Modeling Interference Between OFDM/OQAM and CP-OFDM: Limitations of the PSD-Based Model

To answer the challenges put out by the next generation of wireless networks (5G), important research efforts have been undertaken during the last few years to find new waveforms that are better spectrally localized and less sensitive to asynchronism effects than the widely deployed Cyclic Prefix Orthogonal Frequency Division Multiplexing (CP-OFDM). One of the most studied schemes is OFDM-Offset Quadrature Amplitude Modulation (OFDM/OQAM) based on the PHYDYAS filter pulse. In the recent literature, spectrum coexistence between OFDM/OQAM and CP-OFDM is commonly studied based on the Power Spectral Density (PSD) model. In this paper, we show that this approach is flawed and we show that the actual interference injected by OFDM/OQAM systems onto CP-OFDM is much higher than what is classically expected with the PSD based model in the literature. We show that though using OFDM/OQAM in secondary systems is still advantageous, it brings limited gain in the context of coexistence with incumbent CP-OFDM systems.Comment: 7 pages, 9 figures, ICT 201

On Spectral Coexistence of CP-OFDM and FB-MC Waveforms in 5G Networks

Future 5G networks will serve a variety of applications that will coexist on the same spectral band and geographical area, in an uncoordinated and asynchronous manner. It is widely accepted that using CP-OFDM, the waveform used by most current communication systems, will make it difficult to achieve this paradigm. Especially, CP-OFDM is not adapted for spectral coexistence because of its poor spectral localization. Therefore, it has been widely suggested to use filter bank based multi carrier (FB-MC) waveforms with enhanced spectral localization to replace CP-OFDM. Especially, FB-MC waveforms are expected to facilitate coexistence with legacy CP-OFDM based systems. However, this idea is based on the observation of the PSD of FB-MC waveforms only. In this paper, we demonstrate that this approach is flawed and show what metric should be used to rate interference between FB-MC and CP-OFDM systems. Finally, our results show that using FB-MC waveforms does not facilitate coexistence with CP-OFDM based systems to a high extent.Comment: Manuscript submitted for review to IEEE Transactions on Wireless Communication

Coexistence of OFDM and FBMC for Underlay D2D Communication in 5G Networks

Device-to-device (D2D) communication is being heralded as an important part of the solution to the capacity problem in future networks, and is expected to be natively supported in 5G. Given the high network complexity and required signalling overhead associated with achieving synchronization in D2D networks, it is necessary to study asynchronous D2D communications. In this paper, we consider a scenario whereby asynchronous D2D communication underlays an OFDMA macro-cell in the uplink. Motivated by the superior performance of new waveforms with increased spectral localization in the presence of frequency and time misalignments, we compare the system-level performance of a set-up for when D2D pairs use either OFDM or FBMC/OQAM. We first demonstrate that inter-D2D interference, resulting from misaligned communications, plays a significant role in clustered D2D topologies. We then demonstrate that the resource allocation procedure can be simplified when D2D pairs use FBMC/OQAM, since the high spectral localization of FBMC/OQAM results in negligible inter-D2D interference. Specifically, we identify that FBMC/OQAM is best suited to scenarios consisting of small, densely populated D2D clusters located near the encompassing cell's edge.Comment: 7 pages, 9 figures, Accepted at IEEE Globecom 2016 Workshop

Ultramafic xenoliths from the Bearpaw Mountains, Montana, USA: evidence for multiple metasomatic events in the lithospheric mantle beneath the Wyoming craton

Ultramafic xenoliths in Eocene minettes of the Bearpaw Mountains volcanic field (Montana, USA), derived from the lower lithosphere of the Wyoming craton, can be divided based on textural criteria into tectonite and cumulate groups. The tectonites consist of strongly depleted spinel lherzolites, harzburgites and dunites. Although their mineralogical compositions are generally similar to those of spinel peridotites in off-craton settings, some contain pyroxenes and spinels that have unusually low Al2O3 contents more akin to those found in cratonic spinel peridotites. Furthermore, the tectonite peridotites have whole-rock major element compositions that tend to be significantly more depleted than non-cratonic mantle spinel peridotites (high MgO, low CaO, Al2O3 and TiO2) and resemble those of cratonic mantle. These compositions could have been generated by up to 30% partial melting of an undepleted mantle source. Petrographic evidence suggests that the mantle beneath the Wyoming craton was re-enriched in three ways: (1) by silicate melts that formed mica websterite and clinopyroxenite veins; (2) by growth of phlogopite from K-rich hydrous fluids; (3) by interaction with aqueous fluids to form orthopyroxene porphyroblasts and orthopyroxenite veins. In contrast to their depleted major element compositions, the tectonite peridotites are mostly light rare earth element (LREE)-enriched and show enrichment in fluid-mobile elements such as Cs, Rb, U and Pb on mantle-normalized diagrams. Lack of enrichment in high field strength elements (HFSE; e.g. Nb, Ta, Zr and Hf) suggests that the tectonite peridotites have been metasomatized by a subduction-related fluid. Clinopyroxenes from the tectonite peridotites have distinct U-shaped REE patterns with strong LREE enrichment. They have 143Nd/144Nd values that range from 0·5121 (close to the host minette values) to 0·5107, similar to those of xenoliths from the nearby Highwood Mountains. Foliated mica websterites also have low 143Nd/144Nd values (0·5113) and extremely high 87Sr/86Sr ratios in their constituent phlogopite, indicating an ancient (probably mid-Proterozoic) enrichment. This enriched mantle lithosphere later contributed to the formation of the high-K Eocene host magmas. The cumulate group ranges from clinopyroxene-rich mica peridotites (including abundant mica wehrlites) to mica clinopyroxenites. Most contain >30% phlogopite. Their mineral compositions are similar to those of phenocrysts in the host minettes. Their whole-rock compositions are generally poorer in MgO but richer in incompatible trace elements than those of the tectonite peridotites. Whole-rock trace element patterns are enriched in large ion lithophile elements (LILE; Rb, Cs, U and Pb) and depleted in HFSE (Nb, Ta Zr and Hf) as in the host minettes, and their Sr–Nd isotopic compositions are also identical to those of the minettes. Their clinopyroxenes are LREE-enriched and formed in equilibrium with a LREE-enriched melt closely resembling the minettes. The cumulates therefore represent a much younger magmatic event, related to crystallization at mantle depths of minette magmas in Eocene times, that caused further metasomatic enrichment of the lithosphere

Guy Lemarchand, L’économie en France de 1770 à 1830, De la crise de l’Ancien Régime à la révolution industrielle

Le titre indique clairement le parti choisi par Guy Lemarchand : étudier l’économie française sur le temps long (60 ans), de l’Ancien Régime (20 ans avant 1789) à la fin de la Restauration (30 ans après la fin de la Révolution, 15 ans après celle de l’Empire). La Révolution est en quelque sorte encadrée par les décennies des régimes antérieurs et postérieurs. En cela, l’auteur reste fidèle à ses analyses sur le passage d’une économie d’Ancien Régime à une économie de type moderne, où la Révol..

La noblesse et les biens nationaux dans le departement de l'Eure

En nationalisant puis en vendant les biens de l'Église, de la Couronne et des émigrés, le gouvernement révolutionnaire procède à un vaste transfert de propriété. Avant cela, la fortune foncière de la noblesse représentait près du quart du département de l'Eure. L'aristocratie l'accroît en acquérant des biens de première origine. Mais l'émigration de nombreux nobles réduit ce patrimoine, perte toutefois limitée par les families et le milliard des émigrés. Au total, la noblesse sort affaiblie mais pas ruinée par la vente des biens nationaux, qui consacre l'ascension de la ville et de la bourgeoisie. By nationalizing and then selling the property of the Church, the Crown and the "émigrés", the revolutionary government initiated a great transfer of property. Before, the nobility owned a quarter of the land in the Eure country. The aristocracy, buying property of the first origin, increased it. But the emigration of numerous nobles reduced this heritage, a loss which was nevertheless limited by the families and the milliard of "émigrés". All in all, the nobility appeared to be weakened but not ruined by the sale of the national property wich established the rising of the city dwellers and burgesses

Jean-Marc Moriceau, L’homme contre le loup, Une guerre de deux mille ans

Après avoir publié en 2007 une Histoire du méchant loup. 3 000 attaques sur l’homme en France, xve-xxe siècle, en 2008, La Bête du Gévaudan (1764‑1767) et, en 2010 (avec son collègue géographe Philippe Madeline), Repenser le sauvage grâce au retour du loup. Les sciences humaines interpellées, Jean-Marc Moriceau a décidé d’élargir son propos (il conduit actuellement une enquête européenne sur les relations entre l’homme et le loup). Ces différentes publications (menées à l’occasion avec le con..

Marc Bouloiseau et les biens nationaux

C’est Albert Mathiez qui a proposé, en 1930, à Marc Bouloiseau de travailler sur les biens nationaux de seconde origine. La thèse principale et la thèse secondaire, soutenues à Paris en 1935, sont publiées dès 1937. Devenu un membre influent de la “Commission Jaurès, Marc Bouloiseau a continué de s’intéresser aux biens nationaux. Ses travaux sont à situer dans le courant historiographique dirigé par Georges Lefebvre qui fut d’ailleurs son directeur de thèse. On lui doit d’abord la première ét..

Bruno Colson, Le général Rogniat, ingénieur et critique de Napoléon

La pensée militaire du début du XIXe siècle semble être assez pauvre, en dehors de Jomini et de Clausewitz, seul le nom de Marmont vient à l’esprit. Pourtant les maréchaux et les généraux de l’Empire ne furent pas seulement des entraîneurs d’hommes, parmi ceux qui réfléchirent et écrivirent sur la guerre. Bruno Colson a entrepris de réhabiliter et de faire connaître le général Joseph Rogniat qui publia en 1816 des Considérations sur l’art de la guerre. Napoléon irrité par certaines critiques ..

Jean-Marc Moriceau, L’homme contre le loup, Une guerre de deux mille ans

Après avoir publié en 2007 une Histoire du méchant loup. 3 000 attaques sur l’homme en France, xve-xxe siècle, en 2008, La Bête du Gévaudan (1764‑1767) et, en 2010 (avec son collègue géographe Philippe Madeline), Repenser le sauvage grâce au retour du loup. Les sciences humaines interpellées, Jean-Marc Moriceau a décidé d’élargir son propos (il conduit actuellement une enquête européenne sur les relations entre l’homme et le loup). Ces différentes publications (menées à l’occasion avec le con..