Performance Analysis of SIMO-UWOC System

Abstract

A $\mathcal{T} \times \mathcal{R}$ multiple-input multiple-output (MIMO) based underwater wireless optical communication (UWOC) system employing Intensity Modulation (IM) / Direct Detection (DD) with On-Off keying (OOK) is considered. The UWOC channel is affected by underwater optical turbulence (UOT), which is modeled by Exponential Generalized Gamma (EGG) distribution. The performance of UWOC system is highly dependent on the effect of absorption, scattering and UOT. The EGG underwater optical channel model efficiently describes the optical irradiance induced due to air bubbles, temperature gradient and salinity, thus works well for the entire weak to strong turbulence regimes. The information is sent by $\mathcal{T}$ transmit apertures and received by $\mathcal{R}$ receiver apertures. The bit error rate (BER) analysis is performed for single-input multiple-output (SIMO), multiple-input single-output (MISO) and MIMO configurations for OOK modulation scheme. The closed form BER expression is derived for the SIMO case. For different channel parameters and configurations, the results for the BER performance of SIMO-UWOC and single-input single-output (SISO)-UWOC systems are obtained. For bubble level (BL) 2.4 litres/min and fresh water scenario, 15 dB performance improvement is seen at 10−2 BER for 1 × 2 SIMO with respect to SISO configuration.