186 results about "Fading" patented technology

The invention discloses a 5G waveform-based synchronous channel design method. The method comprises the following steps of: dividing a system working bandwidth into a plurality of sub-bands; determining a candidate frequency domain position of a synchronization channel in each sub-band, wherein the synchronization channel is composed of a PSS and an SSS; and determining values of the PSS sequence and the SSS sequence according to the indexes corresponding to the PSS sequence and the SSS sequence, determining one or more frequency domain positions from the candidate frequency domain positions, and filling the selected frequency domain positions with the PSS sequence and the SSS sequence. In different interference and fading scenes, the time-frequency position of the synchronization channel can be adaptively selected according to interference and fading, so that the frequency domain position of interference and fading is avoided, and better performance is obtained.

The invention discloses a dynamic optimization system and method for a heterogeneous network communication protocol, and particularly relates to the technical field of communication network automation, and the system comprises a unified time base and multi-source state modeling module, a quick change detection and shadow section risk assessment module, a risk gating and hierarchical low-disturbance execution module and a closed-loop feedback and evolution management module. According to the method, a standard recording unit is constructed through unified time base and observation delay compensation, and multi-source communication state alignment is realized; a shadow section joint risk index is calculated based on online filtering and geographical priori, hierarchical low-disturbance strategy arrangement is implemented under the constraint of risk gating and comprehensive cost, and closed-loop feedback and anti-fact evaluation are utilized to drive parameter evolution governance. According to the method, the problems that short-time fading is smoothly masked in a high-speed or strong-shielding environment and unified risk assessment and low-disturbance execution are lacked are solved, the tail time delay, the disorder rate and the packet loss rate are reduced, the communication reliability is improved, and interpretable tradeoff between energy consumption and tariff is achieved.

The invention relates to the technical field of magnetic shielding, and provides a demagnetization method and device for a magnetic shielding device, electronic equipment and a readable storage medium, and the method comprises the steps: collecting a feedback circuit signal of a target magnetic shielding device through a voltage and current collection unit; analyzing the feedback circuit signal by using a signal acquisition processor, determining the current degaussing demand of the target magnetic shielding device, and calculating a degaussing pulse parameter matched with the current degaussing demand; a pulse generating unit is used for generating a target pulse with the adjustable pulse width according to the degaussing pulse parameters, the target pulse is a bipolar square wave pulse, and the adjusting interval of the pulse width comprises the millisecond level and the nanosecond level; and utilizing a pulse switching unit to act the target pulse on the target magnetic shielding device, so that the target magnetic shielding device is subjected to magnetic saturation or magnetic fading. According to the technical scheme provided by one or more embodiments of the invention, the average power demand of the degaussing power supply can be reduced, and the degaussing effect can be improved.

The invention provides a multi-input multi-output permutation index differential chaos shift keying communication system and method, and relates to the technical field of chaos secret communication. Generating two paths of chaotic signals in the modulator, wherein one path is used as a reference signal; delaying the other path, performing mapping permutation by using the index bit, multiplying the modulation bit subjected to space-time coding by a reference signal copy generated by permutation, generating an information signal, combining the information signal with the reference signal, and sending the information signal to a demodulator; and the demodulator is used for respectively delaying and replacing the received transmission signal, carrying out correlation operation on the delayed receiving signal and the replaced receiving signal to obtain an output signal, and carrying out comparative judgment and space-time decoding to recover the index bit and the modulation bit. According to the method disclosed by the invention, the security and the information transmission rate of a communication system are improved through different index bit mapping selection permutation rule methods; and channel fading and noise are suppressed by using multiple antennas, so that the bit error rate performance of a communication system is effectively improved.

The invention discloses a phi-OTDR vibration demodulation method based on double-segment average phase difference, belongs to the technical field of optical fiber sensing vibration demodulation, and solves the problems that in the prior art, phase demodulation is greatly influenced by phase noise such as laser frequency drift, the phase extraction precision and the signal-to-noise ratio are low due to random fluctuation of a phase curve, and the signal-to-noise ratio is low. And phase solving errors are easily caused by interference fading points. According to the method, through band-pass filtering, moving differential positioning, I / Q demodulation after reference point selection, unwinding, mean value removal and calculation of the average phase difference of two segments, the phase variation corresponding to vibration is extracted, and the demodulation precision is improved. Through the two-segment average phase difference method, the influence of phase noise and interference fading is suppressed, and the signal-to-noise ratio and stability of phase demodulation are improved; the frequency modulation pulse is replaced to break through restrictions of spatial resolution and sensing distance, high sidelobe suppression can be realized without windowing the NLFM pulse, the signal-to-noise ratio is not damaged, and the vibration detection positioning accuracy is improved.

Some wireless communications systems modulate signals for transmission via a channel. Probabilistic shaping may utilize non-uniformly distributed modulation constellations to increase spectral efficiency. In some cases, wireless fading may occur in a multiple-input and multiple-output (MIMO) channel, which may cause a loss of the shaping gain from probabilistic shaping. Some examples of approaches to linear MIMO demodulation for probabilistic shaping using auxiliary dimensions are provided. A wireless device may receive information indicating a non-uniform probabilistic distribution of a modulation constellation for a MIMO signal. One or more symbols of the MIMO signal may be transmitted or received via a channel. The wireless device may demodulate the symbol based at least in part on a transformation of the modulation constellation to a subspace using dimensions associated with the non-uniform probabilistic distribution and a point of the transformed modulation constellation nearest to a projected symbol in the subspace.

Techniques are disclosed to detect deep fading caused by magnitude drop and rapid phase change on channels within a frequency band of a narrowband wireless radio operating in a BMS-like environment with strong multipath. The techniques may identify an interference channel, a deep fading channel, or a weak signal channel. A channel assessment algorithm may receive packets on one of multiple channels to determine a received signal strength for each packet associated with the channel. The algorithm may determine a PER associated with the channel based on a number of packets received in error and a difference between the received signal strength of each packet and a reference signal strength associated with other channels of the frequency band. The PER may be compared with a PER threshold. The channel may be excluded from use by the wireless radio if the PER for the channel is greater than the PER threshold.

The invention relates to the technical field of unmanned aerial vehicles, in particular to a self-adaptive tracking unmanned aerial vehicle spectrum detection module which comprises a dynamic fingerprint database generation unit, a deep reinforcement learning decision unit, an intention prediction and compensation unit, an extended tracking control unit and a federal learning evolution unit. The dynamic fingerprint database accurately depicts the spatial-temporal characteristics of the signals; the deep reinforcement learning optimizes detection parameters in real time; the intention prediction unit actively compensates signal fading; the cross-modal data fusion improves the tracking robustness; therefore, the system has high-precision and high-reliability tracking capability in a complex environment.

The invention relates to the technical field of satellite navigation terminals, and discloses a Beidou terminal capable of intelligently evaluating multiple states. Comprising a Beidou positioning module used for acquiring a Beidou signal corresponding to the Beidou terminal; the control module is configured to execute the following steps: performing time sequence modeling on the propagation time delay, the geometric distribution factor, the ionosphere influence parameter and the troposphere influence parameter of the Beidou signal to generate a positioning reliability index so as to realize positioning state evaluation; performing conjoint analysis on the Beidou signal, and outputting a data credibility grade; processing the inertial navigation data, the terrain elevation data, the sky satellite geometric distribution factor and the multi-terminal altitude difference data corresponding to the Beidou terminal through a convolutional neural network to generate a three-dimensional environment interference coefficient; and fusing the channel fading parameter, the network topology data, the communication antenna signal-to-noise ratio, the transmission rate change parameter and the data integrity parameter corresponding to the Beidou terminal, and calculating a communication link stable value to realize communication state evaluation.

The invention discloses an anti-interference unmanned aerial vehicle cellular edge removal computing resource allocation method in an air-space-ground integrated network, which comprises the following steps of: firstly, constructing an air-space-ground integrated network architecture comprising a low-orbit satellite, an unmanned aerial vehicle cluster and a ground user, and establishing satellite interference space distribution mapping based on a satellite orbit and an interference measurement result; and then adopting a user-centered dynamic clustering strategy, combining with a large-scale fading coefficient and interference intensity, adaptively selecting a cooperation cluster scale and member composition, and forming an unmanned aerial vehicle cooperation cluster. Then establishing an uplink communication model of an explicitly introduced satellite direct-connected user co-frequency interference term, and on the basis, constructing a three-section end-to-end time delay model comprising wireless transmission time delay, parallel computing time delay and forward pass and backhaul time delay related to a cooperative cluster scale and a quantization bit number; according to the method, the cooperative cluster scale and the quantization bit number are used as time delay optimization variables together, controllable optimization of end-to-end time delay is achieved, the propulsion energy consumption of the unmanned aerial vehicle is considered, and therefore the unloading efficiency and the overall energy efficiency of the cellular edge removal computing system are improved.

The invention relates to the technical field of free space optical communication, in particular to an atmospheric turbulence adaptive optical compensation method for wireless laser communication, which comprises the following steps of: performing light beam coarse tracking by using a fast reflector to eliminate tilt drift; monitoring the received light intensity of the wavefront sensor in real time, and setting a threshold value for mode judgment; when a channel is good, a Kalman filtering algorithm is adopted to predict and compensate system delay, modal decoupling is carried out on reconstructed wavefront, a large-stroke deformable mirror is controlled to correct low-frequency large-amplitude aberration, and a micro-electro-mechanical deformable mirror is controlled to correct high-frequency residual error; and when the channel is in deep fading or the detector fails, the blind optimization mode is automatically switched, the state of the large-stroke deformable mirror is locked, and SPGD iterative control is applied to the micro-electro-mechanical deformable mirror based on the communication light intensity. According to the invention, through a double-deformable mirror frequency division cooperation and hybrid sensing strategy, the problems of insufficient bandwidth, limited stroke, easy interruption and the like of a traditional system under strong turbulence are effectively solved, and the optical fiber coupling efficiency and the robustness of a communication link are significantly improved.

The invention belongs to the technical field of terahertz communication physical layer security, and particularly relates to a terahertz physical layer key generation method based on leaky-wave antenna space-spectrum coupling characteristics. According to the invention, the sensitivity of the effective antenna gain of the leaky-wave antenna to the frequency and the spatial propagation direction is utilized to make up for the defect of low eavesdropping channel doubtful degree caused by lack of small-scale fading in terahertz communication, and the conditional generative adversarial network is designed to accurately speculate the equivalent channel power gain. A physical layer key is generated based on the estimated channel power gain. According to the method, the channel power gain can be accurately estimated from the received signal strength with noise and auxiliary information, the reciprocity of an equivalent channel is enhanced, and the method has a lower key mismatch rate and a higher key generation rate; under the condition of different signal-to-noise ratios, good key generation performance can be kept.

The invention discloses an implementation method of a sub-connection active STAR-RIS assisted secure communication system. A base station, a sub-connection active STAR-RIS, a legal user and an eavesdropping user are included. According to the invention, M units of STAR-RIS are grouped into L sub-arrays, and an amplifier is shared to reduce power consumption and cost; with maximization of system secrecy energy efficiency as a target, base station beam forming, STAR-RIS reflection / transmission coefficients and amplifier amplification coefficients are jointly optimized; and solving the non-convex optimization problem by adopting an efficient algorithm based on block coordinate descent. According to the invention, the hardware overhead and the system power consumption are effectively reduced through the sub-connection structure, meanwhile, the secure transmission efficiency of the system is remarkably improved through joint optimization, multiplicative fading is overcome, and an efficient and reliable solution can be provided for 6G secure communication.

The invention discloses an interference fading point compensation method for a coherent phi-OTDR (Optical Time Domain Reflectometer), which comprises the following steps of: identifying an interference fading point on the basis of complex envelope characteristics obtained by coherent receiving and I / Q (Input / Output) demodulation, and performing interpolation reconstruction on a fading point echo vector by using a neighborhood non-fading point on a complex plane, so as to recalculate a phase and a differential phase; therefore, phase demodulation failure and differential phase artifacts caused by fading can be suppressed. According to the method, on the premise of not increasing hardware transformation, differential phase artifacts and abnormal stripes caused by phase demodulation failure at a fading point are reduced, the stability of a differential phase result and event identifiability are improved, and relatively low calculation complexity is kept to adapt to offline or quasi-real-time processing.

The invention discloses a low-voltage power line carrier communication network repeater deployment method and system, and relates to the technical field of power communication. The method comprises the following steps: (1) according to PLC network topology information, acquiring an STA set which cannot directly communicate with a CCO, and inputting model parameters; (2) calling a general optimization solver to carry out model solution to obtain a solution result; (3) if the feasible solution exists, outputting a PCO deployment mark; if not, adjusting the received signal threshold value and the transmitting power, and repeating the step (2); and (5) once a feasible solution is obtained or the model parameter reaches the set limit value, the solution is ended. According to the deployment planning model constructed by the invention, the optimal deployment position of the PCO in the network is solved by taking the minimum weighted sum of the total transmission time delay and the total cost as a target and taking the received signal strength and the single-hop relay as constraints; the problem that seamless coverage of a low-voltage power distribution network is difficult to realize by single-hop communication due to high background noise and frequency selective fading of a PLC channel is solved.

The present invention provides an interleaving method and a related device for mapping a virtual resource block to a physical resource block (VRB-to-PRB) during a sub-band full duplex (SBFD) period, and a method for mapping a virtual resource block to a physical resource block (VRB-to-PRB) during the SBFD period of the sub-band full duplex (SBFD) period of the sub-band full duplex (SBFD) period of the sub-band full duplex (SBFD) period of the sub-band full duplex (SBFD) period of the virtual resource block to the physical resource block (VRB-to-PRB). In one embodiment, the method includes performing a VRB-to-PRB interleaving during the SBFD to interleave resource blocks (RBs) and map a VRB beam to a PRB beam in a first DL frequency domain and a second DL frequency domain. By the method, the VRB-to-PRB interleaving is enhanced in the SBFD operation, thereby being able to benefit from less frequency selective fading.

The invention provides a low-altitude cellular-free network signal detection method under wireless forward pass constraint, which belongs to the field of wireless communication and digital signal processing, and comprises the following steps: establishing a signal transmission model based on a low-altitude cellular-free network architecture; in the period, each air AP obtains a local signal processing result; transmitting signals of the air APs are distributed on B subcarriers so as to send local signal processing results to the central processing unit in real time; the central processing unit performs combination detection on the ground user signals to obtain a final ground user signal detection result; and after the period is ended, each air AP sends the channel statistical information of the period to the central processing unit, and the central processing unit optimizes the local processing matrix of each air AP and sends the optimized local processing matrix to each air AP. According to the method, the uplink rate of the ground user can be effectively improved, and meanwhile, the problems of channel fading, multiple access and network expandability of a wireless forward link are solved.

Disclosed herein are systems and methods of predicting fading loss of signals transmitted between a ground-based transceiver and an aircraft based upon a two-ray fading model that incorporates elevation information of an environment. Some examples of the disclosure are directed to determine fading loss using a plurality of geofences that are determined based on a plurality of planar shapes.

This invention relates to the field of unmanned aerial vehicle (UAV) communication technology, and in particular to a communication method for a dual-channel UAV line-of-sight (LAS) communication system. The method includes: acquiring communication quality, acquiring the optimal transmission frequency, acquiring the UAV's mission priority, transmitting video stream data, and performing multipath fading compensation steps. The method sets up high-frequency and low-frequency channels, calculates frequency quality indicators using signal-to-noise ratio (SNR), signal rate, and bit error rate (BER), and dynamically selects the optimal transmission frequency. Communication resources are allocated based on mission priority to ensure priority transmission of critical commands. Innovatively, differential geometry theory is used for multipath fading compensation, mapping the communication signal to a Riemannian manifold space, extracting fading features, and optimizing the processing. High- and low-frequency channel collaborative compensation is achieved, with mutual enhancement through received spectrum analysis and training sequence correction. Adaptive QAM modulation is supported, dynamically adjusting modulation parameters according to manifold curvature to construct a star-shaped multi-node communication network.

The invention provides a signal processing method, receiving end equipment, a signal processing device and a storage medium. The method comprises the steps that the receiving end equipment determines a target precoding matrix and a target equalization matrix which enable the signal to interference plus noise ratio (SINR) of a received symbol to be maximized; wherein the target precoding matrix satisfies a transmitting power constraint condition and a waveform subcarrier energy constraint condition, and the target equalization matrix satisfies a power normalization constraint condition; sending the target pre-coding matrix to the transmitting end equipment, wherein the target pre-coding matrix is used for the transmitting end equipment to perform pre-coding processing on the transmitting symbol sequence; and if a signal sent by the transmitting end equipment after precoding processing is received, carrying out equalization processing on the received signal based on the target equalization matrix to obtain a received symbol sequence. Therefore, the influence of channel fading can be compensated to the greatest extent, the PAPR can be reduced, and the anti-fading performance and the anti-limiting distortion performance of the signal can be improved at the same time.

The application provides a method, device and storage device for inhibiting fading interference, selects a main lobe and two first-order side lobes, extracts three sub-bands by using a filter with the same width as the main lobe, adds the intensity of three curves obtained by performing inverse Fourier transform on the three sub-bands by using a rotation vector summation method to obtain a new signal, extracts the phase information of each vibration point on the new signal curve by amplitude demodulation, sets a threshold range according to the corresponding relationship between the amplitude and the phase of Rayleigh scattering, selects the phase, retains the phase outside the threshold range, averages the phase in the threshold range, thereby avoids the wrong phase point, and obtains the final phase demodulation image of the vibration point for eliminating fading interference. The application has the beneficial effects that: the coherent fading is eliminated without multiple frequency data, the detection times are reduced, the cost is reduced, the real-time demodulation speed is accelerated, and the wrong phase demodulation is avoided.

The present invention proposes a quantum key distribution phase codec and a corresponding coding and decoding device and system. The phase codec includes: a beam splitter, two polarization orthogonal rotation reflection devices optically coupled to the beam splitter via two arms, and a phase modulator arranged on one of the two arms. One or each of the two reflection devices includes a polarization beam splitter having an input port and two output ports, and is coupled to the corresponding arm via the input port of the polarization beam splitter. The two output ports of each polarization beam splitter are optically coupled to each other via a polarization-maintaining fiber twisted 90 degrees, so that the light pulses output by the two output ports are both coupled to the slow axis transmission of the polarization-maintaining fiber or to the fast axis transmission of the polarization-maintaining fiber. The present invention enables stable encoding and decoding interference of input light pulses of arbitrary polarization states, solving the problem of polarization-induced fading causing the system to be unable to operate stably in phase-encoded and time-bit-phase-encoded quantum key distribution applications.

The utility model provides an automatic frequency hopping image transmission communication system, which comprises at least one host and a plurality of slaves in wireless communication with the host, and the host and the slaves respectively comprise a frequency hopping communication circuit. The frequency hopping communication circuit is composed of a chip which supports the fastest 100 hops per second and is provided with 80 channels, the channel interval is 30 kHz, the self-correlation coefficient is 0.4, the mutual relation is 0.5, the frequency hopping sequence length is at least 80, and the synchronization time is three frames of 10 milliseconds. The host and the slave of the image transmission communication system adopt the chip supporting the frequency hopping technology for communication, single-frequency communication is not used any more, so that interference signals are difficult to aim at specific frequencies to interfere, the stability and the reliability of communication are improved, the chip supporting the frequency hopping technology can send and receive signals at different frequencies, and the communication efficiency is improved. And the influence of signal fading and multipath effect is effectively avoided.

The invention discloses an uplink single carrier subsystem in a heterogeneous MIMO channel environment, and relates to the technical field of wireless data transmission, the uplink single carrier subsystem comprises a transmission data acquisition module, a preprocessing module, a channel characteristic processing module, a channel monitoring module, a channel optimization module and an execution module, the transmission data acquisition module is divided into a channel characteristic unit and a transmission signal unit, wherein the channel characteristic unit is used for collecting multipath fading data and channel data, the transmission signal unit is used for collecting the signal-to-noise ratio of a transmission signal, and the channel characteristic processing module is divided into a multipath fading processing unit and a channel capacity processing unit. According to the system, a data acquisition technology and a neural network algorithm are closely combined with a modern information technology, multipath fading data and channel data are accurately captured, a channel monitoring model is constructed in combination with the neural network algorithm, and real-time and comprehensive monitoring on multipath fading and channel capacity abnormity of a channel is achieved.

Techniques are disclosed for detecting deep fading caused by a magnitude drop and rapid phase change on channels within a frequency band of a narrowband wireless radio operating in a BMS-type environment with strong multipath. The techniques can identify an interference channel, a deep fading channel, or a weak signal channel. A channel estimation algorithm can receive packets on one of multiple channels to determine a received signal strength for each packet associated with the channel. The algorithm can determine a PER associated with the channel based on a number of erroneously received packets and a difference between each packet's received signal strength and a reference signal strength associated with other channels of the frequency band. The PER can be compared to a PER threshold.The channel may be excluded from use by the wireless radio if the PER for the channel is greater than the PER threshold.

Disclosed herein are systems and methods of predicting fading loss of signals transmitted between a ground-based transceiver and an aircraft based upon a two-ray fading model that incorporates elevation information of an environment. Some examples of the disclosure are directed to determine fading loss using a plurality of geofences that are determined based on a plurality of planar shapes.

Some wireless communications systems modulate signals for transmission via a channel. Probabilistic shaping may utilize non-uniformly distributed modulation constellations to increase spectral efficiency. In some cases, wireless fading may occur in a multiple-input and multiple-output (MIMO) channel, which may cause a loss of the shaping gain from probabilistic shaping. Some examples of approaches to linear MIMO demodulation for probabilistic shaping using auxiliary dimensions are provided. A wireless device may receive information indicating a non-uniform probabilistic distribution of a modulation constellation for a MIMO signal. One or more symbols of the MIMO signal may be transmitted or received via a channel. The wireless device may demodulate the symbol based at least in part on a transformation of the modulation constellation to a subspace using dimensions associated with the non-uniform probabilistic distribution and a point of the transformed modulation constellation nearest to a projected symbol in the subspace.

This invention proposes a method for generating broadband signals that is resistant to dispersion fading based on an electro-optical modulator. By rationally changing the phase of the driving signal, a chirp signal with opposite chirp signs can be generated during the beat frequency, thereby switching between single chirp and double chirp. Furthermore, this scheme proposes carrier-suppressed single-sideband modulation of the chirp signal, which effectively avoids amplitude fading caused by dispersion in optical fiber transmission while eliminating interference signals that fall within the chirp signal band after the beat frequency. The proposed scheme based on the DP-DPMZM integrated device is easy to integrate, has a simple structure, and is low-cost. The generated dual-band chirp signal can be flexibly switched between up-chirp, down-chirp, and double chirp, greatly improving the flexibility of the system. Furthermore, it effectively eliminates amplitude fading caused by dispersion in optical fiber transmission, significantly increasing the transmission distance of traditional systems. This scheme is expected to provide technical support for the development of future high-performance radar technology.

The invention discloses a server-free edge function reliability deployment method and system based on reinforcement learning, and the method is oriented to server-free edge calculation, takes the minimization of long-term network cost as a target, and systematically solves the problems of high cold start cost, limited resources, difficult reliability guarantee and the like. A system model including user movement, channel fading, function deployment and a backup mechanism is constructed, four types of costs of cold start, maintenance, transmission and punishment are accurately described and converted into a Markov decision process, and a state-action-award framework is utilized to realize dynamic decision. The PPO algorithm fusing the greedy strategy to assist the action selection is further provided, and a function deployment scheme meeting the reliability constraint is efficiently generated under the condition that resources are limited. According to the method, through fusion of reinforcement learning and a greedy strategy, the problems of feasibility, reliability and cost of function deployment in server-free edge computing are solved, and the method has the capabilities of efficient deployment, adaptive scheduling and long-term performance optimization.

Techniques are disclosed to detect deep fading caused by magnitude drop and rapid phase change on channels within a frequency band of a narrowband wireless radio operating in a BMS-like environment with strong multipath. The techniques may identify an interference channel, a deep fading channel, or a weak signal channel. A channel assessment algorithm may receive packets on one of multiple channels to determine a received signal strength for each packet associated with the channel. The algorithm may determine a PER associated with the channel based on a number of packets received in error and a difference between the received signal strength of each packet and a reference signal strength associated with other channels of the frequency band. The PER may be compared with a PER threshold. The channel may be excluded from use by the wireless radio if the PER for the channel is greater than the PER threshold.