SGER: Algorithms and Architectures for Low Cost High Data Rate Acoustic Modems

集成、混合和复杂的系统罗纳德·A·伊尔蒂斯加州大学圣巴巴拉分校SGER：用于低成本高数据速率声学调制解调器的算法和体系结构智力价值：新的和正在进行的海洋科学项目，包括长期生态研究(LTER)站点和海洋天文台倡议对用于水下联网的低成本、开放体系结构的声学调制解调器有多种需求。这项探索性研究确定了单载波频域均衡(SC-FDE)是否是用于高速、远距离水声通信的正交频分复用(OFDM)的可行替代方案。SC-FDE在更低的功率变化和更低的编码复杂度要求方面具有潜在的显著优势。水声信道具有长、稀疏的多径特性和快速的时变(多普勒扩展)特性，给通信系统设计者带来了极大的挑战。研究人员先前为低数据速率的直接序列水声调制解调器开发了一种稳健的匹配追踪(MP)信道估计器，该估计器被应用于SC-FDE和ofdm。进行并列比较以确定SC-FDE在水下信道中是否可行，以及其相对于ofdm的功率和复杂度优势是否在水声环境中保持。SC-FDE和ofdm都需要纠错编码来在远距离声学信道上通信。研究了结合匹配跟踪和卷积编码的新的迭代译码和信道估计技术，以便于实时实现。现有的试验台用于评估SC-FDE和ofdm调制解调器的性能。广泛的影响：广泛的海洋科学和生态研究项目需要实时水声通信。这项研究的结果可能是为海洋研究人员提供现成的声学网络的重要的第一步。由水下网络实现的研究可以对我们理解海底物理环境和海洋生物之间的相互作用产生广泛影响，包括世界各地珊瑚礁健康的关键问题。该项目还为海洋科学、信号处理和网络研究方面的研究生提供交叉培训。

Integrative, Hybrid and Complex SystemsRonald A. IltisUniversity of California-Santa BarbaraSGER: Algorithms and Architectures for Low Cost High Data Rate Acoustic ModemsIntellectual Merit: New and ongoing ocean sciences projects, including Long-Term Ecological Research (LTER) sites and the Ocean Observatories Initiative have multiple needs for low-cost, open architecture acoustic modems for underwater networking. This exploratory research determines if single-carrier frequency domain equalization (SC-FDE) is a viable alternative to orthogonal frequency-division multiplexing (OFDM) for high-speed, longer range acoustic communications. SC-FDE has potentially significant advantages over OFDM in terms of lower power variation and lower-complexity coding requirements. The underwater acoustic channel is challenging to the communication systems designer due to its long, sparse multipath characteristics and rapid time-variation (Doppler spread). A robust Matching Pursuits (MP) channel estimator, previously developed for lower data rate direct-sequence acoustic modems by the investigators, is applied here to both SC-FDE and OFDM. Side-by-side comparisons are performed to determine if SC-FDE is feasible in the underwater channel and if its power and complexity advantages over OFDM hold in the acoustic regime. Both SC-FDE and OFDM require error correction coding to communicate over the long range acoustic channel. New iterative decoding and channel estimation techniques combining Matching Pursuits and convolutional coding are investigated for real-time implementation. Existing testbeds are used to evaluate SC-FDE and OFDM modem performance.Broader Impact: Real-time acoustic communications is required for a broad range of ocean sciences and ecological research projects. The results of this research could be an important first step to off-the-shelf availability of acoustic networking for oceanographic researchers. Research enabled by underwater networking can have broad impacts on our understanding of interactions between the physical undersea environment and marine life, including the critical question of health of coral reefs worldwide. This project also provides cross-training to graduate students in ocean sciences, signal processing and networking research.