Publication Detail

Space-Frequency Coded OFDM for Underwater Acoustic Communications

Eduard V. Zorita, Milica Stojanovic
6 pp.
MITSG 12-35
$5.50 DOM / $7.50 INT

This work proposes an adaptive receiver for the
space-frequency block coding scheme, in which Alamouti coding
is applied over the carriers of an OFDM system with the
aim of obtaining transmit diversity in an underwater acoustic
channel. The receiver relies on the assumption that the channel
transfer function does not change much over two consecutive
carriers, and that the channel is slowly time-varying. Building
on these assumptions we propose an adaptive channel estimation
method based on Doppler prediction and time-smoothing, which
effectively reduces the pilot overhead. System performance is
demonstrated using real data transmitted over a shallow water
channel in the 10-15 kHz acoustic band from a vehicle moving at
0.5-2 m/s, using QPSK and a varying number of carriers ranging
from 64 to 1024. Results demonstrate a uniform gain over the
single-transmitter case.

type: Presentations

Parent Project

Project No.: 2007-R/RT-2/RCM-21
Title: Acoustic Communication Networks for Distributed Autonomous Underwater Platforms