Progressive Intercarrier and Co-channel Interference Mitigation for Underwater Acoustic MIMO-OFDM

MIMO-OFDM has been actively studied for high data rate communications over the bandwidthlimited underwater acoustic (UWA) channels. Unlike existing receivers that treat the intercarrier interference (ICI) as additive noise, in this paper we consider 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: 1) compressed-sensing (CS) based sparse channel estimation, 2) soft-input-soft-output minimum mean square error (MMSE)/Markov Chain Monte Carlo (MCMC) detector for interference mitigation, and 3) soft nonbinary LDPC decoding. In addition to simulation, we use real data from the SPACE08 and MACE10 experiments 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 underwater acoustic systems. Index Terms Iterative receiver, sparse channel estimation, intercarrier interference, co-channel interference, underwater acoustic communications. The work by J.-Z. Huang, S. Zhou and J. Huang are supported by the ONR grant N00014-09-1-0704 (PECASE). P. Willett is supported by ONR under contacts N00014-10-10412 and N00014-09-10613. The work by J. Preisig is supported by the ONR grants N00014-07-10738 and N00014-07-10184. This work was presented in part at the 44th Asilomar Conference on Signals, Systems, and Computers, Pacific Grove, CA, 2010 [1]. November 21, 2011 DRAFT WIRELESS COMMUNICATIONS AND MOBILE COMPUTING, WILEY, TO APPEAR 2