A Seminar on Software Defined Radio (SDR) and Cognitive Radio Systems (CRS) was held at the ITU, Geneva, on 4 February 2008, to share information on activities and research towards the development and application of these technologies and to provide a high-level view of the Radiocommunication issues that might be improved through the use of SDR and CRS. The seminar included a number of presentations on general issues, concepts, specific research projects and opportunities[1].

The seminar was formally opened by Mr. Valery Timofeev, Director, ITU Radiocommunication Bureau (BR), who welcomed the participants and in his opening remarks highlighted that this kind of seminar follows the tradition of the ITU-R of creating seminars and workshops associated with the meetings of the working parties and study groups on topics of particular interest.  These events enable the dissemination of information and informal open discussions of the relevant issues and technologies; that complement the formal work of the working parties.  The topics of SDR and CRS have received lots of attention lately; WRC-11 Agenda Item 1.19 and the associated Resolution 956 (WRC-07) consider the impact of these technologies.  These technologies may also play a role in relation to the WRC-11 studies that address the international spectrum regulatory framework through the famous Resolution 951.  Mr. Timofeev shared with the audience the surprising impression he got that very same morning from a meeting with industry top management; he fears that the studies on Resolution 951 might be a little bit late compared with the developments of technology and we might not be able to meet the new challenges which will be definitively before the Radiocommunication sector.  Thus, he remarked, while discussing the particular items of this seminar we must keep in mind that they may be even more important that we can see right now.

The first session at the seminar included a summary of the work to-date on SDR and CRS within ITU-R and the motivation for WRC-11 Agenda Item 1.19 from the point of view of its main proponents: the Arab States and Europe. This included a discussion of possibilities, such as a cognition supporting pilot channel, use database information, use of white space, and whether to use dedicated frequency bands. It was pointed out that a particular study had found that 50% of the allocated spectrum in a particular country was unused all the time.

Various technical presentations in two subsequent sessions described advanced research being carried out in Canada, Europe and Japan, as well as standardization activities in IEEE. Interesting insights were also provided by looking back at the progress of technology, application performance requirements, and the business impacts. 

Four Canadian projects were described. One project uses cognitive radio capabilities to sense unused TV channels in the VHF/UHF TV broadcast bands to extend broadband access in low population density rural areas. Another one explores the use of a co-existence control channel to implement collaborative WiMAX networks.  Another project uses a cognitive radio overlay on WiFi in support of improved municipal RLAN operation as well as very low-cost backhaul technologies.  The fourth project uses cognitive radio to assist managing a mix of MIMO and beamforming techniques to maintain high data rate links.

The European projects include the European Commission (EC) FP6 E²R Programme, recently completed, and the objectives of the EC FP7 E³ Project that is now starting. The concept of Cognitive Pilot Channel (CPC) and examples of CPC dimensioning for urban and rural scenarios were described. Another European project, “Urban Planning for RadioCommunications (URC) and Cognitive Radio” investigates solutions for opportunistic use of the spectrum but controlled (optimized and secured) including a network of disseminated sensing to assist in avoiding interference and by providing real-time information to regulators on the quality of the spectrum that is being managed.

Detailed information on Japanese activities was presented, particularly on some developed multi-band and tunable devices (amplifier, bandpass filter, mixer, and antenna) in the frequency range 400 MHz – 6 GHz and a prototype for cognitive radio.

The activities of the IEEE Standards Coordinating Committee 41 (SCC41) on Dynamic Spectrum Access (DSA) networks were presented.  Some of the challenges were also described, including the evolution of global regulations and the development of cooperative relationships among those engaged in standardization.

The seminar programme allowed plenty of time for discussions.  Some of it centered on how much regulation is needed for the new capabilities, regulatory conditions, co-existence issues, and integrity requirements for the cognitive channel. Regulation needs depend on whether a vertical model (i.e., only one group responsible) or a horizontal model (i.e., multiple groups) is used; for a vertical segment there is no need for new regulations. The consideration of coexistence scenarios is a difficult regulatory problem; two aspects to be considered are the sensing levels for existing radiocommunication systems, which may be different for each frequency segment, and having prior knowledge about systems because some systems do not transmit (receive-only systems.  For the cognitive pilot channel integrity authentication and privacy are very important to prevent unauthorized or malicious users to gain knowledge of the existing systems. It was also pointed out that the ownership of the cognitive pilot channel manager needs to be considered carefully to avoid anticompetitive aspects.

Another area of discussion focused on the contrast between today’s context of operator properties, including the evolution of way to assign spectrum such as beauty concepts, auctions, etc., and the future business model where operators and regulators, including secondary operators, will require a new context to operate.

An article in the March 2008 issue of the ITU News magazine has also appeared.

The regulatory work on SDR and CDR will continue in ITU-R Working Party 1B, responsible for the preparations for WRC-11 Agenda Item 1.19, “to consider regulatory measures and their relevance, in order to enable the introduction of software-defined radio and cognitive radio systems, based on the results of ITU‑R studies, in accordance with Resolution 956 (WRC‑07)”.

The technical work will also continue in the services working parties, such as Working Party 5A (under Questions ITU‑R 230-2/8 and 241-1/8), where a technical report on SDR has already been produced[2] and another one on CRS is underway[3].