Residual Doppler Effect Analysis of the FBMC/OQAM Communication System in Underwater Acoustic Channel

The filterbank multicarrier (FBMC) waveform has better properties in spectral as compared to the Orthogonal Frequency Division Multiplexing (OFDM) and it exhibits good anti-interference performance. We mainly consider an important variety of the FBMC systems, namely FBMC based on offset orthogonal amplitude modulation (FBMC/OQAM). This letter presents an analysis of the residual Doppler effect in the multipath underwater acoustic (UWA) channel for the FBMC/OQAM system. Assuming the received signal has gone through coarse non-uniform Doppler compensation by resampling, we model the compensated signal with residual Doppler effect and multipath effect. Especially, we derive a simplified closed-form expression for the received FBMC signal after non-uniform Doppler compensation under the signal-to-interference ratio. The theoretical results and the simulations show better compliance in the UWA multipath channel. Furthermore, the results obtained demonstrate that FBMC has better BER performance than the cyclic prefix (CP) based OFDM in the case of residual Doppler effect under the UWA channel.