318 results about "Artificial noise" patented technology

An active control of an unwanted noise signal at a listening site radiated by a noise source uses a reference signal that has an amplitude and / or frequency such that it is masked for a human listener at the listening site by the unwanted noise signal and / or a wanted signal present at the listening site in order to adapt for the time-varying secondary path in a real time manner such that a user doesn't fell disturbed by an additional artificial noise source.

The invention discloses a cooperative relay security transmission method based on artificial noise interference, wherein the whole transmission process is completed in two time slots; in the first time slot, an information source broadcasts available information fused with artificial noise to a relay and an eavesdropper, and before broadcasting, the artificial noise is pre-coded by a null space orthogonal base of a channel from the information source to the relay, and the available information is pre-coded by using a maximal ratio transmission strategy; and in the second time slot, the relay decodes and transmits the received information, and meanwhile the information source sends the artificial noise to interfere the receiving of the eavesdropper. According to the cooperative relay security transmission method based on artificial noise interference, as interferences are implemented in both the two transmission time slots for the eavesdropper, the reception signal-to-interference-and-noise-ratio of the eavesdropper can be effectively reduced, thereby the system security performance is enhanced, and the security transmission of the information is ensured; in addition, in order to improve the use ratio of the system power, the power can be set through working out the optimal power distribution factor of the system, and thereby the optimal system security performance can be achieved with the lowest power consumption.

In the present invention, an image processing method includes a dividing process, a performing process, and a superimposing process. In the dividing process, an image is divided into plural local portions. In the performing process, the blurring processing is performed on at least one of the plural local portions. In the superimposing process, the artificial noise is superimposed on the at least one local portion.

The invention discloses a physical layer safety method based on artificial noise power distribution, and relates to a physical layer safety method. The objective of the invention is to solve the problems of high confidentiality interruption probability and poor confidentiality in an existing broadcasting system. The method comprises the following steps: 1, transmitting a signal by a transmitting end; 2, calculating a received signal reaching the kth legal receiver end and a received signal reaching the eavesdropper end; 3, calculating the signal to interference plus noise ratio of the kth legal receiver and the signal to interference plus noise ratio of the eavesdropper; 4, calculating the instantaneous confidentiality capacity of the kth legal receiver; 5, calculating an optimal artificial noise power distribution factor; and 6, calculating the confidentiality interruption probability according to different artificial noise power factors, and drawing a change curve of the confidentiality interruption probability along with the artificial noise power distribution factor to obtain the artificial noise power distribution factor meeting the requirements. The invention is applied to the field of physical layer security of a wireless broadcast communication system.

The invention discloses a physical layer safety transmission method used for an SIMO wireless communication system. Firstly, a receiving expecting party emits a random reference signal reversely, an emitting party scrambles and transmits symbols to be transmitted through the received reference signal, and finally the receiving expecting party demodulates the received signal through the known reference signal to obtain information transmitted by the emitting party. In the first step, the multi-antenna receiving party sends not only the reference signal, but also an artificial noise signal, the space where the artificial noise signal is located is in quadrature with a main channel vector, so that the artificial noise has no influence on receiving the reference signal of the emitting expecting party. For an eavesdropper, due to different channels, eavesdropping is interfered with by artificial noise signals, the random reference signal is difficult to evaluate accurately, the probability of successfully eavesdropping encrypted signals is greatly reduced, and safety transmission of the SIMO wireless communication system is guaranteed finally.

The invention provides an artificial noise assisted large-scale MIMO security statistical precoding method. In the method, a cell base station is configured with a large-scale antenna array, and large-scale beam coverage is realized on the whole cell by utilizing a unified unitary transformation matrix. The base station uses beam domains of legal users and eavesdropping users in a cell to count channel information and injects artificial noise into the channel to reduce the decoding capability of the eavesdropping users, and performs statistical precoding design on the signals sent to each legal user and the artificial noise sent to the eavesdropping users according to the criterion of maximizing the system reachable traversal security and rate lower bound. In the moving process of each legal user and each eavesdropping user, the base station intermittently acquires statistical channel information and dynamically updates a statistical precoding result. According to the invention, the problem that the base station side only knows the design of the beam domain secure transmission signal of the statistical channel information is solved, the realization complexity is reduced, and meanwhile, the introduction of artificial noise improves the security of system transmission.

The invention provides a relay physical level safe transmission method and belongs to the field of communication. According to the invention, a relay node is, while under a full duplex working mode, is configured with a plurality of antennas, and adopts decode-and-forward protocol. The method designs a pre-coded array to be an artificial noise, and allows the relay node to transmit a hybrid signal of an expectation signal and the artificial noise to an object node at each time slot. A bugging node can bug the hybrid signal. The object node can eliminate the designed artificial noise from the hybrid signal so as to decode the expectation signal, while the bugging node fails to do the decoding. According to the invention, the method also derives and acquires the safety rate of the system, acquires the optimal power allocation polity between the expectation signal and the artificial noise. According to the invention, the method can effectively deal with bugging behavior and explicitly increase safety property of the system.

The invention discloses two robust beam forming methods for an MISO wiretap channel based on interruption probability constraints. Two robust beam forming schemes for the MISO wiretap channel are provided, a method of bisection, semidefinite relaxation and a Bernstein-type inequality are utilized to transform a nonconvex problem with the interruption probability constraints into a series of semidefinite programming problems in the absence of artificial noise assistance, so that the optimal robust beam forming design is obtained; the total transmitting power is divided into two parts of a useful signal and artificial noise in the presence of artificial noise assistance, through transforming the nonconvex problem with the interruption probability constraints into the semidefinite programming problems, the optimal design of robust beam forming of the useful signal and a covariance matrix of the artificial noise is obtained; the secrecy rate of a communication system is effectively improved, the wiretapping capability of a user is reduced and the security of the communication system is improved.

The invention belongs to the technical field of physical layer security, and provides a secret transmission method of a wireless energy-carrying cooperative system, and the transmission method comprises the steps: realizing system secret rate maximization on the basis of comprehensively considering energy collection constraint and cooperative interference performance; A relay node of the system isprovided with a plurality of antennas and works in a full duplex mode, a power switching mode is adopted for energy collection and data receiving and transmitting, artificial noise is sent for collaborative interference while information signals are forwarded, and the signal-to-noise ratio of a destination node is increased by adjusting an antenna array matrix by adopting a beam forming technology; According to the method, the energy collection constraint and the cooperative interference performance are comprehensively considered, the maximum confidentiality rate is taken as an objective function, and the optimal values of an energy collection factor and a cooperative interference power distribution factor are solved; Simulation results show that the proposed confidential transmission scheme can effectively improve the confidentiality rate of the system.

The invention relates to OFDM (Orthogonal Frequency Division Multiplexing) system signal sending method, receiving method and device. The methods comprise the steps of: carrying out serial / parallel conversion on an input signal for constellation modulation; encrypting the signal subjected to the constellation modulation, wherein the encrypting operation includes the steps of: implementing paseudorandom constellation diagram rotation on the signal subjected to the constellation modulation, and adding weak artificial noise in the signal subjected to paseudorandom constellation diagram conversion, wherein each constellation point rotates a random angle which is appointed by a system sending end and a legal receiving end; and emitting after carrying OFDM modulation. The methods and the device can obtain higher safety and confidentiality by using the randomness of the constellation diagram rotating angle and the inconvertibility of the weak artificial noise, and can ensure the compatibility with the traditional communication system.

The invention discloses a robust security beam forming method based on multi-objective optimization. The robust security beam forming method comprises the following steps: step a, establishing a satellite-ground fusion cognitive network under the condition of spectrum sharing of a satellite communication network and a ground cellular network; step b, setting a secondary user signal-to-interference-and-noise ratio threshold gamma s, an eavesdropping user signal-to-interference-and-noise ratio limit gamma e, the maximum transmitting power Pmax of the base station and the maximum interference power of the base station to the primary user in the satellite-ground fusion cognitive network; step c, establishing two optimization problems of secondary user reachable safety rate maximization and base station transmitting power minimization; step d, establishing a multi-objective optimization problem by adopting a weighted Chebyshev method; and step e, solving a transmitting beam forming weight vector of the base station and an applied artificial noise vector by adopting continuous convex estimation, Taylor series expansion and an interior point method. According to the robust security beam forming method based on multi-objective optimization provided by the invention, compromise between maximization of the reachable security rate and minimization of the transmitting power of the base station can be realized, so that the physical layer security transmission performance of a satellite-ground fusion cognitive network is effectively improved.

The invention discloses a safe transmission method in an MIMO Y eavesdropping network based on real interference alignment. According to the method, through utilization of a real interference alignment technology and an artificial noise technology, through construction of useful signal precoding matrixes and interference suppression matrixes, inter-user interference signals at legal user positions are located in null spaces of receiving suppression matrixes; and noise signals are completely eliminated through linear combination. Moreover, through construction of a noise signal coding matrix at a relay position, the noise signals are completely aligned to receiving signal spaces of eavesdropping users, so the eavesdropping users cannot eavesdrop the signals and the whole multi-user eavesdropping network can obtain multiple safe communication channels.

An active control of an unwanted noise signal at a listening site radiated by a noise source uses a reference signal that has an amplitude and / or frequency such that it is masked for a human listener at the listening site by the unwanted noise signal and / or a wanted signal present at the listening site in order to adapt for the time-varying secondary path in a real time manner such that a user doesn't feel disturbed by an additional artificial noise source.

The invention provides an accurate wireless security transmission technology based on a random frequency diversity array (RFDA) and directional modulation (DM). According to the invention, artificial noise (AN) is projected to the desired position-oriented vector zero space to interfere with surrounding potential eavesdroppers, which enhances the security of signal transmission. Compared with a traditional directional modulation technology based on a phased array (PA), the technology provided by the invention uses the random frequency diversity array to elevate security transmission from one dimension (angle) to two dimensions (distance and angle) to realize accurate point-to-point signal transmission. According to the invention, a closed expression of the lower bound of the traversal security rate is acquired; the influence of power allocation and frequency allocation on the performance of the technology provided by the invention is investigated; and compared with the original directional modulation technology, the technology can effectively improve the security transmission rate.

The invention discloses an artificial noise-based cooperative network power allocation method for a main channel and a cooperative channel under a non ideal channel estimation condition. After a transmitting end uses legal communication main channel information obtained in a non ideal channel estimation method, a transmitting signal is designed, power allocation between a useful signal and an artificial noise signal is carried out, on the basis of ensuring the security performance, and useful secrecy messages are transmitted to a legal receiver as much as possible. In addition, in order to improve the security of the secrecy messages, a cooperative jammer (CJ) is added, the CJ uses cooperative channel information obtained in the non ideal channel estimation method to design a transmitting signal to jam an eavesdropping node Eva. Under the condition of only knowing the statistical channel information of an eavesdropping channel at the transmitting end, the system security transmission rate is maximized through optimizing power allocation for the transmitting signal at the transmitting end, and the most effective security transmission of the secrecy messages in the cooperative network is realized.

The invention discloses an uplink secure transmission method based on downlink auxiliary feedback in a 5G communication system. In the first stage, a multi-antenna base station end sends both artificial interference and artificial noise signals on a downlink by means of a wave beam formation technology; and a single-antenna user end receives an emission signal from the base station end, and scrambles the received signal to a to-be-sent secret signal so that a mixed emission signal is formed. In the second stage, the user terminal broadcasts the mixed emission signal; and the base station end receives the mixed emission signal. Since the base station end already knows an artificial interference signal emitted by the base station itself, an expected secret signal can be separated from the received signal. A single-antenna passive eavesdropping end receives mixed signals during both transmission stages, and cannot know any prior information about the artificial interference and artificial noise signals, so the possibility of stealing secret information is low. Therefore, the transmission security of a 5G uplink single-input and multi-output system is effectively guaranteed.

The invention discloses an artificial noise precoding secure transmission method for a full duplex relay system. The method comprises the following steps: an information source adopts an artificial noise precoding scheme to simultaneously broadcast useful signals and artificial noise signals; a relay receives the signals broadcast by the information source and the self-interference at the relay, and a wiretapper receives the signals broadcast by the information source and recoding signals transmitted by the relay; a relay node reduces the influence caused by the self-interference by adopting a self-interference elimination technique; an information sink receives the transmitted signals that are recoded by the relay by adopting a maximal-ratio combining strategy; the signal to interference and noise ratios of the information source to a relay link and the relay to an information sink link are obtained, and the received signal to interference and noise ratios at the information sink and the wiretapper are also calculated; and the instantaneous safety rate of the system is obtained according to the received signal to interference and noise ratios at the information sink and the wiretapper, and an average safety rate is calculated. According to the method disclosed by the invention, the legal channel transmission rate can be increased, and the capacity of wiretap channels can also be effectively reduced.

A telecommunication system with a modem (MCO) having a controlling module (CCO) coupled to a data transmission module (DTM) comprising a transmitter (TX) adapted to transmit channels via a communication line (LN), the channels transporting user data (UD) by means of signals (STX) with modulation having a bitload that is modifiable. The data transmission module comprises an artificial noise generator (ANG) coupled to the transmitter and controlled by the controlling module to inject an artificial noise (AN) into the transmitter. The artificial noise is used to influence the signals transmitted by the data transmission module to the communication line and may be added to the data signals either in the transmit time domain processing module (TXTDP) or in the transmit frequency domain processing module (TXFDP) of the transmitter. The system is particularly advantageous for DSL applications where the margin is larger than 3 dB. This corresponds to distances lower than 4000 meter for an ADSL cable with 50 users.

The invention discloses an energy harvesting relay safety transmission method adopting artificial noise precoding, which is applied to a system including four nodes that are a source, a relay, a sink and a wiretapper. The system requires two time slots to complete transmission. In the first time slot, the source broadcasts signals, the sink and the wiretapper receive the signals, and the relay adopts the maximal ratio to combine received signals, harvest energy and receives a secrecy signal. In the second time slot, the relay obtains state information of a channel from the relay to the sink, an artificial noise auxiliary precoding strategy is adopted to carry out precoding of secrecy information and artificial noise, then an amplification forwarding protocol is used for forwarding coding signals, the sink and the wiretapper receive the coding signals, and the received signals during the two time slots are combined at the maximal ratio. The relay safety transmission method applies artificial noise auxiliary precoding to an energy harvesting relay adopting power distribution, so that the remote transmission system limited in energy is enabled to have the great safety transmission performance.

The invention discloses a physical layer safe communication method designed by combining signal feedback and artificial noise in a wireless communication network. The method comprises a first stage that a sending end sends information needing to be kept secret to a legal receiving end; a second stage that after the legal receiving end receives the information, a certain amount of artificial noise is mixed in the received information, and the mixed signal is fed back to the sending end; and a third stage that the sending end sends feedback signal to the receiving end. The legal receiving end knows the artificial noise mixed in the second stage, so that the legal receiving end can eliminate the artificial noise; an eavesdropping end cannot eliminate the noise, so that the performance is weakened by the artificial noise; and the safe communication between the sending end and the receiving end is realized. According to the scheme, the safe communication between the legal devices can be realized under the condition that the legal communication devices have no antenna, no external helper and no any channel information of the eavesdropping end. The method has superiority in the communication safety aspect.

The invention discloses a physical layer secure transmission method for resisting information eavesdropping of an eavesdropping node. The physical layer secure transmission method comprises the steps that: 1) a source node and a target node sequentially send a training sequence before the beginning of information transmission, so that the source node and the target node estimate equivalent channel information h<n, k> from the source node to the target node, wherein n is contained in {1, ... , Nr}, k is contained in {1, ... , Nt}, Nt is antenna number set by the source node, and Nr is antenna number set by the target node; 2) the source node encodes to-be-transmitted data, obtains a to-be-transmitted symbol and an antenna serial number for transmitting the to-be-transmitted symbol, then adds artificial noise into the to-be-transmitted symbol, and transmits the to-be-transmitted symbol added with the artificial noise to the target node through a selected antenna; 3) and the target node receives the symbol transmitted by the source node, decodes the symbol transmitted by the source node by means of a maximum likelihood decoder, and completes physical layer secure transmission of information. The physical layer secure transmission method can achieve physical layer secure transmission of the information.

The invention discloses a physical layer secure transmission method using the spatial modulation technology. It is assumed that a sender can obtain channel state information of a legal user and an illegal user, the sender obtains an index number and a to-be-sent symbol of a receiving antenna according to to-be-transmitted bit data by using the pre-encoding assisted generalized orthogonal spatial modulation technology, obtains a zero-forcing pre-encoding matrix by using the channel state information between the sender and the legal user, adds artificial noise to a zero space of a channel between the sender and the legal user, and finally figures out the optimal power allocation through the maximum secrecy capacity; and the legal user can smoothly decode the information sent by the sender through the channel state information between the sender and the legal user, and the eavesdropping user is interfered by the artificial noise and cannot correct decoding the information, thereby realizing the security of a physical layer. By adoption of the physical layer secure transmission method disclosed by the invention, higher security capacity can be stably obtained under the same signal-to-noise ratio.

The invention discloses an anti-eavesdropping index modulation OFDM (Orthogonal Frequency Division Multiplexing) transmission method in a multi-antenna system. The method is based on thoughts of orthogonal spatial modulation and artificial noise, and a dimension of an antenna index is added on the basis of a conventional OFDM-IM (Orthogonal Frequency Division Multiplexing-Index Modulation) system.A source node divides original data to be sent into three parts; a first part is called as an antenna index bit and used for determining indexes of at most two activated antennas; a second part is called as a carrier index bit and used for activating a carrier for bearing a signal; a third part is called as a symbol modulation bit and used for mapping the signal to modulate the source node; and according to source node-target node channel state information, the artificial noise is added for a modulation symbol to achieve an anti-eavesdropping effect. A target node respectively adopts an optical maximum likelihood detection algorithm and a suboptimal maximum likelihood detection algorithm based on a log-likelihood ratio. A simulation result shows that a bit error rate of an eavesdropper iskept within a range of about 0.5, and a case that the disclosed scheme can ensure safety of legal transmission is proved.

The invention discloses a collaboration network power distribution method based on artificial noise under a nonideal channel estimation condition of a collaboration channel. The method comprises the steps that S1, a legal receiving end sends pilot sequences to a transmitting end of an transmitting source, and a collaboration jammer; S2, the transmitting end receives the pilot sequence and carries out ideal channel estimation, and the collaboration jammer receives the pilot sequence and carries out nonideal channel estimation; S3, the transmitting end and the collaboration jammer design respective transmitting signals; S4, the transmitting end and the collaboration jammer transmit signals to the legal receiving end and an eavesdropping end at the same time; S5, the optimum transmitting power distribution ratio and the maximum safe transmission rate under the nonideal channel estimation condition of the collaboration channel are calculated; S6, the optimum transmitting power distribution ratio and the maximum safe transmission rate under an ideal channel estimation condition of the collaboration channel are calculated; and S7, the maximum safe transmission rates under the nonideal channel estimation condition and the ideal channel estimation condition are compared. According to the collaboration scheme provided by the method, the condition that an error exists in the channel estimation method of the collaboration channel is taken into full consideration, and the practical power distribution scheme for realizing system safety is proposed.

The invention discloses a design method of a transmitting terminal of a VLC (Visible Light Communication) secure communication system based on QoS (Quality of Service). By pre-coding transmitted signals and adding artificial noise, the direct current bias of the system is minimized under the condition that the SNRs (Signal to Noise Ratios) of a user and an eavesdropper satisfy the QoS limiting condition of secure communication. The influence of channel information errors of the eavesdropper is also sufficiently considered, so that the robustness of the secrecy performance of the system is improved. When secure communication is realized, the direct current bias of the system is effectively reduced, and the utilization rate of energy is improved; and the method is low in complexity and easy to implement in engineering.

The invention provides a multi-relay non-orthogonal multiple access system secure transmission scheme based on artificial noise. The transmission system comprises a source node, two users, an eavesdropping node and a plurality of relay nodes. In the scheme, the whole communication process is divided into four stages: a preparation stage, a multi-relay decoding stage, a relay selection stage and auser decoding stage. System communication is completed in two time slots: a first time slot and information source S broadcast messages to all relay nodes, a message mapping strategy is adopted duringbroadcasting, and the relay receives signals and decodes the signals. In the second time slot, the system performs double-relay selection, selects an optimal relay forwarding user signal from the decodable relay set, and selects an optimal relay sending artificial noise from the undecodable relay set. The relay selection strategy can effectively reduce the complexity and the safety interruption probability of the system while maintaining the diversity gain of the multi-relay system. And the signal-to-noise ratio of the eavesdropping end can be further reduced through artificial noise scrambling, and the safety performance of the system is improved.

The invention provides an optimization method for artificial noise direction modulation based on a frequency control array. The method comprises the steps: enabling a transmitting end to obtain the azimuth and distance of a legal receiver, and extracting a normalized beam vector; calculating the maximum confidential rate difference between a maximum legal receiver and an adjacent eavesdropping receiver; calculating a frequency compensation vector with the maximum confidential capability through a non-convex optimization algorithm, and then calculating a legal receiver guide vector; calculatinga normalized artificial noise projection matrix according to the orthogonality of the artificial noise and the legal receiver guide vector, and obtaining an artificial noise baseband signal based onthe frequency control array. The method realizes the dual control of angle and distance, and realizes the maximum confidential rate difference between the legal receiver and the adjacent eavesdroppingreceiver, and ensures higher-precision physical layer wireless security communication.

The invention discloses a collaborative interference physical layer secure transmission method based on optimal relay selection, which mainly solves a problem of low secret rate and high transmissioncost of a wireless transmission system in the prior art. An implementation scheme of the method is as follows: a destination node D acquires state information of each channel from each relay to the destination node D and the state information of each channel from each relay to an eavesdropping node E, and selecting an optimal relay R according to the state information of the channels; the R generates an artificial noise signal V; a sending node A sends an information signal, and simultaneously, the optimal relay R sends the artificial noise signal; the destination node D receives the information signal, and the eavesdropping node is suffered from interference of the artificial noise signal V while receiving the information signal. In the method provided by the invention, the optimal relayis selected for sending the artificial noise signal, the eavesdropping node is interfered, link quality of an eavesdropping channel is weakened, transmission complexity and transmission cost of the system are reduced, and secret rate of the system is improved, and the method can be used for a secret communication system comprising a plurality of relays.

The invention provides a secure communication method in a non-orthogonal multiple access network assisted by an intelligent reflecting surface, and belongs to the field of multi-user non-orthogonal multiple access network security. By superposing a proper amount of artificial noise in transmitted NOMA information and jointly optimizing an IRS reflection phase, a transmitted beam vector and an artificial noise vector, the sum of transmission rates of legal users is maximized. In addition, the artificial noise signal for controlling transmission can be completely eliminated by a serial interference elimination technology at each legal user side, so that eavesdropping is effectively inhibited under the condition of not influencing legal receiving. Compared with an OMA (Orthogonal Multiple Access) scheme without artificial noise and assisted by a traditional reflecting surface, the invention has the advantages that the network security performance can be remarkably improved, and the application value is very high.

The present invention belongs to the technical field of video raindrop removal, and especially relates to a method and a system for removing raindrops in videos. The method comprises: a step a of reading video frames and performing color space conversion for the video frames; a step b of performing raindrop initial detection through photometric characteristics of static raindrops, performing image edge part identification through a guide filter, and subtracting an edge part from an initial detection result, so as to obtain optimized candidate raindrops; and a step c of obtaining final detection raindrops through a denoising algorithm and raindrop area constraint, and removing the raindrops through a defogging equation and photometric characteristics of dynamic raindrops, so as to obtain a final raindrop removing result. The method of the present invention greatly shortens time required for removing the raindrops, improves raindrop removing efficiency, reduces false detection of raindrop pixels, and avoids introducing of artificial noise, in addition, the method combines the defogging equation and the photometric characteristics of dynamic raindrops to perform raindrop removal processing for images, thereby effectively improving image quality and achieving a good raindrop removal effect.