Software-Defined Radio (SDR) is an innovative paradigm to manage wireless communications. In a SDR system, every radio parameter (e.g. frequency selection, channel width, modulation) is software controlled.

The SDR application panorama continuously grows: FM, AM, DVB-T, VHF, UHF, satellite links, Wi-MAX, WiFi are some examples only; moreover, the base technologies are quickly evolving: high performance DSPs, FPGAs, A/D e D/A converters permit to manage broader requency ranges.

Starting from SDR systems is possible to project and create solutions that implement Cognitive Radio technology: these nodes use information collected by configuration and environment analysis (e.g. radio monitoring to identify available frequencies). Through these information, a Cognitive System can automatically adapt itself in real-time. Cognitive Radio system design includes also signaling among nodes to synchronize radio parameters.

INLAB-CSP and Dipartimento di Elettronica of Politecnico di Torino are jointly managing these activities.

Objectives

This activity target of this activity is to design and implement a Cognitive Radio prototype that can operate at different frequencies. Every radio parameter will be software controlled and will be changed in real-time, starting, for example, from spectrum analysis.

Our project involves design and implementation of SDR and Cognitive Radio modules. We will also evaluate hardware design issues due to:

• wide spectrum range management (e.g. 40-50MHz);
• high bit rate data flows that are real-time exchanged through radio interfaces and PC. For example, working with wide spectrum channel generates flows bigger than 1Gb/s;
• real-time signaling process.

Architecture

The image reassumes in schematic way a SDR system architecture. Main elements are:

• A radio frequency (RF) front-end converting analogue RF signals to base band;
• A/D and D/A converters digitalizing the base band;
• An FPGA that can pre-process data (e.g. decimation).

The resulting data flow can be processed by a PC or by a DSP.