| （英） |
Underwater simultaneous lightwave information and power transfer (USLIPT) is gaining attention as a technology that enables both wireless power transfer and communication for underwater drones and sensors used in seabed resource exploration. Conventional USLIPT systems often use laser diodes (LDs) as transmitters, which offer highly directional, high-power optical signals but require strict optical alignment with the receiver. In this work, we focus on LED-based USLIPT to eliminate the need for precise alignment. Although LEDs have lower directivity and limit the available power for energy transfer, they can simultaneously serve multiple terminals, which makes the application of multiple-access techniques promising.To realize multi-user LED-based USLIPT, we apply DC-biased optical OFDM (DCO-OFDM) and evaluate how the DC bias affects both communication and power transfer performance. We theoretically derive the signal-to-noise ratio (SNR) and delivered power, taking into account clipping caused by insufficient DC bias and signal scaling caused by the transmitter’s dynamic range when the DC bias is large.Our results show that adding a DC bias suppresses clipping noise and improves the SNR, while an excessively large DC bias degrades the SNR due to signal scaling. We also find that the delivered power reaches its maximum at approximately 2 dB of DC bias, limited by the transmitter’s dynamic range, and does not increase further beyond this point. |