Multicolor-Based Bit-Loading for MIMO Underwater Optical Wireless Communication

Traditional underwater communication methods, such as acoustic signaling, are limited by low data rates and high latency due to the slow propagation speed of sound in water. As an alternative, optical wireless communication (OWC) offers the potential for significantly higher data rates and lower latency, leveraging the high speed of light propagation. This paper considers an innovative approach to underwater optical wireless communication where the transmitter employs multiple Light Emitting Diodes (LEDs) or Laser Diodes (LDs) to send data across different wavelengths. The receiver is equipped with an array of photodiodes, each paired with wavelength-selective optical filters to differentiate the incoming signals. The primary objective of this work is to optimize the modulation formats used by the system. This optimization process takes into account the unique characteristics of the underwater optical channel, such as absorption and scattering, as well as the potential crosstalk between channels. By carefully adjusting the modulation formats, the system aims to maximize the data rate while adhering to power and reliability constraints.