Accession Number:

ADA571794

Title:

Advancing Underwater Acoustic Communication for Autonomous Distributed Networks via Sparse Channel Sensing, Coding, and Navigation Support

Descriptive Note:

Annual rept.

Corporate Author:

CONNECTICUT UNIV STORRS DEPT OF ELECTRICAL ENGINEERING AND COMPUTER SCIENCE

Personal Author(s):

Report Date:

2011-09-30

Pagination or Media Count:

15.0

Abstract:

We have three objectives in this project. 1. Advanced communication techniques of sparse channel sensing and nonbinary LDPC coding. Underwater acoustic channels are naturally sparse, but how to effectively exploit the sparsity is a challenging task. We will investigate the recently developed compressive sensing algorithms for sparse channel estimation in the context of multicarrier acoustic communications. On the other hand, channel coding is one integral part of an advanced communication system, and is dispensable in approaching the theoretical limit predicted by the Shannon theory. We will thoroughly investigate nonbinary low-density-parity-check LDPC codes, and especially pursue fast encoding and decoding algorithms and practical implementations. 2. High-resolution ranging and navigation. Wideband multicarrier waveform has a dual use that it can yield precise timing information for the receiver to infer the distance from the sender. With range estimates from multiple buoys, each underwater vehicle can self localize and navigate. We will investigate ranging and tracking algorithms that achieve high positioning accuracy. We aim to integrate the communication and navigation capabilities into the OFDM modem under development, which will greatly facilitate the development of emerging underwater distributed networks. 3. Testbed development and medium access control. We plan to develop a network testbed to illustrate the cooperative networking scenario. We first will determine an effective medium access control protocol to improve the system throughput for multiple users equipped with high-rate OFDM modems. We will then carry out demonstrations in three settings 1 point to point links with advanced communication techniques 2 ranging and navigation in a setup with four buoys and one underwater node and 3 cooperative networking in a setup with four buoys and multiple underwater nodes.

Subject Categories:

  • Acoustics
  • Non-Radio Communications

Distribution Statement:

APPROVED FOR PUBLIC RELEASE