The Internet of Things (IoT) provides a virtual view, via the Internet Protocol, to a huge variety of real life objects, ranging from a car, to a teacup, to a building, to trees in a forest. Its appeal is the ubiquitous generalized access to the status and location of any “thing” we may be interested in. Wireless sensor networks (WSN) are well suited for long-term environmental data acquisition for IoT representation. This paper presents the functional design and implementation of a complete WSN platform that can be used for a range of long-term environmental monitoring IoT applications. The application requirements for low cost, high number of sensors, fast deployment, long lifetime, low maintenance, and high quality of service are considered in the specification and design of the platform and of all its components. Low-effort platform reuse is also considered starting from the specifications and at all design levels for a wide array of related monitoring applications.

Design of a WSN Platform for Long-Term Environmental Monitoring for IoT Applications

A survey of communication/networking in Smart Grids

Wireless sensor networks (WSNs) can be used in agriculture to provide farmers with a large amount of information. Precision agriculture (PA) is a management strategy that employs information technology to improve quality and production. Utilizing wireless sensor technologies and management tools can lead to a highly effective, green agriculture. Based on PA management, the same routine to a crop regardless of site environments can be avoided. From several perspectives, field management can improve PA, including the provision of adequate nutrients for crops and the wastage of pesticides for the effective control of weeds, pests, and diseases. This review outlines the recent applications of WSNs in agriculture research as well as classifies and compares various wireless communication protocols, the taxonomy of energy-efficient and energy harvesting techniques for WSNs that can be used in agricultural monitoring systems, and comparison between early research works on agriculture-based WSNs. The challenges and limitations of WSNs in the agricultural domain are explored, and several power reduction and agricultural management techniques for long-term monitoring are highlighted. These approaches may also increase the number of opportunities for processing Internet of Things (IoT) data.

https://www.mdpi.com/1424-8220/17/8/1781/pdf

Energy-Efficient Wireless Sensor Networks for Precision Agriculture: A Review.

Summary form only given. The layered architecture is one of the key reasons behind the explosive and continuing growth of the Internet. There are, however, special networks in which cross-layer design is appropriate and may even be necessary. Two such cases are small wireless LAN and large-scale sensor networks. We consider first the design of medium access control (MAC) for a small wireless LAN based on a multiuser physical layer. We present a complete characterization of the throughput region and present conditions under which ALOHA is optimal. Next we consider the estimation of signal field using data collected from a large scale sensor network. The impact of medium access control on estimation is examined. We show that there exists a threshold on sensor outage probability above which a distributed random access protocol (such as ALOHA) outperforms the centralized deterministic schedulers.

On cross-layer design of wireless networks

Traditionally, pollution measurements are performed using expensive equipment at fixed locations or dedicated mobile equipment laboratories. This is a coarse-grained and expensive approach where the pollution measurements are few and far in-between. In this paper, we present a vehicular-based mobile approach for measuring fine-grained air quality in real-time. We propose two cost effective data farming models -- one that can be deployed on public transportation and the second a personal sensing device. We present preliminary prototypes and discuss implementation challenges and early experiments.

Real-time air quality monitoring through mobile sensing in metropolitan areas

A new approach, using electromagnetic analysis, is proposed for field-effect transistor model scaling and monolithic-microwave integrated-circuit (MMIC) design. It is based on an empirical distributed modeling technique where the active device is described in terms of an external passive structure connected to a suitable number of internal active sections. On this basis, an equivalent admittance matrix per gate unit width is obtained which, as confirmed by experimental results provided in this paper, is consistent with simple scaling rules. The same technique can also be adopted for a "global approach" to MMIC design where complex electromagnetic phenomena are also taken into account. An example of application concerning this aspect is presented.

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A new approach to FET model scaling and MMIC design based on electromagnetic analysis

Today Wireless Sensor Network are used into an increasing number of commercial solutions, aimed at implementing distributed monitoring and control system in a great number of different application area. In particular the agricultural scenario seems to be one of the most promising application area for WSN due to the necessity of proving the agricultural production chain in terms of precision and quality. This involves a careful system design, since requirements are very strict: battery life-time maximization,robustness, recovery strategies, network flexibility and reconfigurability. This paper shows and describes a practical case study, starting from a real problem and reaching the best architectural solution, with particular focus on the hardware implementation and communication protocol design. A real end-to-end solution has been implemented: several wireless nodes send environmental data every 15 minutes to a master node connected to a GPRS gateway board that forwards data to a remote server using TCP-IP standard protocol. The encouraging and unprecedented results achieved by this approach are supported by several pilot sites into different vineyard in Italy and in France, within which a great amount of environmental data have been collected and analyzed since two years and half.

Agricultural Monitoring Based on Wireless Sensor Network Technology: Real Long Life Deployments for Physiology and Pathogens Control

In this paper, we present a frequency analysis of a compensated impedance inverter and its effective implementation in the context of high-power Doherty amplifier (DPA) design. On the basis of an idealized DPA model, we calculate the expected operative bandwidth and the corresponding maximum drain efficiency as a function of the modulated signal statistics. In addition, we introduce an effective technique for the implementation of the compensated impedance inverter, suitable for preserving its broadband characteristics in the presence of large device’s output capacitance. The implementation technique is based on the generalized equivalent transmission-line equivalence principle, which considers both shortening and lengthening the equivalent transmission lines. We demonstrate that, by the proposed approach, parasitic absorption is possible maintaining a low $Q$ -factor of the equivalent network. The technique is validated by the development of a silicon laterally diffused metal–oxide–semiconductor DPA with optimized peak power and efficiency for applications in the 650–950-MHz band. The fabricated prototype is characterized by an LTE signal with a 20-MHz bandwidth and peak-to-average-power ratio of 7.5 dB and features an average drain efficiency between 37% and 47%, with an average power of 49 dBm across 37.5% of the bandwidth.

Frequency Analysis and Multiline Implementation of Compensated Impedance Inverter for Wideband Doherty High-Power Amplifier Design

Electron device modeling is a challenging task at millimeter-wave frequencies. In particular, conventional approaches based on lumped equivalent circuits become inappropriate to describe complex distributed and coupling effects, which may strongly affect the transistor performance. In this paper, an empirical distributed FET model is adopted that can be identified on the basis of conventional S-parameter measurements and electromagnetic simulations of the device layout. The consistency of the proposed approach is confirmed by robust scaling properties, which enable millimeter-wave small-signal S-parameters to be predicted as a function of the device periphery and number of gate fingers. Moreover, it is shown how the model identified on the basis of standard S-parameter measurements up to 50 GHz can be efficiently exploited in order to obtain reasonably accurate small-signal prediction up to 110 GHz. Extensive experimental validation is presented for 0.2-/spl mu/m pseudomorphic high electron-mobility transistors devices.

/pdf/millimeter-wave-fet-modeling-using-on-wafer-measurements-and-43s6kfx8xk.pdf

Millimeter-wave FET modeling using on-wafer measurements and EM simulation

The monolithic integration of tunneling diodes (TDs) with other semiconductor devices such as HEMTs or HBTs, creates novel quantum functional nonlinear devices and circuits with unique properties: the Negative Differential Resistance (NDR) and the extremely low DC power consumption. In this paper we present an InP-HEMT/spl bsol/TD based voltage controlled oscillator operating in the 6 GHz band suitable for wireless applications. The circuit draws a current of 1.75 mA at 500 mV and generates an output power of -16 dBm The maximum tuning range is 150 MHz and the single sideband-to-carrier ratio (SSCR) is of -105 dBc/Hz at 5 MHz.

Giovanni Collodi

Papers

A new approach to FET model scaling and MMIC design based on electromagnetic analysis

Agricultural Monitoring Based on Wireless Sensor Network Technology: Real Long Life Deployments for Physiology and Pathogens Control

Frequency Analysis and Multiline Implementation of Compensated Impedance Inverter for Wideband Doherty High-Power Amplifier Design

Millimeter-wave FET modeling using on-wafer measurements and EM simulation

Ultra low-power VCO based on InP-HEMT and heterojunction interband tunnel diode for wireless application