Search results for "access"
showing 10 items of 1232 documents
Extended HSUPA coverage and enhanced battery saving opportunities with multiple TTI lengths
2010
3GPP has specified that terminals can be configured to use either 2 or 10 ms transmission time interval in high speed uplink packet access systems. The purpose of this paper is to evaluate the benefit of exploiting a mixture of both of the transmissions time intervals within a cell instead of only one. The study is quantified by means of studying the achievable coverage of voice over IP and possible battery saving benefits. The analysis is conducted with a system level simulator modeling network and terminal behavior in detail. The paper indicates that utilizing a mixture of both transmission time intervals can extend coverage whilst providing enhanced battery saving opportunities.
Welcome to MTI—A New Open Access Journal Dealing with Blue Sky Research and Future Trends in Multimodal Technologies and Interaction
2016
In this era of massive use of computers and other computational devices (e.g., low-cost wearable sensors, smartphones, other smart devices, etc.), the nature of digital data is becoming more complex and heterogeneous.
Misura delle performance finanziarie e patrimoniali delle aziende agricole: proposta operativa per un nuovo modello di rating per le aziende agricole
2012
La profonda evoluzione dei sistemi agricoli negli ultimi anni hanno accresciuto l'attenzione di tutti gli attori istituzionali ed economici rispetto alla problematica dell'accesso al credito per le imprese. Nel passato molto spesso il credito in agricoltura ha usufruito di regimi "speciali"; con l'implementazione delle regole di Basilea 2 (più di recente Basilea 3), le condizioni per l'accesso al credito si sono notevolmente irrigidite. Nell'ambito del settore agricolo, la pressoché assenza di bilanci certificati rende particolarmente difficoltosa questa valutazione. Nel presente lavoro, dopo aver analizzato la letteratura in materia di valutazione del merito creditizio delle aziende agrico…
UMTS radio networks
2006
Publisher Summary This chapter reviews the contributions to the UMTS radio network planning, with the optimization being provided from COST 273 and the real-time tuning, which is related to RRM. The results on UTRAN performance evaluation by the means of simulation tools are also discussed. The UMTS planning includes processes like: the propagation and traffic models, the aspects of parameter planning, and the automatic planning algorithms. An accurate ray-tracing model integrated in a UMTS-capable planning tool allows the radio network planner to reach optimal numbers for the BS deployment and configuration while meeting the service level requirements. Ray tracing can identify the problem …
Performance analysis of Alamouti coded OFDM systems over wideband MIMO car-to-car channels correlated in time and space
2014
In this paper, the performance of Alamouti coded orthogonal frequency division multiplexing (OFDM) systems over car-to-car (C2C) fading channels correlated in time and space is analyzed. Taking different geometrical scattering models into account, a generalized expression of the time-variant transfer function (TVTF) is derived for wideband multiple-input multiple-output (MIMO) C2C channels. We present a generalized expression for the bit error probability (BEP), which will be used to describe the performance of Alamouti coded OFDM systems over different types of C2C channel models, such as the rectangle model, the tunnel model, the street model, and the curve model. The effect of the maximu…
Memory irradiation measurements for the European SMART-1 spacecraft
2005
Three different types of memory circuits, that are intended to be used on board of the European satellite SMART-1, have been radiation hardness tested according to ESA's specification. Since the satellite is equipped with an electric propulsion engine, the spacecraft will be exposed to radiation during a long time when passing the radiation belt of the Earth. A standard DRAM circuit from SAMSUNG will serve as building block of the mass memory of SMART-1, and has been tested for total dose and proton induced single event upset (SEU). The DRAM memory showed surprisingly good resistance against radiation. The proton SEU cross sections for the radiation tolerant SRAM and FIFO circuits have also…
Ultra-Wideband Radio Signals Distribution in FTTH Networks
2008
[EN] The use of an ultra-wideband (UWB) radio technique is proposed as a viable solution for the distribution of high-definition audio/video content in fiber-to-the-home (FTTH) networks. The approach suitability is demonstrated by the transmission of standards-based UWB signals at 1.25 Gb/s along different FTTH fiber links with 25 km up to 60 kin of standard single-mode fiber length in a laboratory experiment. Experimental results suggest that orthogonal frequency-division-multiplexed UWB signals exhibit better transmission performance in FFTH networks than impulse radio UWB signals.
Combined Analysis of OFDM-UWB Transmission in Hybrid Wireless-Optical Access Networks
2009
[EN] The hybrid wireless-optical transmission of ultra-wideband signals employing orthogonal frequency-division multiplexing modulation (OFDM) ultra-wideband (UWB) as defined in the ECMA-368 standard is experimentally analyzed in this letter. The OFDM-UWB signals provide 400 Mb/s per user at optical distances from 5 to 50 km on standard single-mode fiber (SSMF). The analysis includes the wireless radiation from 0 to 3 m after optical transmission. The results indicate a maximum error-vector-magnitude degradation of 2.5 dB measured at 1.5-m radio after 50-km SSMF optical transmission for the first two UWB channels. This degradation translates to 1-m maximum wireless-reach penalty.
An open access database for the evaluation of heart sound algorithms
2016
In the past few decades, analysis of heart sound signals (i.e. the phonocardiogram or PCG), especially for automated heart sound segmentation and classification, has been widely studied and has been reported to have the potential value to detect pathology accurately in clinical applications. However, comparative analyses of algorithms in the literature have been hindered by the lack of high-quality, rigorously validated, and standardized open databases of heart sound recordings. This paper describes a public heart sound database, assembled for an international competition, the PhysioNet/Computing in Cardiology (CinC) Challenge 2016. The archive comprises nine different heart sound databases…
Capacity Analysis in Downlink WCDMA Systems Using Soft Handover Techniques With SIR-Based Power Control and Site Selection Diversity Transmission
2006
This work analyzes the downlink performance of a WCDMA system with site selection diversity transmission power control (SSDT) during soft handover mode. Signal to interference ratio (SIR) power control techniques are modeled and used in the simulations of this analysis. The study is focused on finding the optimum soft handover margin in terms of maximum system capacity under energy-per-bit to noise spectral density ratio (Eb/N0) quality requirements. The results of this analysis show an increase in user capacity of about 15 -20 % for optimum soft handover margins of 5 – 5.5 dB. Nevertheless, the resources required (number of scrambling codes) by base station increase faster than the number …