- Research Article
- Open Access
An Evaluation of Interference Mitigation Schemes for HAPS Systems
© Bon-Jun Ku et al. 2008
- Received: 28 September 2007
- Accepted: 23 May 2008
- Published: 3 June 2008
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 addition, the analysis results provide the proper amount of modification at the transmitting power level of the HUT required for the suitable frequency sharing.
- Power Reduction
- Conventional Scheme
- Mitigation Effect
- International Telecommunication
- User Terminal
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