ISEP – CISTER – Pósteres apresentados a eventos científicos
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Browsing ISEP – CISTER – Pósteres apresentados a eventos científicos by Author "Almeida, Luís"
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- An Analysis of the Two-Ray Propagation Model to Support Near-Surface Overwater Wireless Sensor Networks DesignPublication . Gutiérrez Gaitán, Miguel; Pinto, Luis; Santos, Pedro Miguel; Almeida, LuísIn this work, a thorough analysis based on the two-ray model in the presence of tides is performed. The study aims to provide a tool to guide the deployment of near-surface overwater wireless sensor networks, and thus improve its overall link quality regardless of the variations of the tides. We consider realistic parameters, such as the distance between the nodes and the tide-levels range taken from the mouth of the Douro river, Porto and the Seixal Bay, Lisbon. In future works, we will complement the theoretical analysis with network level simulations and an extended experimental campaign.
- Improving WiFi communication with surface nodes at near-shore on tidal watersPublication . Gutiérrez Gaitán, Miguel; d'Orey, Pedro; Santos, Pedro Miguel; Ribeiro, Manuel; Pinto, Luis; Almeida, Luís; de Sousa, J. BorgesWireless radio links deployed in aquatic areas (e.g., sea, rivers, lakes, estuaries) are affected by the conductive properties of the water surface, strengthening signal reflections and increasing destructive interference. Recurrent natural phenomena (e.g. tides or waves) cause shifts in water levels further impairing propagation over water surfaces. In this work, we aim to mitigate the detrimental impact of tides on link quality by providing tailored link distance/height-design regions that minimize average path losses. We focus on line-of-sight (LOS) over-water links between onshore stations and different types of surface nodes, namely AUVs, buoys, or USVs, using 2.4 GHz and 5 GHz frequency bands. Analytical results targeting mission data transfer scenarios demonstrate that the proposed method outperforms, in both frequency bands, the common practice of placing (i) onshore antennas at the largest possible height and/or (ii) surface nodes at a short but arbitrary distance from the shore. A longer version of this summary was presented at IEEE/MTS OCEANS 2021.
- Wi-Fi-based network systems design over freshwater: Experimental evaluation using COTS devicesPublication . Gutiérrez Gaitán, Miguel; Santos, Pedro Miguel; Pinto, Luis; Almeida, LuísTo experimentally assess the impact of surface reflection on the received signal strength of a set of short-andmedium-range shore-to-shore links (<200 m) that use antennas installed at two heights, at a few meters above surface (<3 m).