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 with guard interval versus OFDM/offsetQAM for high data rate UMTS downlink transmission

Abstract: OFDM modulation using a guard interval, denoted OFDM/QAM, in this paper, is well known for its robustness to multipath time varying propagation channels, and therefore used in several broadcasting and high data rate radio LAN standards OFDM/OQAM modulation is an alternative to it, which has the advantage not to require the use of a guard interval, which leads to a gain in spectral efficiency In this paper, we recall the main characteristics of OFDM/OQAM, and compare it to the OFDM/QAM in a realistic 3G context We propose optimized modulation parameters and provide simulation results The study confirms the interest of considering OFDM modulation for high data rate UMTS downlink transmission Besides, in that context, the gain in spectral efficiency allows OFDM/OQAM to outperform OFDM/QAM performances

Device for processing echo, particularly acoustic echo in a telephone line

Abstract: The device comprises an echo cancelling circuit receiving a first signal and a second signal and a real echo between channels for producing a third signal containing the second signal and a difference between the real echo and the estimated echo. Detectors detect the echo difference and the second signal in the third signal when the level of the third signal exceeds a predetermined threshold. Circuits gain-control the adaptation in the adaptive filtration of the echo cancelling circuit in such a way as to modify the adaptation gain when the second signal is not detected and to prohibit all filtration modifications as long as the second signal is detected. For instance, for an acoustic echo in a telephone set, the echo is not processed when the third signal contains a local speech signal as second signal.

Model-driven adaptation for plastic user interfaces

Abstract: User Interface (UI) plasticity denotes UI adaptation to the context of use (user, platform, physical and social environments) while preserving usability. In this article, we focus on the use of Model-Driven Engineering and demonstrate how the intrinsic flexibility of this approach can be exploited by designers for UI prototyping as well as by end-users in real settings. For doing so, the models developed at design-time, which convey high-level design decisions, are still available at run-time. As a result, an interactive system is not limited to a set of linked pieces of code, but is a graph of models that evolves, expresses and maintains multiple perspectives on the system from top-level tasks to the final UI. A simplified version of a Home Heating Control System is used to illustrate our approach and technical implementation.

Telecommunications network organized in reconfigurable wavelength-division-multiplexed optical loops

Abstract: In a telecommunications network organized in wavelength-division-multiplexed optical loops, each loop has tunable reception means tuned as a function of the density of the network traffic, thus being capable of being reconfigured as a function of requirements. The disclosed system can be applied to public, private and data communication networks.

Resource sharing of TCP connections with different round trip times

Abstract: The performance of TCP connections sharing a common link and the resulting link usage depends on the various round trip times along the connections. Expressions exist for these values only in the homogenous case and heuristics for the general case give uncertain results. In this paper we first derive an exact expression (in the setting of fluid models) for the window evolution of TCP connections with different round trip delays. We next apply this result in a particular context to derive expressions for the maximum window sizes and the throughput of TCP connections as well the idle periods and the utilization of the shared link. We show that a bias in favor of connections with short round trip delays persists even for large buffer sizes. First- and second-order approximations in buffer size are given respectively for small and large buffers. These expressions show that for small buffers small round trip times predominate in global performance while the opposite is true for large buffers.