Sistemas de transmissão multiportadora aplicados em um canal acústico submarino na presença de efeito doppler

Abstract

Presents an analysis of feasibility of the application of multicarrier transmission application in acoustic communication systems for underwater environment. Such analysis encompass (Single-Carrier Frequency Division Multiple Access) SC-FDMA, (Orthogonal Frequency Division Multiplexing) OFDM and (Frequency Shift Keying) FSK systems, with either Zero Forcing (ZF) or minimum mean-square error (MMSE) equalizers. We investigate system performance in a multipath channel and in the presence of Doppler effect. The use of OFDM technique allows high transmission rate, increasing the amount of information allocated in each transmitted block. On the other hand, the SCFDMA technique, besides allowing a high transmission rate, has also the motivation of reducing the peak-to-average power ratio (PAPR). The performance of these systems is assessed through the relation between signal to noise ratio (SNR) and bit error rate. The applicability of filterbank based transceivers with reduced redundancy in each block in underwater communication systems is also analysed. The equalization, in this case, employed a Zero Forcing solution that requires less operations. Computer simulations indicate that this scheme can achieve a similar throughput to that of a conventional multicarrier systems, while keeping the bit error rate significantly lower.