Acoustic multicarrier OFDM for shallow water communication

摘要

In an acoustic multicarrier Orthogonal Frequency Division Multiplex communication system for shallow water, leakage of the transmitted signal into adjacent frequency bins due to Doppler spread is minimised by inserting frequency-dependent guard bands between the carriers, each having a width B greater than the expected Doppler spread. Pilot signals are transmitted at frequencies Fp between channels of centre frequency FcN, and the spacings and centre frequencies are scaled with frequency (since Doppler spread increases with frequency). Phase and frequency differences between adjacent pilots are used to estimate and compensate for delay variation to give constant delay, and data signals are filtered by a Raised Root Cosine (RRC) filter.