NEtwork of Excellence in Wireless COMmunications++ (NEWCOM++)

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Publications

Experimental characterisation of WiMAX propagation in different environments

Publication . Robalo, Daniel Luís Silveira; Oliveira, João; Velez, Fernando; Petrini, Valeria; Barbiroli, Marina; Carciofi, Claudia; Grazioso, Paolo; Fuschini, Franco

The aim of this work is to continue the cooperation on Fixed WiMAX experimental propagation characterization between Instituto de Telecomunicações - DEM of University of Beira Interior, Portugal, Fondazione Ugo Bordoni and the Department of Electronics and Information Systems of the University of Bologna, both from Italy. The field trials addressed different environments, i.e., suburban and open areas in a hilly terrain for the study of the propagation characteristics of WiMAX systems. The IEEE 802.16-2004 equipment operates at 3.5 GHz with a bandwidth of 3.5 MHz. Different antenna heights are considered. The measurements have been performed in outdoor, indoor and mixed environments, with omnidirectional and 120° sectored antennas. In the outdoor environment, results show an adequacy between the trend-curve for the experimental results with the modified Friis equation with propagation exponent 2.71.

2011-04Conference object

Open access

Model for the correlation between quality of service and experience in cognitive radio networks

Publication . Robalo, Daniel; Velez, Fernando J.

This paper proposes a methodology for the development of a correlation model between Quality of Service and Experience in cognitive radio networks. The aim of this research is to provide the cognitive radio networks ecosystem player the tools to assess the contribution of the network performance to the overall level of user's satisfaction. The performance parameters of several types of applications are addressed to highlight how delay, delay variation and information loss affect the service quality. Furthermore we thoroughly discuss, evaluate and test the proposed methodology, i.e., non-linear regression and genetic algorithms, by comparing it to the IETF recommended games MUSE G-Model. The obtained results are very promising. Future work includes verifying the effectiveness of the proposed methodology in the context of more complex fitting equations.

2011-10Conference object

Open access