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Different techniques for measuring packet delivery ratio, packet latency and power usage on single hop radio links have been developed. These techniques were tested with Zolertia Z1 motes running Contiki by measuring the performances of different radio duty cycling protocols using a range of radio wake-up rates and various levels of global radio traffic. Advantages and disadvantages of the different...
The development of wireless technologies sets off new issues regarding exposure of the people to electromagnetic radiation. The non-ionizing dosimetry is focused on the calculation of the dose that can be absorbed by users of a wireless technology. The integration of the variability in the dosimetry is a major issue, especially the one led by the environment. Electromagnetic environment are described...
High order modulations defined in the DVB-S2 standard are very sensitive to the non-linear interference induced by the power amplifier combined with the filters present in the channel. Several methods have been proposed to mitigate this interference. The finite order compensation, or order p compensation, is an analytical method to remove non-linear interference. However, it shows poor performance...
To improve the performance of a DVB-S2 communication channel, it is necessary to remove the non-linear interferences induced by the power amplifier. Due to the presence of filters in the channel, this non-linear interference is also interference with memory. One of the most used techniques to cancel out the interferences in this case is the order p compensation. The order p compensation can be mathematically...
Cognitive radios have been introduced as a dynamic way to share the frequency spectrum within wireless networks. After sensing its environment to discover the available frequency resources, a cognitive network allocates the locally available carriers among its nodes, under the constraint of negligible interference on licensed operators. The allocation, based on partial knowledge of the network parameters,...
In this paper a time reversal (TR) system combined with multiple-input single output (MISO) antennas over ultra-wideband (UWB) channels are experimentally investigated. An analysis on the spatial and temporal properties of the MISO-TR is presented in the special case of an in-car environment. As the TR can benefit from rich scattering environment, the application of the TR in the in-car environment...
Body Area Networks connect low-power wireless bio-sensors, which are placed in close proximity of the human body. In order to reduce energy consumption, a promising solution is to use the ultra-wideband (UWB) technology in a multiple-sensor multiple-antenna (MS-MIMO) system. This paper deals with a new empirical space-time channel model of the ground reflection.
The development of wireless technologies led to the birth of numerical dosimetry for non-ionizing radiation. This paper validates two statistical methods to evaluate SAR for cylindrical body models. The first method is Monte Carlo method in a stochastic physical model of propagation, the second method is an analytical method based on Uncorrelated Scattering assumption. These methods allow a statistical...
Polarized MIMO systems are an efficient solution for reducing inter-antenna correlation while maintaining compact terminal size. In this paper, a time-variant statistical channel model is proposed for tri-polarized antenna systems. The model is based on a coherent and a scattered component, where each component includes inter-channel correlation and cross-polar discriminations. The temporal variations...
Diversity techniques are of importance in the context of cognitive radio networks since they enable the primary and secondary terminals to simultaneously and efficiently share the spectral resources in the same location. In this paper, we investigate a simple, yet powerful, diversity scheme based on the exploitation of the polarimetric dimension. More precisely, we consider a scenario where the cognitive...
This paper investigates the use of the polarization as a diversity technique to allow the joint operation of co-located CDMA networks. We propose a closed-form expression for the link probability of success with respect to the topology of the deployment and the channel characteristics (code orthogonality and degree of polarization). Next, we derive the equivalence between the degree of polarization...
Diversity techniques for cognitive radio networks are important since they enable the primary and secondary terminals to efficiently share the spectral resources in the same location simultaneously. In this paper, we investigate a simple, yet powerful, diversity scheme by exploiting the polarimetric dimension. More precisely, we evaluate a scenario where the cognitive terminals use cross-polarized...
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