7results about How to "Improve anti-intercept performance" patented technology

The invention belongs to the field of wireless communication, and discloses a power wireless local area network information security transmission method and a related device, and the method comprises the steps: obtaining a current physical layer leader sequence and a physical layer header, and carrying out the processing of to-be-transmitted data on the basis of the current physical layer leader sequence and the physical layer header, thereby achieving the dynamic operation of the physical layer leader sequence and the physical layer header. Meanwhile, when data to be transmitted are modulated by adopting an orthogonal frequency division multiplexing technology, a positive value random quantity is introduced to modify a cyclic prefix selection area and length and modify subcarrier parameters, so that the randomness and unpredictability of signal transmission are further improved, and the hiding of physical layer waveform parameters is realized. By dynamically switching the waveform factors of the physical layer, an attacker is difficult to capture and identify the characteristic information of the wireless signal due to the dynamic change, so that the anti-reconnaissance and anti-interception capabilities of the system are greatly improved. A parameter dynamic change rule can be self-formulated for the power wireless local area network, so that the powerful supervision capability of the power industry on the wireless local area network technology can be realized.

This invention discloses a method and apparatus for stable control of UAV swarm formation based on multidimensional transitions, relating to the field of UAV cooperative formation technology. The method includes: upon entering an intelligent communication resilience assurance decision mode, generating action strategies and action values ​​based on the CHZ-search algorithm and current electromagnetic environment state parameters to obtain the optimal frequency hopping basic strategy; utilizing the SD-DDV network and an improved IDEB-AS algorithm to obtain the final double-transition frequency hopping pattern; establishing a multidimensional dynamic spectrum transition communication link; acquiring UAV state information for correction and compensation; and using a formation control law to achieve real-time state estimation and continuous stable control of the UAV formation. This invention can significantly establish a resilient communication link, compensate for communication delays, and perform formation control even when channel quality deteriorates, bit error rate increases, or specific interference characteristics are received, while avoiding flip-transition problems.

The application discloses a MIMO radar waveform design method based on multi-dimensional joint coding, and mainly aims at solving the problems of low waveform design freedom, poor resolution performance and simple waveform form which is easily intercepted. The implementation steps are as follows: constructing a multi-dimensional joint coding MIMO radar waveform initial model; calculating the pulse synthesis result of each sampling point of each target sampling angle by using the echo signal of each target sampling angle of the generated radar array; constructing a cost function of a waveform optimization algorithm according to the sidelobe value of the pulse synthesis result; setting the constraint condition of the waveform optimization algorithm; and optimizing the MIMO radar waveform by using the cost function and the constraint condition. The MIMO radar waveform designed by the application increases the design freedom of the waveform, improves the resolution performance of the radar system on the target, and makes the waveform form complex, thereby improving the anti-interception performance of the waveform.

The invention relates to the technical field of encryption and decryption communication, and discloses an encryption and decryption communication system based on a baseband superposition technology, which comprises a baseband superposition module, a sequence scrambling module and a modulation module which are arranged at a sending end, the demodulation module, the sequence descrambling module and the iteration processing module are arranged at a receiving end. According to the invention, a baseband superposition encryption and decryption method is adopted, code word superposition is carried out at a sending end, information loss is caused, and the checkability of a coding sequence is destroyed in a large proportion, so that the difficulty of cracking a signal specification and obtaining communication information by a third receiver is greatly improved, and the anti-interception capability of information is improved.

The present invention discloses a MIMO radar waveform orthogonal method based on pilot information. The MIMO radar subarrays can first forward the pilot information containing their own waveform working parameters, and the pilot information is modulated into the radar waveform and transmitted through the radar subarray antenna. After intermediate frequency filtering and demodulation, each subarray receiver obtains a signal containing the pilot information of other subarrays. The signal is subjected to short-time Fourier transform to obtain the time-frequency diagram of the pilot information of each subarray. The time-frequency diagram is used to determine whether the waveforms of the subarrays are orthogonal. If the waveforms are not orthogonal, the cost function is used to optimize the parameters in the waveform, and the optimized waveform is used for the MIMO radar. During the target detection process of the MIMO radar, the pilot information is periodically transmitted to continuously sense whether the subarrays of the MIMO radar are orthogonal. The present invention can achieve MIMO radar waveform orthogonality, thereby improving the Doppler resolution, anti-interception capability, and detection and tracking of weak targets of the radar system.

The present application relates to high-speed rail uplink communication security technical field, and proposes a kind of RIS assisted high-speed rail uplink communication security method under multiple eavesdropping cooperative attack.Proposing a kind of RIS assisted high-speed rail uplink communication security method under multiple eavesdropping cooperative attack.For the security threat that multiple passive eavesdroppers exist along the high-speed rail and carry out centralized cooperative interception through maximum ratio combination, a two-hop uplink security communication model from high-speed train to dispatching room is constructed: the first hop uses RIS assisted millimeter wave to realize the uplink wireless communication from high-speed rail to relay, and enhances the legal signal and suppresses eavesdropping by regulating RIS reflected signal;The second hop uses power line communication to transmit signal to terminal, and plays the high security advantage of wired link physical isolation.The present application takes the maximization of system average security rate as the goal, and jointly optimizes mobile relay beamforming vector, RIS phase shift matrix and transmission power allocation;Especially for the extreme environment that multiple eavesdropping cooperative interception superposition system only has statistical channel state information, leading to the optimization problem that objective function falls into complex random expectation item which is extremely difficult to solve, introduce deterministic equivalent transformation to convert it into deterministic form, and solve optimal security parameter configuration by combining alternating optimization algorithm, finally execute by hardware controller.The present application effectively breaks through the double obstacles brought by multiple eavesdropping cooperation and channel uncertainty, and significantly improves the anti-interception ability of high-speed rail uplink communication.

The invention provides an OFDM satellite communication method, device and system based on an improved chaotic system. The method comprises the following steps: generating an integer key sequence based on an improved chaotic system; a sending end performs bit layer chaotic encryption on an original data bit stream by using an integer key sequence to generate a first encrypted bit stream, performs symbol layer chaotic phase encryption and OFDM modulation on the first encrypted bit stream by using the integer key sequence to generate an encrypted signal, and sends the encrypted signal to a receiving end; and the receiving end performs symbol layer chaotic phase decryption and demodulation on the encrypted signal by using the integer key sequence, and performs bit layer chaotic decryption on the demodulated bit stream by using the integer key sequence to obtain a decrypted data bit stream. According to the method and the device, the secret key quality is improved by improving a chaotic system, and the bit layer and the symbol layer are combined for collaborative encryption, so that the encrypted signal presents a noise-like random time-varying characteristic on a constellation diagram and a power spectrum on the premise of not obviously increasing the overhead, and the anti-interception and anti-analysis capability is enhanced.