An Energy Considered Routing Protocol of Free Space Optical Sensor Network

Although free space optical sensor networks (FSOSNs) show merits of larger capacity, higher security and lower energy consumption over conventional radio- frequency (RF) based sensor networks, the directionality of free space optical (FSO) links requires efficient routing protocol for data transmission, because the death of a node may cause a dramatic decrease of network connectivity, resulting in poor packet delivery. In this paper, we propose an energy considered routing protocol (ECRP) for FSOSNs. The ECRP is seeking for a more evenly distributed energy load among sensors by providing each node a set of next hop candidates to communicate with the base station (BS) through the shortest hop path. An energy model is set up, and the performance of ECRP is evaluated and compared with simple-link protocol in terms of connectivity, the number of living nodes, and packet delivery ratio by OPNET simulation.