Search results for "bit rate"
showing 10 items of 15 documents
Performance evaluation of different techniques to estimate subjective quality in live video streaming applications over LTE-Advance mobile networks
2018
Abstract Current mobile service providers are offering Gigabit Internet access over LTE-Advanced networks. Traditional services, such as live video streaming, over wired networks are feasible on these networks. However different aspects should be taken into account due to the fast changing network conditions as well as the constrained resources of the mobile phones, in order to provide a good subjective video quality in terms of Mean Opinion Score (MOS). Our goal is to estimate and predict this subjective metric without information or reference from the original video, known as Non Reference approach. This approach is important for the Service Provider from a practical point of view, becaus…
Experimental demonstration of 160-GHz densely dispersion-managed soliton transmission in a single channel over 896 km of commercial fibers
2003
International audience; We experimentally demonstrate the first 160-GHz densely dispersion-managed soliton transmission in a single channel at 1550 nm over nearly 900 km using commercially available non-zero dispersion-shifted fibers. This performance has been achieved by using a 16 km-long recirculating loop configuration and an appropriate design of the dispersion map.
Hopfield Neural Network - Based Approach for Joint Dynamic Resource Allocation in Heterogeneous Wireless Networks
2006
This paper presents a comprehensive approach to solve the problem of joint dynamic resource allocation (JDRA) in heterogeneous wireless networks using a Hopfield neural network (HNN). A generic formulation for packet services with delay constraints is proposed to decide the optimal bit rate and radio access technology (RAT) allocation. Some illustrative simulations results in a basic scenario are presented to evaluate performance of the proposed algorithm.
Stretched fibre based dispersion compensating module for ultra high-speed telecommunication systems
2008
International audience; In this work, the potential efficiency of a low-loss, tunable second-and third-order dispersion compensating module based on a stretched optical fibre for ultra high-speed telecommunication systems is analysed. Experimental results at a repetition rate of 640 GHz show that precise dispersion compensation could be achieved in the range of +0.038 ps/nm by means of an 11.3 cm maximum stretching of a 48 m long dispersion compensating.
Splitting criterion for hierarchical motion estimation based on perceptual coding
1998
A new entropy-constrained motion estimation scheme using variable-size block matching is proposed. It is known that fixed-size block matching as used in most video codec standards is improved by using a multiresolution or multigrid approach. In this work, it is shown that further improvement is possible in terms of both the final bit rate achieved and the robustness of the predicted motion field if perceptual coding is taken into account in the motion estimation phase. The proposed scheme is compared against other variable- and fixed-size block matching algorithms.
High efficacy of face masks explained by characteristic regimes of airborne SARS-CoV-2 virus abundance
2021
Abstract Airborne transmission is an important transmission pathway for viruses, including SARS-CoV-2. Regions with a higher proportion of people wearing masks show better control of COVID-19, but the effectiveness of masks is still under debate due to their limited and variable efficiencies in removing respiratory particles. Here, we analyze experimental data and perform model calculations to show that this contrast can be explained by the different regimes of abundance of particles and viruses. Because of the large number of particles exhaled during human respiration and vocalization, indoor environments are usually in a particle-rich regime which means that masks cannot prevent the inhal…
Out-of-Band Signaling Scheme for High Speed Wireless LANs
2007
In recent years, the physical layer data rate provided by 802.11 Wireless LANs has dramatically increased thanks to significant advances in the modulation and coding techniques employed. However, previous studies show that the 802.11 MAC operation, namely the distributed coordination function (DCF), represents a limiting factor: the throughput efficiency drops as the channel bit rate increases, and a throughput upper limit does indeed exist when the channel bit rate goes to infinite high. These findings indicate that the performance of the DCF protocol will not be efficiently improved by merely increasing the channel bit rate. This paper shows that the DCF performance may significantly bene…
Cascadability and reshaping properties of a saturable absorber inserted inside a RZ transmission line for future 160-Gbit/s all-optical 2R-regenerato…
2007
International audience; In this prospective work, we analyze the behavior of a quantum-well microcavity saturable absorber component cascaded into a 100-km SMF RZ transmission line in order to annihilate the ghost-pulse phenomenon in the following simplified “...010101...” 160-Gbit/s 2-bit pattern at 1555 nm. Recirculating-loop experiments show a maximal ghost-pulse extinction up to 11.6 dB as well as an intensity extinction ratio enhancement higher than 6 dB over at least 800 km of propagation.
Limits of ultra-high bit rate RZ data transmissions in terrestrial optical fiber systems
2006
We numerically study the limits of the terrestrial optical fiber systems as a function of the bit rate. In particular, we compare for 160-, 320- and 640-Gbit/s the limits of single channel and WDM configurations.
Sensitivity of SHG-FROG for the characterization of ultrahigh-repetition-rate telecommunication laser sources
2004
International audience; We analyze experimentally the sensitivity of second-harmonic generation frequency-resolved optical gating (SHG-FROG) for the complete intensity and phase characterization of both a sinusoidal beat signal and a train of 1.3 ps pulses at a repetition rate of 160 GHz at 1550 nm. Using a commercially-available optical spectrum analyzer in the SHG-FROG set-up, incident pulses with energies of only 125 and 190 fJ, which correspond to the beat signal and the 1.3 ps pulse train, respectively, have been accurately characterized.