Next Milestone: A Multicarrier Acoustic MODEM with Channel- and Network-Adaptivity for Underwater Autonomous Distributed Systems

摘要

We have three objectives in this project: (1) Make OFDM work underwater. The success of multicarrier modulation in the form of orthogonal- frequency-division-modulation (OFDM) in radio channels illuminates a clear path one could take towards high-rate underwater acoustic communications. However, earlier work on the application of OFDM in underwater has only had limited success. We aim to make OFDM work in underwater environments; (2) Channel- and network-aware modulation, coding, and scheduling. We aim to develop a layered coding structure with joint inter- and intra-packet coding. Intra-packet coding uses error-correction codes to deal with channel distortion and ambient noise, while inter-packet coding uses erasure-correction codes to cope with channel and network disruptions. This layered coding approach facilitates non-flow- based data delivery over single or multiple routing-paths, and can autonomously- adapt to channel and network conditions; and (3) Prototype development. We aim to develop a stand-alone OFDM modem prototype that integrates the innovative algorithms developed in this project.