38 results about "Constant envelope" patented technology

The invention provides a communication method and a related device. In the method, after a baseband chip obtains a first symbol sequence to be transmitted, modulation is carried out based on a third symbol sequence containing extended symbols and symbols to be transmitted in the first symbol sequence, and after (N + M) modulation symbols are obtained, the (N + M) modulation symbols are mapped to RE to obtain a second symbol sequence. The second symbol sequence is continuous in phase, and the difference between the head phase and the tail phase is an integral multiple of 2 pi. The CP of the OFDM baseband signal generated by the second symbol sequence and the signal body are continuous in phase, and phase jump does not exist. A phase or frequency modulation mode, such as CPM or LFM, is further adopted for modulation, a waveform with a continuous phase and a constant amplitude can be obtained, and therefore a constant envelope waveform can be obtained. When the method is applied to communication equipment, such as IoT (Internet of Things) equipment, the structure of a transmitter can be simplified, the transmission power consumption is reduced, and the standby life is prolonged.

The invention belongs to the technical field of communication and sensing integration, and particularly relates to a terahertz communication and sensing integration method based on FM-SC-OFDM waveforms. According to the method, the DFT spread spectrum technology is utilized, the PAPR of an FM-OFDM instantaneous frequency OFDM sequence is reduced, the instantaneous frequency / phase sequence property is optimized, the phase demodulation error is relieved, and finally, the inherent communication and sensing performance is further enhanced under the condition that the waveform constant envelope and the frequency offset resistance property are inherited in a lossless mode, so that a complete ISAC architecture is provided. The FM-SC-OFDM is proposed by taking SC-OFDM as an instantaneous frequency sequence, the phase demodulation error effect faced by the FM-OFDM is relieved, the BER performance and the perception precision performance are broken through, and a novel integrated waveform which can avoid the power amplifier nonlinear effect and has strong frequency offset robustness is provided for a THz ISAC system.

The application relates to a time-frequency synchronization method for a high-speed moving platform, which comprises the following steps: at a transmitting end, a preamble sequence is obtained by performing mathematical transformation on a constant envelope zero autocorrelation sequence through a weight factor, conjugate processing and symmetric transformation; at a receiving end, the received signal is processed step by step, (1) the continuously received signal is subjected to mathematical operation with a local weight factor sequence to obtain a timing metric sequence, the maximum value is selected and the corresponding position is recorded to complete symbol timing synchronization; (2) a received pilot sequence is extracted, fractional carrier frequency offset estimation and compensation are carried out, and integer carrier frequency offset estimation and compensation are carried out; (3) the received pilot sequence is extracted, and common phase offset estimation and compensation are carried out by using a local preamble sequence. The application realizes high-accuracy timing acquisition and high-precision frequency offset correction capability under the condition of low signal-to-noise ratio, high dynamic Doppler frequency shift and non-matching of transmitting and receiving end crystal oscillators.

The acoustic signal detection method comprises the following steps: generating a transmitting signal of a constant envelope system according to a signal modulation and time-frequency analysis principle; processing the received underwater acoustic signal data on the basis of beam forming and matched filtering theories to generate a matched related azimuth history graph; executing open peak retrieval in the matched related azimuth history graph, and extracting a peak point set corresponding to a suspected target; according to the azimuth and the time position of the peak point, extracting a time-frequency characteristic pattern of each peak point from the original data; and processing the time-frequency feature map by using a pre-trained dual-channel neural network model to determine a final detection result. The method can improve the accuracy of echo signal detection.

Provided is a discrete Fourier transform (DFT)-spread orthogonal frequency division multiplexing (OFDM) transmission method and transmitter including a phase shifter configured to generate a pi / 2-binary phase shift keying (BPSK) symbol vector by phase-shifting a vector including M BPSK symbols, a DFT spreader configured to generate a DFT-spread pi / 2-BPSK symbol vector by spreading the pi / 2-BPSK symbol vector using an M-point DFT matrix, a circular extender configured to generate a circularly extended pi / 2-BPSK symbol vector by periodically extending the DFT-spread pi / 2-BPSK symbol vector, a frequency domain spectrum shaper configured to generate a frequency domain spectrum shaped pi / 2-BPSK symbol vector by multiplying each element of the circularly extended pi / 2-BPSK symbol vector by each element of a first shaping vector, and a subcarrier allocator configured to allocate the frequency domain spectrum shaped pi / 2-BPSK symbol vector to subcarriers in an allocated frequency range.

The present invention relates to the field of communication technology, and discloses an anti-interference power supply circuit based on constant envelope tracking technology, including: an operational amplifier, a switching switch, a filter circuit, a sampling resistor, a comparator and a push-pull circuit; the output end of the operational amplifier is connected to the first end of the switching switch and the first input end of the comparator; the second end of the switching switch is respectively connected to the input end of the filter circuit or the first end of the sampling resistor; the second input end of the comparator is respectively connected to the output end of the filter circuit, the second end of the sampling resistor and the power input end of the radio frequency power amplifier, and the output end of the comparator is connected to the input end of the push-pull circuit; the output end of the push-pull circuit is connected to the power input end of the radio frequency power amplifier through an inductor. The present invention can effectively track the envelope input signal in a non-interference frequency band, improve work efficiency and reduce power consumption; for the interference frequency band, it can enter the filter path, generate a huge change signal filter for the envelope signal, and reduce interference to the current working frequency band.

To improve the perception performance of an integrated communication and perception system using offset constant envelope OFDM (OFDM), this paper proposes a distance and velocity estimation method based on offset constant envelope OFDM. This method uses an offset constant envelope OFDM signal as the transmission signal for the integrated communication and perception system and uses a 2D-FFT algorithm based on conjugate multiplication to estimate target range and velocity. This method effectively reduces the impact of a non-flat signal spectrum and achieves superior distance and velocity estimation performance.

The invention discloses an interference technical scheme based on GMSK signal characteristics, and relates to the technical field of wireless communication interference. According to the scheme, firstly, differential coding is carried out on a binary random code to obtain a relative code, then a GMSK baseband signal is generated through GMSK modulation, and carrier modulation is carried out; the method is characterized in that a self-adaptive phase modulation forwarding interference signal generation mechanism is designed based on the characteristics of constant envelope and continuous phase change of GMSK signals, and interference signals are generated by constructing a time-varying amplitude disturbance model, a dynamic time delay model and an interference phase model; and finally, superposing the interference signal with the GMSK signal passing through the Gaussian white noise channel to realize effective interference on the GMSK communication signal. According to the method, the GMSK signal characteristics are fully utilized, the interference pertinence is high, the interference effect on a GMSK communication system can be remarkably improved, the interference parameters can be flexibly adjusted according to actual scenes, and the applicability is wide.

The application discloses a CE-OFDM communication and sensing integrated anti-nonlinear DOA estimation method, belongs to the field of communication sensing, and comprises the following steps: generating a 0dB peak-to-average power ratio CE-OFDM signal at a transmitting end, so that the CE-OFDM signal can drive a power amplifier to work in a saturation region, thereby avoiding nonlinear distortion while ensuring high power amplifier efficiency. A uniform linear array is used to receive signals at a receiving end, the signals are decomposed into a frequency domain through discrete Fourier transform, narrowband MVDR spatial spectra are independently calculated for each subcarrier frequency point, wideband spatial spectra are obtained through non-coherent fusion, and finally high-precision DOA estimation is realized through peak value searching. The application fundamentally suppresses power amplifier nonlinear distortion by using the constant envelope characteristic of CE-OFDM, avoids eigenvalue decomposition and source number estimation by combining the IMVDR algorithm, supports frequency point level parallel calculation, and realizes high-precision and low-complexity DOA estimation while ensuring communication reliability.

A method and apparatus for wireless communication are provided. The method comprises the following steps: a first device sends a first signal to a second device; wherein the first signal is transmitted by using a first waveform, and the first waveform is at least one of the following: a constant envelope OFDM waveform based on a DFT-s-OFDM waveform; carrying out enhanced DFT-s-OFDM (Discrete Fourier Transform- A waveform is generated based on a first waveform framework that supports the generation of a plurality of waveforms.

A transmitter may obtain a plurality of symbols encoding data to transmit wirelessly. A transmitter may transform the plurality of symbols using a unitary braid division multiplexing transform to produce a plurality of transformed symbols. A transmitter may scale the plurality of transformed symbols produce a plurality of scaled symbols. A transmitter may modulate a carrier signal by the plurality of scaled symbols to produce a constant envelope signal. A transmitter may transmit the modulated signal.

A transmitter having a transmitter signal processor (TSP) is provided for processing a plurality of signals for transmission to produce an output signal of constant envelope. The TSP has a sum input c

The invention belongs to the technical field of mobile communication, and relates to a method for reducing the PAPR (peak-to-average power ratio) of an OFDM (orthogonal frequency division multiplexing) system based on Riemannian manifold optimization and a gradient descent method, which comprises the following steps of: according to requirements, establishing a channel which not only can suppress the PAPR (peak-to-average power ratio) of a transmitted signal, but also can ensure that a legal user channel can receive information as correctly as possible, and can reduce the PAPR (peak-to-average power ratio); the method comprises the following steps of: firstly, solving a mathematical model in which an eavesdropper user does not receive information as much as possible by using a Riemannian manifold optimization and gradient descent method to obtain a constant envelope pre-coding sending vector of which the modulus length of all elements is 1, then, solving the mathematical model by using a Riemannian manifold optimization method and a gradient descent method to obtain a constant envelope pre-coding sending vector; the method not only suppresses the PAPR of the OFDM signal through the constant envelope precoding technology, but also ensures good BER performance.

A satellite navigation signal generation apparatus may comprise: a signal generator generating a first satellite navigation signal, a second satellite navigation signal, and a third satellite navigation signal; a modulator modulating signals with same phases, which are generated by configuring an amplitude and a phase of an in-phase component and an amplitude and a phase of a quadrature-phase component based on a relationship of absolute sample values corresponding respectively to variable instantaneous powers of the first to third satellite navigation signals, into different chip pulse waveforms; and a multiplexer performing constant envelope multiplexing on the satellite navigation signals modulated by the modulator, wherein the modulator performs chip pulse modulation in which the absolute sample value of the first satellite navigation signal and the absolute sample value of the second satellite navigation signal have a first value A and a second value B with a frequency of 0.5, respectively.

An apparatus, comprising: means for decomposing an input signal into a plurality of substantially constant envelope components; a quadrature path for each of the substantially constant envelope components; means for performing discrete phase control in each of the quadrature paths; an amplifier in each of the quadrature paths; and means for combining the output signals from the quadrature paths.

Systems, methods, and computer-readable storage media for generating and utilizing radar signals with embedded data are disclosed. Data is encoded onto a CPM waveform, which is then combined with a base radar waveform to produce a radar-embedded communication (REC) waveform. Both the CPM waveform and the base radar waveform may have a continuous phase and constant envelope, resulting in the REC waveform having a continuous phase and constant envelope. The changing (e.g., on a pulse-to-pulse basis) nature of the REC waveform causes RSM of clutter which may result in residual clutter after clutter cancellation, decreasing target detection performance of the radar system. In an aspect, various parameters may be utilized to dynamically adjust the performance of the radar system for a particular operating scenario, such as to enhance radar signal processing or enhance data communication capabilities.

This application provides a data transmission method, apparatus, electronic device, computer-readable storage medium, and computer program product. The method includes: receiving downlink control information (DCI) transmitted by a network device and carried on a physical downlink control channel (PDCCH), wherein the DCI is used to indicate the transmission mode and the resource location of downlink data of the first terminal device; receiving the downlink data based on the DCI; wherein the transmission mode includes a constant envelope transmission mode, so that downlink data transmission can adopt a constant envelope transmission mode in this process, thereby improving downlink communication performance.

A transmitter may obtain a plurality of symbols encoding data to transmit wirelessly. A transmitter may transform the plurality of symbols using a unitary braid division multiplexing transform to produce a plurality of transformed symbols. A transmitter may scale the plurality of transformed symbols produce a plurality of scaled symbols. A transmitter may modulate a carrier signal by the plurality of scaled symbols to produce a constant envelope signal. A transmitter may transmit the modulated signal.

A method by which a first device generates a multiplexing signal in a communication system, according to an embodiment, comprises the steps of: identifying first to third transmission powers, which are the respective transmission powers of first to third signals to be multiplexed and transmitted; generating an intermodulation component of the first to third signals; multiplying the first to third signals and the intermodulation component on the basis of the first to third transmission powers; and generating a multiplexing signal having a constant envelope by quadrature-phase-combining, with a linear combination result of the multiplied first and second signals, a linear combination result of the multiplied third signal and the multiplied intermodulation component, wherein the third transmission power can be greater than or equal to the second transmission power, and the second transmission power can be greater than or equal to the first transmission power.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a network node may obtain a demodulation reference signal (DMRS) having a constant envelope in a time domain. The network node may generate a communication signal based at least in part on multiplexing the DMRS with a plurality of data resource elements. Numerous other aspects are described.

The invention discloses a non-orthogonal multiple access system communication method based on index modulation and constant envelope modulation. According to the method, the number of activated subcarriers is selected at a sending end according to the bit number of data needing to be transmitted by users, index modulation is carried out on the subcarriers of all the users, and OFDM signals are embedded into phases of constant envelope signals through phase modulation after signals of all the users are superposed; and at a receiving end, firstly eliminating the cyclic prefix of the received signal, then carrying out channel estimation and equalization processing through pilot frequency, then deducing channel frequency response corresponding to each symbol by adopting a cubic spline interpolation method, and finally demodulating the user signal. According to the method, the robustness of the non-orthogonal multiple access system can be enhanced, and the low bit error rate can still be kept when the power difference between the users is not significant. The peak-to-average power ratio of the non-orthogonal multiple access system is greatly reduced, and the power consumption cost is reduced. And the anti-interference capability of the communication system on the frequency selective fading under the Rayleigh channel is obviously enhanced.

A transmitter may obtain a plurality of symbols encoding data to transmit wirelessly. A transmitter may transform the plurality of symbols using a unitary braid division multiplexing transform to produce a plurality of transformed symbols. A transmitter may scale the plurality of transformed symbols produce a plurality of scaled symbols. A transmitter may modulate a carrier signal by the plurality of scaled symbols to produce a constant envelope signal. A transmitter may transmit the modulated signal.

A transmitter signal processor (TSP) for use in combining, amplified, and transmitting multiple independent signals while maintaining an approximately constant envelope, the processor comprising a feedback network whereby an error signal between the sum of the signals and the output of a constant envelope process in the TSP is calculated, and for each input signal, this error signal is correlated with the input signal to model the effect of errors in the receiver, and a feedback signal is generated by multiplying each error signal by its corresponding input signal, summing the result for each such input signal, and then subtracting the feedback signal from the sum input. The constant envelope process may be all digital, such as a normalization process, and / or may comprise part of an analog transmit chain, such as an amplifier, frequency converter, or filter.

The invention discloses a short-wave power amplification device capable of dynamically adjusting a power supply, which comprises a power supply adjusting module, a radio-frequency power amplification module and a monitoring module, and works in a mode 1 that a direct-current power supply is directly supplied to the radio-frequency power amplification module and is suitable for amplifying constant envelope signals in the fields of radar and communication countermeasure; the radio frequency power amplifier can work in a nearly saturated state to obtain relatively high efficiency; mode 2, a dynamically changing power supply voltage is generated by tracking a control signal waveform, the method is suitable for amplification of amplitude modulation communication type signals with a certain peak-to-average power ratio, and it is ensured that the radio frequency power amplifier has high efficiency under any instantaneous output amplitude through cooperation with the envelope changing power supply voltage; and the mode 3 adopts a sensor for detecting the load state of the power tube to know whether the power amplifier works in a full range, and adjusts the power supply voltage to deal with the efficiency deterioration caused by the underload of the power tube under the severe load condition. By means of the mode, the efficiency of the radio frequency power amplifier under different application signal waveforms and severe load conditions is improved.

A multiple-access constant envelope orthogonal frequency division multiplexing (OFDM) method and wireless communication system are disclosed. The method and system include a transmitter that sequentially processes the information and / or information bits of each user by digital modulation, symmetric mapping, frequency-domain to time-domain transformation, phase modulation, time-domain to frequency-domain transformation, frequency domain offsetting, frequency-domain to time-domain transformation, and cyclic prefix addition to obtain a baseband transmission signal, which is then sent to one or more receivers through a channel, and a receiver that sequentially processes the received signal by time-domain to frequency-domain transformation, user signal separation, equalization offsetting, frequency-domain to time-domain transformation, phase demodulation, another time-domain to frequency-domain transformation, demapping, and decision-making to obtain detection results for the corresponding user. The present method and system reduce data overlap between users and decrease inter-user interference by applying different phase rotations and / or different offsets to different users, thereby enhancing system performance.

The invention belongs to the field of wireless communication, and particularly discloses a time synchronization method and system based on a constant envelope zero autocorrelation sequence in OFDM communication and a storage medium, and the method comprises the following steps: at a sending end, inserting a synchronization lead code at the front end of each OFDM frame, the synchronization lead code is constructed by adopting the constant envelope zero autocorrelation sequence with excellent correlation characteristics, and the synchronization lead code is constructed by adopting the constant envelope zero autocorrelation sequence with excellent correlation characteristics; sequence weighting is introduced into a lead code, and a symmetric sequence is additionally added to counteract a weighting effect; a fast Fourier transform starting point estimation algorithm is designed by fully utilizing the structural characteristics of a synchronous lead code, so that a timing metric curve only presents a sharp main peak and has no obvious side lobe. The time synchronization method is designed by using the constructed lead code and the corresponding starting point estimation algorithm, the time synchronization success rate can still be further improved under the conditions that the signal-to-noise ratio is low and a receiving end weighting sequence does not need to be strictly aligned with a sending end, and the method can realize higher synchronization precision through simulation experiment verification.

The present invention belongs to the field of radar signal processing technology, and specifically relates to a method for designing a synaesthesia integrated signal waveform based on a continuous frequency modulation signal. The synaesthesia integrated signal waveform of the present invention has the following characteristics: a pulse duration period of the integrated signal is T, and according to the number of bit symbols modulated in each pulse duration period, it is divided into N equal parts in the time domain, and the duration of the sub-pulses of each segment is equal. The frequency modulation slope of each segmented signal is determined by the modulated bit information. The end frequency of each segmented signal is the initial frequency of the next segmented signal, and the frequency of the entire integrated signal changes nonlinearly, but within each segmented signal, the signal frequency changes linearly. The integrated signal has a constant envelope and is phase continuous. In addition, through the designed integrated signal structure characteristics, the matched filter demodulation method is improved, and by limiting the frequency range, the influence of the system background noise on the demodulation is reduced, thereby improving the signal-to-noise ratio.

Aspects of the present disclosure relate to a method for constant envelope modulation. The method includes processing a first time-domain in-phase and quadrature (I / Q) composite signal, processing a second time-domain I / Q composite signal, combining the first time-domain I / Q composite signal and the second time-domain I / Q composite signal into a doublet pair signal, and forming a sum of the first waveform and the second waveform to obtain a constant envelope. The first time-domain I / Q composite signal is described by a first waveform and contains an intended high order modulation with a high peak-to-average ratio (PAR) and an envelope modulation as a function of time, and the second time-domain I / Q composite signal is described by a second waveform with an envelope change over time and a phase change over time of the second waveform defined as a function of the first waveform.

The invention relates to a target echo detection method for an external radiation source radar of a non-constant envelope waveform system, and the method comprises the steps: carrying out the equal-length segmentation of a received baseband signal containing a target echo, and obtaining K segments of sub-baseband signals; performing pulse compression processing on each segment of sub-baseband signal segment by segment to obtain K pulse compression signals; performing traversal processing on the K pulse compression signals, performing unit vector extraction operation on the pulse compression signals during traversal processing, and performing fast Fourier transform on extracted unit vectors to obtain distance and Doppler two-dimensional output; and performing constant false alarm detection on the distance and Doppler two-dimensional output to obtain target distance and Doppler information. The target echo signal detection success rate can be effectively improved.

A global navigation satellite system (GNSS) is disclosed comprising a transmitter. The transmitter is configured to: receive a plurality of frequencies; determine a minimum frequency from the plurality of frequencies; determine a maximum frequency from the plurality of frequencies; determine a carrier from the minimum frequency and the maximum frequency; determine a set of subcarriers from the carrier and the plurality of frequencies; identify optimal radius of desired phase points to select optimal subcarriers from the set of subcarriers; determine inter-modulation terms with a minimal energy based on the optimal subcarriers; and generate multi-carrier constant envelope waveforms based on the inter-modulation terms.