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Abdul-Nabi S.,Lebanese University | Abdul-Nabi S.,European University of Brittany | Khalil A.,Lebanese University | Khalil A.,European University of Brittany | And 2 more authors.
2013 3rd International Conference on Communications and Information Technology, ICCIT 2013 | Year: 2013

In this paper, we study Network Coding (NC) at switching level. We use novel algorithms and a new header to route coded messages to various destinations. Coding is based on address correlation and decoding is performed only at destination. The main characteristics of our approach is the use of adaptive memory to validate decoding capability at destination and converting multicasted messages to unicasted. We also argue that there are benefits in applying such approach and finally we examine the design of the new added header to hold adaptive memories. © 2013 IEEE. Source

Aznabet M.,Abdelmalek Essaadi University | El Mrabet O.,Abdelmalek Essaadi University | Floch J.M.,Institute Of Electronics And Telecommunications Of Rennes Ietr | Falcone F.,Public University of Navarra | Drissi M.,Institute Of Electronics And Telecommunications Of Rennes Ietr
Waves in Random and Complex Media | Year: 2015

In this paper, we report a new design of a compact coplanar waveguide-fed printed antenna with complementary split ring resonator (CSRR). The designed antenna consists of two CSRRs, with same geometrical parameters, printed symmetrically into the top layer. The overall volume of the proposed antenna is only 30 × 20 × 0.8 mm3 (0.58λ0 × 0.39λ0 × 0.015λ0), where λ0 is the wavelength of the simulated resonance frequency. The resonance frequency of the antenna is essentially defined by geometrical parameters of the CSRR, which makes it suitable for various wireless communication systems. The characteristics of the proposed antenna have been investigated using simulation software CST Microwave Studio and experimental results. The measured and simulated results show good agreement, providing a simple and low-cost design. © 2014 © 2014 Taylor & Francis. Source

Serhir M.,Institute Of Electronics And Telecommunications Of Rennes Ietr | Besnier P.,Institute Of Electronics And Telecommunications Of Rennes Ietr | Drissi M.,Institute Of Electronics And Telecommunications Of Rennes Ietr
IEEE Transactions on Antennas and Propagation | Year: 2010

A method to derive an equivalent radiation source for planar antennas is presented. This method is based on spherical near-field (NF) data (measured or computed) to ascertain an equivalent set of infinitesimal dipoles placed over the main antenna aperture. These produce the same antenna radiation field, both inside and outside the minimum sphere enclosing the antenna. A spherical wave expansion (SWE) of the NF data is written in terms of infinitesimal dipoles using a transition matrix. This matrix expresses the linear relations between the transmission coefficients of the antenna and the transmission coefficients of each dipole. The antenna a priori information are used to set the spatial distribution of the equivalent dipoles. The translational and rotational addition theorems are exploited to derive the transmission coefficients of the dipoles. Once the excitation of each dipole is known, the field at any aspect angle and distance from the antenna is rapidly calculated. Computations with EM simulation data of an antenna array illustrate the reliability of the method. © 2009 IEEE. Source

Dubois T.,Institute Of Electronics And Telecommunications Of Rennes Ietr | Helard M.,Institute Of Electronics And Telecommunications Of Rennes Ietr | Crussiere M.,Institute Of Electronics And Telecommunications Of Rennes Ietr | Germond C.,Thales Alenia
Eurasip Journal on Wireless Communications and Networking | Year: 2013

Time reversal (TR) is considered as a promising technique for green and multi-user communications thanks to its time and space focusing properties. TR can be viewed as a precoding scheme which can be combined with orthogonal frequency division multiplexing (OFDM) and easily carried out in a multiple transmit antenna context. This paper analyzes the performance of TR for a multiple-input single-output (MISO) OFDM system and provides a comparison with maximum ratio transmission (MRT) and equal gain transmission (EGT) precoding techniques. The analytical performance of the three precoding techniques is derived by computing the capacity and the bit error rate (BER) as a function of the transmit signal-to-noise ratio (SNR). First, the capacity analysis highlights the ability of the TR system to provide higher bit rates than the MRT system at low SNRs, while the capacity of the MRT system is the highest at high SNRs. From the obtained BER analytical expressions, the diversity exploitation of each system is discussed. In particular, it is shown that the TR system only exploits half the available diversity, while the systems using EGT or MRT exploit the full diversity. Hence, contrary to what is expected from the theoretical capacity analysis, the TR system is shown to underperform the other precoding schemes in terms of BER. To overcome such a drawback, the combination of TR with classical adaptive modulation techniques is studied, allowing the achievable throughput to be increased without destroying the focusing properties of TR. It is then observed that TR takes advantage of adaptive modulations and outperforms the other schemes at low SNRs. In this study, analytical results and closed-form expressions of capacity and BER performance are provided and confirmed through Monte Carlo simulations. © 2013 Stolojescu-Crisan and Isar; licensee Springer. Source

Sentucq B.,Institute Of Electronics And Telecommunications Of Rennes Ietr | Sharaiha A.,Institute Of Electronics And Telecommunications Of Rennes Ietr | Collardey S.,Institute Of Electronics And Telecommunications Of Rennes Ietr
2013 7th European Conference on Antennas and Propagation, EuCAP 2013 | Year: 2013

A new electrically small antenna design based on a metamaterial-inspired structure driven by an electrically small monopole antenna is presented. This antenna of λ0/19×λ0/19 size works in the UHF band and offers a simulated efficiency of 75%, with an average maximum gain of 0.86dB and a directivity of 2.12dB in the matched bandwidth of 5.2MHz. This antenna is then used in a compact array of two identical elements in order to achieve a higher directivity. Two arrays are compared: one with two driven elements and a parasitic array with only one of the two elements driven. The design details, simulated and measured radiation characteristics of the antenna system and antenna arrays are reported. © 2013 EurAAP. Source

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