Decision Feedback Equalization for Underwater Acoustic Channels

Deepthi Chander (05407003)

Pallavi Manohar (05407002)

Features of Underwater Acoustic (UWA) channels

Underwater acoustic channels - severely bandlimited

• High temporal and spatial variability of channel conditions and multipath propagation.

• Digital transmission-severe ISI caused.• Non-Gaussian noise environments.

Simulation Set-up

• Rayleigh fading for shallow water , medium-range channel

• Slowly fading UWA channel

(Currently, time invariant scenario)• Noise: AWGN, log-Normal• Decision Feedback Equalizer (DFE)• Adaptive algorithm: RLS

feedforwardfilter

Input

+ Symboldecision

feedbackfilter

-

Estimated symbol

AdaptiveAlgorithm (RLS)

Training symbol

+

-error

Decision Feedback Equalizer

MSE convergence (AWGN)

MSE convergence (lognormal noise)

Error percent vs SNR (AWGN)

Error percent vs SNR (lognormal noise)

Further Work

• Obtaining UWA channel model for time varying multipath:

PROSIM (propagation channel simulator)

Acoustic Toolbox (Ocean Acoustics Library)

THANK YOU