26 results about "Sampling frequency offset" patented technology

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 application discloses a dynamic SFO compensation method and system for an unmanned aerial vehicle based on combination of a frequency domain and a time domain, and the method comprises the following steps: acquiring a radio frequency signal by using the unmanned aerial vehicle, and performing frequency down conversion on the radio frequency signal to obtain a baseband signal; performing synchronous processing on the baseband signal to obtain a synchronization parameter; extracting a pilot sequence from the baseband signal based on the synchronization parameter, and calculating a sampling frequency offset based on the pilot sequence; calculating a resampling ratio based on the sampling frequency offset; and performing resampling on the baseband signal according to the resampling ratio to obtain a baseband signal after SFO compensation. The application can realize accurate SFO compensation and reduce the communication performance decline of the unmanned aerial vehicle caused by the SFO.

Embodiments of the present disclosure provide a solution for ambient IoT. In a solution, a first device receives, from a second device, scheduling control information indicating at least one of: a plurality of time domain transmission resources or information associated with a transmission time duration. The first device determines a starting time of a time domain transmission resource based on an index of the time domain transmission resource, the transmission time duration and a first value, wherein the first value is received from the second device or determined based on at least one of a sample frequency offset (SFO) or a maximum number of time domain transmission resources. The first device transmits, to the second device, a data transmission at the starting time.

The application provides a pilot multi-step differential-based orthogonal frequency division multiplexing sampling frequency offset estimation method. The method comprises: selecting two time domain symbols containing equally spaced pilot subcarriers in the allocated resource block, and removing the cyclic prefix of the received signals of the two time domain symbols respectively; based on the known pilot symbols, demodulating the pilot subcarrier sequences on the two time domain symbols to obtain a first pilot sequence and a second pilot sequence; performing multi-step differential correlation on the pilot index dimension of the complex exponential sequence, normalizing the correlation sums under each step length according to the effective item number to obtain a corresponding correlation quantity sequence; performing vector summation on the correlation quantity sequence and performing an angle operation once, and calculating an intermediate quantity based on the maximum differential step length; and determining the sampling frequency offset estimation value of the receiver relative to the transmitter according to the intermediate quantity. The application can reduce the calculation complexity, avoid phase folding processing and facilitate fixed-point implementation.

The invention provides a channel phase extraction method, system and device based on a preamble symbol and a pilot symbol, and a storage medium, and relates to the technical field of wireless communication of the mobile Internet of Things. The method comprises the following steps: a receiver on a gateway receives a LoRa signal sent by a transmitter of a transmitting end node; the receiver determines carrier frequency offset and window time offset according to a lead code symbol and a start frame separator in the received LoRa signal; performing compensation on the received LoRa signal to eliminate phase offset caused by carrier frequency offset and window time offset; determining a sampling frequency offset according to a spectrum peak interval between adjacent lead code symbols in the compensated signal; and performing compensation on the compensated signal to eliminate phase offset caused by sampling frequency offset so as to obtain a re-compensated signal, and determining the channel phase of the channel of the LoRa signal according to the spectrum peak phase of a plurality of pilot symbols with known coding values in the re-compensated signal.

Techniques for collision resolution in Ambient Internet of Things (A-IoT) communications are described. A reader device obtains sampling frequency offset (SFO) indications for received random access messages and generates collision indicators based on the SFOs. The reader device may then allocate resources for subsequent transmissions using various strategies, such as omitting allocations for colliding devices, providing multiple allocations, or matching allocations to specific SFO values. A-IoT devices receive these allocations along with collision indicators and adjust their subsequent transmissions accordingly, either by selecting from multiple resources or generating new access sequences. This approach enables efficient collision handling while accommodating the limitations of low-complexity A-IoT devices.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, an ambient Internet-of-Things (A-IoT) device may receive, from a reader device, a first message, wherein the first message includes a type indication associated with whether the first message is associated with a clock adjustment. The A-IoT device may selectively transmit, to the reader device, a second message based on whether the first message is associated with the clock adjustment. Numerous other aspects are described.

The invention relates to a sequence determination method, communication equipment, a storage medium and a program product, and belongs to the technical field of communication. The method comprises the following steps: the terminal equipment receives indication information; and determining at least one of a first sequence and a second sequence according to the indication information, the first sequence being used for determining at least one of the following: determining an initial position of a first channel, an initial sampling frequency offset (SFO) estimation of the first channel, and a channel estimation of the first channel, and the second sequence being used for at least one of the SFO estimation of the first channel and the channel estimation. According to the method disclosed by the invention, the first sequence and / or the second sequence are indicated through the indication information, so that the receiving end can timely and correctly decode the signal containing the first sequence and / or the second sequence. Particularly, the first sequence and the second sequence are indicated at the same time through the same indication information, so that joint indication of the first sequence and the second sequence is achieved, and indication overhead is reduced.

The invention provides a three-dimensional joint parameter estimation method based on Wi-Fi (Wireless Fidelity) beam forming feedback information (BFI). The three-dimensional joint parameter estimation method based on the Wi-Fi beam forming feedback information (BFI) is characterized in that the three-dimensional joint parameter estimation method based on the Wi-Fi beam forming feedback information (BFI) is provided; the method comprises the following steps: firstly, acquiring BFI of a direct path and a target reflection path between transceivers; secondly, constructing the BFI into a three-dimensional matrix about three dimensions of an antenna, a subcarrier and a data packet, performing smooth decoherence processing on the matrix, and calculating a covariance matrix of the smoothed matrix; secondly, performing characteristic decomposition on the covariance matrix to obtain a signal subspace and a noise subspace; and finally, constructing a spectral function, and obtaining an angle of departure (AOD) between a direct path and a target reflection path, relative time delay and relative Doppler frequency shift through spectral peak search. Based on the three parameters obtained through estimation, the method can be applied to scenes such as positioning or breathing monitoring. According to the method, complete channel state information (CSI) does not need to be accessed, the CSI can be directly extracted from the communication process, and the method has natural robustness for carrier frequency offset and sampling frequency offset, and is easier to realize large-scale popularization and application.

Methods, systems, and devices for wireless communications are described. A reader device may communicate with multiple ambient internet of things (A-IoT) devices. The reader device and the ambient devices may implement random access procedures. The reader device may transmit a query message (a msg0) that allocates random access resources for the A-IoT devices to transmit a random access message (a msg1). The query message may indicate sampling frequency offset (SFO) demands associated with the random access resources. The A-IoT devices may select random access resources for transmission of random access messages (e.g., msg1s) based on the SFOs of the A-IoT devices and the indicated SFO demands associated with the random access resources.

The application relates to a sampling frequency offset tracking method and device, computer equipment and a storage medium, which comprises the following steps: performing signal synchronization processing according to the frame structure of a received signal to obtain a frame starting point; performing preliminary sampling frequency offset compensation and channel estimation according to a preamble symbol to obtain a preamble channel estimation result; performing decision feedback channel estimation according to a data symbol to obtain a decision feedback signal estimation result; performing correlation operation on time domain channel response signal sampling points corresponding to effective peak positions to obtain a correlation value; calculating a residual sampling frequency offset according to the correlation value, updating a sampling frequency offset estimation value in combination with a filter coefficient, performing iterative sampling frequency offset compensation according to the updated sampling frequency offset estimation value, and tracking the sampling frequency offset in real time. The application generates channel estimation values based on a preamble symbol and a data symbol respectively, realizes real-time tracking of the sampling frequency offset symbol by symbol, and realizes real-time tracking without a pilot.

The invention provides a demodulator optimization method and system in satellite coherent communication, and the method comprises the steps: S1, carrying out the clock recovery operation of a satellite coherent communication receiving signal through a clock recovery module, and eliminating the sampling frequency offset in the signal; s2, after clock recovery is completed, delay estimation is carried out on an X polarization signal and a Y polarization signal in the received signals, and phase deviation between the two polarization signals is obtained. S3, loading the phase deviation value to an interpolator of a clock recovery module, and performing delay compensation on the X polarization signal and the Y polarization signal through the interpolator; s4, the X polarization signal and the Y polarization signal after delay compensation are input into an equalizer, decoupling of the two polarization signals is completed through the equalizer, the main diameter coefficient of the equalizer is kept at the high bit width, and the bypass coefficient of the equalizer is sequentially reduced in bit width. According to the invention, the polarization delay compensation function is multiplexed to the interpolator of the clock recovery module, so that on the premise of not increasing hardware overhead, the performance loss is effectively eliminated, the error rate of the system is reduced, and the hardware complexity of the equalizer is reduced at the same time.

The application discloses a kind of 5G wireless network health state monitoring method, belong to network optimization technical field, method includes: 5G wireless network data is sampled;Sampling frequency offset model is constructed;Through sampling frequency offset model, the sampling frequency offset value is calculated to determine the influence degree of sampling frequency offset to wireless traffic;Through a variety of analysis methods, extract the abnormal characteristics in 5G wireless network traffic data;According to sampling frequency offset value and abnormal characteristics, the health state of 5G wireless network is comprehensively judged.In the application, the sampling frequency offset value and abnormal characteristics of 5G wireless network data are extracted, and the health state of 5G wireless network is automatically and comprehensively judged according to the sampling frequency offset value and abnormal characteristics, which avoids mechanical one by one investigation, improves the efficiency of troubleshooting, and has high investigation accuracy, which can meet the quality of a large number of signals in peak period.

The invention discloses an unmanned aerial vehicle dynamic SFO compensation method and system based on frequency domain and time domain combination, and the method comprises the steps: obtaining a radio frequency signal through an unmanned aerial vehicle, and carrying out the down-conversion of the radio frequency signal, and obtaining a baseband signal; performing synchronization processing on the baseband signal to obtain a synchronization parameter; extracting a pilot frequency sequence from the baseband signal based on the synchronization parameter, and calculating a sampling frequency offset based on the pilot frequency sequence; calculating a resampling ratio based on the sampling frequency offset; and resampling the baseband signal according to the resampling ratio to obtain the baseband signal after SFO compensation. According to the invention, accurate SFO compensation can be realized, and the reduction of the communication performance of the unmanned aerial vehicle caused by SFO is reduced.

Techniques for collision resolution in Ambient Internet of Things (A-IoT) communications are described. A reader device obtains sampling frequency offset (SFO) indications for received random access messages and generates collision indicators based on the SFOs. The reader device may then allocate resources for subsequent transmissions using various strategies, such as omitting allocations for colliding devices, providing multiple allocations, or matching allocations to specific SFO values. A-IoT devices receive these allocations along with collision indicators and adjust their subsequent transmissions accordingly, either by selecting from multiple resources or generating new access sequences. This approach enables efficient collision handling while accommodating the limitations of low-complexity A-IoT devices.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, an ambient Internet-of-Things (A-IoT) device may receive, from a reader device, a first message, wherein the first message includes a type indication associated with whether the first message is associated with a clock adjustment. The A-IoT device may selectively transmit, to the reader device, a second message based on whether the first message is associated with the clock adjustment. Numerous other aspects are described.

This invention discloses a sampling frequency offset compensation method, apparatus, electronic device, and storage medium, relating to the field of digital signal processing technology. The sampling frequency offset compensation method includes: determining the current data transmission rate and estimated sampling frequency offset of the data to be compensated; determining a step value between compensation samples based on the current data transmission rate and estimated sampling frequency offset; determining the current delay compensation value of the current compensation sample corresponding to the data to be compensated and the next delay compensation value of the next compensation sample based on the step value; determining a register pointer adjustment rule based on the current delay compensation value, the next delay compensation value, and the step value; updating the register pointer according to the pointer adjustment rule, reading the data to be compensated from the register, and performing sampling frequency offset compensation on the data to be compensated based on the current delay compensation value, thereby achieving dual compensation of pointer adjustment and delay difference adjustment, as well as frequency offset compensation under the same clock domain, effectively eliminating sampling frequency offset.

The invention discloses a non-intrusive indoor person existence detection method based on WiFi signal time sequence characteristics, and provides a sensing architecture with a physical layer and a model layer cooperatively integrated aiming at the problem that extremely weak breathing signals are difficult to capture in a multipath environment. Firstly, channel state information is extracted from a WiFi physical layer, a subcarrier dynamic selection strategy based on sensitivity variance is utilized, a feature subset most sensitive to human body micro-actions is screened from a full frequency band, and phase linear compensation is carried out by removing errors such as sampling frequency deviation; and then, constructing a space-time attention LSTM model, carrying out weighted empowerment on a multi-subcarrier path in a space dimension, locking an action feature fragment in a time dimension, and realizing high-precision identification of dynamic walking and static breathing states. According to the invention, the detection accuracy of static personnel in a complex multipath environment reaches 94.5%, and the method has the advantages of extremely high multipath interference resistance and low-cost deployment, and is widely applied to the field of intelligent home environment perception.

An apparatus, method and computer program. The present disclosure relates to an Internet of Things device comprising at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the Internet of Things device at least to perform: receiving a first physical reader-to-device channel transmission comprising first timing information from a reader; receiving, from the reader, a second physical reader-to-device channel transmission comprising second timing information; determining a duration between the first physical reader-to-device channel transmission and the second physical reader-to-device channel transmission based on at least one of the first timing information or the second timing information; and determining a sampling frequency offset between a sampling clock of the device and a sampling clock of the reader based on the duration.

Methods, systems, and devices for wireless communications are described. A reader device may communicate with multiple ambient internet of things (A-IoT) devices. The reader device and the ambient devices may implement random access procedures. The reader device may transmit a query message (a msg0) that allocates random access resources for the A-IoT devices to transmit a random access message (a msg1). The query message may indicate sampling frequency offset (SFO) demands associated with the random access resources. The A-IoT devices may select random access resources for transmission of random access messages (e.g., msg1s) based on the SFOs of the A-IoT devices and the indicated SFO demands associated with the random access resources.

The disclosed process addresses transmission of data from a device to a reader (D2R) in communication systems where devices receive reader-to-device (R2D) transmissions. Methods to determine the appropriate time and frequency resources for the D2R transmission based on the device's sampling frequency offset (SFO) capability is disclosed. The device receives an R2D transmission in a first slot, which specifies two sets of resources for D2R transmission: a first set and a second set. The device compares its SFO capability with a pre-defined threshold. If the device's SFO capability is below the threshold, it uses resources from the first set, which are allocated to time and frequency slots occurring before a specified number of slots (N) from the first slot. Conversely, if the SFO capability exceeds the threshold, the device uses resources from the second set, which are allocated to slots occurring after N slots from the first slot.

In some implementations, a reader receives a first message (e.g., msg1) from an ambient internet of things (A-IoT) device indicating a sequence of bits. The reader generates a second message (e.g., msg2) indicating a tag identifier (ID) including a sequence identifier associated with the sequence of bits and a sampling frequency offset (SFO) identifier associated with the with the first message. The reader transmits the second message to the device, where the tag ID is indicative of a resource allocation for the device to transmit a third message (e.g., msg3) to the reader. The tag ID is 16 bits. The reader and device are communicating in a code division multiplexing (CDM) communication system.

The invention relates to the technical field of information and communication, and particularly provides a sampling frequency offset compensation method, a processor, a system and a storage medium, and the method comprises the steps: obtaining a plurality of OFDM symbols in real time; determining a sampling frequency offset estimation value based on the plurality of pilot frequency subcarriers in each OFDM symbol; normalizing the sampling frequency offset estimation value into a first phase rotation correction value corresponding to a unit OFDM symbol period, and calculating a second phase rotation correction value corresponding to the current symbol period when the mth OFDM symbol period arrives, so as to superpose the second phase rotation correction value into a corresponding equalization phase factor, generating a total phase rotation correction factor for a single subcarrier in m OFDM symbol periods; and performing reverse phase rotation on the target subcarrier frequency domain signal based on the total phase rotation correction factor. According to the method and the device, the compensation amount of the receiving end of the OFDM system is accurately matched with the actually experienced frequency offset cumulant, so that effective compensation of the sampling frequency offset between the communication nodes is realized.

The invention relates to a sampling frequency offset tracking method and device, computer equipment and a storage medium, and the method comprises the steps: carrying out the signal synchronization processing according to a frame structure of a received signal, and obtaining a frame starting point; performing preliminary sampling frequency offset compensation and channel estimation according to the preamble symbol to obtain a preamble channel estimation result; performing decision feedback channel estimation according to the data symbols to obtain a decision feedback signal estimation result; performing correlation operation based on the time domain channel response signal sampling point corresponding to the effective peak value position to obtain a correlation value; residual sampling frequency offset is calculated according to the correlation value, a sampling frequency offset estimation value is updated in combination with the filter coefficient, and iterative sampling frequency offset compensation is carried out according to the updated sampling frequency offset estimation value so as to track the sampling frequency offset in real time. According to the invention, the channel estimation values are respectively generated based on the lead code symbols and the data symbols, symbol-by-symbol real-time tracking of the sampling frequency offset is realized, and real-time tracking can be realized without pilot frequency.

This invention discloses a method for joint synchronization of long-sequence phase of wireless signals and its ISAC action recognition method and device, belonging to the interdisciplinary field of radar signal processing and wireless communication. This invention aims to solve the problem of high-performance sensing with low-cost hardware in ISAC. Specifically, multi-carrier frequency-shift linear frequency modulation technology is used at the transmitting end to embed communication data while maintaining the characteristics of the radar detection waveform. To address the random carrier frequency offset, random sampling frequency offset, and random sampling time offset introduced by hardware non-ideals, a joint synchronization neural network is designed. A long-sequence feature extraction module captures long-sequence phase drift, achieving high-precision parameter decoupling and compensation in a single operation. Subsequently, the synchronized single-channel time-frequency features are combined with an environment-aware feature fusion network, and an adaptive gating fusion mechanism is used to eliminate static environmental clutter, achieving highly robust action gesture recognition.

The disclosed process addresses transmission of data from a device to a reader (D2R) in communication systems where devices receive reader-to-device (R2D) transmissions. Methods to determine the appropriate time and frequency resources for the D2R transmission based on the device's sampling frequency offset (SFO) capability is disclosed. The device receives an R2D transmission in a first slot, which specifies two sets of resources for D2R transmission: a first set and a second set. The device compares its SFO capability with a pre-defined threshold. If the device's SFO capability is below the threshold, it uses resources from the first set, which are allocated to time and frequency slots occurring before a specified number of slots (N) from the first slot. Conversely, if the SFO capability exceeds the threshold, the device uses resources from the second set, which are allocated to slots occurring after N slots from the first slot.