Cognitive radio

1. Introduction

The cognitive radio concept has been first introduced by Joseph Mitola in its PhD thesis. It is based on the software defined radio concept, which is a new design concept of a transceiver where most parts can be modified by software. For example, a radio which baseband could be adapted in function of some constraints on the baud rate, the power, the transmission distance, the reliability of the communications,...

Once you have a transceiver which parameters can be updated by software, the next step is to make this transceiver able to adapt these parameters by itself, depending on its electromagnetic surrounding. This is the concept of cognitive radio.

2. Some examples of cognitive radio

Radios with flexible transceiver chain can already be found in the market. For example PDA where several standards are supported (WiFi, 3G, Bluetooth, GSM,...) or products such as Unik by Orange which support both WiFi and 3G. These products may be defined as SDR since their baseband processing part can be adapted to the wished supported standard. Nevertheless, the SDR concept is larger.

Products such as Unik are the first cognitive radios. Indeed, to reduce the load of IMT(GSM or 3G) networks, these products are able to switch to the WiFi standard if a compatible access point is detected in their neighborhood. The cognitive part is then to detect these WiFi access points and to switch the standard of the communication if possible.

The cognitive radio concept may be extended to many kind of applications. For example, a PDA supporting several interfaces for data communications may choose by itself the most adapted standard to its need and to its electromagnetic surrounding. This kind of problem is studied in the French ANR project DEMAIN.

3. Opportunist radio

Another application for cognitive radio is opportunist radio. The idea is that an opportunist radio senses its electromagnetic neighborhood to determine the unused frequency bands and to use one of them. More information is available on this page.

4. External links

• Wikipedia page about cognitive radio
• Mitola dissertation
• Unik by Orange
• French ANR project DEMAIN