MMSE beamformer based on partial FFT demodulation for OFDM underwater acoustic communications

Gema Piñero, Andrew C. Singer

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Underwater Acoustic (UWA) communications have to deal with channels that exhibit widely time-spreading multipath responses, together with Doppler spreading and limited bandwidth. These features seriously limit data throughput, even for sophisticated modulation schemes. Focusing on the large time-spreading characteristics, we analyze in this paper an OFDM UWA system such that the channel is longer than the Cyclic Prefix (CP) used. Under this condition, and considering an array of hydrophones at the receiver, we propose in this paper a Minimum Mean Square Error (MMSE) beamformer that makes use of two partial FFTs of half the original number of subcarriers to demodulate the OFDM signal. We show that one of the two demodulated signal can be received without Inter-Symbol Interference (ISI), even for longer-than-CP channels, and that the MMSE beamformer automatically is steered to direct and reflected paths obtaining an improvement of 4 dB in the Signal-to-Noise Ratio (SNR) and a reduction of 2 to 3 times the Bit Error Rate (BER) with respect to a conventional Delay-and-Sum (DS) beamformer.

Original languageEnglish (US)
Title of host publicationProceedings of the 20th European Signal Processing Conference, EUSIPCO 2012
Pages2308-2312
Number of pages5
StatePublished - Nov 27 2012
Event20th European Signal Processing Conference, EUSIPCO 2012 - Bucharest, Romania
Duration: Aug 27 2012Aug 31 2012

Publication series

NameEuropean Signal Processing Conference
ISSN (Print)2219-5491

Conference

Conference20th European Signal Processing Conference, EUSIPCO 2012
CountryRomania
CityBucharest
Period8/27/128/31/12

Keywords

  • OFDM
  • Underwater Acoustic Communications
  • broadband acoustic beamformer

ASJC Scopus subject areas

  • Signal Processing
  • Electrical and Electronic Engineering

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