Adaptive OFDM for underwater acoustic channels with limited feedback

Andreja Radosevic, Tolga M. Duman, John G. Proakis, Milica Stojanovic

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

6 Scopus citations

Abstract

In this paper we analyze the performance of adaptive orthogonal frequency division multiplexing (OFDM) for underwater acoustic (UWA) communications. Our goal is to maximize the system throughput under a target average bit error rate (BER). We consider two different schemes based on the level of adaptivity: in the first scheme only the modulation levels are adjusted while the power is allocated uniformly across the sub-carriers, whereas in the second scheme, both the modulation levels and the power are adjusted adaptively. We exploit a feedback from the receiver in two forms: one that conveys the modulation alphabet and quantized power levels to be used for each sub-carrier, and another that conveys a quantized estimate of the sparse channel impulse response. We compare these two strategies based on the average number of bits per OFDM block needed to achieve a pre-specified target average BER. In both cases we predict the channel one travel time ahead so as to improve the performance in the presence of a long propagation delay. The second approach is shown to be advantageous, as it requires significantly fewer feedback bits for the same system throughput. The effectiveness of the proposed schemes is demonstrated using real channel measurements recorded in shallow water off the western coast of Kauai, Hawaii, in June 2008.

Original languageEnglish (US)
Title of host publicationConference Record of the 45th Asilomar Conference on Signals, Systems and Computers, ASILOMAR 2011
Pages975-980
Number of pages6
DOIs
StatePublished - Dec 1 2011
Event45th Asilomar Conference on Signals, Systems and Computers, ASILOMAR 2011 - Pacific Grove, CA, United States
Duration: Nov 6 2011Nov 9 2011

Publication series

NameConference Record - Asilomar Conference on Signals, Systems and Computers
ISSN (Print)1058-6393

Other

Other45th Asilomar Conference on Signals, Systems and Computers, ASILOMAR 2011
CountryUnited States
CityPacific Grove, CA
Period11/6/1111/9/11

ASJC Scopus subject areas

  • Signal Processing
  • Computer Networks and Communications

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    Radosevic, A., Duman, T. M., Proakis, J. G., & Stojanovic, M. (2011). Adaptive OFDM for underwater acoustic channels with limited feedback. In Conference Record of the 45th Asilomar Conference on Signals, Systems and Computers, ASILOMAR 2011 (pp. 975-980). [6190156] (Conference Record - Asilomar Conference on Signals, Systems and Computers). https://doi.org/10.1109/ACSSC.2011.6190156