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: Editorial Cognitive Radio and Dynamic Spectrum Sharing Systems | Hindawi Publishing Corporation EURASIP Journal on Wireless Communications and Networking Volume 2008 Article ID 278016 3 pages doi 2008 278016 Editorial Cognitive Radio and Dynamic Spectrum Sharing Systems Ivan Cosovic 1 Friedrich K. Jondral 2 Milind M. Buddhikot 3 and Ryuji Kohno4 1 DoCoMo Communications Laboratories Europe GmbH 80687 Munich Germany 2 Institut fur Nachrichtentechnik Universitat Karlsruhe TH 76128 Karlsruhe Germany 3 Networking and Network Management Research Wireless Network Elements Research Alcatel-Lucent Bell Labs NJ 07733-3030 USA 4 Division of Physics Electrical Computer Engineering Yokohama National University Yokohama 240-8501 Japan Correspondence should be addressed to Ivan Cosovic cosovic@ Received 16 April 2008 Accepted 16 April 2008 Copyright 2008 Ivan Cosovic et al. 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 original work is properly cited. The vision behind software radio SR is to realize the communication specific signal processing of a radio as far as possible on programmable hardware. An ideal SR samples the received signal directly at the antenna and its hardware consists of a general purpose processor that is connected with analog-to-digital and with digital-to-analog converters. A radio that uses an analog radio frontend for signal conditioning and employs digital signal processors as well as field programmable gate arrays is referred to as software defined radios SDRs . Cognitive radios CRs are self-learning intelligent SDRs that are able to monitor their environment and to adapt to actual conditions like available base stations standards or channel properties. Most important CR properties are for example self-location spectrum awareness transmission power control or radio signal analysis. By extending cognitive radio principles to a network layer a concept of cognitive
