Analysis and experimental evaluation of forward error correction codes for underwater acoustic communications

In recent years, underwater acoustic sensor networks have experienced an increased interest, in both the academia and the industry domain, for their application in maritime sea life and resource monitoring, as well as the possibility of automating many underwater maintenance and exploration activities. Due to the low bitrates and the long propagation delays that characterize the acoustic communication channel, we have that strong forward error correction (FEC) codes should be employed in order to build robust links between the underwater nodes of a sensor network. In this work, we present an analysis of the different forward error correction codes provided by two software frameworks, i.e. Liquid and Libfec, in the context of underwater acoustic communications. The analysis is performed by means of simulations over AWGN and burst error channels, and results in the context of bandwidth-limited and power-limited regimes are presented. We also attempted at using an additional library, called AFF3CT, to simulate the effects of a more advanced LDPC code, while keeping into consideration the difficulties that need to be addressed in case of an integration with Liquid. To validate the simulation results, we performed an experimental evaluation on the Piovego Canal with two SuM acoustic modems. Improvements over the modem source code are also presented and discussed.