Real-Time Channel Sounding for Channel-Adaptive Data Links

The development of wideband mobile communications systems requires a good knowledge of the characteristics of the mobile channel as described by its impulse response. Such impulse response can be modeled as a tapped delay line with delays, amplitudes and phases associated with each tap. In order to obtain satisfactory estimates of these parameters and to determine delay spread, Doppler spread and the channel scattering function, a real-time channel sounder is required. This paper focuses on the hardware implementation of a real-time channel sounder, on an Innovative-DSP X6-400M Software-Defined-Radio platform based on a Xilinx Virtex-6 FPGA. The real-time channel sounder has been developed in VHDL and implemented with Xilinx ISE AND Xilinx System Generator design, simulation and analysis softwares. In order to visualize the measured channel scattering function, a graphical user interface has been created. Testing of the channel sounder using a channel emulator allowed to verify the proper operation of the project

Neural Networks and SDR Modulation schemes for wireless mobile nodes: a synergic approach

International audienceIn this paper, we envisage the possibility to exploit, in a synergic way, the Software Defined Radio (SDR) capability and the mobility support for wireless devices to dynamically compute the most suitable modulation scheme and the best position in order to improve both the coverage and connectivity in a specific area. The combined approach is based on a Neural/Genetic technique and wireless nodes are able to self-organize in a totally distributed way by using only local information. The extreme adaptability to the network conditions and application level constraints makes the proposed approach well suited for different communication scenarios such as standard monitoring or disaster recovery. The system performance has been evaluated by dealing a suite of simulation tests to show as the controlled mobility paradigm, coupled with the intrinsic re-configuring SDR capabilities of such wireless devices, allows to increase the network performances both in terms of coverage and connectivity by dynamically adapting the modulation schemes to the specific communication scenario