Optimum design parameters for ultra-low-power RF transceivers in wireless sensor networks

In wireless sensor networks, the need for ultra-low power consuming nodes is one of the main motivations for research in such field. Because radio sections in sensor nodes contribute to a large extent to the overall power consumption, the focus of this study is on the RF transceiver. The aim is to reduce the average power consumption which depends significantly on the circuit architecture design, operating data rate, and duty cycle. In a symmetric communicating system, due to the tradeoff between transmitting power and receiver sensitivity on one hand, as well as between phase noise tolerance and power dissipation in local oscillators on the other hand, the design and operating parameters of the transceiver need to be determined from the perspective of the average power consumption. Therefore, in our study, as an initial step in system design, the optimum for instantaneous data rate, noise figure, and oscillator power budget are analytically determined. The analysis is carried out, taking into consideration an existing in-channel wideband interference, on two transceiver architectures: RF envelope detection and conventional heterodyne. The transceiver in both architectures employs on-off-keying modulation and duty cycling. The optimums are then calculated numerically based on design constants obtained from a frequently-cited RF envelope transceiver, indicating that an energy efficiency improvement of up to 5 dB can still be achieved

Wireless distance estimation with low-power standard components in wireless sensor nodes

In the context of increasing use of moving wireless sensor nodes the interest in localizing these nodes in their application environment is strongly rising. For many applications, it is necessary to know the exact position of the nodes in two- or three-dimensional space. Commonly used nodes use state-of-the-art transceivers like the CC430 from Texas Instruments with integrated signal strength measurement for this purpose. This has the disadvantage, that the signal strength measurement is strongly dependent on the orientation of the node through the antennas inhomogeneous radiation pattern as well as it has a small accuracy on long ranges. Also, the nodes overall attenuation and output power has to be calibrated and interference and multipath effects appear in closed environments. Another possibility to trilaterate the position of a sensor node is the time of flight measurement. This has the advantage, that the position can also be estimated on long ranges, where signal strength methods give only poor accuracy. In this paper we present an investigation of the suitability of the state-of-the-art transceiver CC430 for a system based on time of flight methods and give an overview of the optimal settings under various circumstances for the in-field application. For this investigation, the systematic and statistical errors in the time of flight measurements with the CC430 have been investigated under a multitude of parameters. Our basic system does not use any additional components but only the given standard hardware, which can be found on the Texas Instruments evaluation board for a CC430. Thus, it can be implemented on already existent sensor node networks by a simple software upgrade.Comment: 8 pages, Proceedings of the 14th Mechatronics Forum International Conference, Mechatronics 201

mTOSSIM: A simulator that estimates battery lifetime in wireless sensor networks

Knowledge of the battery lifetime of the wireless sensor network is important for many situations, such as in evaluation of the location of nodes or the estimation of the connectivity, along time, between devices. However, experimental evaluation is a very time-consuming task. It depends on many factors, such as the use of the radio transceiver or the distance between nodes. Simulations reduce considerably this time. They allow the evaluation of the network behavior before its deployment. This article presents a simulation tool which helps developers to obtain information about battery state. This simulator extends the well-known TOSSIM simulator. Therefore it is possible to evaluate TinyOS applications using an accurate model of the battery consumption and its relation to the radio power transmission. Although an specific indoor scenario is used in testing of simulation, the simulator is not limited to this environment. It is possible to work in outdoor scenarios too. Experimental results validate the proposed model.Junta de Andalucía P07-TIC-02476Junta de Andalucía TIC-570

Method and system for spatial data input, manipulation and distribution via an adaptive wireless transceiver

A method and system for spatial data manipulation input and distribution via an adaptive wireless transceiver. The method and system include a wireless transceiver for automatically and adaptively controlling wireless transmissions using a Waveform-DNA method. The wireless transceiver can operate simultaneously over both the short and long distances. The wireless transceiver is automatically adaptive and wireless devices can send and receive wireless digital and analog data from various sources rapidly in real-time via available networks and network services

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