322 results about "Frequency-division multiplexing" patented technology

The invention provides a frequency division multiplexing multi-beam anti-interference method for a shaped antenna, and the method comprises the steps: obtaining the signal data of each frequency band according to the multi-beam spatial domain data received by the shaped antenna and a filter of a frequency domain corresponding to the working frequency band of each beam; performing high-resolution spatial spectrum estimation on the signal data of each frequency band by adopting a MUSIC algorithm to obtain an incoming wave space direction of an interference signal; according to the incoming wave space direction of the interference signal, on the basis of a preset multi-beam zeroing anti-interference strategy, self-adaptive weights of all same-frequency beams are obtained in a spatial domain and frequency domain two-dimensional combined processing mode; the adaptive weights of the same-frequency beams are combined, a comprehensive directional diagram is obtained, and a multi-beam interference zeroing result is obtained, according to the method, the whole airspace is covered with the beams of different frequency points, and space-frequency combined suppression of airspace complex interference is achieved.

The invention relates to a hydrogen storage station safety monitoring method and system based on a wireless passive three-signal sensor, and belongs to the technical field of safety monitoring. Wireless passive three-signal sensor nodes are deployed in a hydrogen storage station to form a three-dimensional monitoring network; the temperature, strain and hydrogen detection units of the sensor are simultaneously excited through the multi-frequency-band signal transceiver, so that parallel acquisition of three-parameter signals is realized; performing signal decoupling, temperature compensation and primary risk assessment by using an edge computing gateway; deep data mining and risk assessment are carried out through a cloud early warning platform in combination with a digital twinborn model; wherein multi-parameter signal decoupling is realized by adopting a frequency division multiplexing and wavelet denoising algorithm, and safety early warning is carried out in combination with a three-level early warning decision tree. The hydrogen storage station electric spark risk can be eliminated, high-precision synchronous monitoring of temperature, strain and hydrogen concentration is achieved, and the hydrogen leakage early warning time is shortened.

The invention discloses a multi-channel analog-to-digital converter for multi-channel frequency division multiplexing and a conversion circuit and method thereof, and the frequency division multiplexing multi-channel analog-to-digital conversion circuit comprises an analog frequency conversion module which is used for receiving N paths of modulation clock signals, and generating N paths of modulation clock signals according to the modulation clock signals, n paths of input signals are modulated to preset frequencies of the input signals respectively, and N paths of modulation signals are obtained; wherein N is greater than or equal to 2, and N is a positive integer; the frequency bands where the N paths of modulation signals are located are not overlapped; the analog adder is used for combining the N paths of modulation signals to obtain one path of analog signal; the input end of the analog-digital conversion module is connected with the analog-digital conversion module; the digital logic control module is used for receiving the N paths of modulation clock signals and separating the digital signals into N paths of digital signals which are output in parallel. Multi-channel analog-to-digital conversion can be realized by adopting one analog-to-digital converter, the hardware volume, cost and power consumption can be reduced, and the analog-to-digital conversion rate and precision can be improved.

The invention discloses an earthquake early warning device and method based on campus broadcast, and the method comprises the steps: carrying out the building response coupling analysis through receiving an early warning signal of an earthquake monitoring center, generating an earthquake magnitude-building coupling feature, and mapping the earthquake magnitude-building coupling feature into an enhanced early warning source adaptive to an acoustic environment; acoustic cavity detection is carried out based on threatened area identification, and differential playing topology is constructed; extracting a high-risk gathering area through personnel density scanning, generating personalized evacuation guiding content and determining a playing priority; high-precision time sequence control is realized by adopting a synchronous reference anchor point technology, and a multi-mode playing domain is constructed through carrier modulation and frequency division multiplexing; and finally, an acoustic navigation field is utilized to guide accurate scheduling and playing of audio signals, differential playing and accurate coverage of early warning information can be realized according to the anti-seismic characteristics and acoustic environment characteristics of different buildings, and an intelligent acoustic solution is provided for campus earthquake early warning.

The invention discloses a polymorphic sleep data fusion self-attention sleep system and method. The system comprises a data acquisition module which is responsible for acquiring environmental data and physiological data of a user; the signal preprocessing module is used for performing segmentation, normalization and de-noising processing on the collected EEG and EOG signals; the frequency division multiplexing module is used for decomposing the preprocessed signal frame into a plurality of narrowband signals by using a frequency division multiplexing technology; the feature extraction module is used for extracting features from the decomposed narrowband signals; the model training module is used for training a model by utilizing the feature set; the sleep staging module is used for performing real-time or offline sleep staging through the trained model; the sleep quality evaluation module is used for calculating a sleep quality index based on a sleep staging result; the correlation analysis module is used for performing correlation analysis on the relationship between different sleep stages and the sleep quality indexes to generate a quality evaluation model; and the early warning system module is used for setting an early warning threshold value according to the sleep quality evaluation result and the quality evaluation model.

The invention relates to a phase-sensitive optical time domain reflectometer based on a parallel frequency division multiplexing sequence. Continuous laser is divided into a local path and a detection path through an optical coupler; the local path is input to the polarization coherent receiving module, the detection path is converted into a pulse laser sequence with intensity modulation through a light intensity modulator driven by a radio frequency signal provided by the signal generation circuit module, and the radio frequency signal is composed of two frequency division multiplexing sequences with difference; the pulse laser sequence enters the sensing link to be measured to generate Rayleigh backscattered light, and the Rayleigh backscattered light and local continuous laser are subjected to beat frequency coherent receiving through a circulator; and the signal acquisition circuit is used for sampling and analyzing the interference signal, and performing frequency domain comparison on an interleaving result of the two frequency division multiplexing pulse sequences to eliminate a harmonic frequency and retain a real strain signal frequency. Compared with the prior art, the non-harmonic strain signal measurement is realized, the high-frequency response performance and the high-precision strain measurement capability are excellent, and meanwhile, the long-distance coverage capability is also realized.

The invention provides an MEMS (Micro Electro Mechanical System) micromirror array chip, a module and optical scanning equipment. The MEMS micromirror array chip comprises a plurality of micromirror structures, a substrate, a vertical lead structure and a capacitance angle sensing structure, according to the micro-mirror array chip integrated with the capacitive sensor, array-level real-time angle detection, feedback control and high-precision scanning angle detection are realized, and the micro-mirror array chip is fast in driving and resistant to interference; meanwhile, the wiring density is reduced by frequency division multiplexing isolation signals; in addition, the application of a monolithic integrated capacitance angle sensor in a high-density micro-mirror array chip is realized by a thick substrate with a silicon through hole; and finally, the micromirror array chip of the monolithic integrated capacitance angle sensor is used for precision optical scanning equipment, a photoelectric angle detector is omitted, optical scanning high-precision real-time angle detection and feedback control, high-precision angle detection and high-speed scanning are realized, the use design is convenient, and the cost is low.

The invention relates to the technical field of optical fiber communication and sensing, and discloses an optical fiber coding and positioning integrated sensing device based on frequency division multiplexing and an application method, and the optical fiber coding and positioning integrated sensing device comprises a light source module, a coupler module, a frequency division multiplexing module, a sensing optical fiber network, a signal demodulation module, a positioning sensing module and a main control unit. According to the optical fiber coding and positioning integrated sensing device based on frequency division multiplexing and the application method thereof, a light source module generates broadband continuous optical signals, a coupler module realizes optical signal coupling and separation, a frequency division multiplexing module integrates sub optical signals, and an optical fiber sensing unit of a sensing optical fiber network senses and encodes external physical quantities. The positioning sensing module realizes accurate positioning, the signal demodulation module separates sub optical signals and extracts information, the main control unit operates in a coordinated manner, processes and analyzes data and outputs a result, all the modules cooperate to form an efficient and stable monitoring system, the requirements for multi-physical-quantity synchronous monitoring and accurate position positioning in a large-scale and long-distance scene are met, and the system performance is improved.

The invention provides an optical fiber transmission receiving signal prediction model training method, a prediction method and equipment, and relates to the technical field of transmission, and the training method comprises the steps: generating a training sample corresponding to a transmitting signal according to the transmitting signal generated by a transmitting end in a continuous spectrum nonlinear frequency division multiplexing system in advance, and training a neural network model based on the training sample to perform mixed domain feature extraction, multi-scale processing and attention feature extraction based on a peak perception attention mechanism on the training sample to obtain received signal prediction result data and optimize the neural network model so as to train the neural network model as an optical fiber transmission received signal prediction model. According to the method and the device, the received signal in the continuous spectrum nonlinear frequency division multiplexing system can be predicted, the accuracy of performing received signal prediction by adopting the trained optical fiber transmission received signal prediction model can be improved, and further the research and development period of the modeling process of the optical fiber communication system and the computing resource consumption of research and development equipment can be reduced.

The invention discloses a double-index modulation simulated radio frequency division multiplexing (AFDM) communication method. The method comprises the following steps: step 1, a transmitting end performs serial-parallel change; step 2, obtaining a transmission signal according to the index position of the joint selection AFDM activation subcarrier in the mapping table, the modulation bit mapping and the pre-chirp parameter of the activation subcarrier; step 3, obtaining a time domain signal; 4, performing parallel-serial conversion on the time domain signal; step 5, performing propagation transmission through a time-varying channel based on the time domain signal; step 6, constructing a time domain channel matrix, and performing serial-to-parallel conversion on the time domain receiving signal to obtain a receiving signal; step 7, performing channel estimation on the chirp parameter equivalent channel matrix; step 8, detecting an activated subcarrier position, an activated subcarrier modulation bit and an activated subcarrier pre-chirp parameter based on the chirp parameter equivalent channel matrix, and performing pre-chirp parameter transformation; and step 9, recovering the bit stream through parallel-serial change. The spectrum efficiency of the AFDM system is further improved, and the bit error rate is reduced.

The invention discloses a frequency division multiplexing RFID tag signal parallel receiving method based on an SIC architecture, which comprises the following steps: firstly, constructing a frequency division multiplexing UHF RFID system, performing subcarrier modulation on respective Miller codes by tags by using M values of 4, 8, 12 and 16, deducing the power spectrum density of a Miller subcarrier modulation sequence based on the Wiener-Singqin theorem, and finally, performing frequency division multiplexing on the Miller subcarrier modulation sequence according to the power spectrum density of the Miller subcarrier modulation sequence. The method comprises the following steps of: quantitatively analyzing the interference degree generated by tags of other channels in different frequency channels, performing power estimation through FFT (Fast Fourier Transform), estimating the amplitude and radio frequency phase of each tag by utilizing the known interference degree, calculating the SIR (Signal to Interference Ratio) of each tag, sequencing, and demodulating in sequence according to the SIR size until the last tag signal is demodulated. According to the method provided by the invention, the parallel receiving of the frequency division multiplexing RFID tags can be realized, so that the reader-writer can simultaneously inventory a plurality of tags in a single time slot, thereby effectively improving the identification efficiency and throughput rate of the UHF RFID system, and improving the ability of the UHF RFID system to adapt to application scenarios in which massive tags need to be quickly accessed in a large-scale Internet of Things.

The application belongs to the technical field of distributed optical fiber sensing, and particularly relates to a long-distance distributed optical fiber broadband acoustic vibration sensing system. The application utilizes the same laser to transmit and generate back Rayleigh scattering light and interference light in the same sensing optical fiber, and further constructs a distributed optical fiber acoustic vibration sensing system combined with Φ-OTDR and MZI, which comprehensively utilizes the performance advantages of both, utilizes a very simplified optical system scheme, realizes the function fusion of the two sensing structures on one sensing optical fiber, reduces the resource waste caused by the transmission of sensing signals by different sensing optical cables respectively, maximizes the optical fiber resource utilization rate, and reduces the system cost; utilizes a frequency division multiplexing demodulation scheme in the digital domain, expands the frequency response range on the basis of ensuring the high positioning accuracy of the system, realizes the simultaneous detection of the two systems by a single core, simultaneously realizes the high positioning accuracy and the continuous non-blind area detection in the broadband frequency range, and improves the reliability.

The present application relates to the technical field of communications, and discloses a transmission method, a terminal, and a network side device. The transmission method in the embodiments of the present application comprises: a terminal determines a transmission mode for one or at least two transmission objects, wherein the transmission mode comprises using the same or different modes for transmission, or the transmission mode is associated with at least one of the waveform, initialization parameters, scrambling mode, sequence, phase or rotation phase used when using the same or different modes for transmission, the transmission object comprises a signal or a channel or a part of the signal or a part of the channel, and the at least two transmission objects are transmitted by means of frequency division multiplexing (FDM) or in the form of a discrete frequency domain; and the terminal transmits the one or at least two transmission objects on the basis of the transmission mode.

Various aspects of the present disclosure relate to a device and methods for a network-controlled repeater (NCR) device to efficiently expand a coverage area of a base station. The repeater device transmits to base station(s) a beam designation of beams of the repeater device capable of communicating with user devices via a third access link. In response, the base station(s) determining that the beam designation identifies two or more user devices in a first beam of the two or more beams that should be serviced using frequency division multiplexing. The base station(s) transmits a configuration to the repeater device for transmission of a downlink and reception of an uplink on the third link between the repeater device and the two or more user devices using the first beam.

The invention belongs to the field of gas detection and measurement, and discloses a multi-component gas detection system and method based on vmd self-adaptive frequency division, the system innovatively combines a frequency division multiplexing technology and a variational mode decomposition (VMD) algorithm, and realizes high-precision detection of multi-component gas. A digital signal carrying multi-component gas concentration information is obtained through a data acquisition card, a complex signal is subjected to self-adaptive decomposition by using a VMD algorithm, and a characteristic absorption signal of the multi-component gas is effectively separated. According to the method, the modal parameters of the VMD are iteratively optimized by adopting a k optimization algorithm, the accurate distinguishing of overlapped absorption spectral lines is realized by increasing the modal density, the analysis capability of a dense spectrum is improved, and the interference of interference noise and electronic noise is remarkably reduced. Second harmonic signals are extracted through software demodulation, and gas concentration information is inverted according to the second harmonic signals. Experiments show that compared with a traditional frequency division multiplexing scheme, the method has the advantages that the detection precision is improved, and the method is particularly suitable for synchronous detection of multi-component trace gas under a complex background.

Aspects of the present disclosure are directed to techniques to ensure that other UEs that may have reserved resources within the same resource selection window are allowed (or at least not prevented) from gaining access to the shared channel during their respective reserved resource period for both Out-of-COT and in-COT preemption window period.

The invention relates to the technical field of low-orbit satellite communication, and discloses a multi-channel simultaneous calibration method, system and device based on FDM (frequency division multiplexing) and a medium, which realize high-precision synchronous estimation and compensation of multi-channel amplitude, phase and delay parameters through a frequency division multiplexing and parallel processing mechanism based on FDM. The problem of channel inconsistency in coaxial cable FDM transmission is effectively solved, the calibration efficiency and the system transmission performance are remarkably improved on the premise that the high precision that the amplitude error is not larger than 0.2 dB, the phase error is not larger than 2 degrees and the delay error is lower than 0.01 sampling point is ensured, meanwhile, the calculation complexity and the sequence overhead are reduced, and the system performance is improved. The method is suitable for calibration requirements of high-frequency-width multi-channel systems such as a large phased array of a low-orbit satellite and the like.

Various aspects of the present disclosure generally relate to communication. In some aspects, a first device may determine a frequency division multiplexing (FDM) configuration for a set of component carriers associated with a cable frequency spectrum, wherein each component carrier in the set of component carriers is associated with a number of multiple input multiple output (MIMO) layers. The first device may communicate with a second device over a cable infrastructure according to the FDM configuration for the set of component carriers. Numerous other aspects are described.

The invention discloses a space-time-frequency resource multiplexing transmission opportunity sharing method for coordinating multiple satellite flash access points, and belongs to the technical field of high-density deployment of multiple satellite flashes. The method comprises the following steps: acquiring channel state information (CSI) and beam direction parameters of the STA in a specified micro time slot; constructing a dynamic coordination group mechanism to obtain a dynamic coordination group member list and optimized beam forming parameters; constructing a fusion framework of frequency division multiplexing and space division multiplexing; and adopting adaptive resource scheduling to obtain an AP-STA link scheduling scheme and the transmission rate of each link. Through the dynamic coordination group construction and beam forming technology, dynamic compatible group division among a plurality of star flash access points is realized, the same frequency interference is reduced by more than 30%, the number of concurrent connections is increased, and the SINR of a transmission link in a high-density scene is ensured to always meet the service requirements; meanwhile, combined scheduling of TDD time-division dual-time slots and spectrum resources is realized through an enhanced resource allocation frame, and multi-AP concurrent transmission in a single time slot is realized in a single-Hertz frequency band.

The invention provides a multi-element physical quantity sensing node device for a communication-inductance fusion submarine optical cable, and relates to the technical field of ocean communication and sensing, and the device comprises a communication signal input module which is used for receiving a communication signal of a submarine optical cable; the multi-element sensing module comprises a temperature sensor, a speed sensor and an acceleration sensor and is used for collecting sensing signals of the seabed environment, and the sensing signals comprise temperature data, speed data and acceleration data; the multi-dimensional signal modulation module consists of a phase modulator, an amplitude modulator and a frequency modulator and is used for receiving and modulating the sensing signal; the optical fiber coupler is used for performing frequency division multiplexing coupling on the communication signal and the sensing signal subjected to multi-dimensional modulation; and the optical amplifier is used for performing power amplification on the coupled fusion signal. The temperature, the speed and the acceleration are monitored at the same time, the situation that the communication capacity is reduced due to the fact that sensing signal transmission occupies a communication channel is avoided, and the modulation dimension is extensible.

The invention relates to the technical field of medical surgical navigation, and discloses an intraoperative instrument position real-time visual tracking system which comprises a preoperative three-dimensional reconstruction unit, an intraoperative positioning unit, a coordinate matching unit, an error compensation unit and a visual display unit which are in bidirectional communication through a data bus. According to the intraoperative instrument position real-time visual tracking system and method, the problem of electromagnetic interference is solved through a magnetoelectric fusion positioning engine and a dynamic magnetic field calibration module, and the magnetoelectric fusion positioning engine receives a gradient magnetic field signal generated by an electromagnet array and an electric field signal of a body surface reference electrode; the dynamic magnetic field calibration module is combined with the frequency division multiplexing technology to separate double-frequency signals, then space-time registration is carried out through the magnetoelectric conversion matrix, alignment of a magnetic sensor and a magnetic beacon coordinate system is not needed, magnetic field distortion caused by a metal instrument can be counteracted, angle calculation errors can be reduced through bimodal signal complementation even if the posture of the instrument changes, and the precision of the instrument is improved. And positioning accuracy is improved.

The application provides a phase-sensitive optical time domain reflectometer, a measurement method and a readable storage medium, wherein a signal generation circuit of the phase-sensitive optical time domain reflectometer is configured to generate a radio frequency signal to drive an optical intensity modulator to modulate probe light, so that two groups of frequency division multiplexing sequences with differences can be used to synchronously detect a sensing optical fiber to be measured, a differential unfolding algorithm is combined to accurately solve a phase change amount in adjacent sampling intervals, and then demodulation results corresponding to different frequency parts are respectively unfolded to obtain unfolded phase results, so that the problem of large strain phase folding is solved and a large strain range is recovered, and further, the unfolded phase results are rearranged and combined in time sequence through time sequence interleaving processing of the unfolded phase results, so that a high sampling rate and a distortion-free reconstruction result are reconstructed, and therefore, the application can realize accurate measurement of high frequency response and large strain range dynamic strain.

The invention provides a fractional order digital-analog hybrid forward transmission method and system, and the method comprises the steps: a signal processing and transmitting step: at a transmitting end, splitting a wireless signal into two parts, carrying out different-order digital-analog hybrid modulation on the two parts, and then carrying out frequency division multiplexing to realize fractional-multiple bandwidth expansion; and a signal receiving and processing step: at a receiving end, demodulating the two parts of different-order digital-analog hybrid radio-over-fiber signals, and recovering a wireless signal. According to the invention, by adopting fractional order digital-analog hybrid modulation, the problem that general digital-analog hybrid modulation can only realize integral multiple bandwidth expansion is solved, and the effect of improving the flexibility of a forward transmission system is achieved.

The present application relates to the technical field of communications. Disclosed are a communication method and apparatus, and a network device and a terminal device. The method comprises: a network device sending a wake-up signal at a frequency-domain location or a time-domain location, wherein the frequency-domain location or the time-domain location corresponds to a first terminal device identifier portion; and correspondingly, a terminal device monitoring the wake-up signal at the frequency-domain location or the time-domain location. It can be seen that since a frequency-domain location or a time-domain location can correspond to a first terminal device identifier portion, and different frequency-domain locations or different time-domain locations can correspond to different first terminal device identifier portions, the network device can, at different frequency-domain locations or different time-domain locations, wake up terminal devices having different terminal device identifiers. Correspondingly, terminal devices having different identifiers can monitor respective wake-up signals at different frequency-domain locations or different time-domain locations, thereby implementing frequency division multiplexing of a plurality of wake-up signals.

The invention discloses a TFDM-PON system correction method and device, and the method comprises the steps: an OLT receives a dual-polarization signal transmitted by an ONU based on time division multiplexing or time-frequency division multiplexing, the dual-polarization signal comprises a target signal sequence corresponding to X / Y polarization, and the target signal sequence is an IQ period complex signal, and an I path and a Q path of the IQ period complex signal are single-tone signals of a first frequency and a second frequency respectively; target parameters including target transmitting and receiving end frequency deviation, IQ time delays of a target transmitting end and a target receiving end and target power deviation among ONUs are calculated based on Fourier transform and frequency domain symmetry of the dual-polarization signals, so that the ONUs carry out frequency, time delay and power correction according to the target parameters. Subcarrier crosstalk caused by frequency offset in TDM uplink burst transmission, mirror image crosstalk caused by IQ imbalance and performance degradation caused by power imbalance between subcarriers are eliminated, the bit error rate is reduced, and the system robustness is improved.

The application discloses an anti-interference pulse laser frequency division multiplexing optical coding wireless communication system and method, provides an optical wireless communication system based on pulse laser, and realizes an anti-interference pulse laser frequency division multiplexing optical coding communication method. Relying on the convergence effect of the light collector, a stable and anti-interference system receiving end is realized, the anti-interference capability of the whole system is realized through a pulse laser source and a multi-channel light splitting module, the utilization rate of the spectrum in the system communication process is improved, and the pulse laser transmission of frequency division multiplexing is realized.

The invention relates to a communication method, a terminal, network equipment, a system and a storage medium. The method comprises: sending a first configuration parameter to a terminal, the first configuration parameter being used for determining first frequency information of an uplink communication signal, and receiving the uplink communication signal sent by the terminal according to the first frequency information, the uplink communication signal being carried by a back reflection signal corresponding to a CW signal. Therefore, the first frequency information of the uplink communication signal sent by the terminal is determined according to the first configuration parameter, and the uplink communication signal is transmitted based on the first frequency information, so that frequency division multiplexing of the Internet of Things equipment for backscattering based on the CW signal in the communication transmission process is realized.

The embodiment of the application provides a kind of unmanned plane high-precision positioning and tracking method and device based on AFDM waveform, through echo signal and local linear frequency modulation reference signal analog domain dechirp mixing is low-pass filtered and baseband sampling to obtain baseband difference frequency data write signal processing buffer area, combined with affine frequency division multiplexing modulation parameter driven discrete affine Fourier transform time delay Doppler domain two-dimensional spectrum peak search and interpolation refinement to obtain target distance estimate and Doppler frequency shift estimate encapsulation as positioning and tracking parameter group, through flight control unit according to preset trajectory constraint condition executes position solution to obtain current positioning coordinate joint tracking filter state update to obtain target tracking trajectory data output to ground monitoring terminal, effectively solve the deficiency of traditional technology in analog domain difference frequency preprocessing, time delay Doppler domain high-precision parameter estimation and flight control linkage tracking filtering output etc., provide technical support for unmanned plane high-precision positioning and accurate tracking.

A method includes: a network device sends a first synchronization signal / physical broadcast channel block on a first resource in resources corresponding to at least two candidate synchronization signal / physical broadcast channel blocks (SSBs), where the at least two candidate SSBs are respectively located at least two frequencies in a single serving cell or a single bandwidth part in a frequency division multiplexing manner; and the network device sends resource information of the first SSB.

In the communication method, a first device generates a first signal, the first signal comprises M1 elements, M1 is determined based on M2 and a first parameter, M1 is a positive integer greater than M2, and M2 is a positive integer. The first device precodes the first signal to obtain a second signal, wherein the second signal comprises M1 elements. And the first device sending a third signal on a first frequency domain resource, the first frequency domain resource including M2 frequency domain units, the third signal being generated based on M2 elements selected from M1 elements included in the second signal. Visibly, according to the method, the time domain FTN is realized by transmitting the information amount of the M1 elements included in the first signal on the M2 frequency domain units. According to the method, the symbol duration is not changed, when the method is applied to a scene of multi-user frequency division multiplexing or MU-MIMO transmission, the symbol durations adopted by multiple users are the same, the CPs are aligned, and inter-user interference caused by different symbol durations of the multiple users is avoided.