Researchers from South Korea have developed a new framework for Simultaneous Wireless Information and Power Transfer (SWIPT)-aided nonorthogonal multiple access (NOMA) systems for IoT. The project was led by Dong-Wook Seo from the Division of Electronics and Electrical Information Engineering at Korea Maritime and Ocean University.
The team’s work improved the energy efficiency of such systems by applying SWIPT-aided NOMA to a distributed antenna system (DAS). The approach also increased the spectral efficiency of Industrial Internet of Things devices.
“By applying a DAS with supporting antennas relatively close to edge users alongside a central base station, SWIPT-NOMA’s loss with growing distance can be reduced efficiently. This improves information decoding and energy harvesting performance,” explained Seo.
The researchers formulated a three-step iterative algorithm to maximise the energy efficiency of the SWIPT-NOMA-DAS system. They first enhanced the power allocation for the central IoT controller. After that, the team jointly optimised the power allocation for NOMA signalling and power splitting (PS) assignment for SWIPT while minimising the data rates and harvested energy requirements.
Finally, the researchers analysed an outage event in which the system cannot provide sufficient energy and data rates, extending the joint power allocation and PS assignment optimisation method to the multi-cluster scenario.
They validated their algorithm through extensive numerical simulations, finding that the proposed SWIPT-NOMA-DAS system is five times more energy efficient than SWIPT-NOMA without DAS. Also, it shows a more than 10% improvement in performance over SWIPT-OMA-DAS.
“This technology ensures very efficient energy consumption and offers various advantages such as convenience, low power, and battery life extension,” Seo pointed out. “It can be applied to smartphones, laptops, wearable devices, and electric vehicles. Most importantly, the SWIPT-NOMA-DAS system can optimise resource allocation and efficiently perform wireless charging and information transmission for users in an IoT environment,” the professor concluded.
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