针对无线光通信中湍流信道下正交频分复用索引调制(orthogonal frequency division multiplexing index modulation, OFDM-IM)传输速率不高、误码率性能不佳等问题,通过在不同激活子载波上加载2种不同模式的星座符号的方式,并结合离散...针对无线光通信中湍流信道下正交频分复用索引调制(orthogonal frequency division multiplexing index modulation, OFDM-IM)传输速率不高、误码率性能不佳等问题,通过在不同激活子载波上加载2种不同模式的星座符号的方式,并结合离散小波变换提出了一种零填充三模光正交频分复用索引调制(zero-padded tri-mode optical OFDM-IM,ZTM-OOFDM-IM)。详细介绍了信号的映射过程,利用矩量母函数推导出其理论误码率,并在弱湍流信道下与已有的光OFDM-IM与双模光OFDM-IM (dual-mode optical OFDM-IM,DM-OOFDM-IM)进行了对比。结果表明,在保证传输速率的条件下,ZTM-OOFDM-IM有效改善了系统的误码性能。相较于光OFDM-IM和DM-OOFDM-IM,当误码率为10-3时,所提系统的信噪比分别改善了约2.8和3.2 dB。展开更多
Applying the theorems of Mobius inverse and Dirichlet inverse, a general algorithm to obtain biorthogonal functions based on generalized Fourier series analysis is introduced. In the algorithm, the orthogonal function...Applying the theorems of Mobius inverse and Dirichlet inverse, a general algorithm to obtain biorthogonal functions based on generalized Fourier series analysis is introduced. In the algorithm, the orthogonal function can be not only Fourier or Legendre series, but also can be any one of all orthogonal function systems. These kinds of biorthogonal function sets are used as scramble signals to construct biorthogonal scramble modulation (BOSM) wireless transmission systems. In a BOSM system, the transmitted signal has significant security performance. Several different BOSM and orthogonal systems are compared on aspects of BER performance and spectrum efficiency, simulation results show that the BOSM systems based on Chebyshev polynomial and Legendre polynomial are better than BOSM system based on Fourier series, also better than orthogonal MCM and OFDM systems.展开更多
为提高无线自组网的传输距离,提升其市场应用价值,引进5G通信技术,设计研究无线自组网自适应调制方法。首先,假定无线自组网下每一个节点都有一个唯一的身份标识号码(Identity Document,ID),根据节点的传输与通信能力,建立无线自组网节...为提高无线自组网的传输距离,提升其市场应用价值,引进5G通信技术,设计研究无线自组网自适应调制方法。首先,假定无线自组网下每一个节点都有一个唯一的身份标识号码(Identity Document,ID),根据节点的传输与通信能力,建立无线自组网节点信息传输函数,设定5G通信下无线自组网节点信息传输协议与格式;其次,引进Xilinx IP Core,进行节点的调制编码;最后,进行自由空间传输时,计算无线自组网单跳链路对于信号的接收功率,以此为依据,设计无线自组网传播信号信噪比计算与自适应调制。实验结果证明,使用设计的方法进行无线自组网自适应调制可以有效提高无线自组网的通信与信号传输范围。展开更多
文摘对广播电视无线数字化系统中应用到的多项核心技术进行了深入剖析和探讨。首先,分析调制技术,介绍了调频(Frequency Modulation,FM)/调幅(Amplitude Modulation,AM)调制的原理,并阐述了数字调制技术如正交幅度调制(Quadrature Amplitude Modulation,QAM)、正交频分多址(Orthogonal Frequency Division Multiple Access,OFDMA)等的工作机制与优势。其次,探讨数字电视广播的传输技术,包括地面数字电视传输标准和卫星传输技术。再次,重点分析音视频编码、信道编码等信号处理技术,说明它们在压缩数据、抗干扰方面的作用。最后,介绍多频网(Multi Frequency Network,MFN)和单频网(Single Frequency Network,SFN)两种网络配置方式的不同。通过应用这些技术,我国已构建起规模庞大、技术先进的广播电视无线发射网络,为人们获取音、视频信息提供保障。
文摘Applying the theorems of Mobius inverse and Dirichlet inverse, a general algorithm to obtain biorthogonal functions based on generalized Fourier series analysis is introduced. In the algorithm, the orthogonal function can be not only Fourier or Legendre series, but also can be any one of all orthogonal function systems. These kinds of biorthogonal function sets are used as scramble signals to construct biorthogonal scramble modulation (BOSM) wireless transmission systems. In a BOSM system, the transmitted signal has significant security performance. Several different BOSM and orthogonal systems are compared on aspects of BER performance and spectrum efficiency, simulation results show that the BOSM systems based on Chebyshev polynomial and Legendre polynomial are better than BOSM system based on Fourier series, also better than orthogonal MCM and OFDM systems.
文摘为提高无线自组网的传输距离,提升其市场应用价值,引进5G通信技术,设计研究无线自组网自适应调制方法。首先,假定无线自组网下每一个节点都有一个唯一的身份标识号码(Identity Document,ID),根据节点的传输与通信能力,建立无线自组网节点信息传输函数,设定5G通信下无线自组网节点信息传输协议与格式;其次,引进Xilinx IP Core,进行节点的调制编码;最后,进行自由空间传输时,计算无线自组网单跳链路对于信号的接收功率,以此为依据,设计无线自组网传播信号信噪比计算与自适应调制。实验结果证明,使用设计的方法进行无线自组网自适应调制可以有效提高无线自组网的通信与信号传输范围。
