A realistic evaluation of indoor positioning systems based on Wi-Fi fingerprinting: The 2015 EvAAL–ETRI competition

Pre-print versionThis paper presents results from comparing different Wi-Fi fingerprinting algorithms on the same private dataset. The algorithms where realized by independent teams in the frame of the off-site track of the EvAAL-ETRI Indoor Localization Competition which was part of the Sixth International Conference on Indoor Positioning and Indoor Navigation (IPIN 2015). Competitors designed and validated their algorithms against the publicly available UJIIndoorLoc database which contains a huge reference- and validation data set. All competing systems were evaluated using the mean error in positioning, with penalties, using a private test dataset. The authors believe that this is the first work in which Wi-Fi fingerprinting algorithm results delivered by several independent and competing teams are fairly compared under the same evaluation conditions. The analysis also comprises a combined approach: Results indicate that the competing systems where complementary, since an ensemble that combines three competing methods reported the overall best results.We would like to thank Francesco Potortì, Paolo Barsocchi, Michele Girolami and Kyle O’Keefe for their valuable help in organizing and spread the EVAALETRI competition and the off-site track. We would also like to thank the TPC members Machaj Juraj, Christos Laoudias, Antoni Pérez-Navarro and Robert Piché for their valuable comments, suggestions and reviews. Parts of this work were funded in the frame of the Spanish Ministry of Economy and Competitiveness through the “Metodologiías avanzadas para el diseño, desarrollo, evaluación e integración de algoritmos de localización en interiores” project (Proyectos I+D Excelencia, código TIN2015-70202-P) and the “Red de Posicionamiento y Navegación en Interiores” network (Redes de Excelencia, código TEC2015-71426- REDT). Parts of this work were funded in the frame of the German federal Ministry of Education and Research programme "FHprofUnt2013" under contract 03FH035PB3 (Project SPIRIT).info:eu-repo/semantics/acceptedVersio

Transceiver Design Concept for Cellular and Multispot Diffusing Regimes of Transmission

<p>A number of attempts have been made in an effort to combine the advantages of line-of-sight and diffuse configurations for indoor optical wireless communications via sophisticated combinations of elements that are characteristic for these architectures. A different approach has been followed in the present investigation, namely, developing a transceiver capable of operating in both configurations. It is proposed that the transceiver design be based on the utilization of two-dimensional arrays of infrared light-emitting devices and photodetectors. Basic design parameters of transceiver optics are derived from considerations about link blockage and system compliance with the unique features of line-of-sight and diffuse methods of transmission.</p

A novel statistical model for turbulence-induced fading in free-space optical systems

Due to copyright restrictions, the access to the full text of this article is only available via subscription.In this paper, we propose a new probability distribution function which accurately describes turbulence-induced fading under a wide range of turbulence conditions. The proposed model, termed Double GG distribution, is based on a doubly stochastic theory of scintillation and developed via the product of two Generalized Gamma (GG) distributions. The proposed Double GG distribution generalizes many existing turbulence channel models in a closed-form expression and provides an excellent fit to the published plane and spherical waves simulation data. We finally evaluate the performance of a free-space optical system over the Double GG turbulence channel and derive closed-form expressions for the bit error rate, assuming intensity modulation/ direct detection with on-off keying.TÜBİTA

Bidirectional Fiber Amplifiers

NRC publication: Ye

A novel statistical channel model for turbulence-induced fading in free-space optical systems

Due to copyright restrictions, the access to the full text of this article is only available via subscription.In this paper, we propose a new probability distribution function which accurately describes turbulence-induced fading under a wide range of turbulence conditions. The proposed model, termed double-generalized gamma (double GG), is based on a doubly stochastic theory of scintillation and developed via the product of two generalized gamma distributions. The proposed double GG distribution generalizes many existing turbulence channel models and provides an excellent fit to the published plane and spherical waves simulation data. Using this new statistical channel model, we derive closed form expressions for the outage probability and the average bit error as well as corresponding asymptotic expressions of free-space optical communication systems over turbulence channels. We demonstrate that our derived expressions cover many existing results in the literature earlier reported for gamma-gamma, double-Weibull and K channels as special cases.TÜBİTA

Orthogonal-Polarization Reflective Star Couplers

NRC publication: Ye

Optical wireless multi-spot diffusing: a MIMO configuration

Optical (infrared) wireless communications links offer an attractive solution for indoor applications. To enable terminal mobility and reduce temporal dispersion, we use a configuration known as Multi-Spot-Diffusing (MSD), which is a Multi-Input, Multi-Output (MIMO) architecture. In this configuration, a transmitter generates multiple narrow beams that get uniformly spread over a reflection surface accessible to a service area. A multi-branch receiver with each branch having access to a diffusing spot (generated by transmitter) combines signals on its branches. This scheme creates multiple virtually ideal communications channels between a base station and terminals. This paper considers issues involved in the design of a transmitter-based holographic spot array generator. The generator produces equally-spaced diffusing spots on the room ceiling and/or walls. To overcome power limitation set by eye safety requirements, a receiver optical concentrator is proposed. Furthermore, to improve receiver signal-to-noise ratio, an optical filter that rejects optical noise is needed. Thus, functionally receiver branch optical front-end consists of an optical concentrator and an optical band-pass filter. A single holographic optical element, capable of performing both functions is proposed. Link performance is investigated by providing equivalent link model and comparing probability of error for a bare and a holographic receiver. From performance evaluations, our results show that it is possible to achieve an increase of 11 dB in the SNR and improve power budget by reducing the path loss by over 6 dB.Conference PresentationConference PaperPublishe