In this paper, we propose a cooperative transmission scheme for underwater acoustic sensor networks to enhance the network performance. Relay nodes are exploited as virtual antennas to achieve diversity gains. Based on the distinct characteristics of the underwater channel such as high transmission loss, propagation delay, and ambient noises, the paper presents a distributed cooperative scheme including networking protocols and cooperative transmissions at the physical layer in order to enhance the reliability by providing diversity gains through intermediate relay nodes. Destinations and potential relays are selected from a set of neighbor nodes that utilize distance cost and local measurement of the channel conditions into calculation. The simulation and numerical results show that the proposed scheme outperforms the traditional direct transmission schemes in terms of average energy consumption, packet delivery ratio, and end-to-end delay.
Available online: https://www.ieeexplore.ieee.org/document/6533341