A dual-hop topology-aware routing protocol for underwater optical wireless sensor networks

Underwater optical wireless communication (UOWC) is an emerging technology for underwater wireless sensor networks (UWSNs). Compared with acoustic waves and radio frequency waves, optical waves can provide higher data rates and lower latency. However, given the limited transmission range and energy supply, as well as the existence of communication void regions in UOWC which may further deteriorate its transmission performances (e.g. packet deliver rate), effective multi-hop routing schemes are highly desirable for UOWC to expand its transmission range with satisfactory performance. In this paper, we propose a dual-hop topology-aware (DHTA) routing algorithm for UOWC. By adopting dual-hop routing strategy, the proposed algorithm reduces the packet entry possibility into void regions, and thus improves the packet deliver rate. And by selecting the next relay node considering both the available distance of transmission and the deviation of transmission direction, the proposed algorithm can effectively reduce the average energy consumption of the network. Besides, a threshold is employed by the proposed algorithm for energy balance to prevent excessive energy consumption of some nodes. The simulation results verify that the proposed DHTA routing algorithm effectively alleviates the effluence of void regions on forwarding packet and increases the packet delivery rate (PDR), with reduced average energy consumption and energy standard deviation.