Impact of Random Receiver Orientation on HE‐AR Region for UWOC Systems With SLIPT

ABSTRACT This study investigates the often‐overlooked impact of random transmitter–receiver misalignment on energy‐efficient simultaneous lightwave information and power transfer (SLIPT) in underwater wireless optical communication (UWOC) systems. Focusing on a two‐node setup with angular misalignment over a turbulence‐induced fading channel, we derive closed‐form expressions for the average harvested energy (HE) and average achievable rate (AR). HE denotes the average energy collected at the sensor node, while AR represents the average rate at which data can be reliably transmitted over the UWOC link. Our analysis reveals a fundamental trade‐off between HE and AR, showing that a higher bias () increases HE but reduces the AR, highlighting the HE‐AR trade‐off. As the randomness in transmitter–receiver orientation increases, the HE‐AR region boundary shrinks and shifts leftward, indicating the detrimental impact of misalignment. Furthermore, we demonstrate that employing light‐emitting diodes (LEDs) with larger half‐power beamwidths can mitigate the performance degradation caused by misalignment. We also study the influence of horizontal link distance and different water types on the HE‐AR region. The derived expressions are validated through computer simulations.