Non-Orthogonal Multiple Access (NOMA) for Underwater Acoustic Communication

In this paper we investigate the application of the non-orthogonal multiple access (NOMA) technique for multiuser underwater acoustic (UWA) communication. The NOMA scheme can be implemented using either orthogonal frequency division multiplexing (OFDM) or filterbank multicarrier (FBMC) modulation for waveform shaping. In order to boost the throughput over a 1 km time-varying underwater acoustic channel (UAC), spatially multiplexed multiple-input multiple-output (MIMO) systems are considered. We evaluate the bit error rate (BER), packet error rate (PER) and maximum bit rate performances of Turbo-coded NOMA-OFDM and NOMA-FBMC systems for a 2-user scenario where both users utilize the same frequency bandwidth. It is shown that while both the NOMA-OFDM and NOMA-FBMC systems show comparable performance in terms of BER and PER, the MIMO NOMA-FBMC system however achieves higher bit rates than the OFDM-based system.