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Progressive intercarrier and co-channel interference mitigation for underwater acoustic multi-input multi-output orthogonal frequency-division multiplexing

Multi-input multi-output orthogonal frequency-division multiplexing MIMO-OFDM has been actively studied for high data rate communications over the bandwidth-limited underwater acoustic UWA channels. Unlike existing receivers that treat the intercarrier interference ICI as additive noise, in this paper, the proposed receiver considers ICI explicitly together with the co-channel interference CCI due to parallel transmissions in MIMO-OFDM. Using a recently developed progressive receiver framework, the proposed receiver starts with low-complexity ICI-ignorant processing and then progresses to ICI-aware processing with increasing ICI levels. The key components of the proposed receiver include the following: 1 compressed sensing-based sparse channel estimation, 2 soft-input soft-output minimum mean square error/Markov chain Monte Carlo detector for interference mitigation, and 3 soft nonbinary low-density parity check decoding. In addition to simulation, we use real data from the Surface Processes and Acoustic Communications Experiment 2008 SPACE08 and the Mobile Acoustic Communications Experiment 2010 MACE10 to verify the system performance, where the transmitter in SPACE08 was stationary and that in MACE10 was slowly moving. Simulation and experimental results show that explicitly addressing ICI and CCI significantly improves the performance of MIMO-OFDM in UWA systems. Copyright © 2012 John Wiley & Sons, Ltd.