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An Optimized Propagation Model based on Measurement Data for Indoor Environments

Morocho-Yaguana M., Ludeňa-González P., Sandoval F., Poma-Vélez B., Erreyes-Dota A.

Journal of Telecommunications and Information Technology

2018

nr 2

69--75

Propagation is an essential factor ensuring good coverage of wireless communications systems. Propagation models are used to predict losses in the path between transmitter and receiver nodes. They are usually deﬁned for general conditions. Therefore, their results are not always adapted to the behavior of real signals in a speciﬁc environment. The main goal of this work is to propose a new model adjusting the loss coeﬃcients based on empirical data, which can be applied in an indoor university campus environment. The Oneslope, Log-distance and ITU models are described to provide a mathematical base. An extensive measurement campaign is performed based on a strict methodology considering different cases in typical indoor scenarios. New loss parameter values are deﬁned to adjust the mathematical model to the behavior of real signals in the campus environment. The experimental results show that the model proposed oﬀers an attenuation average error of 2.5% with respect to the losses measured. In addition, comparison of the proposed model with existing solutions shows that it decreases the average error signiﬁcantly for all scenarios under evaluation.

A collaborative control scheme for haptics-based blind wheelchair driving

Urdiales C., Fernandez-Carmona M., Peula J.M., Annicchiarricco R., Sandoval F., Caltagirone C.

Prace Naukowe Politechniki Warszawskiej. Elektronika

2010

z. 175, t. 1

3-22

In this paper, a new approach to shared control for wheelchair driving assistance to visually challenged people is presented. Our system estimates how much help the user needs to solve a situation in a reactive fashion and combines his/her commands with assistant to continuously produce an emergent motor behavior. Thus, the better the person drives, the more control he/she is awarded with. Attempts to drive in unsafe directions or far from a set goal also reduce user contribution to wheelchair motion. Efficiency changes are perceived by people as speetl reduction. Users may sample different headings and acknowledge that they are on their way when they gain back speed.The approach has been tested at Casa Agevole in Fondazione Santa Lucia (FSL) with blindfolded volunteers. All volunteers managed to finish a mildly complicaled trajectory with door crossing and major turns in collaborative mode.