Title :
MIMO-OFDM for High-Rate Underwater Acoustic Communications
Author :
Li, Baosheng ; Huang, Jie ; Zhou, Shengli ; Ball, Keenan ; Stojanovic, Milica ; Freitag, Lee ; Willett, Peter
Author_Institution :
Dept. of Electr. & Comput. Eng., Univ. of Connecticut, Storrs, CT, USA
Abstract :
Multiple-input-multiple-output (MIMO) techniques have been actively pursued recently in underwater acoustic communications to increase the data rate over the bandwidth-limited channels. In this communication, we present a MIMO system design, where spatial multiplexing is applied with orthogonal-frequency-division-multiplexing (OFDM) signals. The proposed receiver works on a block-by-block basis, where null subcarriers are used for Doppler compensation, pilot subcarriers are used for channel estimation, and a MIMO detector consisting of a hybrid use of successive interference cancellation and soft minimum mean square error (MMSE) equalization is coupled with low-density parity-check (LDPC) channel decoding for iterative detection on each subcarrier. The proposed design has been tested using data recorded from three different experiments. A spectral efficiency of 3.5 b/s/Hz was approached in one experiment, while a data rate of 125.7 kb/s over a bandwidth of 62.5 kHz was achieved in another. These results suggest that MIMO-OFDM is an appealing solution for high-data-rate transmissions over underwater acoustic channels.
Keywords :
Doppler effect; MIMO communication; OFDM modulation; channel estimation; interference suppression; iterative decoding; least mean squares methods; parity check codes; space division multiplexing; underwater acoustic communication; Doppler compensation; LDPC; MIMO detector; MIMO system design; MIMO-OFDM; bandwidth 62.5 kHz; bandwidth-limited channel; bit rate 125.7 kbit/s; channel estimation; interference cancellation; iterative detection; low-density parity-check channel decoding; minimum mean square error equalization; multiple-input-multiple-output technique; orthogonal-frequency-division-multiplexing signal; pilot subcarrier; spatial multiplexing; underwater acoustic channels; underwater acoustic communication; Iterative equalization; multiple-input–multiple- output (MIMO); orthogonal-frequency-division-multiplexing (OFDM); underwater acoustic communication;
Journal_Title :
Oceanic Engineering, IEEE Journal of
DOI :
10.1109/JOE.2009.2032005