Fast prototyping of an SDR WLAN 802.11b receiver for an indoor positioning system

Indoor positioning systems (IPS) are emerging technologies due to an increasing popularity and demand in location based service (LBS). Because traditional positioning systems such as GPS are limited to outdoor applications, many IPS have been proposed in literature. WLAN-based IPS are the most promising due to its proven accuracy and infrastructure deployment. Several WLAN-based IPS have been proposed in the past, from which the best results have been shown by so-called fingerprint-based systems. This paper proposes an indoor positioning system which extends traditional WLAN fingerprinting by using received signal strength (RSS) measurements along with channel estimates as an effort to improve classification accuracy for scenarios with a low number of Access Points (APs). The channel estimates aim to characterize complex indoor environments making it a unique signature for fingerprinting-based IPS and therefore improving pattern recognition in radio-maps. Since commercial WLAN cards offer limited measurement information, software-defined radio (SDR) as an emerging trend for fast prototyping and research integration is chosen as the best cost-effective option to extract channel estimates. Therefore, this paper first proposes an 802.11b WLAN SDR beacon receiver capable of measuring RSS and channel estimates. The SDR is designed using LabVIEW (LV) environment and leverages several inherent platform acceleration features that achieve real-time capturing. The receiver achieves a fast-rate measurement capture of 9 packets per second per AP. The classification of the propose IPS uses a support vector machine (SVM) for offline training and online navigation. Several tests are conducted in a cluttered indoor environment with a single AP in 802.11b legacy mode. Finally, navigation accuracy results are discussed

A Fast-rate WLAN Measurement Tool for Improved Miss-rate in Indoor Navigation

Recently, location-based services (LBS) have steered attention to indoor positioning systems (IPS). WLAN-based IPSs relying on received signal strength (RSS) measurements such as fingerprinting are gaining popularity due to proven high accuracy of their results. Typically, sets of RSS measurements at selected locations from several WLAN access points (APs) are used to calibrate the system. Retrieval of such measurements from WLAN cards are commonly at one-Hz rate. Such measurement collection is needed for offline radio-map surveying stage which aligns fingerprints to locations, and for online navigation stage, when collected measurements are associated with the radio-map for user navigation. As WLAN network is not originally designed for positioning, an RSS measurement miss could have a high impact on the fingerprinting system. Additionally, measurement fluctuations require laborious signal processing, and surveying process can be very time consuming. This paper proposes a fast-rate measurement collection method that addresses previously mentioned problems by achieving a higher probability of RSS measurement collection during a given one-second window. This translates to more data for statistical processing and faster surveying. The fast-rate collection approach is analyzed against the conventional measurement rate in a proposed testing methodology that mimics real-life scenarios related to IPS surveying and online navigation

A Reduced Complexity Cross-correlation Interference Mitigation Technique on a Real-time Software-defined Radio GPS L1 Receiver

The U.S. global position system (GPS) is one of the existing global navigation satellite systems (GNSS) that provides position and time information for users in civil, commercial and military backgrounds. Because of its reliance on many applications nowadays, it's crucial for GNSS receivers to have robustness to intentional or unintentional interference. Because most commercial GPS receivers are not flexible, software-defined radio emerged as a promising solution for fast prototyping and research on interference mitigation algorithms. This paper provides a proposed minimum mean-squared error (MMSE) interference mitigation technique which is enhanced for computational feasibility and implemented on a real-time capable GPS L1 SDR receiver. The GPS SDR receiver SW has been optimized for real-time operation on National Instruments' LabVIEW (LV) platform in conjunction with C/C++ dynamic link libraries (DLL) for improved efficiency. Performance results of said algorithm with real signals and injected interference are discussed. The proposed SDR receiver gains in terms of BER curves for several interferers are demonstrated

Obtaining the ideal smoked bacon: What is the influence of the product space and multivariate procedure to construct the external preference mapping?

Identifying the ideal product is the most important step in new product development and improvement of existing ones. The aim of this study was to identify the ideal smoked bacon using PrefMFA and PrefMap considering three different sensory spaces obtained via descriptive analysis (DA), projective mapping (PM) and CATA questions. Six smoked bacons were characterized by ten trained assessors using DA, and by two consumers panel using PM (n=93) and CATA questions (n=100). Also, one hundred consumers indicated their overall liking using a nine-point hedonic scale. The results showed that both techniques identified an ideal product. However, the sensory method has a greater effect than the multivariate procedure to obtain the sensory spaces prior to the preference mapping. Subsequent studies with other food matrices are still necessary in order to generalize our results

Receptive tourism in Paraguay: a review of their contribution to the economy during the period 2003 – 2017

Este material tiene como objetivo presentar los efectos generados por el ingreso de turistas al Paraguay, específicamente en materia económica. Para lograr el propósito trazado con este trabajo, se diseñó una investigación de nivel exploratorio y descriptivo, de tipo bibliográfico – documental, en la que se recurre entre otras herramientas al cálculo de índices sugeridos por distintos organismos internacionales. Este país posee diversos atractivos turísticos y económicos que atraen a los visitantes, aunque la información disponible es muy limitada. Esto constituye una dificultad para los trabajos de investigación a ser desarrollados. Entre los resultados más importantes se encuentran la relevancia del turismo como industria de exportación, la cual se ha expandido notoriamente durante el periodo que abarca este estudio, y su rol para la generación de ingresos de divisas al país por medio de la llegada de turistas, principalmente de los países limítrofes.This paper has the purpose of presenting the effects generated by the incoming of tourists to Paraguay, specifically in economic matters. To achieve the purpose outlined in this paper, an exploratory and descriptive level research was designed. In addition, it has been considered a bibliographic - documentary research. Several tools was used, especially suggested indexes by international organizations.  This country has several tourist and economic attractions which attracts visitors but despite the information about the activity is limitated. That is a difficulty for the researchers and their works. Among the most outstanding results are the relevance of tourism as an export industry and its importance for the generation of international currency income through the tourists, especially from bordering countries