Telesonar Signaling Measurements
Abstract
LONG-TERM GOAL. Advanced undersea acoustic communication (telesonar) modems will be capable of probing the transmission channel and automatically adapting signaling parameters to the channel response.[1, 2] OBJECTIVE. This project quantifies the relative performance of telesonar signaling techniques with respect to the probed channel response, observed ocean environment, and model predictions. APPROACH. Prior research, development and testing have concentrated on specific modem signaling techniques for channel tolerance, high bit-rate, or multi-user access.[3] Evaluating the relative performance of these signaling methods using existing data is perilous because of excessive parametric variations in the transmission medium, transmit electronics, receive electronics, receive SNR, frequency band, etc. This FY99-start project pursues a systematic understanding of telesonar capability by exploring the fundamental relationships between the observed environmental conditions, the measured channel scattering function, and the realized signaling performance. We use standard oceanographic methods to quantify channel boundary (i.e., seafloor and sea surface) conditions and channel medium (i.e., ocean volume) properties. These environmental observations drive physics-based predictive models[4] to anticipate sound propagation effects. We minimize experimental error through the use of carefully designed navigation, transmit, receive, and record systems that provide commonality and fidelity for all signaling techniques under evaluation. We use specialized acoustic probes to directly observe the time- and frequency-dependent channel scattering function. Having thus gained empirical control of the test channel, we transmit a diverse collection of communication waveforms and tally performance achieved by real-time processing and post-mortem analysis. Sequential transmission of test waveforms provides continuity of channel conditions and justifies comparative evaluation.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 30, 1999
- Accession Number
- ADA630128
Entities
People
- Joseph A. Rice
- Vincent K. Mcdonald