Wireless Interference Identification with Convolutional Neural Networks

The steadily growing use of license-free frequency bands requires reliable coexistence management for deterministic medium utilization. For interference mitigation, proper wireless interference identification (WII) is essential. In this work we propose the first WII approach based upon deep convolutional neural networks (CNNs). The CNN naively learns its features through self-optimization during an extensive data-driven GPU-based training process. We propose a CNN example which is based upon sensing snapshots with a limited duration of 12.8 {\mu}s and an acquisition bandwidth of 10 MHz. The CNN differs between 15 classes. They represent packet transmissions of IEEE 802.11 b/g, IEEE 802.15.4 and IEEE 802.15.1 with overlapping frequency channels within the 2.4 GHz ISM band. We show that the CNN outperforms state-of-the-art WII approaches and has a classification accuracy greater than 95% for signal-to-noise ratio of at least -5 dB

Wireless body sensor networks for health-monitoring applications

This is an author-created, un-copyedited version of an article accepted for publication in Physiological Measurement. The publisher is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at http://dx.doi.org/10.1088/0967-3334/29/11/R01

Statistical analysis of indoor RSSI read-outs for 433 MHz, 868 MHz, 2.4 GHz and 5 GHz ISM bands

This paper presents statistical analysis of RSSI read-outs recorded in indoor environment. Many papers concerning indoor location, based on RSSI measurement, assume its normal probability density function (PDF). This is partially excused by relation to PDF of radio-receiver's noise and/or together with influence of AWGN (average white Gaussian noise) radio-channel – generally modelled by normal PDF. Unfortunately, commercial (usually unknown) methods of RSSI calculations, typically as "side-effect" function of receiver's AGC (automatic gain control), results in PDF being far different from Gaussian PDF. This paper presents results of RSSI measurements in selected ISM bands: 433/868 MHz and 2.4/5 GHz. The measurements have been recorded using low-cost integrated RF modules (at 433/868 MHz and 2.4 GHz) and 802.11 WLAN access points (at 2.4/5 GHz). Then estimated PDF of collected data is shown and compared to normal (Gaussian) PDF

A search for 21 cm HI absorption in AT20G compact radio galaxies

We present results from a search for 21 cm associated HI absorption in a sample of 29 radio sources selected from the Australia Telescope 20 GHz survey. Observations were conducted using the Australia Telescope Compact Array Broadband Backend, with which we can simultaneously look for 21 cm absorption in a redshift range of 0.04 < z < 0.08, with a velocity resolution of 7 km/s . In preparation for future large-scale H I absorption surveys we test a spectral-line finding method based on Bayesian inference. We use this to assign significance to our detections and to determine the best-fitting number of spectral-line components. We find that the automated spectral-line search is limited by residuals in the continuum, both from the band-pass calibration and spectral-ripple subtraction, at spectral-line widths of \Deltav_FWHM > 103 km/s . Using this technique we detect two new absorbers and a third, previously known, yielding a 10 per cent detection rate. Of the detections, the spectral-line profiles are consistent with the theory that we are seeing different orientations of the absorbing gas, in both the host galaxy and circumnuclear disc, with respect to our line-of-sight to the source. In order to spatially resolve the spectral-line components in the two new detections, and so verify this conclusion, we require further high-resolution 21 cm observations (~0.01 arcsec) using very long baseline interferometry.Comment: 16 pages, 8 figures and 5 tables; accepted for publication in MNRAS (version 2 based on proof corrections

Five new real-time detections of Fast Radio Bursts with UTMOST

We detail a new fast radio burst (FRB) survey with the Molonglo Radio Telescope, in which six FRBs were detected between June 2017 and December 2018. By using a real-time FRB detection system, we captured raw voltages for five of the six events, which allowed for coherent dedispersion and very high time resolution (10.24 $\mu$s) studies of the bursts. Five of the FRBs show temporal broadening consistent with interstellar and/or intergalactic scattering, with scattering timescales ranging from 0.16 to 29.1 ms. One burst, FRB181017, shows remarkable temporal structure, with 3 peaks each separated by 1 ms. We searched for phase-coherence between the leading and trailing peaks and found none, ruling out lensing scenarios. Based on this survey, we calculate an all-sky rate at 843 MHz of $98^{+59}_{-39}$ events sky$^{-1}$ day$^{-1}$ to a fluence limit of 8 Jy-ms: a factor of 7 below the rates estimated from the Parkes and ASKAP telescopes at 1.4 GHz assuming the ASKAP-derived spectral index $\alpha=-1.6$ ($F_{\nu}\propto\nu^{\alpha}$). Our results suggest that FRB spectra may turn over below 1 GHz. Optical, radio and X-ray followup has been made for most of the reported bursts, with no associated transients found. No repeat bursts were found in the survey.Comment: 13 pages, 11 figures, submitted to MNRA

Exploiting Wireless Sensors: a gateway for 868MHz sensors

[ANGLÈS] The great interest in monitoring everything around us has increased the number of sensors that we utilize in our daily lives. Furthermore, the evolution of wireless technologies has facilitated their ubiquity. Moreover, is in locations such as homes and offices where exploitation of the data from these sensors has been more important. For example, we want to know if the temperature in our home is adequate, otherwise we want to turn on the heating (or cooling) system automatically and we want to be able to monitor the environment of the home or office remotely. The knowledge from these sensors and the ability to actuate devices, summon human assistance, and adjust contracts for electrical power, heating, cooling, etc. can facilitate a myriad of ways to improve the quality of our life and potentially even reduce resource consumption. This master?s thesis project created a gateway that sniffs wireless sensor traffic in order to collect data from existing sensors and to provide this data as input to various services. These sensors work in the 868 MHz band. Although these wireless sensors are frequently installed in homes and offices, they are generally not connected to any network. We designed a gateway capable of identifying these wireless sensors and decoding the received messages, despite the fact that these messages may use a vendor?s proprietary protocol. This gateway consists of a microcontroller, a radio transceiver (868-915 MHz), and an Ethernet controller. This gateway enables us to take advantage of all the data that can be captured. Thinking about these possibilities, imultaneously acquiring data from these various sensors could open a wide range of alternatives in different fields, such as home automation, industrial controlling? Not only can the received data be interesting by itself; but when different sensors are located in the same environment we can exploit this data using sensor fusion. For example, time differences in arrival and differences in signal strength as measured t multiple receivers could be used to locate objects. The final aim of this thesis project is to support diverse applications that could be developed using the new gateway. This gateway creates a bridge between the information that is already around us and our ability to realize many new potential services. A wide range of opportunities could be realized by exploiting the wireless sensors we already have close to us.[CASTELLÀ] El gran interés en el seguimiento de todo lo que nos rodea ha incrementado el número de sensores que utilizamos en nuestra vida diaria. Por otra parte, la evolución de la tecnología inalámbrica ha facilitado su instalación. Es en lugares como casas y oficinas donde el aprovechamiento de los datos de estos sensores ha sido más importante. Por ejemplo, si queremos saber si la temperatura en casa es la adecuada para activar el sistema de calefacción (o refrigeración) de forma automática. La capacidad para accionar dispositivos externos y ajustar los contratos de energía eléctrica, calefacción, refrigeración, etc. puede facilitar una gran variedad de formas de mejorar la calidad de nuestra vida y, potencialmente, incluso reducir el consumo de recursos. Este proyecto de tesis ha creado una gateway que detecta el tráfico de sensores inalámbricos con el fin de recoger datos de los sensores existentes y proporcionarlos como entrada a varios servicios. Estos sensores funcionan en la banda de 868 MHz. A pesar de que estos sensores inalámbricos son frecuentemente instalados en hogares y oficinas, generalmente no están conectados a ninguna red. Hemos diseñado una gateway capaz de identificar estos sensores inalámbricos y descodificar los mensajes recibidos, aunque estos mensajes pueden utilizar un protocolo exclusivo del propietario. Esta gateway consta de un microcontrolador, un transceptor de radio (868-915 MHz) y un controlador Ethernet. Esta gateway nos permite tomar ventaja de todos los datos que se pueden capturar. Pensando en todas estas posibilidades a la vez, la adquisición de los datos de estos diversos sensores podría abrir una amplia gama de alternativas en diferentes campos, como la automatización del hogar, control industrial ... No sólo los datos recibidos pueden ser interesantes, sino que los diferentes sensores que se encuentran en el mismo entorno pueden explotar estos datos mediante la fusión de sensores. Por ejemplo, las diferencias de tiempo en la llegada y las diferencias en intensidad de la señal, según lo que determina múltiples receptores también podría ser utilizado para localizar objetos. El objetivo final de este proyecto de tesis es dar apoyo a las diversas aplicaciones que pueden ser desarrolladas utilizando la nueva gateway. Esta gateway crea un puente entre la información que ya está a nuestro alrededor y nuestra capacidad de realizar muchos nuevos servicios potenciales. Una amplia gama de posibilidades puede ser generada mediante la explotación red de sensores inalámbricos que ya están presentes en nuestro alrededor.[CATALÀ] El gran interès en el seguiment de tot el que ens envolta ha incrementat el nombre de sensors que utilitzem en la nostra vida diària. D'altra banda, l'evolució de la tecnologia sense fils ha facilitat la seva instal·lació. És en llocs com cases i oficines on l'aprofitament de les dades d'aquests sensors ha estat més important. Per exemple, si volem saber si la temperatura a casa és l'adequada per activar el sistema de calefacció (o refrigeració) de forma automàtica. La capacitat per accionar dispositius externs i ajustar els contractes d'energia elèctrica, calefacció, refrigeració, etc. pot facilitar una gran varietat de formes de millorar la qualitat de la nostra vida i, potencialment, fins i tot reduir el consum de recursos. Aquest projecte de tesi ha creat una gateway que ensuma el tràfic de sensors sense fils amb la finalitat de recollir dades dels sensors existents i proporcionar-les com a entrada de diversos serveis. Aquests sensors funcionen a la banda de 868 MHz. Malgrat aquests sensors sense fils són sovint instal·lats en llars i oficines, generalment no estan connectats a cap xarxa. Hem dissenyat una gateway capaç d'identificar aquests sensors sense fil i descodificar el missatges rebuts, tot i que aquests missatges poden utilitzar un protocol exclusiu del propietari. Aquesta gateway consta d'un microcontrolador, un transceptor de ràdio (868-915 MHz) i un controlador Ethernet. Aquesta gateway ens permet prendre avantatge de totes les dades que es poden capturar. Pensant en totes aquestes possibilitats a la vegada, l'adquisició de les dades d'aquests diversos sensors podria obrir una àmplia gamma d'alternatives en diferents camps, com ara l'automatització de la llar, control industrial ... No només les dades rebudes poden ser interessants, sinó que els diferents sensors que es troben en el mateix entorn poden explotar aquestes dades mitjançant la fusió de sensors. Per exemple, les diferències de temps en l'arribada i les diferències en intensitat del senyal segons el que determina múltiples receptors també podria ser utilitzat per localitzar objectes. L'objectiu final d'aquest projecte de tesi és donar suport a les diverses aplicacions que poden ser desenvolupades utilitzant la nova gateway. Aquesta gateway crea un pont entre la informació que ja està al nostre voltant i la nostra capacitat de realitzar nous serveis potencials . Una àmplia gamma de possibilitats pot ser generada mitjançant l'explotació de la xarxa de sensors sense fils que ja tenim a prop nostre