12 results about "Rayleigh fading" patented technology

The application discloses a STAR-RIS assisted short packet communication broadcast system optimization method based on TD3, utilizes statistical channel state information of a broadcast system under a Rayleigh fading channel to design a passive beamforming joint optimization method based on a double-delay deep deterministic policy gradient algorithm, and improves the performance of the short packet communication broadcast system. Specifically, firstly, a transmission reflection type reconfigurable intelligent surface assisted short packet communication broadcast system model is constructed, including system composition, channel modeling, and introduction of a coupling phase shift model of a physically achievable transmission reflection type reconfigurable intelligent surface; secondly, a base station end active beamforming and transmission reflection type reconfigurable intelligent surface passive beamforming joint optimization method based on a double-delay deep deterministic policy gradient algorithm is constructed by utilizing statistical channel state information to maximize the minimum value in the average reachable rate of each user, so that all users can obtain good communication quality, and high-reliability low-latency broadcast communication is realized.

The invention discloses an RSMA wireless communication system secure transmission method based on STAR-RIS, and belongs to the technical field of wireless communication. Based on a related Rayleigh fading channel model, a cascade channel average gain from a base station to a user through STAR-RIS is firstly deduced, a simplified analysis method is provided, the average channel gain is directly used for deducing a closed expression of a system security outage probability (SOP), and the secure diversity gain characteristic of the system is further determined by analyzing the asymptotic SOP of a high signal-to-noise ratio area; the security performance of the method is obviously better than that of an STAR-RIS assisted NOMA scheme and an STAR-RIS assisted OMA scheme, and the flexible resource allocation mechanism of the method has more advantages in interference control and secure transmission guarantee; according to the method, the power distribution coefficients of the public information and the private information of the RSMA are optimally designed, the rate and power ratio of the two types of information streams can be dynamically and flexibly adjusted according to the actual situation, and the appropriate balance of the transmission security of the two types of information streams is realized.

Communication systems are described that use signal constellations, which have unequally spaced (i.e. ‘geometrically’ shaped) points. In many embodiments, the communication systems use specific geometric constellations that are capacity optimized at a specific SNR, over the Rayleigh fading channel. In addition, ranges within which the constellation points of a capacity optimized constellation can be perturbed and are still likely to achieve a given percentage of the optimal capacity increase compared to a constellation that maximizes dmin, are also described. Capacity measures that are used in the selection of the location of constellation points include, but are not limited to, parallel decode (PD) capacity and joint capacity.

The invention provides an RIS-assisted cellular-free large-scale MIMO network security energy efficiency optimization method. The method comprises the following steps: establishing an RIS-assisted cellular-free large-scale MIMO network model under a Rician fading channel; acquiring estimated channel state information of aggregation channels between the base station and the user equipment and between the base station and the eavesdropper by adopting a linear minimum mean square error estimation method; performing downlink channel data transmission based on the estimated channel state information; deriving a lower bound of a user reachable rate and an upper bound of an eavesdropper leakage rate according to a downlink channel data transmission result; deducing a safety reachable rate expression and a safety energy efficiency expression according to the lower bound of the user reachable rate and the upper bound of the eavesdropper leakage rate; based on the safety energy efficiency expression, a non-convex optimization problem containing RIS phase shift and power distribution is established, an iterative optimization algorithm is adopted for solving, and the iterative optimization algorithm decouples the original problem into an RIS phase shift optimization sub-problem and a power distribution optimization sub-problem for alternate solving until convergence is achieved to a local optimal solution meeting all constraints.

The invention provides a high-frequency ionized layer channel simulation method and system, a medium and a product, and relates to the technical field of wireless communication, and the method comprises the steps: generating an initial Doppler frequency spectrum according to a preset frequency spectrum mode and a Doppler frequency spectrum generation function; a frequency domain filtering method is adopted, the complex Gaussian white noise is filtered through the initial Doppler spectrum, and a Rayleigh fading process related to a time domain is generated; generating multipath time delay based on exponential distribution, and applying a time domain-related Rayleigh fading process to each time delay path to obtain a channel impulse response; performing statistical analysis on the channel impulse response to obtain a channel statistical characteristic parameter; and comparing the channel statistical characteristic parameter with a preset standard limit value, and outputting a compliance verification result. By implementing the method, the possible problem that a model is too simplified and is disjointed with actual channel characteristics in a traditional simulation method can be solved, and the dependence on a complex and changeable real channel environment is reduced.

The invention discloses a communication and interference integrated transmission method, which comprises the following steps of: determining a frequency band range to be interfered by an own side according to a communication frequency band of an illegal user; the method comprises the following steps: generating a plurality of cosine signals with different carrier frequencies, modulating own information to be sent, and mapping the modulated information to the phase of each cosine signal; determining the amplitude and carrier frequency of the cosine signal by using an intelligent superposition algorithm so as to construct a superposed signal, so that the superposed signal presents a flat white noise characteristic in a communication frequency band of an illegal user; and then the superposed signal is sent through an own transmitter. The superposed signal passes through a Rayleigh fading channel and is subjected to amplitude fading and phase rotation; a receiving end receives the superposed signals subjected to Rayleigh fading and additive Gaussian white noise, and demodulates and judges the received signals to obtain phases in each cosine signal; and a final judgment result is obtained by combining a signal to interference plus noise ratio and maximum likelihood judgment, so that own information is recovered.

The application belongs to the intersection of unmanned aerial vehicle navigation and communication technology, and particularly relates to a low-altitude unmanned aerial vehicle path planning method for guaranteeing communication quality, comprising the following steps: firstly, discretizing the flight space into a three-dimensional grid with vertices as path points; then, determining the line-of-sight / non-line-of-sight state of the path points and base stations and calculating the occlusion coefficient through a Bresenham three-dimensional straight line algorithm, combining a Rician / Rayleigh fading model to complete signal-to-noise ratio quantization, and screening out reliable path points meeting the communication and safety double constraints; subsequently, planning an optimal reliable flight path by using 26-dimensional full-dimensional neighborhood search and double cost function calculation based on an improved CAD algorithm; and in the flight process, triggering dynamic re-planning through real-time SNR monitoring to adapt to sudden changes in the environment. The application realizes communication guarantee for the whole flight of the unmanned aerial vehicle, has reproducibility and robustness, effectively avoids the risk of communication interruption, and provides a key technology for reliable flight of urban low-altitude unmanned aerial vehicle logistics, inspection and other scenes.

The application provides a LoRa device radio frequency fingerprint identification method and device based on a conditional diffusion model, and the method comprises the following steps: acquiring radio frequency signals of different LoRa devices; pre-processing the radio frequency signals to obtain a training data set; constructing a conditional diffusion model, and training the conditional diffusion model by using the training data set; in the training process, introducing Rayleigh fading multiplicative interference and additive Gaussian noise to simulate the multipath fading characteristics of real LoRa device communication; generating a radio frequency fading signal by using the trained conditional diffusion model, and adding the generated radio frequency fading signal to the training data set to obtain an enhanced data set; training a pre-constructed radio frequency fingerprint identification model by using the enhanced data set; and identifying the radio frequency fading signal of a LoRa device to be identified by using the trained radio frequency fingerprint identification model, so as to obtain the category corresponding to the LoRa device to be identified; thereby improving the device identification accuracy under a multipath channel.

The invention discloses a secret key lossless transmission method based on semantic communication, and the method comprises the steps: 1, segmenting a to-be-transmitted secret key according to batches, adding a batch mark in front of each segment, and generating a corresponding two-dimensional code image through two-dimensional code coding; 2, a channel noise model is adopted to simulate the transmission process of key data, channels comprise additive Gaussian white noise and Rayleigh fading channels, the noise injection intensity is controlled by setting the signal-to-noise ratio, and the influence of channel noise on the key data is simulated; step 3, the receiving end uses the semantic communication model to restore and reconstruct the two-dimensional code image, and the definition and identifiability of the damaged two-dimensional code are improved; step 4, decoding the reconstructed two-dimensional code image, and recovering corresponding secret key data; and step 5, calculating and comparing the hash values of the restored key and the original key, and verifying the content integrity. According to the method, the recovery capability of the two-dimensional code under the condition of low signal-to-noise ratio is enhanced by introducing the semantic communication model, and the method has good robustness.

The invention discloses a multi-symbol STBC-LoRa joint radar communication system performance analysis method. According to the method, expressions of radar fuzzy functions of transmitted waveforms with different symbol numbers can be deduced, and the correctness of the expressions is verified through simulation. And simulation analysis of radar performance is carried out from the angles of radar echo processing and a fuzzy function. Simulation results show that the method not only can successfully identify the potential target through echoes, but also can reduce the PSLR of the delay dimension fuzzy function of the transmitted waveform along with the increase of the number of symbols, improve the Doppler resolution, and reduce the influence of cross correlation between antennas on the radar performance. Therefore, the radar performance can be synchronously improved under the condition of improving the communication rate. According to the method, a Rayleigh fading channel transmission model is constructed in a communication dimension, bit error rate characteristics of LoRa signals before and after coding are compared and analyzed, and it is found that the coded LoRa signals have more excellent bit error rate performance in a Rayleigh fading channel.

The invention provides a radiation source fingerprint identification data enhancement method based on a double-constraint GAN, and relates to the technical field of communication signal processing, and the method comprises the steps: building a Rayleigh fading channel based on a Jakes model, and generating a frequency domain transmission function; constructing a double-constraint generative adversarial network, adopting a least square GAN loss function to constrain the adversarial process of a generator and a discriminator, introducing fingerprint feature matching loss constraint to generate sample feature fidelity, and outputting a superposed channel noise and fading effect by the generator; and balancing the adversarial loss and the feature matching loss until the network converges and outputs an enhanced sample by alternately optimizing parameters of the discriminator and the generator. The technical problems that in the prior art, a data training network obtained through a data enhancement algorithm under the small sample condition is low in recognition accuracy and poor in generalization ability are solved. The technical effects of improving the fingerprint identification accuracy and generalization ability of the radiation source under the small sample condition and keeping the fingerprint features are achieved.

The invention discloses an energy harvesting D2D communication system long-term energy efficiency optimization method and system based on reinforcement learning and Lyapunov optimization, and relates to the technical field of power control and energy efficiency optimization, and the method comprises the steps: firstly carrying out the modeling of energy arrival and task arrival according to a Poisson process; and calculating the time-varying channel gain according to the path loss and the Rayleigh fading characteristic. And constructing a Lyapunov function to derive a Lyapunov drift term, and embedding the Lyapunov drift term into a reward function of reinforcement learning. In the reinforcement learning part, a self-adaptive double-depth Q network structure based on a Dropout mechanism is adopted, a state vector is used as input, and self-adaptive balance of exploration and utilization is realized through randomization of Q value distribution. And the intelligent agent dynamically adjusts the transmission power of the EH-D2D system according to the optimal action output by the training network, realizes the stability of parameter updating through the target network, and realizes long-term energy efficiency optimization and queue stability in an energy collection environment.