An Integrated Energy Efficient Data Retrieval Protocol for Underwater Delay Tolerant Networks

In large-scale underwater sensor networks where sparsely deployed clusters of underwater nodes need to relay information back to the base station, end-to-end links may either not be available or feasible. In such cases, a retrieval device needs to travel into the underwater field to collect data from the nodes, resulting in a certain amount of delay until the data is available at the base station. In this paper, we propose an energy efficient protocol for such delay tolerant data retrieval applications. This protocol can be optimized to reduce retrieval time and energy consumption and is highly customizable to suit various network sizes and application requirements. It adopts efficient erasure codes (LT codes) and forward error correction codes (LDPC codes) to overcome the challenges in an underwater acoustic environment, such as large and variable propagation delay, low and narrow bandwidth and limited energy resources. This protocol also provides a modularized framework in which further improvements can be easily implemented.