127 results about "Carrier frequency offset" patented technology

The invention provides a communication radiation source individual identification method based on time domain and time sequence coding constellation diagram feature fusion. The method is used for realizing stable identification of different transmitters under non-ideal conditions of carrier frequency offset, noise interference and the like. The method comprises the following steps: firstly, carrying out normalization and fixed-length interception on a received I / Q signal, and calculating an oversampling multiple according to a symbol rate and a time resolution; then, a time domain and time sequence coding constellation diagram double-branch feature extraction network is constructed, a time domain structure feature is extracted from a time domain branch by adopting a one-dimensional modified ResNet18, and a constellation diagram with time information is generated from a time sequence coding constellation diagram branch through a time sequence coding constellation module and the feature that the phase changes along with time is extracted; and carrying out joint modeling on the two types of features through a trainable weighted fusion mechanism. In the training stage, the performance of the model is improved by adopting cross entropy loss, an Adam optimizer, learning rate scheduling and an early stop strategy. In the reasoning process, input signals are classified by using the model weight with the highest verification accuracy, and a communication radiation source individual identification result is output. Experimental results show that the method can effectively enhance the frequency offset robustness and generalization ability of the model, realizes high-precision identification of the individual communication radiation source, and is suitable for the fields of security access of the Internet of Things, spectrum monitoring, electronic countermeasures and the like.

The application provides an uplink sensing integrated system signal processing method and device and a storage medium, comprising: performing coarse synchronization on a first signal received by a plurality of antennas to obtain a first time offset, a first carrier frequency offset and a second signal after coarse synchronization; performing preliminary channel estimation according to the second signal to obtain an estimated first channel state information tensor; performing deep learning based on a hybrid neural network according to the first channel state information tensor to obtain an estimated second channel state information tensor, a second time offset and a second carrier frequency offset; performing tensor decomposition according to the second channel state information tensor, and acquiring sensing information according to the first time offset, the first carrier frequency offset, the second time offset and / or the second carrier frequency offset. The application realizes more accurate synchronization error estimation and channel state information denoising, guarantees more reliable communication performance, and realizes high-precision positioning and speed measurement of sensing.

This disclosure provides methods, components, devices and systems for carrier frequency offset compensation between access points for coordinated beamforming sounding and transmission. During a channel sounding phase of a CBF operation, a first AP acting as a frequency reference may transmit a frequency reference frame. A second AP may use the frequency reference frame to estimate a CFO and pre-compensate for the CFO for subsequent transmissions during the channel sounding phase and during a transmission phase of the CBF operation. In some examples, the first AP may own a shared TXOP of the transmission phase. The second AP may receive a frequency reference frame for estimating the CFO. In some other examples, the second AP may own the shared TXOP. The second AP may request the first AP to transmit the frequency reference frame. Alternatively, the second AP may use a CFO value estimated during the channel sounding phase.

This disclosure provides methods, components, devices and systems for interference mitigation (IM) mode signaling designs for a physical layer protocol data unit (PPDU). Some aspects relate to IM mode signaling designs according to which a wireless communication device determines a tone plan in accordance with an ON or OFF state of the IM mode. For example, an ON state of the IM mode may correspond to a first tone plan and an OFF state of the IM mode may correspond to a second tone plan. The first tone plan may define first fixed pilot tone locations, with pilot tones at the first fixed pilot tone locations being usable as IM pilot tones and / or usable as carrier frequency offset (CFO) pilot tones. The second tone plan may define second fixed pilot tone locations, with pilot tones at the second fixed pilot tone locations being exclusively usable as CFO pilot tones.

The invention provides a time-frequency synchronization method and device and a medium, and relates to the technical field of communication. The method comprises the following steps: a receiving end receives a signal transmitted by a satellite; estimating and compensating the carrier frequency offset (CFO) of the signal so as to compensate the Doppler frequency shift of the central subcarrier of the signal; and estimating and compensating the sampling frequency offset (SFO) of the signal so as to compensate the residual Doppler frequency shift components of other subcarriers of the signal after the Doppler frequency shift of the central subcarrier is compensated. Aiming at the problem that a communication system fused with satellites can generate large Doppler frequency shift, the carrier frequency offset (CFO) and the sampling frequency offset (SFO) are estimated and compensated, so that the influence of the Doppler frequency shift on communication is better reduced.

The present disclosure relates to a device and a communication method for appropriately determining: the timing and the frequency of an R2D signal used for CFO calibration; and the detection of the R2D signal used for the CFO calibration. The device, which has lower complexity than a Narrow Band Internet of Things (NB-IoT) device, comprises: a reception unit that receives a reception signal including control information from a wireless communication device; and a control unit that determines which sequence / pattern / length is to be detected from a signal of a clock acquisition part of the reception signal on the basis of the control information in the reception signal. The control unit determines to use a signal of the sequence / pattern / length detected from the clock acquisition part for timing calibration and calibration of a carrier frequency offset.

The invention discloses a carrier frequency offset and I / Q joint compensation method and system for a Bluetooth receiver, and the method comprises the steps: obtaining an initial receiving signal of the Bluetooth receiver, and carrying out the time domain preprocessing and fast Fourier transform, thereby obtaining a frequency spectrum; calculating normalized frequency offset based on the spectral line with the maximum amplitude in the frequency spectrum; according to the normalized frequency offset, adaptively selecting a target interpolation algorithm to obtain a fine carrier frequency offset estimation value; carrying out smoothing processing, and carrying out frequency offset compensation on the initial receiving signal by using a smoothed frequency offset estimation value to obtain a baseband I / Q signal; performing low-pass filtering, down-sampling and DC removal processing on the baseband I / Q signal to obtain a zero-mean baseband signal; and estimating a gain imbalance parameter and a phase imbalance parameter based on the zero-mean baseband signal, performing blind compensation, and outputting a compensated orthogonal I / Q signal. According to the method, the carrier frequency offset is estimated with high precision through a dynamic selection interpolation algorithm, I / Q imbalance is compensated cooperatively, and the demodulation performance and robustness of the Bluetooth receiver are improved.

Provided in the embodiments of the present application are a communication method and a related device. In the method, a first device sends a first signal and a second signal, wherein the first signal is used for transmitting data, the second signal is used for being modulated by a second device to obtain a third signal, the third signal is a feedback signal of response data, and the second signal is also used for carrier frequency offset (CFO) calibration of a third device. On the basis of the solution, the second signal sent by the first device to the second device is not only used for signal modulation of the second device, but is also used for CFO calibration of the third device, that is, data transmission of the second device and the CFO calibration of the third device are realized by means of the second signal, so as to meet the communication requirements of both the second device and the third device, thereby improving the communication efficiency.

This invention discloses a method and system for radio frequency fingerprinting of narrowband IoT transceivers. The method involves a receiver acquiring wireless messages sent by the transceiver to be identified, obtaining in-phase / orthogonal discrete sample sequences, locating and extracting preamble sample segments, performing a short-time Fourier transform on the preamble sample segments to generate a spectrogram energy matrix, and extracting compressed time-frequency features through singular value decomposition. The main component of the carrier frequency offset is obtained based on the cross-correlation peak position shift between rising and falling chirps, and the carrier frequency offset correction component is obtained based on the phase drift of adjacent rising chirps. The compressed time-frequency features and the carrier frequency offset estimation results are concatenated into a fused feature vector, which is then input into a convolutional neural network classification model to output the device category and category confidence. This invention reduces the dependence on channel location features and decreases model input overhead, making it suitable for online identification of narrowband IoT devices.

The invention belongs to the technical field of wireless communication, discloses a high-precision frequency synchronization method for an OTFS system, and provides a coarse and fine carrier frequency offset hierarchical estimation scheme for solving frequency offset by mainly using a differential phase between adjacent symbols and solving the problem of poor frequency offset estimation precision in the existing frequency synchronization algorithm. Coarse frequency offset estimation compensates carrier frequency offset to a working range of fine frequency offset estimation while ensuring a frequency offset estimation range, then the fine frequency offset estimation is utilized to further improve estimation precision, and the frequency offset estimation method provided by the invention achieves estimation precision close to a theoretical limit with low implementation complexity, and has a wide application prospect. Compared with a traditional single-stage frequency offset estimation method, the method has obvious advantages.

Methods, systems, and apparatus for wireless communication are described. A user equipment (UE) may receive a first indication of a set of reference signal instances within a resource set. The UE may receive a second indication of a resource element format for the reference signal instances in the reference signal instance set, the resource element format including one or more empty resource elements and one or more reference signal resource elements. The UE may further receive a reference signal from a base station for estimating a carrier frequency offset (CFO) based on the first indication of the set of reference signal instances and the second indication of the resource element format for the reference signal instances. The UE may then communicate with the base station based on the received reference signal.

This invention discloses a wireless continuous communication synchronization method and system based on time-frequency joint feedback correction. The method includes: a slave device calculating a carrier frequency offset estimate and a timing estimate L of the received signal using a preamble sequence; calculating a remaining carrier frequency offset estimate and a remaining timing offset estimate using an auxiliary pilot; and the slave device locating the starting point of the data stream based on the timing estimate L. The slave device then feeds back the carrier frequency offset estimate ΔF, the remaining carrier frequency offset estimate, and the remaining timing offset estimate to a global synchronization controller. This invention's wireless continuous communication synchronization method and system utilizes the timing estimate L estimated by the time-domain preamble sequence to locate the data stream. The global synchronization controller then corrects the relationship between the data stream frequency and its location based on the carrier frequency offset estimate, the remaining carrier frequency offset estimate estimated by the frequency-domain auxiliary pilot, and the remaining timing offset estimate.

The invention discloses a high-spectral-efficiency and high-speed FTN (Fourier Transform Network) transmission method based on pseudo code auxiliary carrier synchronization, which belongs to the field of high-frequency wireless communication, and comprises the following steps: a transmitting end composites a low-speed pseudo code pilot signal into a high-speed FTN signal by adopting a frequency division multiplexing mode to obtain a composite signal and outputs the composite signal; a receiving end performs down-conversion on the received composite signal, and the composite signal is separated by a filter to obtain a low-speed pseudo code pilot frequency sequence and a high-speed FTN sequence; carrying out carrier frequency offset estimation based on the low-speed pseudo code pilot frequency sequence to obtain a frequency offset estimation value; performing frequency offset compensation on a receiving end carrier by adopting the frequency offset estimation value to obtain a compensated high-speed FTN sequence; and carrying out symbol estimation on the compensated high-speed FTN sequence by adopting a forward backtracking continuous symbol sequence detection algorithm to obtain a received signal. According to the invention, the receiving sensitivity and the system robustness can be ensured while high-spectrum-efficiency transmission is realized.

This invention discloses a bidirectional continuous-variable quantum key distribution method and system based on frequency division duplexing in a single-transceiver ring network. The method is based on a monolithically integrated silicon photonics transceiver chip. By pre-setting optical carrier frequency offsets for the forward and reverse links, it isolates the quantum signal from Rayleigh backscattering noise in the fiber in the frequency domain. The transmitting end generates a broadband waveform containing quantum signals and pilot signals, which is transmitted bidirectionally through a single optical fiber. The receiving end uses a laser source from the same chip as the local oscillator for coherent heterodyne detection. A digital signal processing module performs orthogonalization correction, phase recovery, and matched filtering to suppress noise and extract the quantum signal to generate a secure key. This invention solves the problems of inflexible networking, low fiber utilization, and severe scattering noise interference in bidirectional transmission over a single fiber caused by the separation of the transmitting and receiving ends in integrated continuous-variable quantum key distribution systems. It provides a low-cost and highly flexible solution for metropolitan quantum ring networks.

The invention discloses a radio frequency fingerprint extraction method and device, electronic equipment and a storage medium. The radio frequency fingerprint extraction method comprises the following steps: sampling a received signal, and carrying out down-conversion to obtain a baseband signal; frame synchronization is carried out on the baseband signal, carrier frequency offset compensation and phase offset compensation are carried out on the signal after frame synchronization, and a target signal is obtained; converting the target signal to a frequency domain to obtain a frequency domain representation; and according to the frequency domain representation of the target signal, a phase curvature feature is extracted as a radio frequency fingerprint, and the phase curvature feature is a second-order difference of phases between adjacent frequency points. According to the method, linear phase distortion introduced by channels can be effectively eliminated, and only nonlinear phase response caused by transmitter hardware distortion is reserved, so that robust radio frequency fingerprint extraction is realized under various channel conditions, and reliable support is provided for high-precision physical layer identity authentication.

Embodiments of the present disclosure provide a method for suppressing channel replica caused by carrier frequency offset (CFO). The method includes: generating, by an analog-to-digital converter (ADC), a plurality of samples after receiving a sequence of chips by an antenna; accumulating, by an accumulator, the plurality of samples to generate an initial channel impulse response (CIR); comparing the CFO with a threshold value; in response to the CFO being greater than the threshold value, applying a filtering operation on the initial CIR estimate, the filtering operation configured to reduce an intensity of a sidelobe in the initial CIR estimate while maintaining an intensity of a main lobe in the initial CIR estimate; and generating a final estimated CIR based on the filtered initial CIR estimate.

This invention discloses a cross-receiver radio frequency fingerprinting method, system, and terminal device, relating to the field of wireless communication security technology. The invention estimates the carrier frequency offset of the received IQ signal by decoupling the transmitter and receiver carrier frequency offsets; extracts the slope and curvature of the frequency domain phase as domain-invariant features; constrains the consistency of features of the same device across different receivers based on contrastive learning; employs optimal transmission alignment of the spectral envelope distribution of different receivers to reduce inter-domain offset; and achieves cross-receiver device identification through joint optimization of invariant features. By estimating the carrier frequency offset and decoupling the transmitter and receiver frequency offsets, extracting the frequency domain phase slope and curvature as domain-invariant features, and combining contrastive learning to constrain the consistency of features of the same device across receivers with optimal transmission alignment of the spectral envelope distribution of different receivers, this invention achieves reliable device access authentication and identification under receiver-less conditions, improving the model's generalization ability and stability.

The application is a satellite 5G large dynamic high-speed transmission real-time receiving and time synchronization method and system based on FPGA, and belongs to the technical field of wireless communication.The system is provided with a real-time receiving module, a time synchronization module and the like at the receiving end of a satellite-ground transmission link.The method comprises the following steps: the receiving end stores data into a DDR3 in real time by using an asynchronous FIFO, and performs time synchronization once every transmission half-frame signal;the starting point of a symbol is calculated in a multi-symbol combination mode, the content of each symbol is obtained according to the starting point of the symbol, a correlation value is calculated according to a known PSS sequence, the starting point of the half-frame signal is obtained, and subsequent CP removal and demodulation operations are continuously performed;the application solves the problem of timing synchronization difficulty caused by large time delay and large frequency offset, realizes low complexity and timing synchronization error not affected by carrier frequency offset under the premise of ensuring accuracy, and can be used for the time synchronization process of a satellite mobile communication system with large dynamic frequency offset.

This invention provides a frequency offset estimation method and apparatus for scenarios with large frequency offset. The method includes: performing windowing processing on the delay conjugate multiplication sequence of a signal sequence under different target delay values ​​based on a preset detection time window, obtaining multiple window data corresponding to the delay conjugate multiplication sequence; summing the window data to obtain a summation result corresponding to each window data; determining the optimal frequency offset phase metric corresponding to different target delay values ​​based on the summation result; and merging the optimal frequency offset phase metrics corresponding to each target delay value to obtain a frequency offset estimate of the signal sequence. This invention effectively improves the accuracy of carrier frequency offset estimation.

This invention relates to the field of airborne power management technology and discloses a method and system for detecting abnormal intrusions into an unmanned aerial vehicle (UAV) airborne network. The method includes: acquiring the broadcast coordinate data and broadcast speed data of the node to be detected; simultaneously reading the measured received signal power value and measured carrier frequency offset value of the node's signal reaching the local end; calculating the relative straight-line distance and relative radial velocity based on the local motion reference to determine the theoretical reference signal power value and theoretical reference frequency shift value; calculating the comprehensive residual index of the measured characteristics and the theoretical reference characteristics; and outputting a radio frequency shutdown command to the power management unit when the comprehensive residual index exceeds a judgment threshold. This invention identifies unauthorized access through physical layer energy characteristics, prevents abnormal nodes from illegally occupying airborne power resources, ensures the energy security of the battery system, and reduces the additional power loss generated by processing abnormal data.

The invention provides a carrier frequency offset detection method and system, and the method comprises the steps: carrying out the quartic operation and discrete Fourier transform of an input signal sequence, and obtaining ffout; repeating M times to accumulate the power of the ffout obtained each time to obtain fftpow; based on the maxval, the minval and the fftsum, setting an error flag state in combination with a preset first threshold value and a preset second threshold value; and finally, updating the carrier frequency offset according to the mark state, or judging that the detection result is unreliable, and not updating the carrier frequency offset. The fair carrier frequency offset monitoring method is low in complexity, and the false detection probability can be obviously reduced under the condition of low signal-to-noise ratio.

The application discloses a kind of communication signal parameter blind estimation methods, devices and program products for intelligent instrument, involve signal identification field, to with low complexity calculation cost, accurately estimate the carrier frequency offset value of electromagnetic signal, symbol rate and pulse shaping filter type.The application carries out normalization to received signal, carrier frequency offset rough correction, estimates carrier frequency offset and meets rate, carries out the pre-estimation of pulse shaping filter type from the spectrum diagram of rough correction signal, and, for square root raised cosine filter / Raised cosine filter, first sequentially carrier frequency offset correction is carried out to first signal, based on square root raised cosine filter Matching filter, and based on symbol rate construction constellation diagram, finally according to constellation diagram, distinguish whether square root raised cosine filter or Raised cosine filter.The application realizes comprehensive, accurate, reliable estimation to electromagnetic signal parameter with low calculation complexity, realizes the automation and wisdom of electromagnetic signal measurement.

A first station (STA) receives from a second STA a first frame and transmits a physical layer protocol data unit (PPDU) to the second STA. Based on the first frame comprising an indication for the first STA to use a first mode to transmit the PPDU, the first STA transmits the PPDU using the first mode and a first carrier frequency offset of the PPDU is based on a second carrier frequency offset of the first frame. The first mode may comprise an enhanced long range (ELR) operation mode.

A first station (STA) receives from a second STA a first frame and transmits a physical layer protocol data unit (PPDU) to the second STA. Based on the first frame comprising an indication for the first STA to use a first mode to transmit the PPDU, the first STA transmits the PPDU using the first mode and a first carrier frequency offset of the PPDU is based on a second carrier frequency offset of the first frame. The first mode may comprise an enhanced long range (ELR) operation mode.

This invention relates to the field of baseband communication technology, specifically to a rapid detection method for mobile terminals involved in a case based on signal sensing. The method involves down-converting the captured air interface radio frequency signal into a baseband data stream, extracting the random access preamble sequence and removing the cyclic prefix during the physical layer synchronization phase, performing a Fast Fourier Transform on the preamble sequence to extract the carrier frequency offset estimate and the inter-symbol phase difference sequence, and combining them to generate a baseband physical layer feature vector. This feature vector is then subjected to a time-domain sliding cross-correlation operation with a pre-stored baseband fingerprint database of the involved terminal. When the cross-correlation peak exceeds the decision threshold and the frequency offset change rate is consistent, a detection trigger signal is output and the timestamp is locked. This invention bypasses the higher-layer signaling parsing and encryption cracking stages, directly using baseband waveform features at the physical layer to complete the matching judgment, eliminating the processing delay and decryption failure risk caused by the step-by-step parsing of the protocol stack, and achieving rapid detection of the involved mobile terminal.

Technologies related to tracking carrier frequency offset (CFO) are described. A predicted CFO estimate can be determined before a packet is received. This predicted CFO estimate can be used to modulate a packet preamble based on the predicted CFO estimate. The corrected preamble is used to determine an actual CFO estimate. A combination of the predicted CFO estimate and the previous CFO estimate is used to correct part of the next packet. The functionality of the predicted CFO estimate depends on the output of a machine learning model based on packet properties.

A modulation parameter blind identification method, system and device for a non-cooperative OTFS system, and a medium, the method comprising: performing OTFS modulation on a sending end signal, and transmitting the signal through multipath fading and a noise channel; the OTFS system blind identification receiving end receives an undemodulated OTFS signal and processes the undemodulated OTFS signal in two steps: performing OTFS frame structure parameter blind identification based on a cyclostationary autocorrelation function to obtain a delay dimension lattice number, a cyclic prefix (CP) length and a Doppler dimension lattice number; time-frequency synchronization parameter estimation: estimating symbol clock skew by using a delay dimension and Doppler dimension combined autocorrelation method to obtain symbol initial clock skew; estimating carrier frequency offset by using a CP-tail phase difference method to obtain a carrier frequency offset factor; according to the method, the modulation parameters of the OTFS system can be obtained under the condition that pilot frequency or prior frame information cannot be predicted in non-cooperative communication, meanwhile, the method has the capability of inhibiting multipath and mobile Doppler, and key technical support is provided for passive monitoring, classification and reconnaissance of non-cooperative OTFS signals.

Methods and wireless communication devices for MIMO packet detection, include receiving input data by a receiver, performing peak detection by a two-tiered approach including an outer loop and an inner loop to generate candidates composing of detected peaks from correlation outputs, and driving final start of packet and carrier frequency offset measurements from the candidates as a final packet detection result. The outer loop iterates on (Rx, STS) combination pairs, and the inner loop runs peak detection on the input data by one or more correlators for each of the (Rx, STS) combination pairs. Rx is one of the receiving antennas of the receiver and STS is one of space-time streams received by the receiver. In some embodiments, one or more winning candidates are selected from the candidates based on a score computed from information related to the detected peaks for each candidate, and the final packet detection result is derived from the winning candidates.

The invention relates to the technical field of industrial wireless communication, in particular to a time-frequency joint calibration method based on carrier frequency offset and terminal equipment, and the method comprises the steps that the terminal equipment receives a downlink wireless frame sent by access point equipment, obtains the carrier frequency offset through a known reference signal in the frame, and transmits the carrier frequency offset to the access point equipment; the offset represents the relative deviation of the frequency of the crystal oscillator and is stored; when time synchronization calibration or uplink transmission is needed, the offset is read, and the local timestamp growth rate is adjusted or frequency pre-compensation is carried out on an uplink signal. The terminal equipment comprises a receiving unit, a processing unit, a storage unit, a reading unit, a time calibration unit and a frequency compensation unit. According to the invention, time-frequency joint calibration is realized by using single frequency offset estimation, trigger frame interaction is reduced, system control overhead and communication delay are reduced, and synchronization precision and signal orthogonality of multi-user uplink orthogonal frequency division multiple access transmission are improved.