This paper studies an intelligent reflecting surface (IRS)-aided multiple-input-multiple-output (MIMO) full-duplex (FD) wireless-powered communication network (WPCN), where a hybrid access point (HAP) operating in FD broadcasts energy signals to multiple devices for their energy harvesting (EH) in the downlink (DL) and meanwhile receives information signals from devices in the uplink (UL) with the help of an IRS. Taking into account the practical finite self-interference (SI) and the non-linear EH model, we formulate the weighted sum throughput maximization optimization problem by jointly optimizing DL/UL time allocation, precoding matrices at devices, transmit covariance matrices at the HAP, and phase shifts at the IRS. Since the resulting optimization problem is non-convex, there are no standard methods to solve it optimally in general. To tackle this challenge, we first propose an element-wise (EW) based algorithm, where each IRS phase shift is alternately optimized in an iterative manner. To reduce the computational complexity, a minimum mean-square error (MMSE) based algorithm is proposed, where we transform the original problem into an equivalent form based on the MMSE method, which facilities the design of an efficient iterative algorithm. In particular, the IRS phase shift optimization problem is recast as an second-order cone program (SOCP), where all the IRS phase shifts are simultaneously optimized. For comparison, we also study two suboptimal IRS beamforming configurations in simulations, namely partially dynamic IRS beamforming (PDBF) and static IRS beamforming (SBF), which strike a balance between the system performance and practical complexity.
翻译:本文研究的是智能的反映表面(IRS)的智能(IRS) 辅助多投入-多输出(IMIMO) 的全倍化(FD) 无线动力通信网络(WPCN),在FD中运行的混合接入点(HAP)将能源信号传输到下行(DL)的多个装置,用于在下行(EH)中收集能源,同时在IRS的帮助下接收来自上行(UL)设备的信息信号。考虑到实际的有限自我干预(SI)和非线性EH模式,我们通过联合优化DL/UL时间分配、设备预编码矩阵、在HAP中运行的混合接入点(HAP)将能量信号传输到多个装置,用于在下行(DL)中,由于由此产生的优化是非电流化(ULL),因此没有标准的方法可以最优化地解决上端(ULL) 。为了应对这一挑战,我们首先建议基于元素(EWEW) 的算法,每个IRS 阶段的转换为交替方式。为了降低计算复杂性,在IRS/UDRS的系统中,一个最起码的变动过程是我们所设计的系统。