No abstract

Many wireless sensor network applications require sensor nodes to be deployed on the ground or other surfaces. However, there has been little effort to characterize the large-and small-scale path loss for surface-level radio communications. We present a comprehensive measurement of path loss and fading characteriztics for surface-level sensor nodes in the 400 MHz band in both flat and irregular outdoor terrain in an effort to improve the understanding of surface-level sensor network communications performance and to increase the accuracy of sensor network modeling and simulation. Based on our measurement results, we characterize the spatial small-scale area fading effects as a Rician distribution with a distance-dependent K-factor. We also propose a new semi-empirical path loss model for outdoor surface-level wireless sensor networks called the Surface-Level Irregular Terrain (SLIT) model. We verify our model by comparing measurement results with predicted values obtained from high-resolution digital elevation model (DEM) data and computer simulation for the 400 MHz and 2.4 GHz band. Finally, we discuss the impact of the SLIT model and demonstrate through simulation the effects when SLIT is used as the path loss model for existing sensor network protocols. General Terms: Performance, DesignAdditional Key Words and Phrases: Modeling of systems and physical environments, foundations of sensor networks, simulation tools and environments, surfacelevel communications ACM Reference Format: Chong, P. K. and Kim, D. 2013. Surface-level path loss modeling for sensor networks in flat and irregular terrain.

No abstract

In this paper, we present a real application system based on wireless sensor network (WSN) for fence surveillance which is implemented on our development platform for WSN, called ANTS (An evolvable Network of Tiny Sensors). Our system, called the WFS system, is expanded to connect and control a robot (UGV/UAV) and a camera sensor network for the purpose of fence surveillance. Two kinds of sensor nodes, ground nodes and fence nodes, are deployed and collaborative detection is performed and the result is reported to the base station (BS). The BS does not only give a control message to the camera to show the place where an event has occurred, but it also issue orders to the robots to extend the communication distance of the system, to approach and sense the object more precisely, or even to attack an enemy autonomously. This paper describes various techniques and know-how to fulfill a WSN-based integrated surveillance system. A new adaptive threshold algorithm to detect intruders is proposed and some sensing results in the real field of our system are shown. In conclusion, we show the high accuracy of the WFS system.