Comparative Analysis of FSK and GFSK Modulation Techniques for an Underwater Wireless Acoustic Modem

Underwater Wireless Communication systems deployed by the military helps build a strong marine defense security of a nation state. An Underwater Acoustic Modem (UAM) is the heart of the Underwater Wireless Sensor Networks (U-WSN). Various UAMs employ CDMA Spread spectrum based FSK modulation for data transmission. However it suffers multipath reflections besides possessing higher susceptibility to noise along with limited bandwidth in the acoustic environment both of which together contribute to a higher BER and consequently lower data rates. GFSK modulation, on the other hand leads to higher data rates because of its higher Power Spectral Density (PSD) and higher spectral efficiency compared to FSK modulation. The simulations of both the modulation schemes have been done using MATLAB 15.0. The comparative analysis of FSK and GFSK modulation for two UAMs separated by a distance of 150cm over an AWGN channel followed by the two path Rayleigh fading channel has concluded a lower BER and higher PSD in case of both the UAMs using GFSK modulation.