio-frequency signals for transmission by the antenna based on the self-interference-compensated signals and square-wave local oscillator waveforms. The digital transmitter may include a self-interference canceller that generates the self-interference-compensated signals. The self-interference-compensated signals may mitigate the creation of self-interferer repetition replicas that land on the carrier frequency of the radio-frequency signals. This may allow the radio-frequency signals to be free from error vector magnitude degradation and spectral regrowth that would otherwise be produced due to self-interference in the radio-frequency signals output by the DAC.

Group delay determination in a communication circuit is disclosed. The communication circuit includes a power amplifier circuit that amplifies a radio frequency (RF) signal based on a modulated voltage and a power management integrated circuit (PMIC) that generates the modulated voltage. Herein, the PMIC includes a group delay determination circuit to determine a relative group delay between the modulated voltage and a modulated current, which is internal to the power amplifier circuit and unknown to the PMIC, solely based on signals known to the PMIC. The determined relative group delay can help to time align the modulated voltage with the modulated current at the power amplifier circuit to improve error vector magnitude (EVM) and / or adjacent channel leakage ratio (ACLR). Further, by determining the relative group delay based on known signals to the PMIC, it is possible to achieve good time alignment between the modulated voltage and the modulated current.

Methods, systems, and devices for wireless communication are described. The described techniques may provide an adaptive digital post-distortion (DPoD) process and reporting of modulation and coding scheme (MCS) indices for communications between a user equipment (UE) and a network entity. The UE may select a kernel for the DPoD process from a set of kernels indicated by the network entity based on a target error vector magnitude (EVM). Additionally or alternatively, the UE may determine a limit for an MCS index for use by the network entity in communication with the UE based on a power limit of the UE and an EVM associated with the MCS. The network entity and the UE may communicate accordingly using the MCS restriction requested by the UE and the determined DPoD kernel.

The invention relates to an OFDM (Orthogonal Frequency Division Multiplexing) vector signal analysis device and method, belongs to the technical field of communication, and solves the problems of high test cost and low flexibility of an EVM (Error Vector Magnitude Error) of an OFDM system in the prior art. The method comprises the following specific steps: a signal generation module used for generating first baseband data of an OFDM signal; the software radio transmitter is used for caching the first baseband data, modulating the first baseband data into a corresponding radio frequency signal and transmitting the radio frequency signal to a tested system; the software radio receiver is used for collecting the radio frequency signal forwarded and output by the tested system, demodulating the radio frequency signal to obtain second baseband data of the OFDM signal, and sending the second baseband data to the data processing module; and the data processing module is used for processing the second baseband data based on the first baseband data to obtain a vector amplitude error of an output signal of the tested system, so that low-cost and high-flexibility EVM test is realized.

The invention provides a multi-point relay node selection method which can be applied to the field of network routing control in a wireless communication system. The method comprises the following steps of: calculating a routing distance between a node and a two-hop neighbor node by using a routing metric according to a two-hop neighbor table of the node; the routing metric at least comprises one of hop count, error vector magnitude and expected transmission times; screening nodes by using a routing distance to obtain a shortest path node set; and in response to redundant nodes existing in the shortest path node set, eliminating the redundant nodes to obtain a multi-point relay node set. According to the method, the node for providing the optimal communication path can be effectively selected by weighting the election, so that the stability and the efficiency of the network are ensured; redundant forwarding is further reduced by eliminating redundant nodes, and the communication efficiency is improved. The invention further provides a multi-point relay node selection device, equipment and a storage medium.

A network node, such as a gNB, determines an adjacent channel leakage power ratio (ACLR) requirement relaxation for a UE and transmits, to the UE, first information of the ACLR requirement relaxation

An electronic device may include wireless circuitry with a baseband processor, a digital transmitter, a digital-to-analog-converter (DAC), and an antenna. The baseband processor may produce baseband signals. The digital transmitter may generate self-interference-compensated signals based on the baseband signals. The DAC may generate radio-frequency signals for transmission by the antenna based on the self-interference-compensated signals and square-wave local oscillator waveforms. The digital transmitter may include a self-interference canceller that generates the self-interference-compensated signals. The self-interference-compensated signals may mitigate the creation of self-interferer repetition replicas that land on the carrier frequency of the radio-frequency signals. This may allow the radio-frequency signals to be free from error vector magnitude degradation and spectral regrowth that would otherwise be produced due to self-interference in the radio-frequency signals output by the DAC.

The invention relates to the technical field of communication, and discloses a low-error vector amplitude radio frequency front end, which comprises an antenna switch, and an FDD signal filter, a TDD signal filter, a phase compensation load, a first antenna and a second antenna which are respectively connected with the antenna switch, a receiving channel and a transmitting channel of the TDD signal are dynamically switched; when the TDD signal receiving channel is switched to, disconnecting the phase compensation load from the FDD signal channel; when the TDD signal transmission channel is switched to, the phase compensation load is connected to the FDD signal channel, and the impedance characteristic of the TDD signal filter in the frequency band of the FDD signal is simulated, so that the load driven by the FDD signal channel is consistent with the load phase when the TDD signal is in a receiving state, and the error vector amplitude of transmitting the FDD signal is reduced. According to the invention, a low error vector amplitude can be maintained in an ENDC scene, and the communication quality in the scene is improved.

Measuring MDEVM of a DUT includes splitting an RF signal output by a DUT into first and second RF signals; acquiring and digitizing the first and second RF signals in first and second channels without demodulating the first and second RF signals; performing equalization of the first and second RF signals; measuring first and second modulation distortion (MD) error vectors of the equalized first and second RF signals; performing cross-correlation of the first and second MD error vectors across the first and second channels; averaging the cross-correlated MD error vectors over symbols and packets of the RF signal; and dividing the averaged cross-correlated MD error vectors by signal power of an ideal signal to obtain cross-correlated MDEVMs over a time period or bandwidth of a waveform of the RF signal, where performing the cross-correlation suppresses contribution of uncorrelated noise.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive an indication of a modulation and coding scheme (MCS). The UE may receive an instruction to modify fidelity of an uplink transmission. The UE may transmit the uplink transmission using the MCS and using at least one transmission parameter that is selected to increase or decrease an error vector magnitude associated with the uplink transmission. Numerous other aspects are described.

A method for wireless communication at a user equipment (UE) and related apparatus are provided. In the method, the UE receives an indication of a requested value of an error vector magnitude (EVM) for a resampling process for an input signal from a network entity. The UE further processes the input signal using the resampling process and a set of parameters to obtain a processed signal. The set of parameters is based on the requested value of the EVM. The UE then communicates the processed signal with the network entity.

A radio frequency (RF) test device such as a spectrum analyzer may include an RF attenuator to attenuate a received RF signal; a mixer to down-convert the attenuated RF signal; an IF attenuator to attenuate the down-converted signal; an analog-to-digital converter (ADC) to digitize the attenuated, down-converted signal; and a processor, which may select attenuation values for one or more of the RF attenuator and the IF attenuator based on an error magnitude vector (EVM) analysis, an RF signal type, and a signal level at an input of the ADC. The processor may use a look-up table for the selection. Initial attenuation values may be selected based on an expected RF signal type, RF signal frequency, or RF signal bandwidth. The attenuation values may also be selected in an iterative manner stepping the attenuation values up or down.

The present invention relates to a system and method for monitoring multicore fibres (MCF). The system comprises a unit that generates the optical signal; a unit that processes and monitors this original signal; and the crosstalk and backscattering signals that are generated when the generated optical signal is transmitted through a fibre connecting two FIFOs. The method analyses these signals produced at different powers and determines a threshold defining a malfunction that switches off the laser in addition to transmitting radio signals over fibre without affecting data traffic quality, as assessed by the Error Vector Magnitude (EVM).

Systems and methods for adaptive transmit power control in a wireless communication device are described. In particular, the method includes setting a power level of a baseband signal at a baseband subsystem, setting a power level of a digital frontend (DFE) radio frequency (RF) signal at a DFE subsystem, setting a gain of a variable gain amplifier (VGA) at a RF FE subsystem, and optimizing a transmit power of the system based on adaptively controlling the power level of the baseband signal, the power level of the DFE RF signal, and the gain of the VGA to meet a target error vector magnitude (EVM) for a corresponding modulation and coding scheme (MCS) value.