The first work, with title “Decentralized Q-learning for Aggregated Interference Control in Completely and Partially Observable Cognitive Radio Networks ” and authored by Ana Maria Galindo and Lorenza Giupponi, received the best paper award in the 7th Annual IEEE Consumer Communications & Networking Conference (IEEE CCNC 2010) held in Las Vegas, Nevada, USA, from 9 to 12 of January 2010. This conference is sponsored by IEEE Communications Society and is devoted to sharing the latest advances in consumer centric communications applications and enabling technologies.
The contribution deals with the problem of aggregated interference generated by multiple cognitive radios (CR) at the receivers of primary (licensed) users. In particular, a secondary CR system based on the IEEE 802.22 standard for wireless regional area networks (WRAN) is considered and modelled through a multi-agent system where the multiple agents are the different secondary base stations in charge of controlling the secondary cells. The paper proposes a form of real-time multi-agent reinforcement learning, known as decentralized Q-learning, to manage the aggregated interference generated by multiple WRAN cells. Both situations of complete and partial information about the environment are considered. By directly interacting with the surrounding environment in a distributed fashion, the multi-agent system is able to learn, in the first case, an optimal policy to solve the problem and, in the second case, a reasonably good suboptimal policy. Simulation results reveal that the proposed approach is able to fulfil the primary user interference constraints, without introducing signalling overhead in the system.
This work was carried out in the framework of Newcom++ project, funded by the European Commission.
The second work, with title “Active Antenna Oscillator Systems in Substrate Integrated Waveguide (SIW) Technology” and authored by Francesco Giuppi, Apostolos Georgiadis, Maurizio Bozzi, Ana Collado and Luca Perregrini, received the best student paper award in the 4th European Conference on Antennas and Propagation (EuCAP 2010), held in Barcelona, Spain, from 12 to 16 of April 2010.
This conference, supported by the top level Associations in Antennas & Propagation and technically supported by IEEE, provides, through its presentations and exhibition, the ideal place for the exchange of scientific and technical information, both at academic and industrial levels, and fosters collaboration and cooperation in the Antenna & Propagation domain both at European and global levels.
CTTC’s contribution proposes active antenna oscillator and coupled oscillator topologies, whose elements are cavity backed antenna oscillators implemented in substrate integrated waveguide (SIW) technology. Compact single substrate implementations are demonstrated. The cavity backed topology allows one to resolve potential heat dissipation problems, and provides a design parameter to control coupling among the oscillator elements. EM simulation and harmonic balance analysis are used to design the radiating structures and trace the various existing periodic steady state solutions. Measurements of small size prototypes are presented. These compact, low cost implementations could be useful in radar and communication applications.
This work is the result of a collaboration with University of Pavia, Italy, and it was carried out in the framework of COST Action IC0803-RF / Microwave Communication Subsystems for Emerging Wireless Technologies (RFCSET).
In addition to this, another work realized by the Communications Subsystem area, “Hybrid Nonlinear and Electromagnetic Design of an Active Oscillator SIW Cavity Backed Slot Antenna”, presented by Francesco Giuppi, Apostolos Georgiadis, Maurizio Bozzi, Selva Via, Ana Collado, and Luca Perregrini received the second best student paper award in the Applied Computational Electromagnetics Society (ACES) 2010 Conference, organized in April 2010 in Tampere, Finland. CTTC’s contribution focuses on a compact, single substrate, active cavity backed slot antenna oscillator, whose cavity is implemented in Substrate Integrated Waveguide (SIW) technology. The cavity backed topology allows one to resolve potential heat dissipation problems in high power applications and array configurations, and may provide better phase noise performance. Combined EM simulation and harmonic balance analysis are used to design the radiating structure. Transient simulation is used to verify the stability of the steady state solutions. An X-band prototype was designed and fabricated. This compact, low cost antenna topology could be useful in radar and communication applications.
Finally, CTTC’s researcher Julien Perruisseau-Carrier received the 2010 Raj Mittra Travel Grant, for the category of Junior researchers, awarded by the IEEE Antennas and Propagation Society to support conference travel by graduate students and scientists conducting research in the area of electromagnetic theory and applications. The awardees selection is primarily based upon the candidate's potential or demonstrated aptitude for research.
