Orange S.A.

About: Orange S.A. is a company organization based out in Paris, France. It is known for research contribution in the topics: Terminal (electronics) & Signal. The organization has 6735 authors who have published 9190 publications receiving 156440 citations. The organization is also known as: Orange SA & France Télécom.

OFDM/OQAM with Hermitian Symmetry: Design and Performance for Baseband Communication

Abstract: OFDM/OQAM is a special type of multi-carrier modulation that can be considered as an alternative to conventional OFDM with cyclic prefix (CP) for transmission over multi- path fading channels. Indeed, as it requires no guard interval, it has the advantage of a theoretical higher spectral efficiency. In this paper, we propose a new version of OFDM/OQAM named in short HS-OQAM, where HS means that an Hermitian Symmetry property is used to directly provide a modulated real-valued signal. We analyze the links between HS-OQAM to Wavelet OFDM (WOFDM) modulation and Wilson-based modulated filter banks. The performances of HS-OQAM are compared to the ones of CP-OFDM for the transmission over Power Line Communication (PLC) channels.

Method for the treatment of compressed sound data for spatialization

Abstract: The invention relates to the treatment of sound data for spatialized restitution of acoustic signals. At least one first and one second series of weighting terms are obtained for each acoustic signal, said terms representing a direction of perception of said acoustic signal by a listener. The acoustic signals are then applied to at least two sets of filtering units, which are disposed in parallel, in order to provide at least one first and one second output signal (L,R), corresponding to a linear combination of signals provided by said filtering units, which are respectively weighted by the weighting terms of the first and second series. According to the invention, each acoustic signal to be treated is at least partially compression coded and is expressed in the form of a vector of sub-signals associated with respective frequency sub-bands. Matrix filtering applied to each vector is carried out by each filtering unit in the space of the frequential sub-bands.

x2 Cryptanalysis of the SEAL Encryption Algorithm

Abstract: SEAL was first introduced in [1] by Rogaway and Coppersmith as a fast software-oriented encryption algorithm. It is a pseudorandom function which stretches a short index into a much longer pseudorandom string under control of a secret key pre-processed into internal tables. In this paper we first describe an attack of a simplified version of SEAL, which provides large parts of the secret tables from approximately 224 algorithm computations. As far as the original algorithm is concerned, we construct a test capable of distinguishing SEAL from a random function using approximately 230 computations. Moreover, we describe how to derive some bits of information about the secret tables. These results were confirmed by computer experiments.

Quantifying the Effectiveness of Mobile Phone Virus Response Mechanisms

Abstract: Viruses that infect smartphones are emerging as a new front in the fight against computer viruses. In this paper, we model the propagation of mobile phone viruses in order to study their impact on the dependability of mobile phones. We propose response mechanisms and use the models to obtain insight on the effectiveness of these virus mitigation techniques. In particular, we consider the effects of multimedia messaging system (MMS) viruses that spread by sending infected messages to other phones. The virus model is implemented using the Mobius software tool and is highly parameterized, enabling representation of a wide range of potential MMS virus behavior. Using the model, we present the results of four illustrative MMS virus scenarios simulated with and without response mechanisms. By measuring the propagation rate and the extent of virus penetration in the simulation phone population, we quantitatively compare the effectiveness of mobile phone virus response mechanisms.

On the capacity of OFDMA 802.16 systems

Abstract: In this paper, we calculate analytically the capacity of an OFDMA 802.16 system. We consider a multi-cell network and obtain the expected number of collisions for an arbitrary number of users in each interfering cell. We next obtain, for different SNR ratios corresponding to different modulation schemes, the probability of QoS degradation when collision occurs between subcarriers of two cells. We eventually calculate analytically, for a multi-service system, the proportion of symbols with poor QoS in steady-state under a given offered load. Our numerical applications show, for both adaptive and elastic traffics, how to evaluate the performance of a WiMAX system, and how to choose a modulation scheme that insures a good QoS.