In this paper we give a thorough study of radio propagation models suitable for smart city applications and select two channel models for coverage prediction of wireless sensor networks for two typical propagation environments that often occurs in smart city applications, namely the open area plane earth model for open areas and the four slope channel model for street canyons and tunnels. The measurement campaigns performed at three carrier frequencies applied for wireless sensor networks in Europe i.e. 400 MHz, 868 MHz and 2.4 GHz, reveals, that in open areas the plane earth model fits the measurements better than two slope model and four slope channel model gives sufficiently high accurate path loss prediction in tunnels and street corridors. The obtained results were used also for the planning of the experimental semantic sensor network in the project J2-4197.
COBISS.SI-ID: 27429159
In this paper we propose a system architecture for wireless sensor networks (WSNs) that makes various types of sensors, sensor data and metadata, discoverable, accessible and controllable over the Internet. This architecture is able to provide sensor as a service functionality using standard communication protocols on the Internet and WSN side. We describe the components of the proposed architecture and then we provide the reference implementation based on the VESNA sensor platform equipped with the open source Contiki OS and its standard protocol stack for constrained devices. We also provide initial performance evaluation of the WSN part of the proposed system architecture. This paper represents an early description of the system architecture designed in the J2-4197 project. Extended and enhanced version with performance evaluation is under preparation for the submission to an international conference and a journal.
COBISS.SI-ID: 26851879
In this paper we present steps involved in planning a wireless sensor network for the LOG-a-TEC outdoor testbed, part of the CREW federation for cognitive radio experiments. Based on the initial testbed requirements and estimates of the management network load we have selected two clusters of locations from a large pool of possible locations. We have then performed a verification step. By measuring signal strength and packet loss with a mobile setup we have verified that nodes in the chosen testbed configuration would be able to form a usable mesh network. The described network design procedure was used also for the planning of the experimental sensor network environment in the project J2-4197.
COBISS.SI-ID: 26852903