## 1 Introduction  
Wireless communication has attracted substantial attention in recent years as a promising field of research due to its versatility and economic benefits, particularly with the advent of sixth-generation (6G) communications. As a result, wireless sensor networks have found extensive applications in various aspects of our lives, such as medical, industrial manufacturing, and the Internet of Things (IoT) [1, 2, 3, 4]. However, there are still issues that need to be addressed in wireless communication systems, such as equipment service life, complex environments, and the impact of channel states on energy harvesting and information transmission [5, 6]. The topic of energy harvesting is constantly in the news, as we need energy in all aspects of our lives. While renewable energy sources such as wind, solar, and hydraulic potential are frequently used, some devices, such as artificial hearts and forest monitoring systems, cannot easily compensate for the lack of energy. Therefore, radio frequency (RF) wireless energy harvesting and usage have become a primary research topic in these fields. In an RF wireless energy harvesting system, the uplink information transfer and the downlink wireless energy harvesting are limited, leading to unsatisfactory system performance and restrictions [7]. Therefore, it is essential to distribute the time for sending packets and energy harvesting consistently to reduce the impact on system performance [8]. Energy-harvesting technologies have shown great potential in powering small electronic devices without the need for external power sources. However, existing energy-harvesting devices suffer from large size and low power conversion efficiency. To address these challenges, a better approach to energy harvesting was proposed in paper [9], that is, metasurfaces and metamaterial structures are proposed as collectors for energy-harvesting devices that provide higher conversion efficiency in smaller sizes. One such example is the bow-tie multi-band rectenna with slots proposed in a paper by [PERSON] et al. This rectenna is designed for ambient wireless energy harvesting for autonomous IoT sensors, featuring a high-conversion-efficiency multi-band rectification circuit composed of four single-ring rectifiers. The paper also proposes a power management circuit to store and convert the harvested voltage, smoothing the direct current (DC) output voltage and improving system performance [10]. The design of energy-harvesting devices must meet certain standards to ensure optimal system performance. In this regard, [PERSON] et al. divided the rectenna into antenna rectification impedance bandwidth and antenna radiation characteristics, in accordance with wireless power transfer (WPT) and antenna design for environmental RF energy harvesting application standards [11]. In another paper, the non-orthogonal multiple access (NOMA) protocol is studied to transmit IoT relay node data together with source node data in the presence of interfering signals. The outage probability, throughput and total throughput are mathematically derived, and a representative performance comparison method is given [12]. Finally, a paper by [PERSON] et al. presents the design of a three-band high-gain multi-beam ambient RF energy-harvesting system utilizing hybrid combination. This system maximizes the use of harvested RF energy by utilizing frequency, space, and polarization simultaneously. A broadband hybrid combination is proposed that enables energy harvesting at low RF power densities while maintaining the wide frequency and spatial coverage required for ambient RF energy harvesting [13]. In paper [14], the limited sensitivity and nonlinearity of far-field RF energy harvesting are presented and their effects quantified. Furthermore, a linear model and two nonlinear models are proposed, and the differences in wireless information and power transfer designs for each model are shown in single-user and multi-user deployments [15].