LOCALIZATION OF ENERGY HARVESTING EMPOWERED UNDERWATER OPTICAL WIRELESS SENSOR NETWORKS

Abstract

This paper proposes a received signal strength (RSS)based localization
framework for energy harvesting underwater optical wireless sensor networks (EHUOWSNs),
where the optical noise sources and channel impairments of seawater pose
significant challenges on range estimation. In UOWSNs energy limitation is another
major problem due to the limited batterypower and difficulty to replace or recharge
the battery of an underwater sensor node. In the proposed framework, sensor nodes
with insufficient battery harvest ambient energy and start communicating once they
have sufficient storage of energy. Network localization is carried out by measuring
the RSSs of active nodes, which are modeled based on the underwater optical
communication channel characteristics. Thereafter, block kernel matrices are
computed for RSS-based range measurements. Unlike the traditional shortest-path
approach, the proposed technique reduces the estimation error of the shortest path for
each block kernel matrix. Once the complete block kernel matrices are available, a
closed form localization technique is developed to find the location of every optical
sensor node in the network. An analytical expression for the Cramer Rao lowerbound
(CRLB) is also derived as a benchmark to evaluate the localization performance of
the developed technique. Extensive simulations show that the proposed framework
outperforms the well-known network localization techniques