The intelligent reflecting surface(IRS)is considered a core technology of next-generation mobile communica-tion.It has significant advantages in enhancing network coverage,spectrum efficiency,energy efficiency and deployment cost.The aerial intelligent reflecting surface(AIRS),which combines the high mobility of the air platform and the high-quality link characteristics provided by the intelligent reflecting surface,can effectively assist the transmission from the base station to the users in complex communication scenarios and enhance the network coverage.A joint optimization problem of the base station beamforming,AIRS deployment location and phase shift design for the AIRS was studied for AIRS assisted multi-user massive multiple input multiple output(MIMO)systems.Under the condition of the statistical channel state information(CSI)being known,an optimization scheme of system ergodic sum rate based on block coordi-nate descent(BCD)was proposed.Firstly,an optimization model was established by jointly optimizing the transmit beam-forming at base station,the placement and the phase shift for AIRS.Secondly,the nonconvex optimization problem was decoupled into three subproblems that were easy to deal with by BCD algorithm.Finally,lagrange multiplier method,relax-ation variable method and RMSProp gradient descent algorithm were used to solve the subproblems respectively.The simulation results show that the proposed optimization scheme can effectively improve the ergodic sum rate of the system with good convergence properties.
关键词
大规模多输入多输出/空中智能反射面/统计信道状态信息/位置优化/波束成形
Key words
massive multiple input and multiple output/aerial intelligent reflecting surface/statistical channel state informa-tion/location optimization/beam forming
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