This paper considers an active intelligent reflecting surface (IRS)-aided wireless powered communication network (WPCN), where devices first harvest energy and then transmit information to a hybrid access point (HAP). Different from the existing works on passive IRS-aided WPCNs, this is the first work that introduces the active IRS in WPCNs. To guarantee fairness, the problem is formulated as an amplifying power-limited weighted sum throughput (WST) maximization problem, which is solved by successive convex approximation technique and fractional programming alternatively. To balance the performance and complexity tradeoff, three beamforming setups are considered at the active IRS, namely user-adaptive IRS beamforming, uplink-adaptive IRS beamforming, and static IRS beamforming. Numerical results demonstrate the significant superiority of employing active IRS in WPCNs and the benefits of dynamic IRS beamforming. Specifically, it is found that compared to the passive IRS, the active IRS not only improves the WST greatly, but also is more energy-efficient and can significantly extend the transmission coverage. Moreover, different from the symmetric deployment strategy of passive IRS, it is more preferable to deploy the active IRS near the devices.

翻译：本文认为这是一个积极的智能反射表面(IRS)辅助无线动力通信网络(WPCN),设备首先收获能量,然后将信息传送到混合接入点(HAP)。不同于现有的被动IRS辅助WPCN的工程,这是在WPCN中引入活性IRS的第一件工作。为了保证公平,这一问题被写成一个扩大电力限制加权总和的最大投入(WST)的问题,通过连续的凝固近似近似技术和分数编程解决。为了平衡性能和复杂程度的权衡,在活跃的IRS中考虑三种组合,即用户适应性IRS成型、上链接适应性IRS成型和静态IRS成型。数字结果表明,在WPCN中采用活性IRS的超强性和动态IRS成型的好处。具体地发现,与被动的IRS相比,积极性IRS不仅大大改进了WST,而且还使IRS的成型结构化装置得到更高的改进,而且使IRS的投射范围与IRS的节能性更接近,并且能性地扩大了IRS的发射范围。