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.

Coding/decoding of digital audio signals

Abstract: A method of hierarchical coding of a digital audio frequency input signal into several frequency sub-bands, including a core coding of the input signal according to a first throughput and at least one enhancement coding of higher throughput, of a residual signal. The core coding uses a binary allocation according to an energy criterion. The method includes for the enhancement coding: calculating a frequency-based masking threshold for at least part of the frequency bands processed by the enhancement coding; determining a perceptual importance per frequency sub-band as a function of the masking threshold and as a function of the number of bits allocated for the core coding; binary allocation of bits in the frequency sub-bands processed by the enhancement coding, as a function of the perceptual importance determined; and coding the residual signal according to the bit allocation. Also provided are a decoding method, a coder and a decoder.

Comparison of Antenna Measurement Facilities With the DTU-ESA 12 GHz Validation Standard Antenna Within the EU Antenna Centre of Excellence

Abstract: The primary objective of many antenna measurement facilities is to provide a specified high accuracy of the measured data. The validation of an antenna measurement facility is the process of proving that such a specified accuracy can be achieved. Since this constitutes a very challenging task, antenna measurement accuracy has been the subject of much research over many years and a range of useful measures have been introduced. Facility comparisons, together with antenna standards, error budgets, facility accreditations, and measurement procedure standards, constitute an effective measure towards facility validations. This paper documents the results of a comparison between 8 European antenna measurement facilities with a specially designed reference antenna, the DTU-ESA 12 GHz validation standard antenna (VAST-12). The electrical and mechanical properties of the VAST-12 antenna are presented and its three different coordinate systems are defined. The primary objective of the comparison is to obtain experience and results that can serve to develop standards for validation of antenna measurement facilities. The paper focuses on the comparison of the radiation pattern and presents not only the measurement data obtained at the facilities, but also investigates several procedures for comparing these data. This includes various definitions of pattern difference and statistical measures as well as a reference pattern. The comparison took place in 2004-2005 as part of the European Union network of excellence called ACE-Antenna Centre of Excellence.

Analysis, improvement and simplification of Prêt à voter with Paillier encryption

Abstract: In this paper, we analyse information leakage in Ryan's Pret a Voter with Paillier encryption scheme (PAV-Paillier). Our analysis shows that although PAV-Paillier seems to achieve a high level of voter privacy at first glance, it might still leak voter's choice information in some circumstances. Some threats are trivial and have appeared in the literature, but others are more complicated because colluding adversaries may apply combined attacks. Several strategies have been suggested to mitigate these threats, but we have not resolved all the threats. We leave those unsolved threats as open questions. In order to describe our analysis in a logical manner, we will introduce an information leakage model to aid our analysis. We suggest that this model can be applied to analyse information leakage in other complex mixnet based e-voting schemes as well. Furthermore, we introduce a simplification of PAV-Paillier. In our proposal, without degrading security properties such as voter privacy, verifiability and reliability, we no longer need to apply the homomorphic property to absorb the voter's choice index into the onion, thus we step back to employ the ElGamal encryption. This results in a simpler and more straightforward threshold cryptosystem. Some other attractive properties of our proposal scheme are: unlike traditional Pret a Voter schemes, the candidate list in our scheme can be in alphabetical order. Our scheme not only handles approval elections, but also it handles ranked elections (e.g. Single Transferable Voting). Furthermore, our scheme mitigates the randomisation attack.

Analysis of the Peak-To-Average Power Ratio for OFDM/OQAM

Abstract: OFDM/OQAM is now a recognized alternative to conventional OFDM for the transmission of signals over multipath fading channels. Indeed with OFDM/OQAM an appropriate pulse-shaping can be introduced to fight against time and frequency dispersion. This paper focuses on a theoretical and experimental analysis of the peak-to-average power ratio (PAPR) for OFDM/OQAM. It is shown that the best complementary cumulative density function (CCDF) is obtained with orthogonal prototype filters.