90,611 research outputs found
Design and Test of a High QoS Radio Network for CBTC Systems in Subway Tunnels
Communications Based Train Control Systems require high quality radio data communications for train signaling and control. Actually most of these systems use 2.4GHz band with proprietary radio transceivers and leaky feeder as distribution system. All them demand a high QoS radio network to improve the efficiency of railway networks. We present narrow band, broad band and data correlated measurements taken in Madrid underground with a transmission system at 2.4 GHz in a test network of 2 km length in subway tunnels. The architecture proposed has a strong overlap in between cells to improve reliability and QoS. The radio planning of the network is carefully described and modeled with narrow band and broadband measurements and statistics. The result is a network with 99.7% of packets transmitted correctly and average propagation delay of 20ms. These results fulfill the specifications QoS of CBTC systems
UAV-Empowered Disaster-Resilient Edge Architecture for Delay-Sensitive Communication
The fifth-generation (5G) communication systems will enable enhanced mobile
broadband, ultra-reliable low latency, and massive connectivity services. The
broadband and low-latency services are indispensable to public safety (PS)
communication during natural or man-made disasters. Recently, the third
generation partnership project long term evolution (3GPPLTE) has emerged as a
promising candidate to enable broadband PS communications. In this article,
first we present six major PS-LTE enabling services and the current status of
PS-LTE in 3GPP releases. Then, we discuss the spectrum bands allocated for
PS-LTE in major countries by international telecommunication union (ITU).
Finally, we propose a disaster resilient three-layered architecture for PS-LTE
(DR-PSLTE). This architecture consists of a software-defined network (SDN)
layer to provide centralized control, an unmanned air vehicle (UAV) cloudlet
layer to facilitate edge computing or to enable emergency communication link,
and a radio access layer. The proposed architecture is flexible and combines
the benefits of SDNs and edge computing to efficiently meet the delay
requirements of various PS-LTE services. Numerical results verified that under
the proposed DR-PSLTE architecture, delay is reduced by 20% as compared with
the conventional centralized computing architecture.Comment: 9,
The Front end of Software-Defined Radio: Possibilities and Challenges
The use of mobile telephony has shown a spectacular\ud
growth in the last 10 years. A side effect of this rapid\ud
growth is an excess of mobile system standards. Therefore,\ud
the Software-Defined-Radio (SDR) concept is emerging as\ud
a potential pragmatic solution: it aims to build flexible radio\ud
systems, which are multi-service, multi-standard, multiband,\ud
re-configurable and re-programmable, by software.\ud
First, this paper presents a global overview of SDR.\ud
Furthermore, it discusses several front-end architectures of\ud
SDR. The goal of this project is to generate knowledge about\ud
designing part of the functionality of SDR, implemented by\ud
rapid prototyping strategies. The focus is on the front end\ud
of SDR. The technological roadmap is taken into account to\ud
evaluate several architectures
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
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Ubiquitous Internet in an integrated satellite-terrestrial environment: The SUITED solution
yesThe current Internet architecture appears to
not be particularly suited to addressing the
emerging needs of new classes of users who wish
to gain access to multimedia services made available
by ISPs, regardless of their location, while
in motion and with a guaranteed level of quality.
One of the main objectives of so-called nextgeneration
systems is to overcome the limitations
of todayÂżs available Internet by adopting an
approach based on the integration of different
mobile and fixed networks. The SUITED project
moves in this direction since it aims at contributing
to the design and deployment of the global
mobile broadband system (GMBS), a unique
satellite/terrestrial infrastructure ensuring
nomadic users access to Internet services with a
negotiated QoS. A description of the main features
of the GMBS architecture, characterized
by the integration of a multisegment access network
with a federated ISP network is given in
this article. The GMBS multimode terminal is
schematically described, and an overview of the
so-called QoS-aware mobility management
scheme, devised for such a heterogeneous scenario,is provided
Development of a dc-ac power conditioner for wind generator by using neural network
This project present of development single phase DC-AC converter for wind
generator application. The mathematical model of the wind generator and Artificial
Neural Network control for DC-AC converter is derived. The controller is designed to
stabilize the output voltage of DC-AC converter. To verify the effectiveness of the
proposal controller, both simulation and experimental are developed. The simulation and
experimental result show that the amplitude of output voltage of the DC-AC converter
can be controlled
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