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Báo cáo hóa học: " Research Article Channel Sensing without Quiet Period for Cognitive Radio Systems: A Pilot Cancellation Approach"

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 Channel Sensing without Quiet Period for Cognitive Radio Systems: A Pilot Cancellation Approach | Hindawi Publishing Corporation EURASIP Journal on Wireless Communications and Networking Volume 2011 Article ID 650619 7 pages doi 10.1155 2011 650619 Research Article Channel Sensing without Quiet Period for Cognitive Radio Systems A Pilot Cancellation Approach Dong Geun Jeong 1 Sang Soo Jeong 2 and Wha Sook Jeon2 department of Electronics Engineering Hankuk University of Foreign Studies Yongin-si Kyonggido 449-791 Republic of Korea 2 School of Electrical Engineering and Computer Science Seoul National University Seoul 151-742 Republic of Korea Correspondence should be addressed to Dong Geun Jeong dgjeong@hufs.ac.kr Received 16 July 2010 Revised 8 December 2010 Accepted 17 January 2011 Academic Editor Ashish Pandharipande Copyright 2011 Dong Geun Jeong 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 cognitive radio CR systems usually arrange for the quiet period to detect the primary user PU effectively. Since all CR users do not transmit any data during quiet period the interference caused by other CR users can be prevented in the channel sensing for PU detection. Even though the quiet period improves the PU detection performance it degrades the channel utilization of CR system. To cope with this problem we propose a channel sensing scheme without quiet period which is based on the pilot cancellation and analyze its performance. The numerical results show that the proposed scheme highly outperforms the existing PU detection schemes. 1. Introduction The cognitive radio CR system exploits the spectrum band that is originally assigned to licensed primary users PUs but not used at a specific time and a specific location. When a PU is activated newly the CR system should move out the spectrum band. Thus to detect the appearance of a PU is one of the most important tasks in CR systems. To detect PU