| On Friday, April 26th 2012, Dr. Thomas Zemen from FTW will give a talk on "Power Efficient Wireless Sensor Networks: Cooperative Methods and Channel Modeling" Location: Johannes Kepler University, Altenbergerstr. 69, 4040 Linz Science-Park 2, Room: S2-053 Abstract: his talk presents a partner selection protocol for enhancing the network lifetime in cooperative wireless networks. The case-study is the cooperative relayed transmission from mixed indoor nodes to a common outdoor access point. A stochastic bivariate model for the spatial distribution of the fading parameters that govern the link performance, namely the Rician K-factor and the path-loss, is proposed and validated by means of real channel measurements. The partner selection protocol is based on the real-time estimation of a function of these fading parameters, i.e., the coding gain. To reduce the complexity of the link quality assessment, a Bayesian approach is proposed that uses the site-specific bivariate model as a-priori information for the coding gain estimation. This link quality estimator allows network lifetime gains almost as if all K-factor values were known. Furthermore, it suits IEEE 802.15.4 compliant networks as it efficiently exploits the information acquired from the received signal strength indicator. Extensive numerical results highlight the trade-off between complexity, robustness to model mismatches and network lifetime performance. We show for instance that infrequent updates of the site-specific model through K-factor estimation over a subset of links are sufficient to at least double the network lifetime with respect to existing algorithms based on path loss information only. Biographie: Thomas Zemen received the Dipl.-Ing. degree (with distinction) in electrical engineering in 1998, the doctoral degree (with distinction) in 2004 and the Venia Docendi (Habilitation) for "Mobile Communications" in 2013, all from Vienna University of Technology. From 1998 to 2003 he worked as Hardware Engineer and Project Manager for the Radio Communication Devices Department, Siemens Austria. Since October 2003 Thomas Zemen has been with FTW Forschungszentrum Telekommunikation Wien, he leads the department "Signal and Information Processing" since 2008. He is the speaker of the national research network for "Signal and Information Processing in Science and Engineering" funded by the Austrian Science Fund (FWF). He is the author or coauthor of four books chapters, 17 journal papers and more than 65 conference communications. His research interests include vehicular channel measurements and modeling, time-variant channel estimation, orthogonal frequency division multiplexing (OFDM), iterative multiple-input multiple-output (MIMO) receiver structures, cooperative communication systems and interference management. Dr. Zemen is an External Lecturer with the Vienna University of Technology and serves as Editor for the IEEE Transactions on Wireless Communications. |
