## 1 Introduction  
Underwater visible light communication (UVLC) is an intensity modulation method accessible by light-emitting diodes (LEDs). Adjusting the LED's light wave outcome may accelerate rapid data transfer speeds. Future networking systems have a lot of potential for this technology. UVLC will soon get closer to flexible connectivity (FC), enabling it to continuously and creatively deploy energy to meet the demands of different frequency bands and improve spectrum utilization. Frequent significant FC technologies are \"Modulation Classification (MC) technologies\". This refers to a piece of information technology that is frequently utilized and capable of autonomous learning and adaptation. MC may help the transmitter correctly identify and change the demodulation modes when the broadcast protocols are altered due to external conditions. Real-time functioning is, therefore, a necessity for MC [1]. The creative improvement of UVLC, in line with the 5 G and 5 GB goals for future wireless communications, will increase operational effectiveness globally while still satisfying the demands of the moment. With minimal eavesdropping, UVLC offers extremely safe data transmission. A downlink data speed of more than 1 Gbps is provided by 5 GB, a sophisticated wireless connectivity messaging technique. However, a drawback of 5 GB is the high expense of building infrastructures. However, the current transfer of VLC by the 6G connection network, as opposed to the 5G network, is more pronounced in terms of augmented machine transmission and hyper-reduced latency communications. RF transmission technologies experience interference, but functional VLC technologies are unaffected. Therefore, VLC may be utilized with significant benefits in industries including the medical field, the oil and gas business, \"nuclear power plants (NPPs)\", underwater interactions, and many more uses where RF wireless communication is not commonly employed [2]. Recent years have seen increased demand for high-speed underwater wireless communication (UWC) techniques due to underwater use cases, including underwater vehicle monitoring, seabed geomorphology, and seawater cleanliness monitoring [3]. Underwater acoustic networking is a well-established method; however, due to its constrained frequency, it has a limited data capacity. Due to radio's energy absorption in saltwater, radio frequencies are not suited for underwater communications. Due to blue and green light's ability to pass through water with comparatively minimal absorption, UVLC, which relies on blue and green semiconductor lasers and LEDs, offers high-performance and affordable UVC solutions [4; 5]. The system model for UVLC features a block architecture with a single photon avalanche diode (SPAD) receiver and one source light-emitting diode (LED). The main advantages of using LED devices for underwater transmission include their fast switching times, excellent illumination, affordability, low electric power consumption, high moisture resistance, and high-speed data transmission capabilities. Figure 1 depicts the general block diagram of the UVLC system model, which employs a single source LED and a single SPAD receiver [6]. The SPAD is used in long-distance VLC systems because of its high sensitivity and excellent detection efficiency. The SPAD is specifically made to operate with a reverse bias voltage substantially larger than the breakdown voltage, as opposed to the avalanche photodiode (APD), which performs with a bias greater than the breakdown voltage. \"D/A expression\" may define the steps involved in decoding (D) and encoding (A) the UVLC codes. While the encoding phase involves transforming the symbols or data items into UVLC codes for transmission, the decoding step entails translating the received UVLC  
Figure 1: General block diagram of UVLC system model. codes back into their original symbols or data elements. Investigators are looking into better modulation methods for UVLC devices to boost transmission rates.