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.

Performance of MIMO radar systems: advantages of angular diversity

Abstract: Inspired by recent advances in multiple-input multiple-output (MIMO) communications, this paper introduces the statistical MIMO radar concept. The fundamental difference between statistical MIMO and other radar array systems is that the latter seek to maximize the coherent processing gain, while statistical MIMO radar capitalizes on the diversity of target scattering to improve radar performance. Coherent processing is made possible by highly correlated signals at the receiver array, whereas in statistical MIMO radar, the signals received by the array elements are uncorrelated. It is well known that in conventional radar, slow fluctuations of the target radar cross-section (RCS) result in target fades that degrade radar performance. By spacing the antenna elements at the transmitter and at the receiver such that the target angular spread is manifested, the MIMO radar can exploit the spatial diversity of target scatterers opening the way to a variety of new techniques that can improve radar performance. In this paper, we focus on the application of the target spatial diversity to improve detection performance. The optimal detector in the Neyman-Pearson sense is developed and analyzed for the statistical MIMO radar. An optimal detector invariant to the signal and noise levels is also developed and analyzed. In this case as well, statistical MIMO radar provides great improvements over other types of array radars.

Spin-charge separation and localization in one dimension.

Abstract: We report on measurements of quantum many-body modes in ballistic wires and their dependence on Coulomb interactions, obtained by tunneling between two parallel wires in an GaAs/AlGaAs heterostructure while varying electron density. We observed two spin modes and one charge mode of the coupled wires and mapped the dispersion velocities of the modes down to a critical density, at which spontaneous localization was observed. Theoretical calculations of the charge velocity agree well with the data, although they also predict an additional charge mode that was not observed. The measured spin velocity was smaller than theoretically predicted.

Using DNA to Power Nanostructures

Abstract: DNA hybridization has been used to power a number of DNA-based nanostructures constructed out of DNA. Here some considerations that go into DNA-based motor design are briefly reviewed. The emphasis will be on the operation of toeholds, single-stranded sections of DNA that facilitate the process of strand removal during certain points in the operation of a DNA-based motor. Reaction kinetics measurements for toehold mediated strand exchange are reported. These measurements have served as a guide for choosing toehold lengths.

Influence of oxygen content on the structural, magnetotransport, and magnetic properties of LaMnO 3 + δ

Abstract: A systematic study of the effect of oxygen content on the structural, magnetotransport, and magnetic properties has been undertaken on a series of ${\mathrm{LaMnO}}_{3+\mathrm{\ensuremath{\delta}}}$ samples, with $\ensuremath{\delta}=0,$ 0.025, 0.07, 0.1, and 0.15. Measurements of the ac initial magnetic susceptibility, magnetization, magnetoresistance, and neutron diffraction, including small-angle neutron scattering (SANS), were performed in the temperature range 1--320 K using high magnetic fields up to 12 T. The antiferromagnetic order found in ${\mathrm{LaMnO}}_{3}$ evolves towards a ferromagnetic order as \ensuremath{\delta} increases. This behavior is accompanied by a drastic reduction of the static Jahn-Teller distortion of the ${\mathrm{MnO}}_{6}$ octahedra. The ferromagnetic coupling weakens for $\ensuremath{\delta}g~0.1.$ The magnetic behavior is interpreted by taking into account two effects caused by the increase in \ensuremath{\delta}: cation vacancies and ${\mathrm{Mn}}^{4+}{/\mathrm{M}\mathrm{n}}^{3+}$ ratio enhancement. The orthorhombic crystallographic structure becomes unstable at room temperature for $\ensuremath{\delta}g~0.1.$ The sample $\ensuremath{\delta}=0.1$ shows a structural transition from rhombohedral to orthorhombic below ${T}_{S}\ensuremath{\approx}300\mathrm{K}$ with a huge change in the cell volume. All the studied compounds were found to be insulating at low temperatures with no appreciable magnetoresistance, except for $\ensuremath{\delta}=0.15,$ in which we observed a large value for the magnetoresistance. The SANS results indicate that magnetic clustering effects are important below ${T}_{C}$ for $\ensuremath{\delta}g~0.07,$ which could explain the intriguing ferromagnetic insulator state. In the $\ensuremath{\delta}=0.07$ and $\ensuremath{\delta}=0.10$ samples we found at temperatures below ${T}_{C}$ magnetic and structural anomalies that are characteristic of charge ordering.

Dispersive multiplexing in multimode optical fiber

Abstract: Recently developed ideas in the field of wireless communications suggest that the presence of scattering can be used to enhance, rather than degrade, the total information capacity of a transmission system. This concept is applied to data transmission over multimode optical fiber, and the result is an optical multiplexing that can increase the capacity of such fiber. Experimental results demonstrate the feasibility of this approach. The technique may play an important role in future high-bandwidth local area networking applications.