The research in underwater communication system is focused towards wireless networks in view of recent developments in wireless technology and increasing need for deep sea data mining. The underwater wireless optical communication (UWOC) have more advantages for short-range wireless links due to very high bandwidth and data rate than acoustic communication. Although UWOC offers high capacity links at low latencies, they suffer from limited communication range due to various distinctive characteristics of underwater channel. A major degrading effect associated with the underwater channel is turbulence-induced fading. To mitigate this fading and to extend the viable communication range, spatial multipath diversity techniques can be adopted over UWOC links. The proposed work evaluates the performance of a multicarrier modulation scheme, i.e., MIMO based DC biased Optical Orthogonal Frequency Division Multiplexing (DCO-OFDM) for underwater wireless optical channel. The simulation of MIMO-DC biased optical OFDM technique employing spatial diversity in underwater optical communication is a novel approach towards the determination of an optimal modulation technique for underwater optical wireless channels. The performance is evaluated based on the various parameters such as Signal to Interference plus Noise Ratio (SINR), Throughput and Bit Error Rate (BER). A simple experiment is conducted to demonstrate the BER performance assessment for different link distance of 0.45 m and 1.5 m with different transmitter and receiver configurations (SIMO and MIMO) for both clear water and coastal water using MIMO DCO OFDM technique.

中文翻译：

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基于MIMO的DCO-OFDM在水下无线光通信系统中的性能研究

鉴于无线技术的最新发展和对深海数据挖掘的日益增长的需求，水下通信系统的研究集中在无线网络上。由于非常高的带宽和数据速率，水下无线光通信（UWOC）比声学通信具有更多的短距离无线链路优势。尽管 UWOC 以低延迟提供高容量链路，但由于水下信道的各种独特特性，它们的通信范围有限。与水下通道相关的主要退化效应是湍流引起的衰落。为了减轻这种衰落并扩展可行的通信范围，可以在 UWOC 链路上采用空间多径分集技术。所提出的工作评估了多载波调制方案的性能，即，用于水下无线光信道的基于 MIMO 的直流偏置光正交频分复用 (DCO-OFDM)。在水下光通信中采用空间分集的 MIMO-DC 偏置光 OFDM 技术的仿真是一种确定水下光无线信道最佳调制技术的新方法。性能评估基于各种参数，例如信号干扰加噪声比 (SINR)、吞吐量和误码率 (BER)。进行了一个简单的实验，以演示使用 MIMO DCO OFDM 技术在清水和沿海水域使用不同的发射机和接收机配置（SIMO 和 MIMO）对 0.45 m 和 1.5 m 的不同链路距离的 BER 性能评估。