Search results for "Communications"
showing 10 items of 3827 documents
Congestion Avoidance Using DYnamic COdec MAnagement: A solution for ISP
2005
The large diffusion of VoIP is an essential key for the success of emerging Internet service providers. These ISPs conflict with the interests of historical and predominant network maintainers which often control the network infrastructure and telephone services. To win this competition, emerging ISPs have to adopt strategic QoS solutions which will capture the attention of network users and phone clients. This paper presents a solution which is able to obtain the same performance of a 64 Kbps channel reducing the costs for over-provisioning network bandwidth. DyCoMa is a mechanism studied for VoIP applications in network with a limited bandwidth for multimedia services. It works preventing…
Multi-Resource Management for Multi-Tier Space Information Networks: A Cooperative Game
2019
With the drastic increase of space information network (SIN) traffic and the diversity of network traffic types, the optimal allocation of the scarce network resources is of great significance for optimizing the SIN system capability. In this paper, we propose a multi-resource management method for multi-tier SIN using the cooperative Nash bargaining solution. Since the original problem is a non-convex problem, we firstly make logarithmic transition, and then find a tightest lower bound function to convert the initial problem into a convex one. In order to carry out the optimal bandwidth and power allocation in SIN, we construct a joint bandwidth and power allocation (JBPA) algorithm. Simul…
Applicability of Interference Coordination in Highly Loaded HSUPA Network
2010
This paper evaluates the performance of highly loaded High Speed Uplink Packet Access (HSUPA) network with and without network wide static Interference Coordination (IC). IC alternates the priorities for user transmission periods throughout the network to achieve reduced interference levels and higher performance. A large variety of combinations including, e.g., different schedulers, cell center/edge user definitions (user splits) and interference targets are investigated in this paper. Performance is analyzed using a quasi-static system level simulator which is also used to support Third Generation Partnership Project (3GPP) standardization work. The simulator contains detailed and commonl…
Robust Transmission for Reconfigurable Intelligent Surface Aided Millimeter Wave Vehicular Communications With Statistical CSI
2022
The integration of reconfigurable intelligent surface (RIS) into millimeter wave (mmWave) vehicular communications offers the possibility to unleash the potential of future proliferating vehicular applications. However, the high-mobility-induced rapidly varying channel state information (CSI) has been making it challenging to obtain the accurate instantaneous CSI (I-CSI) and to cope with the incurable high signaling overhead. The situation may become worse when the RIS with a large number of passive reflecting elements is deployed. To overcome this challenge, we investigate in this paper a robust transmission scheme for the time-varying RIS-aided mmWave vehicular communications, in which, s…
A Novel Energy Harvester for Powering Small UAVs: Performance Analysis, Model Validation and Flight Results
2019
The proposed work aims at exploring and developing new strategies to extend mission parameters (measured as travel distance and mission duration (MD)) of a new class of unmanned vehicles, named Micro Air Vehicles (MAVs). In this paper, a new analytical model, identifying all factors, which determine the MAV power consumption, is presented. Starting from the new model, the design of a nanoarray energy harvester, based on plasmonics nano-antenna technology is proposed. The preliminary study was based on a 22,066,058 22,066,058 ×
On-board Energy Consumption Assessment for Symbolic Execution Models on Embedded Devices
2020
Internet of Things (IoT) applications operate in several domains while requiring seamless integration among heterogeneous objects. Regardless of the specific platform and context, IoT applications demand high energy efficiency. Adopting resource-constrained embedded devices for IoT applications means ensuring low power consumption, low maintenance costs and possibly longer battery life. Meeting these requirements is particularly arduous as programmers are not able to monitor the energy consumption of their own software during development or when applications are finally deployed. In this paper, we discuss on-board real-time energy evaluation of both hardware and software during the developm…
Design and Implementation of an Ultra-Low Power Wake-up Radio for Wireless IoT Devices
2018
In this paper, we present the design and prototype implementation of an ultra-low power wake-up radio for wireless IoT devices. The prototyped wake-up radio consumes only 580nA from 3V power supply, covers distance range of up to 55 meters and achieves a sensitivity of -49.5dBm. This wakeup radio module can easily be integrated into wireless IoT devices and thereby reducing the overall power consumption of the battery powered and energy harvesting based devices. The prolonged life time of the devices can reduce the overall costs when deployed in large scale.
VentQsys: Low-cost open IoT system for CO2 monitoring in classrooms
2021
AbstractIn educational context, a source of nuisance for students is carbon dioxide ($$CO_2$$ C O 2 ) concentration due to closed rooms and lack of ventilation or circulatory air. Also, in the pandemic context, ventilation in indoor environments has been proven as a good tool to control the COVID-19 infections. In this work, it is presented a low cost IoT-based open-hardware and open-software monitoring system to control ventilation, by measuring carbon dioxide ($$CO_2$$ C O 2 ), temperature and relative humidity. This system provides also support for automatic updating, auto-self calibration and adds some Cloud and Edge offloading of computational features for mapping functionalities. From…
Li-ion Battery Modeling and State of Charge Estimation Method Including the Hysteresis Effect
2019
In this paper, a new approach to modeling the hysteresis phenomenon of the open circuit voltage (OCV) of lithium-ion batteries and estimating the battery state of charge (SoC) is presented. A characterization procedure is proposed to identify the battery model parameters, in particular, those related to the hysteresis phenomenon and the transition between charging and discharging conditions. A linearization method is used to obtain a suitable trade-off between the model accuracy and a low computational cost, in order to allow the implementation of SoC estimation on common hardware platforms. The proposed characterization procedure and the model effectiveness for SoC estimation are experime…
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 â¼45% 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.