Underwater Wireless Sensor Networks (UWSNs) are used in applications such as mineral exploration and environmental monitoring, and must offer reliability and energy efficiency. These are related to each other in the sense that the former requires error-correction which in turn requires energy, consuming battery life in an environment where battery replacement and recharging are difficult. This chapter thus addresses the energy efficiency of three suitable error correction methods for UWSNs, namely Automatic Repeat Request (ARQ), Forward Error Correction (FEC) and Network Coding (NC). The performance of the schemes as a function of transmission distance is determined for various packet sizes by using models of attenuation and noise that represent the underwater environment. ARQ offers the lowest efficiency and NC the highest but there is a distance at which FEC becomes the best option rather than NC suggesting a hybrid FEC/NC method.
