为解决当前5G无线网络中高速移动节点信号定位不准确和高稳定分布噪声(high stable distribution noise,HSDN)等特殊偏移噪声降低定位准确性的问题,提出基于电控旋转序列位移接收结构的5G无线网络信号定位算法。利用单一节点接收结构及...为解决当前5G无线网络中高速移动节点信号定位不准确和高稳定分布噪声(high stable distribution noise,HSDN)等特殊偏移噪声降低定位准确性的问题,提出基于电控旋转序列位移接收结构的5G无线网络信号定位算法。利用单一节点接收结构及环接收结构并采取分层方式,构建电控旋转序列位移接收结构;基于待定位信号与中央基站及各层接收节点之间的切线关系,初步估计待测信号方位;针对信号发射环境中的HSDN噪声频率漂移特性,通过信号定位差分机制,联合最优极大似然估计,构建基于差分方式的方位角精度优化机制,降低定位误差。仿真结果表明,与采取单一节点接收方式的GDAM算法及采取单层环接收方式的NUPOS-1算法相比,在HSDN噪声干扰环境下,该算法具有更低的信号定位误差。展开更多
After the Yushu M S 7.1 earthquake on April 14,2010,a large number of aftershocks were recorded by the surrounding permanent network and temporary seismic stations.Due to the distribution of stations,knowledge about v...After the Yushu M S 7.1 earthquake on April 14,2010,a large number of aftershocks were recorded by the surrounding permanent network and temporary seismic stations.Due to the distribution of stations,knowledge about velocity structure,the reliability of seismic phases,and so on,the location result from conventional method is usually of low precision,from which it is difficult to recognize the spatial and temporal distribution and the trends of aftershock activity.In this paper,by using teleseismic waveforms recorded by permanent station,the seismic velocity structure beneath the vicinity is obtained from receiver function stacking and inversion methods.And the Yushu earthquake sequences are relocated from seismic phase data by HypoDD.The results show that the Yushu M S 7.1 earthquake occurred at 13 km depth;the aftershock sequences were distributed mainly in the NWW along the Garzê-Yushu fault,and most aftershocks were concentrated in a 100 km length and 5-20 km depth.Combined with the velocity structure,it can be inferred that the earthquake mainly destroys the high-velocity layer of the upper crust.In the west of the seismic fault near(33.3°N,96.2°E),the aftershock sequences were distributed like a straight column,suggesting there was a comminuted break from 25km depth to the ground.展开更多
Uplink non-orthogonM multiple access （NOMA） is a promising technique to meet the requirements of the fifth generation （5G） and beyond systems. Various NOMA schemes have been proposed in both academia and industry....Uplink non-orthogonM multiple access （NOMA） is a promising technique to meet the requirements of the fifth generation （5G） and beyond systems. Various NOMA schemes have been proposed in both academia and industry. However, most existing schemes assume equal average received power, which limits the performance. We propose three enhancements of uplink NOMA to achieve the requirements of massive connectivity and high reliability in 5G, where unequal average received power is exploited as part of the multiple access signature. First, the optimal sequences targeting to generalized Welch-bound equality （GWBE） are obtained for unequal average received power. Then user grouping with multi-level received powers is proposed for better successive interference cancellation （SIC） at the receiver. Finally, sequence grouping based on the cross-correlation properties of sequences is proposed to reduce inter-and intra-group interference. Simulation results show that by incorporating multi-level received powers and sequence grouping into existing NOMA schemes, for an NOMA system with 400% overloading and fixed signature allocation, 3 dB and 10 dB signal-to-noise ratio （SNR） gains at 0.1 block error rate （BLER） target can be achieved compared with existing NOMA schemes and orthogonal multiple access （OMA）, respectively. Besides, 0.01 BLER target can be achieved while an error floor exists in existing NOMA schemes. Under random sequence selection, collision probability is reduced by multi-level powers. In addition, GWBE sequences achieve lower BLER than existing sequences and the gain is large especially for low BLER requirements. This shows that the proposed scheme can support larger connectivity and higher reliability.展开更多
Y98-61409-23 9913731直接序列扩频接收机中确定捕获概率的门限设置规则的比较=Comparison of threshold setting rules for theprobability of acquisition in a DS spread spectrum receiver[会,英]/Iinatti,J.//1998 Proceedings of ...Y98-61409-23 9913731直接序列扩频接收机中确定捕获概率的门限设置规则的比较=Comparison of threshold setting rules for theprobability of acquisition in a DS spread spectrum receiver[会,英]/Iinatti,J.//1998 Proceedings of the Interna-tional Zurich Seminar on Broadband Communications.—23～28 (MaG)展开更多
文摘为解决当前5G无线网络中高速移动节点信号定位不准确和高稳定分布噪声(high stable distribution noise,HSDN)等特殊偏移噪声降低定位准确性的问题,提出基于电控旋转序列位移接收结构的5G无线网络信号定位算法。利用单一节点接收结构及环接收结构并采取分层方式,构建电控旋转序列位移接收结构;基于待定位信号与中央基站及各层接收节点之间的切线关系,初步估计待测信号方位;针对信号发射环境中的HSDN噪声频率漂移特性,通过信号定位差分机制,联合最优极大似然估计,构建基于差分方式的方位角精度优化机制,降低定位误差。仿真结果表明,与采取单一节点接收方式的GDAM算法及采取单层环接收方式的NUPOS-1算法相比,在HSDN噪声干扰环境下,该算法具有更低的信号定位误差。
基金supported by Institute of Geophysics,China Earthquake Administration(Grant No.DQJB10B04)
文摘After the Yushu M S 7.1 earthquake on April 14,2010,a large number of aftershocks were recorded by the surrounding permanent network and temporary seismic stations.Due to the distribution of stations,knowledge about velocity structure,the reliability of seismic phases,and so on,the location result from conventional method is usually of low precision,from which it is difficult to recognize the spatial and temporal distribution and the trends of aftershock activity.In this paper,by using teleseismic waveforms recorded by permanent station,the seismic velocity structure beneath the vicinity is obtained from receiver function stacking and inversion methods.And the Yushu earthquake sequences are relocated from seismic phase data by HypoDD.The results show that the Yushu M S 7.1 earthquake occurred at 13 km depth;the aftershock sequences were distributed mainly in the NWW along the Garzê-Yushu fault,and most aftershocks were concentrated in a 100 km length and 5-20 km depth.Combined with the velocity structure,it can be inferred that the earthquake mainly destroys the high-velocity layer of the upper crust.In the west of the seismic fault near(33.3°N,96.2°E),the aftershock sequences were distributed like a straight column,suggesting there was a comminuted break from 25km depth to the ground.
文摘Uplink non-orthogonM multiple access （NOMA） is a promising technique to meet the requirements of the fifth generation （5G） and beyond systems. Various NOMA schemes have been proposed in both academia and industry. However, most existing schemes assume equal average received power, which limits the performance. We propose three enhancements of uplink NOMA to achieve the requirements of massive connectivity and high reliability in 5G, where unequal average received power is exploited as part of the multiple access signature. First, the optimal sequences targeting to generalized Welch-bound equality （GWBE） are obtained for unequal average received power. Then user grouping with multi-level received powers is proposed for better successive interference cancellation （SIC） at the receiver. Finally, sequence grouping based on the cross-correlation properties of sequences is proposed to reduce inter-and intra-group interference. Simulation results show that by incorporating multi-level received powers and sequence grouping into existing NOMA schemes, for an NOMA system with 400% overloading and fixed signature allocation, 3 dB and 10 dB signal-to-noise ratio （SNR） gains at 0.1 block error rate （BLER） target can be achieved compared with existing NOMA schemes and orthogonal multiple access （OMA）, respectively. Besides, 0.01 BLER target can be achieved while an error floor exists in existing NOMA schemes. Under random sequence selection, collision probability is reduced by multi-level powers. In addition, GWBE sequences achieve lower BLER than existing sequences and the gain is large especially for low BLER requirements. This shows that the proposed scheme can support larger connectivity and higher reliability.
文摘Y98-61409-23 9913731直接序列扩频接收机中确定捕获概率的门限设置规则的比较=Comparison of threshold setting rules for theprobability of acquisition in a DS spread spectrum receiver[会,英]/Iinatti,J.//1998 Proceedings of the Interna-tional Zurich Seminar on Broadband Communications.—23～28 (MaG)
