Flexicells and SDR4ALL - A cognitive radio test bed

International audienceAdvanced cognitive radio algorithms involve different technical fields like signal processing, wired network communication, computing, etc. Prototyping such systems raise new issues when one wants to find 'off the shelf' bricks, ready for experiments: the integration step is time consuming, is not free of risks of non-compatibility and most of the time does not fall in the scope of a PhD work. For these reasons, many research groups have invested in building a testing platform for their cognitive radio activities. Because the Alcatel Lucent Chair on Flexible Radio is engaged in research covering a wide field of topics, the need for a fully customizable experimental test bed rose and was initiated with SDR4ALL on the radio side, and continued with the FlexiCells project for the infrastructure. This paper presents the platform we are designing at Supélec

Non-Invasive Green Small Cell Network

International audienceFuture low cost wireless networks are expected to provide high data rates with low power consumption. A dense deployment of distributed small-cells, within the existing network infrastructure, is one of the candidate solutions to achieve this goal. Unfortunately, the aggregate signal resulting from the transmission of these multiples small cells can be considered as an electromagnetic (EM) pollution for passive users who do not carry wireless devices. These users are victim of primary electromagnetic "smokers" and request from operators to be spared from these new base stations. The aim of this contribution is to propose an electromagnetic friendly environment with minimum EM pollution, while satisfying the quality of service requirements. The technique employed, called Distributed Space-Time Reversal (DSTR), focuses the energy on active users (equipped with wireless devices) and is able to spare passive users from EM waves. In this contribution, we provide a theoretical analysis of the technique and show the impact of active/passive users with respect to the number of cells

Compensation of analog imperfections In a Ka-band FMCW SAR

International audienceThis paper deals with the compensation of analog imperfections in a Ka-Band FMCW SAR. Due to the presence of phase distortion in the up-conversion and down conversion block, we demonstrate that the calibration of the VCO based on a reference beat signal is range-limited. We propose a post-processing method to compensate the residual sinusoidal nonlinearities of the VCO characteristic as well as the phase distortion coming from the up-conversion and down-conversion block. Processing of SAR data acquisition demonstrates the efficiency of the method

Network Coding with Multimedia Transmission and Cognitive Networking: An Implementation based on Software-Defined Radio

Network coding (NC) is considered a breakthrough to improve throughput, robustness, and security of wireless networks. Although the theoretical aspects of NC have been extensively investigated, there have been only few experiments with pure NC schematics. This paper presents an implementation of NC under a two-way relay model and extends it to two\ua0non-straightforward scenarios: (i) multimedia transmission with layered coding and multiple-description coding, and (ii) cognitive radio with Vandermonde frequency division multiplexing (VFDM). The implementation is in real time and based on software-defined radio (SDR). The experimental results show that, by combining NC and source coding, we can control the quality of the received multimedia content in an on-demand manner. Whereas in the VFDM-based cognitive radio, the quality of the received content in the primary receiver is low (due to imperfect channel estimation) yet retrievable. Our implementation results serve as a proof for the practicability of network coding in relevant applications

Network Coding with Multimedia Transmission and Cognitive Networking: An Implementation based on Software-Defined Radio

Network coding (NC) is considered a breakthrough to improve throughput, robustness, and security of wireless networks. Although the theoretical aspects of NC have been extensively investigated, there have been only few experiments with pure NC schematics. This paper presents an implementation of NC under a two-way relay model and extends it to two non-straightforward scenarios: (i) multimedia transmission with layered coding and multiple-description coding, and (ii) cognitive radio with Vandermonde frequency division multiplexing (VFDM). The implementation is in real time and based on software-defined radio (SDR). The experimental results show that, by combining NC and source coding, we can control the quality of the received multimedia content in an on-demand manner. Whereas in the VFDM-based cognitive radio, the quality of the received content in the primary receiver is low (due to imperfect channel estimation) yet retrievable. Our implementation results serve as a proof for the practicability of network coding in relevant applications

Passive radar testbed and preliminary experiments in recognition of non-cooperative aircraft intruding into controlled airspace

We consider the automatic classification of aircraft observed with a passive radar, thus using illuminators of opportunity. We deployed a testbed and developed classification algorithms. Preliminary tests show a correct recognition rate of 72%.Low-frequency ATR of air targets - Pisane Thesi

Automatic real-time collection of RCS of airplanes in a real bistatic low-frequency configuration using a software defined passive radar based on illuminators of opportunity

peer reviewe

Revisiting VOR transmitters : MIMO passive radar using legacy infrastructure

International audienceVOR is a well-known system used for the routing of aircrafts worldwide. The system is also worth to provide two interesting properties, first to serve as donor to passive radar, second to provide a specific space coding, used for the navigation and that will be precisely explored to localize targets detected in a passive radar mode. VOR is also interesting as it operates in the lower VHF band, a frequency band highly coveted for its counter stealth properties and high detectability of air targets. The paper addresses the potential of this kind of transmitter, considered solely and also in a multistatic configuration