Multicarrier modulation schemes efficiency investigation in shallow water hydroacoustic communication application

High data rate data transmission in hydroacoustic communication in shallow water faces a lot of problems due to the doubly selective nature of the channel, which is characterized by long delay time-varying impulse response and significant Doppler shifting. Multicarrier modulation is a powerful method of inter symbol interference mitigating in these conditions, but significant time-selectivity leads to the inter carrier interference. In this paper the efficiency of different multicarrier schemes is being investigated in the application specified, targeting to choose the viable parameters for each considered scheme, using simulation and analysis of their property. In particular, we consider conventional OFDM, filtered OFDM, windowed OFDM, QAM-FBMC and UFMC, which are combined with fast convergence RLS based equalizer. The simulation is being performed using open source software Filter Bank Multicarrier Modulation. The channel is being simulated using Brest Commercial Harbor experiment from Watermark benchmark, which provides measured characteristics of real impulse responses of the channels in shallow water within band 32.5-37.5 kHz. The theoretical analysis and simulation results show that FBMC approach provides significantly better performance compare to its OFDM counterparts for large number of subcarriers (2500 subcarriers). On the other hand, the realization of FBMC-QAM system in such case is computationally more complex. It is also important that for all considered schemes the performance is highly depend on equalizer characteristics.