tailieunhanh - Báo cáo hóa học: " Research Article An Evaluation of Interference Mitigation Schemes for HAPS Systems"

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 An Evaluation of Interference Mitigation Schemes for HAPS Systems | Hindawi Publishing Corporation EURASIP Journal on Wireless Communications and Networking Volume 2008 Article ID 865393 11 pages doi 2008 865393 Research Article An Evaluation of Interference Mitigation Schemes for HAPS Systems Bon-Jun Ku 1 Do-Seob Ahn 1 and Nam Kim2 1 Department of Global Area Wireless Technology Research Electronics and Telecommunications Research Institute Daejeon 305-350 South Korea 2 Information and Communication Engineering Division Chungbuk National University Cheongju 360-763 South Korea Correspondence should be addressed to Bon-Jun Ku bjkoo@ Received 28 September 2007 Revised 25 February 2008 Accepted 23 May 2008 Recommended by Abbas Mohammed The International Telecommunication Union-Radiocommunication sector ITU-R has conducted frequency sharing studies between fixed services FSs using a high altitude platform station HAPS and fixed-satellite services FSSs . In particular ITU-R has investigated the power limitations related to HAPS user terminals HUTs to facilitate frequency sharing with space station receivers. To reduce the level of interference from the HUTs that can harm a geostationary earth orbit GEO satellite receiver in a space station previous studies have taken two approaches frequency sharing using a separated distance FSSD and frequency sharing using power control FSPC . In this paper various performance evaluation results of interference mitigation schemes are presented. The results include performance evaluations using a new interference mitigation approach as well as conventional approaches. An adaptive beamforming scheme ABS is introduced as a new scheme for efficient frequency sharing and the interference mitigation effect on the ABS is examined considering pointing mismatch errors. The results confirm that the application of ABS enables frequency sharing between two systems with a smaller power reduction of HUTs in a cocoverage area compared to this reduction when conventional schemes are utilized. In .