基于认知无线电的GEO与LEO卫星频谱共存

随着新的宽带多媒体业务的发展,宽带无线频谱的需求日益增长.同时,低轨道(LEO)卫星由于其传输损耗低、传播时延小而被大规模部署.为了更好地利用频谱资源,卫星通信系统普遍采用高轨道(GEO)卫星与LEO卫星频谱共存的方案来提高频谱利用率.在频谱共存的过程中,提出了一种基于动态阈值的能量检测与波束跳跃相结合的算法,以减小L...

Coexistence of GEO and LEO satellite spectrum based on cognitive radio

With the development of new broadband multimedia services, the demand for broadband wireless spectrum has been growing rapidly, which makes spectrum resources scarcer. Meanwhile, low Earth orbit (LEO) satellites deployed on a large scale have the advantages of low transmission loss and small propagation delay. To improve the spectrum utilization rate, a coexistence scheme of geostationary Earth orbit (GEO) satellites and LEO satellites was adopted. In order to avoid the interferences of LEO satellites to GEO satellites during spectrum coexistence, an algorithm combining spectrum sensing and beam hopping was proposed. First, the signal to noise ratio (SNR) of LEO satellite communication was estimated. Then the optimal threshold was selected according to the estimated SNR. An energy detection algorithm based on dynamic threshold was used to discriminate between the GEO satellite signals, and the beam adjustment was carried out according to the judgment results. Simulation results show that the error of the energy detection algorithm based on the dynamic threshold proposed is significantly lower than that of the traditional energy detection algorithm based on fixed threshold and spectrum sensing method based on second order cyclic statistics. When the signal to noise ratio is lower than -10dB the detection error is lower than 0。2, and when the signal to noise ratio is higher than -5dB the detection error approaches zero.