The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 28, 2010
Filed:
Jun. 18, 2008
Shengli Zhou, Mansfield, CT (US);
Baosheng LI, Willington, CT (US);
Peter Willett, Coventry, CT (US);
Milica Stojanovic, Boston, MA (US);
Lee Freitag, Falmouth, MA (US);
Shengli Zhou, Mansfield, CT (US);
Baosheng Li, Willington, CT (US);
Peter Willett, Coventry, CT (US);
Milica Stojanovic, Boston, MA (US);
Lee Freitag, Falmouth, MA (US);
Massachusetts Institute of Technology, Cambridge, MA (US);
University of Connecticut, Farmington, CT (US);
Woods Hole Oceanographic Institution, Woods Hole, MA (US);
Abstract
Advantageous OFDM-based underwater acoustic (UWA) apparatus, systems and methods are provided according to the present disclosure. In general, OFDM transmissions over UWA channels encounter frequency-dependent Doppler drifts that destroy the orthogonality among OFDM subcarriers. The disclosed apparatus, systems, and methods use a two-step approach to mitigate frequency-dependent Doppler drifts for zero-padded OFDM transmissions over fast-varying channels: (1) non-uniform Doppler compensation via resampling to convert a 'wideband' problem into a 'narrowband' problem; and (2) high-resolution uniform compensation on the residual Doppler. The disclosed apparatus, systems and methods are based on block-by-block processing and do not rely on channel dependence across OFDM blocks. Thus, the disclosed apparatus, systems and methods are advantageously applicable for fast-varying UWA channels.