The implementation of 5G mobile networks and utilization of mmWave in such networks provides individuals with an exceptional transmission rate, as noted in reference [8]. Notwithstanding, several issues persist; chief among them is the potentially deleterious consequence whereby the utilization of an ultra-high transmission rate has the potential to cause a significant increase in power consumption amongst wireless devices that are linked within the network. The topic of contemporary academic inquiry pertains to the SWIPT-enabled fifth-generation cellular networks, which exhibit a propitious course of action for tackling the antecedent recognized difficulty. The principal objective of SWIPT technology is to ascertain a suitable allotment scheme for radio frequency (RF) that enhances the balance between dependability and energy efficiency. This objective also takes into account other significant network constraints. The emergence of SWIPT has gained significant traction, as renewable sources of energy, such as solar and wind power, prove to be inadequate under various circumstances. This is owing to the fact that radio frequency signals possess the capacity to convey both data and energy. [21],[23], [24]. The realization of ubiquitous communications of wireless devices in a self-sustainable manner has become a vital requirement for the advancement of 5G technology. Considering this, Simultaneous Wireless Information and Power Transfer have emerged as an indispensable solution that caters to the energy requirements for wireless charging of energy in constrained devices and facilitates the transmission as well as the reception of information.
The utilization of this technology in the charging of sensor nodes situated in remote and difficult-to-reach areas is particularly advantageous due to its cost-effective nature. In [25], a novel conspires for SWIPT has been proposed, wherein energy is transported via an unmodulated, high-power signal whereas the transmission of information is achieved through a relatively weak modulated signal. The experimental findings confirm that a power yield greater than 0.5 mW can be collected from a distance of four meters, thus proving viable for the recharging of numerous 5G-IoT devices. The SWIPT technology, akin to power-line communication, presents an opportunity for considerable advantages, including increased longevity of system operation, heightened spectral efficiency, improved interference mitigation, and reduced transmission latencies. [16], [22]. With regard to the core pillars of the 5G network, it is projected that SWIPT technology will play a pivotal role in facilitating forthcoming industry standards. Conversely, SWIPT introduces a structural transformation for wireless communication networks, resulting in novel architectural challenges. Notably, the evaluation of system performance mandates an equilibrium between the rate of information transmission and energy extracted at the end terminals [18]. A fundamental compromise arises concomitantly with regard to the rate of transmission of information and the magnitude of energy harvested. This was designated by the region of rate and energy which was formed by all possibilities of energy harvested levels and rate of transmitted information [10].
3.1 Mm-wave Communication
The authors of reference [1] conducted channel measurements at both 3.5 GHz and 28 GHz frequencies to evaluate the practicability of SWIPT with millimetre-wave (mmWave) technology. This study reveals that the employment of the 28 GHz frequency is optimal for line-of-sight transmissions with limited scope, whereas the utilization of the 3.5 GHz frequency, which experiences reduced large-scale fading compared to the 28 GHz frequency, is more appropriate for long-range transmissions. As per the findings, the authors have put forth a proposition regarding the present study, introducing a dual-band SWIPT network that incorporates a zone with a high concentration of access points (hot-spot) as well as a zone with expansive geographical coverage. Within this zone of heightened activity, the utilization of a 25 gigahertz frequency enables the instantiation of the concurrent transmission of wireless information and power via a line-of-sight mechanism. In the context of broader coverage, the communication of information is facilitated through the utilization of a 3.5 gigahertz frequency. Ultimately, a mathematical approach to optimizing the allocation of power and channels is introduced, driven by the goal of maximizing the minimum quantity of energy harvested by individuals, with TS structure serving as a foundational principle.
3.2 SWIPT-OFDM Signal Excitation
It proposes two solutions to improve the efficiency of the conversion process in order to ensure system sustainability [9].
The introduction of a new design of OFDM transmitter with selective architecture tailored for the transmission of SWIPT is the first component of the solution. This newly proposed architecture of the transmitter includes an insertion module of excitation, which adds a signal torturing to a segment of the signal broadcast. The module of excitation allows the harvested component of the signal transmitted to be conditioned, resulting in a higher PAPR for that portion of the signals. The conditioned signal is gathered and given via the receiver's dynamic switching capability.
The second element of the approach entails a new design of rectifying circuit that is also optimized for efficient conversion. The rectifying circuit ancestors were modeled and simulated. The single-diode rectifier type outperformed the bridge rectifier. As a result, for efficiency and trade-off analysis, the single-diode rectifier solution was utilized. To analyze the performance, a proposition and evaluation of an analytical formulation detailing the relationship between the rate and energy trade-offs of a receiver in the context of SWIPT transmission are presented. The study also produced the analytical expression for the self-sustainability of the system. In conclusion, Signal conditioning increased the self-sustainability of the selective OFDM system through the adoption of a new architecture of transmitter along with the model of rectifying circuits. [9].