57results about How to "Increase security rate" patented technology

The invention belongs to the technical field of high-frequency wireless communication, and particularly relates to an intelligent reflection surface assisted terahertz communication system design method. The scheme of the invention is as follows: the communication system comprises a base station equipped with NBS antennas, an intelligent reflection surface formed by NIRS reflection array elements,and a mobile user terminal equipped with a single antenna. Through active hybrid beam forming, the base station transmits a transmitting signal to a relay formed by the intelligent reflection indicator in a wave beam form; and the intelligent reflection surface reflects the wave beam to a mobile user side by adjusting the phase of each array element, suppresses a received signal of an eavesdropper, establishes a joint optimization function by taking maximization of a downlink transmission data rate as a target, and optimizes the problem of maximization of a system transmission data rate through a phase search algorithm based on cross entropy. Compared with the traditional technology, the search frequency and the calculation complexity of the intelligent reflection surface phase matrix canbe effectively reduced, and meanwhile, the safety rate of the multi-input single-output terahertz communication system can be improved.

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.

The invention discloses a cooperative wave beam formation method capable of improving physical layer security based on null space. In the prior art, a safety transmission problem when there is a plurality of eavesdropping nodes in a relay network can not be guaranteed. By using the method of the invention, the above problem is mainly solved. The method comprises the steps that 1) a source node sends confidential information to all the relay nodes and a relay carries out weighting processing on a received signal and then forwards to a destination node and the eavesdropping nodes; 2) a received signal to noise ratio of the destination node and the eavesdropping nodes is calculated; 3) according to the received signal to noise ratio, a safe rate of the destination node is calculated; 4) according to the signal after the weighting processing which is performed by the relay, consumption of relay total power and the power is calculated so as to obtain a power constraint; 5) the null space of an equivalent channel matrix of the eavesdropping nodes is calculated so as to obtain a space constraint; 6) under the condition that the power constraint and the space constraint are satisfied, an optimal wave beam shaping weight vector is designed; 7) the optimal wave beam shaping weight vector is distributed to each relay node. By using the method of the invention, the safe rate of the relay network where the plurality of eavesdropping nodes exist can be effectively increased.

The invention discloses a robustness safety design method for a multiple input multiple output (MIMO) communication system. Receiving terminals of the method are each provided with a power separator that divides the received power to realize information decoding of the receiving terminal and energy collection simultaneously. If an idle receiving terminal is a potential eavesdropper, a sending terminal adopts methods of precoding and introducing artificial noise, thereby effectively improving system security rate and transfer efficiency of system energy. When the sending terminal only knows part of channel status information of the idle receiving terminal, the robustness safety design is described as a non-convex semi-infinite optimization problem. The non-convex semi-infinite optimization problem can be changed into a positive semi-definite relaxation problem by use of first order Taylor expansion and S-Procedure theorem, and the effective robustness safety design method can be finally provided through a convex optimization tool based iterative algorithm. With safe communication of the system guaranteed, the safety rate of the sytesm is improved remarkably, the energy transfer efficiency of the system is improved, and the communication and energy demands of the user are better met.

The invention discloses a secure transmission method based on relay strategy selection and resource allocation in a relay OFDM (Orthogonal Frequency Division Multiplexing) network. A communication system model employed by the method comprises a sending node S, N destination receiving nodes (D <1>...D <N >), an eavesdropping node Eve and K relay nodes. The method comprises the steps of for data transmission of each time, in a second time slot, after relay strategy selection and resource allocation, sending data to the relay nodes by the sending node S; and in a second time slot, selecting one of the K relay nodes as a forwarding node to forward the data received in the first time slot to the destination node D, and moreover, eavesdropping information sent to N users by the eavesdropping node Eve. Compared with traditional modes of merely employing AF (Amplify-and-Forward) or DF (Decode-and-Forward), the method has the advantages that a lower private interruption probability is obtained in a relay strategy selection mode, and the performance difference between the method and the two traditional modes is more remarkable under a high signal to noise ratio.

The invention provides a joint beamforming and optimal power allocation method in a bidirectional untrusted relay network. Interference signal pre-coding matrices QA and QB at a source node and a target node are designed, so that power of a collaborative interference signal reaching a relay node is maximized; and useful signal pre-coding matrices FA and FB and a power allocation scheme for each user to send a useful signal and the collaborative interference signal are optimized in a joint mode, so that a reachable safety rate of the network is further improved. According to the invention, theuseful signal is aligned to an equivalent signal space and the interference signal orthogonality is forced; meanwhile, the optimal power allocation of each user is generated; and the safety rate is improved to the greatest extent.

The invention discloses a power optimization method for maximizing the minimum safety rate of downlink non-orthogonal multiple access (NOMA) mobile users of an unmanned aerial vehicle, and relates tothe technical field of information and communication. The objective of the invention is to improve the minimum safety rate of downlink non-orthogonal multiple access (NOMA) mobile users of a maximizedunmanned aerial vehicle. The invention designs a power optimization method for maximizing the minimum safety rate of a downlink non-orthogonal multiple access (NOMA) mobile user of an unmanned aerialvehicle. Poower distribution optimization can be carried out on safe transmission of a large number of NOMA mobile users, and meanwhile, limited resources can be effectively utilized, so that the safety rate of the NOMA mobile users can be effectively improved compared with an average power distribution method while certain service quality of Internet of Things services is guaranteed.

The invention discloses a pre-coding method, based on safety speed optimization, in multi-base-station cooperation scenes, particularly relates to a pre-coding information processing method, based on safety speed optimization, in multi-base-station cooperation scenes, and relates to the technical field of wireless communication pre-coding. The method includes: each base station transmits a training sequence to a user, and a transceiver of the user and an eavesdropper performs channel estimation according to the received signals so as to obtain the channel information between each base station and the user and the channel information between each base station and the eavesdropper; a central processing unit calculates the pre-coding matrixes of all base stations according to the obtained channel information, and feeds each pre-coding matrix to the corresponding base station; each base station pre-codes the same signal and transmits the pre-coded signal to the user; the user and the eavesdropper detect the received signals and estimate the transmitted signals. By the method, safety speed of the maximum systems of the pre-coding matrixes of the base stations are obtained simultaneously, the defect that traditional iteration algorithms cannot guarantee that the obtained solution is the optimal global solution, and system safety speed can be increased effectively.

The invention relates to a full-duplex cooperative scrambling secure transmission method based on optimal user selection of direct path. In the first time slot, the source node sends information to the relay node and the destination user node. At the same time, one user node with the largest signal-to-noise ratio is selected from all the destination user nodes as the legal user node, and the otherdestination user nodes are eavesdropping user nodes. The legal user node sends interference signals to the relay node and destination user node. In the second time slot, the relay node amplifies theinformation received in the first time slot by using the variable gain amplification and forwarding protocol, and forwards the information to the destination user node. The legitimate user continues to send the scrambling signal to the eavesdropping user node. The invention can reduce the receiving signal-to-noise ratio of the eavesdropping channel and ensure the safe transmission of the information.

The invention provides a robustness combined signal processing method of a source end and a relay end of a relay system. The method includes the following steps: transmitting a training sequence to a relay by the source end, carrying out channel estimation and obtaining an estimated channel from the source end to the relay by the relay, transmitting the training sequence to a user side by the relay, carrying out channel estimation and obtaining an estimated channel from the relay to a legal user by the legal user, carrying out channel estimation and obtaining an estimated channel from the relay to an eavesdropping user and a channel error variance by the eavesdropping user, feeding the channel information back to a relay node by a user side, transmitting the channel information to a central processing unit by the relay node, performing an iterative algorithm on a pre-code of the source end and a pre-code of the relay by the central processing unit, transmitting the computed pre-codes to the relay node by the central processing unit, feeding the pre-code of the source end back to the source end by the relay, modulating transmitted signals and transmitting the signals to the relay by the source end, pre-processing the signals and then broadcasting the signals to the users by the relay, and detecting the received signals by the legal user. The method promotes safety performance of the system.

The invention discloses a joint optimization method for the position and wave beam of an intelligent reflecting surface carried on an unmanned aerial vehicle. The method mainly solves the problems that in the prior art, the shielding effect caused by a building is not considered, and safe transmission cannot be carried out under the condition that eavesdropping channel state information is not completely known. According to the invention, aiming at an uplink of an intelligent reflecting surface assisted millimeter wave MIMO system carried on an unmanned aerial vehicle, indirect sight distance links from a legal user to an intelligent reflecting surface IRS and from the IRS to a base station are ensured by optimizing the position of the unmanned aerial vehicle, so that a shielding effect caused by a building is avoided; meanwhile, under the condition that eavesdropping channel state information is not completely known, the safety rate of an IRS-assisted millimeter wave MIMO safety communication system is maximized by jointly optimizing legal user transmitting end beam forming and a phase shift matrix of an intelligent reflecting surface IRS. The method improves the secure transmission performance of a communication system, and can be used for a millimeter wave MIMO system.

The invention relates to a method and a system for improving a security rate of an MIMO security communication system. The method for improving the security rate of the MIMO security communication system is used for realizing the maximal security rate under the constraint of the maximal transmitting power of a transmitting terminal and the number of non-zero elements in an antenna sub-array matrix by using joint beamforming and antenna sub-array forming strategies, so that the relatively high security rate can be obtained under the condition of greatly reducing the cost of the system hardware.

The invention provides a safety rate maximization synthesis method based on general inverse iteration in direction modulation, comprising the following steps of: before designing a useful signal beamforming vector and an artificial noise projection matrix, firstly initializing the two by using a leakage concept, then updating the artificial noise projection matrix by using a general power iterative (GPI), and synchronously updating the useful signal beam forming vector by the Rayleigh-Ritz method. In order to maximize the safety rate, an alternately iterative structure (AIS) is used in designing the useful signal beam forming vector and the artificial noise projection matrix, and the corresponding safety rate needs to be updated in time. Compared with the traditional direction modulationtechnology, the safety rate of the invention is greatly improved at a medium to high signal-to-noise ratio, a useful signal can be demodulated well in a desired direction and is difficult to recover in an undesired direction, thereby better improving the safety performance of the system.

The invention provides a safe alternate iteration method based on beam forming and power distribution in an unmanned aerial vehicle auxiliary direction modulation network. For the problem of how to dynamically adjust power distribution in the flight process of the unmanned aerial vehicle, a maximum signal to noise ratio and a maximum artificial noise ratio are introduced, and a beam forming vectorand an artificial noise projection matrix are dynamically designed along with the flight of the unmanned aerial vehicle. For each fixed time interval in the flight process of the unmanned aerial vehicle, the optimal power distribution strategy can be obtained through alternate iteration of a beam forming vector, an artificial noise projection matrix and a power distribution factor based on the maximum safety rate. Compared with fixed power distribution, the proposed alternate iteration structure can obtain higher safety rate performance gain, and particularly, the safety rate performance is greatly improved under the condition of a small-scale antenna.

The present invention provides a beam forming method in a multi-antenna untrusted relay network. The method comprises of designing the pre-coding matrixes FS and FD to ensure that an untrusted relay node R cannot eavesdrop a useful signal and that a destination node D is able to decode the useful signal so as to improve the reachable safety rate of the network. The method of the invention introduces the multi-antenna technology and does research on a pre-coding design scheme of a multi-antenna untrusted relay network. Through the multi-dimensional signal processing, a transmitted signal is aligned to the useful signal space and orthogonalized to the cooperative interference space so that the transmitted signal and the cooperative interference signal are effectively focused, improving the cooperative interference effect and the safety rate.

The invention relates to a method and system for improving the safety rate of a communication system and a secure communication system. In the method, under the situation that only statistic information of an eavesdropping channel is known, in order to design covariance matrixes of signals and manual noise and guarantee functions and characteristics of information and energy wireless transmission, a covariance matrix of useful information and the covariance matrix of the manual noise are optimized according to the safety capacity, so that an information receiver obtains the safety rate to the largest extent under constraint conditions of transmission power of a transmitter and constraint conditions of wireless energy received by an energy receiver. By means of the method and system for improving the safety rate of the communication system and the secure communication system, under the condition that legal users and eavesdroppers are in the same system and only the statistic information of the eavesdropping channel is known, the covariance matrixes of the useful information and the manual noise are designed, and the safety capacity of the information receiver is maximized, so that the rate of the communication system is increased and meanwhile information and energy wireless transmission is guaranteed.

The invention discloses a data transmission method and a data transmission device based on SM-MIMO. The data transmission method comprises steps that a null space matrix is determined by singular value decomposition of an MIMO channel matrix on a receiving end; an interference signal is determined according to the null space matrix, a corresponding weight vector, and a random signal; and by adopting the SM technology, the interference signal and a to-be-transmitted signal are transmitted. The interference signal is added to the to-be-transmitted signal, and the interference signal is determined according to the MIMO channel matrix singular value decomposition from a transmitting end to the receiving end, and therefore no interference on the receiving end is caused by the interference signal, and an eavesdropper is affected by the interference signal, and the safety speed of the receiving end is improved, and in addition, the safety of the data transmitted to the receiving end is guaranteed.

The invention provides an RIS-assisted cognitive radio wireless safety communication transmission method using part of CSI (Channel State Information), which is used for enabling a secondary transmitter and a secondary user to communicate with a main transmitter and a main user in the same frequency band in an RIS-assisted large-scale MIMO cognitive radio wireless safety communication system. Ensuring that the interference of the secondary transmitter on the primary user is within a certain threshold value, setting an initial value of an RIS reflection coefficient matrix, and designing a beam forming matrix by using part of CSI; designing an RIS reflection coefficient matrix by using the partial CSI according to the beam forming matrix; and repeating the operation until the system security rate converges. According to the method, the spectrum efficiency can be effectively improved on the premise that part of CSI is known, the problem of spectrum scarcity is relieved in an actual communication scene, and the safety rate of a system is improved.

The invention belongs to the field of communication, and particularly relates to a secure transmission method of millimeter waves. The method considers that a secure transmission scheme is designed in a scene that an eavesdropper has learning ability, so that the system security rate is maximum. According to the method, the Markov process is used for modeling the eavesdropping probability of the wave beam, and an optimal wave beam is selected for transmission at each moment, which is equivalent to that limited resources are used in the place with the highest benefit, so that the safety rate of the system reaches the maximum value.