Two-channel directional modulation system based on four-dimensional antenna array

Abstract

The invention discloses a two-channel directional modulation system based on a four-dimensional antenna array. The basic structure comprises an antenna array, a radio frequency modulation switch, a power division network, a local oscillation source, a switch management system, a time sequence memory, a baseband signal source 1, a baseband signal source 2 and the like. The biggest innovation of thetwo-channel directional modulation system lies in that under the condition of no phase shifter, directional modulation and secure communication of two paths of signals in space can be realized only by using a radio frequency modulation switch, and the transmitting direction of the signals can be adjusted by changing a switch sequence. Modulation modes of BPSK, QPSK, QAM and the like can be used,and a good secret communication effect is achieved. Compared with an existing security system based on a four-dimensional antenna array, the method has the advantages of being simple in structure, lower in cost, flexible and convenient to adjust and the like. The present invention is used in a wireless communication system.

Description

technical field [0001] The invention belongs to the field of wireless communication, and particularly relates to the use of a four-dimensional antenna array to perform dual-direction directional modulation and secure communication. Background technique [0002] The traditional wireless communication system is based on key encryption, and its security depends heavily on the complexity of the key, which has gradually exposed its security risks. Different from the traditional high-level key encryption technology, the most significant feature of physical layer security is that there is no need for complex digital keys to encrypt private information, but the security of information transmission is studied from the perspective of information theory, which fully utilizes the physical properties of wireless channels. Layer characteristics, including fading, noise and interference, enable secure communication without additional consumption of spectrum resources. Direction modulation...

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Problems solved by technology

[0003] Saad Mufti et al. introduced a dual-channel directional modulation using only phase control in their paper titled "Dual Channel Broadcast using Phase-Only Directional Modulation System" published in the 2018 IEEE International Symposium on Antennas and Propagation & USNC / URSI National Radio Science Meeting system, but the use of a large number of phase shifters will increase the cost of the system, and the transmission rate will be limited to a certain extent; Southeast University discloses a direction modulation method using random perturbation of unit antennas in CN103701514, by randomizing unit antennas to transmit weighting coefficients, resulting in Distortions of constellation points in undesired directions also vary randomly in the absence of noise

But this method can't realize multi-channel confidential communication at the same time; Xi'an Jiaotong University discloses a wireless communication network joint signal feedback and artificial noise physical layer security communication method in CN106131824A, this invention interferes with illegal eavesdroppers by introducing artificial noise correct information, but this method does not consider the implementation of multi-channel signals, and needs to use a phase shifter to change the direction of signal transmission; the University of Electronic Science and Technology of China announced a security communication system and method based on a four-dimensional antenna array in CN102857280, but its Only one-way signal transmission and secure communication can be realized, and the transmission direction of the signal cannot be adjusted arbitrarily

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