Soft Frequency Reuse with Large Propagation Delays for Interference Mitigation in Underwater Acoustic Networks

The available bandwidth for underwater acoustic (UWA) communication and networks is very limited, and frequency reuse is one of the important techniques to improve spectrum efficiency and system capacity. In this paper, a soft frequency reuse (SFR) system is proposed for UWA sensor networks, with the consideration of physical layer channel features including propagation attenuation and delay. As the propagation speed of UWA signal is very slow, the time arrived at one user from multiple senders are obviously different, herein a new idea to mitigate inter-cell interference based on both sub-bands allocation and propagation delay difference has been proposed for UWA networks. The simulation results have shown that, with the proposed methods, UWA sensor network can achieve better signal to interference plus noise ratio (SINR) and spectrum efficiency in comparison to traditional FFR and SFR.