Alcatel-Lucent

About: Alcatel-Lucent is a based out in Stuttgart, Germany. It is known for research contribution in the topics: Signal & Network packet. The organization has 37003 authors who have published 53332 publications receiving 1430547 citations. The organization is also known as: Alcatel-Lucent S.A. & Alcatel.

The ERICA Switch Algorithm for ABR Traffic Management in ATM Networks

Abstract: We propose an explicit rate indication scheme for congestion avoidance in ATM networks. In this scheme, the network switches monitor their load on each link, determining a load factor, the available capacity, and the number of currently active virtual channels. This information is used to advise the sources about the rates at which they should transmit. The algorithm is designed to achieve efficiency, fairness, controlled queueing delays, and fast transient response. The algorithm is also robust to measurement errors caused due to variation in ABR demand and capacity. We present performance analysis of the scheme using both analytical arguments and simulation results. The scheme is being implemented by several ATM switch manufacturers.

Constrained multicast routing in WDM networks with sparse light splitting

Abstract: As wavelength division multiplexing (WDM) technology matures and multicast applications become increasingly popular, supporting multicast at the WDM layer becomes an important and yet challenging topic. In this paper, we study constrained multicast routing in WDM networks with sparse light splitting, i.e., where some switches are incapable of splitting light (of copying data in the optical domain) due to evolutional and/or economical reasons. Specifically, we propose four WDM multicast routing algorithms, namely, re-route-to-source, re-route-to-any, member-first, and member-only. Given the network topology, multicast membership information, and light splitting capability of the switches, these algorithms construct a source-based multicast "light-forest" (consisting one or more multicast trees) for each multicast session. While the first two algorithms can build on a multicast tree constructed by IP (which does not take into consideration the splitting capability of the WDM switches), the last two algorithms attempt to address the joint problem of optimal multicast routing and sparse splitting in WDM networks. The performance of these algorithms are compared in terms of the average number of wavelengths used per forest (or multicast session), average number of branches involved (bandwidth) per forest as well as average number of hops encountered (delay) from a multicast source to a multicast member. The results obtained from this research should present new and exciting opportunities for further theoretical as well as experimental work.

Structural Characterization of Various Chiral Smectic- C Phases by Resonant X-Ray Scattering

Abstract: We report the results of resonant x-ray diffraction at the sulfur $K$-edge performed upon free-standing films of a thiobenzoate liquid-crystal compound. Our data provide the first direct structural evidence of distinct periodicities in several chiral Sm-C phases, including 2-layer, 3-layer, and 4-layer superlattices in $\mathrm{Sm}\ensuremath{-}{C}_{A}^{*}$, $\mathrm{Sm}\ensuremath{-}{C}_{\mathrm{FI}1}^{*}$, and $\mathrm{Sm}\ensuremath{-}{C}_{\mathrm{FI}2}^{*}$, respectively. In $\mathrm{Sm}\ensuremath{-}{C}_{\ensuremath{\alpha}}^{*}$, periodicity incommensurate with the layer spacing was detected. The racemic compound version was also studied. The results are consistent with a ``clock model'' of the $\mathrm{Sm}\ensuremath{-}{C}^{*}$ variant structures.

Quasi-particle properties from tunneling in the v = 5/2 fractional quantum Hall state.

Abstract: Quasi-particles with fractional charge and statistics, as well as modified Coulomb interactions, exist in a two-dimensional electron system in the fractional quantum Hall (FQH) regime. Theoretical models of the FQH state at filling fraction \(v={^{5}}/{_{2}}\) make the further prediction that the wave function can encode the interchange of two quasi-particles, making this state relevant for topological quantum computing. We show that bias-dependent tunneling across a narrow constriction at \(v={^{5}}/{_{2}}\) exhibits temperature scaling and, from fits to the theoretical scaling form, extract values for the effective charge and the interaction parameter of the quasi-particles. Ranges of values obtained are consistent with those predicted by certain models of the \({^{5}}/{_{2}}\) state.

Decode-and-Forward Cooperative Diversity with Power Allocation in Wireless Networks

Abstract: We study power allocation for the decode-and-forward cooperative diversity protocol in a wireless network under the assumption that only mean channel gains are available at the transmitters. In a Rayleigh fading channel with uniformly distributed node locations, we aim to find the power allocation that minimizes the outage probability under a short-term power constraint, wherein the total power for all nodes is less than a prescribed value during each two-stage transmission. Due to the computational and implementation complexity of the optimal solution, we derived a simple near-optimal solution. In this near-optimal scheme, a fixed fraction of the total power is allocated to the source node in stage I. In stage II, the remaining power is split equally among a set of selected nodes if the selected set is not empty, and otherwise is allocated to the source node. A node is selected if it can decode the message from the source and its mean channel gain to the destination is above a threshold. In this scheme, each node only needs to know its own mean channel gain to the destination and the number of selected nodes. Simulation results show that the proposed scheme achieves an outage probability close to that for the optimal scheme obtained by numerical search, and achieves significant performance gain over other schemes in the literature