IRS-assisted MISO system energy-saving communication scheme under security constraints

Aiming at the high security and high energy consumption risks of downlink multiple input single output (MISO) systems assisted by intelligent reflecting surface (IRS), the transmission beamforming of the base station(BS), and the phase shift matrix of IRS are jointly considered for the transmission of the system. A system transmission power minimization problem under the constraint of a legal user secrecy rate was constructed. Then a second-order cone programming algorithm based on successive convex approximation(SCA) is proposed to solve the problem. The proposed algorithm simultaneously updates all optimization variables in each iteration and obtains a suboptimal solution to the original problem. The simulation results show that compared with the proposed baseline scheme, the algorithm in this paper achieves lower transmit power while ensuring the confidentiality quality of legitimate users.