tailieunhanh - Báo cáo hóa học: " Research Article Distributed Cooperation among Cognitive Radios with Complete and Incomplete Information"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Research Article Distributed Cooperation among Cognitive Radios with Complete and Incomplete Information | Hindawi Publishing Corporation EURASIP Journal on Advances in Signal Processing Volume 2009 Article ID 905185 13 pages doi 2009 905185 Research Article Distributed Cooperation among Cognitive Radios with Complete and Incomplete Information Lorenza Giupponi and Christian Ibars Centre Tecnologic de Telecomunicacions de Catalunya CTTC Av. del Canal Olimpic s n 08860 Castelldefels Spain Correspondence should be addressed to Lorenza Giupponi Received 30 January 2009 Accepted 20 May 2009 Recommended by John Chapin This paper proposes that secondary unlicensed users are allowed to opportunistically use the radio spectrum allocated to the primary licensed users as long as they agree on facilitating the primary user communications by cooperating with them. The proposal is characterized by feasibility since the half-duplex option is considered and incomplete knowledge of channel state information can be assumed. In particular we consider two situations where the users in the scenario have complete or incomplete knowledge of the surrounding environment. In the first case we make the hypothesis of the existence of a Common Control Channel CCC where users share this information. In the second case the hypothesis of the CCC is avoided which improves the robustness and feasibility of the cognitive radio network. To model these schemes we make use of theory of exact and Bayesian potential games. We analyze the convergence properties of the proposed games and we evaluate the outputs in terms of quality of service perceived by both primary and secondary users showing that cooperation for cognitive radios is a promising framework and that the lack of complete information in the decision process only slightly reduces system performance. Copyright 2009 L. Giupponi and C. Ibars. This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use distribution and reproduction in any medium provided the