Search results for "Architecture"

A method for modeling the battery state of charge in wireless sensor networks

2015

In this paper we propose a method for obtaining an analytic model of the battery State-of-Charge (SoC) in wireless sensor nodes. The objective is to find simple models that can be used to estimate accurately the real battery state and consequently the node lifetime. Running the model in the network nodes, we can provide the motes with the required information to implement applications that can be considered as battery-aware. The proposed methodology reduces the computational complexity of the model avoiding complicated electrochemical simulations and treating the battery as an unknown system with an output that can be predicted using simple mathematical models. At a first stage, during a se…

An over-the-distance wireless battery charger based on RF energy harvesting

2017

An RF powered receiver silicon IC (integrated circuit) for RF energy harvesting is presented as wireless battery charger. This includes an RF-to-DC energy converter specifically designed with a sensitivity of -18.8 dBm and an energy conversion efficiency of ∼45% at 900 MHz with a transmitting power of 0.5 W in free space. Experimental results concerned with remotely battery charging using a complete prototype working in realistic scenarios will be shown.

E-bike battery charging: Methods and circuits

2013

Today, academic and industrial research is focused on innovative battery charging methods to ensure complete mobility of both handheld devices and electric vehicles. Wireless power transfer is actually the leading strategy even if efficiency related issues are to be solved for a successful marketing. In this paper, a wireless battery charging station is proposed for electric assisted pedal bikes. If compared with existing wireless solutions, the proposed system architecture improves power conversion efficiency of the charging equipment. The simulation model of the whole charging station is described in detail. The transmitter, receiver and inductive coupling circuits are described and desig…

Wireless Power Transmission for house appliances: A small-scale resonant coupling prototype

2016

This paper presents a low cost prototype of wireless power transfer system based on resonant coupling. The system here proposed can be useful for house appliances battery charging systems: as a matter of fact, it consists mainly of two copper wire coils or windings, placed one in front of the other on the same axis. By exploiting the coils resonance coupling effect, electric energy can be transferred from the inductor coil to the receiver in order to charge the batteries. Low cost experimental tests demonstrated the effectiveness of the proposed wireless power transfer prototype, being it capable to reach an efficiency of about 80% and more along a distance of 30 cm.

Optimization of urban delivery systems based on electric assisted cargo bikes with modular battery size, taking into account the service requirements…

2021

The implementation of new forms of urban mobility is a fundamental challenge for improving the performance of city logistic systems in terms of efficiency and sustainability. For such purposes, the exploitation of electric vehicles is currently being investigated as an alternative to traditional internal combustion engines. In particular, the employment of lightweight electric cargo bikes is seen as an attractive possibility for designing improved city distribution systems. Such vehicles, however, present substantial limitations related to their endurance, speed, power, and recharging times; therefore, their configuration must be optimized considering the actual operational context and the …

Beitrag zur Gebäude-Statistik der Stadt Riga für das Jahr 1866

1868

Vorwort. I. Capitel. Die Zahl und Nutzung der Gebäude II. Capitel. Der Besitzstand der Gebäude III. Die Besteuerung der Gebäude IV. Capitel. Die Wohnungen. Anhang 1. Instruction zur Abschätzung sämmtlicher Immobilien im Polizeibezirk der Stadt Riga. Anhang 2. Uebersicht über die nach Zimmerzahl, Höhenlage und Miethzins gegliederten Wohnungen, Buden und Kellerräume in den einzelnen Quartalen der Stadt. Tabelle I-XXI

Offenes Antwortschreiben an das Stadt-Amt zu Riga

1885

Robust Transmit Beamforming for Underlay D2D Communications on Multiple Channels

2020

Underlay device-to-device (D2D) communications lead to improvement in spectral efficiency by simultaneously allowing direct communication between the users and the existing cellular transmission. However, most works in resource allocation for D2D communication have considered single antenna transmission and with a focus on perfect channel state information (CSI). This work formulates a robust transmit beamforming design problem for maximizing the aggregate rate of all D2D pairs and cellular users (CUs). Assuming complex Gaussian distributed CSI error, our formulation guarantees probabilistically a signal to interference plus noise ratio (SINR) above a specified threshold. In addition, we al…

Reliable Underlay D2D Communications over Multiple Transmit Antenna Framework

2020

Robust beamforming is an efficient technique to guarantee the desired receiver performance in the presence of erroneous channel state information (CSI). However, the application of robust beamforming in underlay device-to-device (D2D) communication still requires further investigation. In this paper, we investigate resource allocation problem for underlay D2D communications by considering multiple antennas at the base station (BS) and at the transmitters of D2D pairs. The proposed design problem aims at maximizing the aggregate rate of all D2D pairs and cellular users (CUs) in downlink spectrum. In addition, our objective is augmented to achieve a fair allocation of resources across the D2D…

Relay selection in FDD amplify-and-forward cooperative networks

2017

In this paper, the problems of relay selection and distributed beamforming are investigated for bi-directional dual-hop amplify-and-forward frequency-division duplex cooperative wireless networks. When using individual per-relay maximum transmission power constraint, it has been proven that the relay selection and beamforming optimization problem becomes NP hard and requires exhaustive search to find the optimal solution. Therefore, we propose a computationally affordable sub-optimal multiple relay selection and beamforming optimization scheme based on the l1 norm squared relaxation. The proposed scheme performs the selection for the two transmission directions, simultaneously, while aiming…