High Altitude Platform(HAP) must compensate for relative motion with respect to the ground because of the stratosphere complexity,which is important to guarantee Quality of Service(QoS) in intended coverage area.With ...High Altitude Platform(HAP) must compensate for relative motion with respect to the ground because of the stratosphere complexity,which is important to guarantee Quality of Service(QoS) in intended coverage area.With analysis on HAP movement models for predicting the geographical coverage in the cases of shift horizontally and vertically,yaw,roll and pitch,the mechanisms of steerable antennas movement compensation are investigated.The mechanism is applied to a scenario of 127 cell architecture,with a cell cluster size of four.By the simulation results of Carrier to Interference Ratio(CIR),the steerable antenna movement compensation mechanism decrease influence of HAP movement and guarantee effective coverage of the service area.展开更多
In this paper,a Doppler scaling fast Fourier transform（Doppler-FFT）algorithm for filter bank multi-carrier（FBMC）is proposed,which can efficiently eliminate the impact of the Doppler scaling in satellite communicat...In this paper,a Doppler scaling fast Fourier transform（Doppler-FFT）algorithm for filter bank multi-carrier（FBMC）is proposed,which can efficiently eliminate the impact of the Doppler scaling in satellite communications.By introducing a Doppler scaling factor into the butterfly structure of the fast Fourier transform（FFT）algorithm,the proposed algorithm eliminates the differences between the Doppler shifts of the received subcarriers,and maintains the same order of computational complexity compared to that of the traditional FFT.In the process of using the new method,the Doppler scaling should be estimated by calculating the orbital data in advance.Thus,the inter-symbol interference（ISI）and the inter-carrier interference（ICI）can be completely eliminated,and the signal to interference and noise ratio（SINR）will not be affected.Simulation results also show that the proposed algorithm can achieve a 0.4 d B performance gain compared to the frequency domain equalization（FDE）algorithm in satellite communications.展开更多
A distributed power allocation scheme was presented to maximize the system capacity in dense small cell networks. A new signaling called inter-cell-signal to interference plus noise ratio （ISINR） as well as its modi...A distributed power allocation scheme was presented to maximize the system capacity in dense small cell networks. A new signaling called inter-cell-signal to interference plus noise ratio （ISINR） as well as its modification was defined to show the algebraic properties of the system capacity. With the help of ISINR, we have an easy way to identify the local monotonicity of the system capacity. Then on each subchannel in iteration, we divide the small cell evolved node B＇s （SeNBs） into different subsets. For the first subset, the sum rate is convex with respect to the power domain and the power optimally was allocated. On the other hand, for the second subset, the sum rate is monotone decreasing and the SeNBs would abandon the subchannel in this iteration. The two strategies are applied iteratively to improve the system capacity. Simulations show that the proposed scheme can achieve much larger system capacity than the conventional ones. The scheme can achieve a promising tradeoffbetween performance and signaling overhead.展开更多
文摘High Altitude Platform(HAP) must compensate for relative motion with respect to the ground because of the stratosphere complexity,which is important to guarantee Quality of Service(QoS) in intended coverage area.With analysis on HAP movement models for predicting the geographical coverage in the cases of shift horizontally and vertically,yaw,roll and pitch,the mechanisms of steerable antennas movement compensation are investigated.The mechanism is applied to a scenario of 127 cell architecture,with a cell cluster size of four.By the simulation results of Carrier to Interference Ratio(CIR),the steerable antenna movement compensation mechanism decrease influence of HAP movement and guarantee effective coverage of the service area.
基金supported by the National Natural Science Foundation of China (No. 91438116)by the Program for New Century Excellent Talents in University of China (No. NCET-12-0030)+1 种基金by the National Hi-Tech R&D Program of China (No. 2015AA7014065)by the Shanghai Aerospace Science and Technology Innovation Fund (No. SAST2015089)
文摘In this paper,a Doppler scaling fast Fourier transform（Doppler-FFT）algorithm for filter bank multi-carrier（FBMC）is proposed,which can efficiently eliminate the impact of the Doppler scaling in satellite communications.By introducing a Doppler scaling factor into the butterfly structure of the fast Fourier transform（FFT）algorithm,the proposed algorithm eliminates the differences between the Doppler shifts of the received subcarriers,and maintains the same order of computational complexity compared to that of the traditional FFT.In the process of using the new method,the Doppler scaling should be estimated by calculating the orbital data in advance.Thus,the inter-symbol interference（ISI）and the inter-carrier interference（ICI）can be completely eliminated,and the signal to interference and noise ratio（SINR）will not be affected.Simulation results also show that the proposed algorithm can achieve a 0.4 d B performance gain compared to the frequency domain equalization（FDE）algorithm in satellite communications.
基金supported by the Hi-Tech Research and Development Program of China (2014AA01A701)the Funds for Creative Research Groups of China (61121001)
文摘A distributed power allocation scheme was presented to maximize the system capacity in dense small cell networks. A new signaling called inter-cell-signal to interference plus noise ratio （ISINR） as well as its modification was defined to show the algebraic properties of the system capacity. With the help of ISINR, we have an easy way to identify the local monotonicity of the system capacity. Then on each subchannel in iteration, we divide the small cell evolved node B＇s （SeNBs） into different subsets. For the first subset, the sum rate is convex with respect to the power domain and the power optimally was allocated. On the other hand, for the second subset, the sum rate is monotone decreasing and the SeNBs would abandon the subchannel in this iteration. The two strategies are applied iteratively to improve the system capacity. Simulations show that the proposed scheme can achieve much larger system capacity than the conventional ones. The scheme can achieve a promising tradeoffbetween performance and signaling overhead.
