Underwater wireless optical communication is the best alternative for many applications especially for high bandwidth data communication between underwater objects and vehicles. The implementation of coding scheme along with advanced modulation technique and equalisation methods is identified as a key research scope for enhancing the performance of the system. In this paper, the coded generalised frequency division multiplexing (GFDM) technology is employed to provide high-data rates and less out-of-band emission. The Bose-Chaudhuri-Hocquenghem (BCH) and Reed-Solomon (RS) coding schemes along with equalisation techniques namely normalised least mean square (NLMS)-based decision feedback equalisers (DFE), minimum mean square error (MMSE) and zero forcing (ZF) are utilized to reduce inter symbol interference (ISI). The bit error rate (BER) performance is evaluated in the presence of pointing error (PE) and turbulence using Monte Carlo channel modelling simulations. The results showed that RS coding with NLMS-DFE outperforms other techniques and achieves a BER of roughly 10−5 with a signal-to-noise ratio levels below 20 dB. The simulation results demonstrate that RS code with 15 total symbols per code word and 3 data symbols, i.e., RS (15, 3) and BCH code with 31 total symbols in a code word and 6 data symbols, i.e., BCH (31, 6) provided the best error performance among other coding schemes employed. It is inferred that RS (15, 3) coded 2 × 2 multiple input multiple output systems with NLMS-DFE achieved a BER value of 1.1925 ×  10−5 at 11 dB which is 16 dB less than uncoded system. Thus, the coded GFDM improves overall BER performance and has the potential to provide higher reliability for internet of underwater things (IoUT) applications.

The corrosion resistance Cr₃C₂-25%NiCr and Ni-20%Cr coatings were deposited on the alloy A-286 by high-velocity oxy-fuel (HVOF) coating, and the high-temperature corrosion features were evaluated at 700 and 850°C in Na₂SO₄-5%NaCl-7.5%NaVO₃ atmosphere. Deposited coatings are dense and well-adherent to the substrate. A scanning electron microscope (SEM) is used to analyze the structure of the corroded samples. Results showed that Cr₃C₂ -25%NiCr coating provides better resistance to corrosion at 700°C, which is attributed to the protective Cr₂O₃ development. The coated metal was exposed at 850°C, and a higher corrosion rate was observed compared to 700°C, indicating that the temperature influenced the oxidation rate. The coating failure (crack) was noticed on the Cr₃C₂-25%NiCr coated surface when exposed at 850°C, and no damages are in the Ni-20%Cr coating.