Cognitive Radio

Description of research

Currently, each wireless standard has its own statically allocated piece of the electromagnetic spectrum. With many wireless services in existence and many more to come, spectrum is becoming scarce. At any given time and any given location, only a fraction of the services is using their allocated piece of the spectrum. Therefore, large parts of the spectrum remain virtually unused. A Cognitive Radio (CR) is a device that can sense the spectrum, determine the unused frequencies (known as “white space”), and then communicate with other CRs in these unused parts of the spectrum. Therefore, a CR offers the opportunity to use the spectrum more efficiently, allowing more data to be transmitted. In the words of J.S. Adelstein: “White spaces are the blank pages on which we will write our broadband future.” If CRs can be produced at low-cost and with low energy consumption, the concept has many practical advantages:

-	Emergency services can communicate more reliably during an emergency, and they can include high data rate content like photos and video;

-	Everyone can make a phone call at 00:00 on New Year's Eve without overloading the GSM-network;

-	Wireless indoor network connections can be much faster;

-	Rural areas that are otherwise restricted to phone lines can have broadband internet access (signals in the TV band can propagate over large distances);

-	Soldiers can carry one CR to handle all military communication standards instead of having to carry five different radio sets.

CMOS technology provides the means for low-cost production. However, the desired wideband operation (as opposed to the optimized fixed-frequency transceivers that are in use today) and the required spectral sensing make the realization a real challenge. Key research questions are:

-	What spectral sensing technique(s) should be used if practical non-idealities of CMOS circuits are taken into account?

-	What modulation should be used when interference with adjacent signals in the spectrum is not allowed?

-	How can spectral sensing and modulation processing be implemented in a power-efficient way?

-	How can a flexible wideband transceiver be designed without the use of fixed external high-quality RF-filters?

Advisor(s)

dr.ing. Eric Klumperink dr.ir. André Kokkeler

prof.dr.ir. Gerard Smit prof.dr.ir. Bram Nauta

Duration: 15-11-2008 till 15-11-2012

Project: Ad-hoc Dynamic Radio-spectrum Exploitation via Multi-phase (AD-REM) Radio

Sponsor: STW

Strategic Research Orientation

WiSe - Wireless and Sensor Systems

Links to relevant web pages:

My personal employee page ICD website CAES website

Pictures