Signal strength sensitivity and its effects on routing in maritime wireless networks

Unlike terrestrial networks, the received signal strength in maritime wireless networks are subjected to perturbations due to the sea movement. Surface motions at sea cause variations in antenna heights and orientations of the communicating node (e.g. ships and buoys), thus affecting the received signal strength. In order to minimize such undesirable effects, we carried out a detailed study of the relationship between sea waves and the received signal strength. The effect of antenna gain variations due to tilting of antenna masts were studied by modeling sea waves. The channel path-loss variations were studied using a two-ray path-loss model for the maritime environment. Our analysis showed that the sea wave movements affect both short and longer links. We proposed a simple scheme to avoid the use of unstable links and implemented it on the QualNet network simulator. We carried out IEEE 802.16-based mesh network simulations with sea terrain and path loss models. We observed performance improvements in packet delay and throughput when the stable link selection scheme was used.