The rejuvenation of non-geostationary orbit(NGSO)satellite communication holds the promise of seamless and ubiquitous broadband access from the space.However,the NGSO constellations must share the scarce radio spectru...The rejuvenation of non-geostationary orbit(NGSO)satellite communication holds the promise of seamless and ubiquitous broadband access from the space.However,the NGSO constellations must share the scarce radio spectrum resources with geostationary orbit(GSO)satellite systems,which results in dynamically changing and unevenly distributed interference to GSO systems.In this context,the ultra-large-scale NGSO constellation incurs a more complicated interference environment with GSO systems,which raises urgent demands on inter-system interference evaluation.In this case,we investigate the inter-system downlink interference from a NGSO satellite mega-constellation to a GSO earth station.Specifically,we consider the scenario where the NGSO and GSO earth stations are co-located,and apply a novel visibility analysis method in the interference modeling to reduce computation redundancy.The interference evaluation is then performed through comprehensive simulations,in which the Starlink constellation with more than 4000 satellites is examined for the first time.The simulation results demonstrate various states of interference on the GSO earth station at different deployment locations.It reveals that the number of visible satellites could influence the angle between the main lobe directions of NGSO satellites and the GSO earth station antenna,which further affects the interference level.展开更多
An analysis of mutual interfering sources on RF systems using dual-band (Ka / X) radar is presented. The purpose of this paper is to improve operational performance of the system from the point of view of EMC design. ...An analysis of mutual interfering sources on RF systems using dual-band (Ka / X) radar is presented. The purpose of this paper is to improve operational performance of the system from the point of view of EMC design. The experimental dual-band antenna system have decreased the disturbing effects of most mutual interfering sources.展开更多
Based on the study of the characteristics of the cloud, firstly the interference mechanism of the capacitance proximity fuze passing through the cloud has been studied. Analysis shows that the medium property of the c...Based on the study of the characteristics of the cloud, firstly the interference mechanism of the capacitance proximity fuze passing through the cloud has been studied. Analysis shows that the medium property of the cloud only, has little effect on the capacitance proximity fuze. Secondly, the adherence interference of the cloud to capacitance proximity fuze has been studied for the first time in this paper. Then finite element analysis (FEA) method has been used to simulate the adherence interference of the cloud. Simulation result shows that the cloud adherence effect interferes the output of the capacitance fuze greatly. At last, experiments have been made for the study of the cloud interference.展开更多
The cognitive radio （CR） technology is believed to improve the spectrum efficiency. However, the interference problem has become a critical issue due to the coexistence of primary systems and CR systems. In this pap...The cognitive radio （CR） technology is believed to improve the spectrum efficiency. However, the interference problem has become a critical issue due to the coexistence of primary systems and CR systems. In this paper, the interferences in CR based cellular networks are discussed. Interference scenarios are analyzed, considering different interference sources. Meanwhile, an improved model named ＇Cognitive Interference Ring＇ is introduced to describe the interference range of each secondary user （SU）. Depending on the above analysis, graph coloring based dynamic power allocation （GCDPA） scheme is proposed for interference avoidance. Simulation results demonstrate that in CR based cellular networks, the interferences to primary users （PUs） can be effectively mitigated with the proposed GCDPA scheme, and the system throughput and power efficiency are both improved.展开更多
基金the Beijing Natural Science Foundation.L222003the National Key Research and Development Program.2020YFB1806100。
文摘The rejuvenation of non-geostationary orbit(NGSO)satellite communication holds the promise of seamless and ubiquitous broadband access from the space.However,the NGSO constellations must share the scarce radio spectrum resources with geostationary orbit(GSO)satellite systems,which results in dynamically changing and unevenly distributed interference to GSO systems.In this context,the ultra-large-scale NGSO constellation incurs a more complicated interference environment with GSO systems,which raises urgent demands on inter-system interference evaluation.In this case,we investigate the inter-system downlink interference from a NGSO satellite mega-constellation to a GSO earth station.Specifically,we consider the scenario where the NGSO and GSO earth stations are co-located,and apply a novel visibility analysis method in the interference modeling to reduce computation redundancy.The interference evaluation is then performed through comprehensive simulations,in which the Starlink constellation with more than 4000 satellites is examined for the first time.The simulation results demonstrate various states of interference on the GSO earth station at different deployment locations.It reveals that the number of visible satellites could influence the angle between the main lobe directions of NGSO satellites and the GSO earth station antenna,which further affects the interference level.
文摘An analysis of mutual interfering sources on RF systems using dual-band (Ka / X) radar is presented. The purpose of this paper is to improve operational performance of the system from the point of view of EMC design. The experimental dual-band antenna system have decreased the disturbing effects of most mutual interfering sources.
文摘Based on the study of the characteristics of the cloud, firstly the interference mechanism of the capacitance proximity fuze passing through the cloud has been studied. Analysis shows that the medium property of the cloud only, has little effect on the capacitance proximity fuze. Secondly, the adherence interference of the cloud to capacitance proximity fuze has been studied for the first time in this paper. Then finite element analysis (FEA) method has been used to simulate the adherence interference of the cloud. Simulation result shows that the cloud adherence effect interferes the output of the capacitance fuze greatly. At last, experiments have been made for the study of the cloud interference.
基金supported by the National Natural Science Foundation of China (61001116)International Scientific and Technological Cooperation Program (S2010GR0902)State Emphasis Special Project 2009ZX03003-011-02
文摘The cognitive radio （CR） technology is believed to improve the spectrum efficiency. However, the interference problem has become a critical issue due to the coexistence of primary systems and CR systems. In this paper, the interferences in CR based cellular networks are discussed. Interference scenarios are analyzed, considering different interference sources. Meanwhile, an improved model named ＇Cognitive Interference Ring＇ is introduced to describe the interference range of each secondary user （SU）. Depending on the above analysis, graph coloring based dynamic power allocation （GCDPA） scheme is proposed for interference avoidance. Simulation results demonstrate that in CR based cellular networks, the interferences to primary users （PUs） can be effectively mitigated with the proposed GCDPA scheme, and the system throughput and power efficiency are both improved.
