67 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).

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 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 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 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.

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.

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.

The invention relates to a system and method for estimating signal-to-noise ratio (SNR) and noise variance from error vector magnitude (EVM). In one embodiment, 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 an error vector magnitude (EVM) value using the one or more symbols, identify a quadrature amplitude modulation (QAM) size, determine a signal-to-noise ratio (SNR) value using the EVM value and the QAM size, and adjust a transmission rate of a transmitter based at least on the SNR value.

Various aspects of the present disclosure relate to maximum power reduction (MPR) indication based on an error vector magnitude (EVM). An apparatus, such as a network equipment (NE), determines an MPR value for a user equipment (UE), where the MPR value satisfies an EVM requirement. The NE transmits an indication of the determined MPR value to the UE and the UE performs transmissions using the MPR value.

The application discloses a terahertz co-frequency interference characteristic evaluation method and system based on cross-domain mapping, relates to the technical field of terahertz wireless communication and electromagnetic compatibility, and solves the technical problems that link vulnerability is difficult to quantify and there is a lack of system-level correlation between radio frequency physical indicators and baseband demodulation performance in the prior art.The application collects power information of a receiving end under an interference-free injection and a co-frequency interference injection environment in a radio frequency power domain, calculates an interference signal ratio and a signal-to-interference-and-noise ratio, maps radio frequency power domain parameters to a modulation error ratio MER and an error vector magnitude EVM in a symbol decision domain, evaluates interference attenuation in combination with a spatial geometry variable in a spatial geometry domain, and comprehensively evaluates terahertz co-frequency interference characteristics by comprehensively considering radio frequency power domain indicators, symbol decision domain indicators and spatial geometry domain indicators.The application has good operability and reproducibility, and provides support for standardized testing, network deployment and safety boundary definition of a terahertz communication link.

The application relates to the field of satellite communication and discloses a satellite communication anti-interference transmission system, which comprises a phase rotation compensation module for removing Doppler frequency shift components; a channel state sensing unit for calculating an error vector magnitude variation gradient of pilot symbols; a transmission strategy control unit for generating a transmission reconstruction pulse when the variation gradient exceeds a slope threshold value; and a physical layer framing unit for truncating a physical layer long frame in response to the transmission reconstruction pulse, dividing residual service data into independent microframes, and reducing modulation order. The application uses a channel state variation gradient to capture interference energy injection characteristics, compresses a transmission strategy reconstruction response delay, effectively reduces data loss caused by transient error codes, and guarantees the physical continuity of a key data link in an electromagnetic countermeasure environment.

A method of error vector magnitude, EVM, minimization for a radio frequency, RF, measurement equipment is provided. The method comprises: measuring the EVM of a receive, RX, chain of the RF measurement equipment in accordance with a transmit, TX, feedback signal; and responsive to a trigger event, actuating one or more power-adjusting members interposed in the RX chain in accordance with the measured EVM of the RX chain. Among others, the RF measurement equipment is thereby consistently operated based on optimal power levels in the RX chain.

Methods, systems, and devices for wireless communication are described. The described techniques allow a receiving device to estimate an error vector magnitude (EVM) associated with each antenna port of a transmitting device and report the EVM to the transmitting device to improve communication throughput. The receiving device may receive a respective pilot signal from each antenna port of the transmitting device, and may estimate an EVM for each antenna port from a distortion value associated with each respective pilot signal. In some examples, a receiving device may isolate distortion values from a pilot signal according to a channel response measurement of the pilot signal and a channel noise estimate of a wireless channel between a transmitting device and the receiving device. Additionally or alternatively, the receiving device may identify the transmitter EVM using a Maximum Ratio Combining (MRC) technique.

Disclosed are a channel estimation method, apparatus and device, relating to the technical field of communications, comprising: determining an original data signal according to a first channel estimation result, the first channel estimation result being obtained by performing channel estimation on a received data signal; performing demodulation, hard decision and modulation on the original data signal to obtain reference load data; and optimizing the first channel estimation result based on a preset target optimization function and the reference load data to obtain a second channel estimation result. According to the technical scheme, the channel estimation result is optimized through the reference load data, the channel estimation precision is improved, the robustness of a communication system is enhanced, and the error vector amplitude measurement accuracy under the complex channel condition is improved.

The application provides a satellite-ground joint nonlinear linear distortion correction method and device based on reinforcement learning, and the method comprises the following steps: establishing a joint distortion model; wherein the joint distortion model comprises power amplifier nonlinear distortion and channel linear distortion in a satellite-ground communication link; establishing a state space; wherein the state space comprises signal characteristics, channel environment and power amplifier state in the satellite-ground communication link; establishing an action space; wherein the action space comprises adjustment of a predistorter at a transmitting end, adjustment of a clipping threshold at the transmitting end and adjustment of an equalizer at a receiving end; establishing a joint reward function; wherein the joint reward function comprises an error vector magnitude, power amplifier output power and a bit error rate in the satellite-ground communication link; and using a deep reinforcement learning algorithm to train a correction model according to the state space, the action space and the joint reward function, so as to correct the joint distortion model, realize joint correction of the power amplifier nonlinear distortion and the channel linear distortion, and optimize signal quality.

Apparatuses and methods for negotiation and signaling for cooperative control of power amplifier nonlinearity are disclosed. At least some example embodiments may allow signaling to support the design and deployment of cooperative control of power amplifier nonlinearity for digital pre-distortion (DPD) applications in user equipment and digital post-distortion (DPoD) applications in network nodes, where digital pre-distortion may be used to control out-of-band transmissions (e.g., adjacent channel leakage ratio (ACLR)), and digital post-distortion (DPoD) applications in network nodes. And digital post-distortion may be used to control in-band transmission (e.g., error vector magnitude (EVM)).