Outage probability analysis using transmit laser selection technique for underwater optical wireless communication system under varying turbulence with pointing errors and attenuation losses

We present an analytical investigation of the outage probability performance in underwater optical wireless communication systems employing the transmit laser selection (TLS) strategy. The TLS approach selects a single laser source that maximizes the received signal-to-noise ratio (SNR), thereby enhancing link reliability. The analysis incorporates the effects of varying oceanic turbulence induced by fluctuations in temperature and salinity, along with attenuation losses and receiver pointing errors. A closed-form expression for the outage probability is derived using a cascaded Gamma–Gamma and hyperbolic tangent log-normal fading model to accurately characterize the turbulence conditions. The derived expressions are evaluated under various system parameters, including SNR thresholds, data rates, water types, and pointing error variances. Monte Carlo simulations are conducted to validate the accuracy of the analytical results, demonstrating strong agreement with theoretical predictions.