An automatic method for classifying frequency shift keying(FSK),minimum shift keying(MSK),phase shift keying(PSK),quadrature amplitude modulation(QAM),and orthogonal frequency division multiplexing(OFDM)is proposed by...An automatic method for classifying frequency shift keying(FSK),minimum shift keying(MSK),phase shift keying(PSK),quadrature amplitude modulation(QAM),and orthogonal frequency division multiplexing(OFDM)is proposed by simultaneously using normality test,spectral analysis,and geometrical characteristics of in-phase-quadrature(I-Q)constellation diagram.Since the extracted features are unique for each modulation,they can be considered as a fingerprint of each modulation.We show that the proposed algorithm outperforms the previously published methods in terms of signal-to-noise ratio(SNR)and success rate.For example,the success rate of the proposed method for 64-QAM modulation at SNR=11 dB is 99%.Another advantage of the proposed method is its wide SNR range;such that the probability of classification for 16-QAM at SNR=3 dB is almost 1.The proposed method also provides a database for geometrical features of I-Q constellation diagram.By comparing and correlating the data of the provided database with the estimated I-Q diagram of the received signal,the processing gain of 4 dB is obtained.Whatever can be mentioned about the preference of the proposed algorithm are low complexity,low SNR,wide range of modulation set,and enhanced recognition at higher-order modulations.展开更多
Automatic modulation classification is the process of identification of the modulation type of a signal in a general environment. This paper proposes a new method to evaluate the tracking performance of large margin c...Automatic modulation classification is the process of identification of the modulation type of a signal in a general environment. This paper proposes a new method to evaluate the tracking performance of large margin classifier against signal-tonoise ratio （SNR）, and classifies all forms of primary user＇s signals in a cognitive radio environment. For achieving this objective, two structures of a large margin are developed in additive white Gaussian noise （AWGN） channels with priori unknown SNR. A combination of higher order statistics and instantaneous characteristics is selected as effective features. Simulation results show that the classification rates of the proposed structures are well robust against environmental SNR changes.展开更多
针对联合自适应调制编码(adaptive modulation and coding,AMC),自动重传请求(automatic repeatrequest,ARQ)与包分割传输3种机制的通信系统,提出了一种ARQ多帧动态周期反馈机制,并建立了分析此系统的马尔可夫链模型,得到了包平均时延...针对联合自适应调制编码(adaptive modulation and coding,AMC),自动重传请求(automatic repeatrequest,ARQ)与包分割传输3种机制的通信系统,提出了一种ARQ多帧动态周期反馈机制,并建立了分析此系统的马尔可夫链模型,得到了包平均时延、平均反馈次数、平均掉包率和系统吞吐量等多种性能指标。在此基础上提出了在服务质量(quality of service,QoS)条件约束下,以最大化系统有效吞吐量为目标的双向链路跨层最优化算法。仿真结果表明,提出的马尔可夫链模型能精确预测系统的性能,与现有的单帧反馈和多帧固定周期反馈相比,提出反馈机制可达到更大的系统有效吞吐量。展开更多
在异构卫星网络动态组网时,为了解决星上软件通信适配器对物理层调制模式识别率低的问题,提出了一种适合低信噪比和贫先验知识的自动调制模式识别算法.该算法以高斯白噪声信道作为信道模型,选取信号高阶累积量和经典统计量作为特征参数...在异构卫星网络动态组网时,为了解决星上软件通信适配器对物理层调制模式识别率低的问题,提出了一种适合低信噪比和贫先验知识的自动调制模式识别算法.该算法以高斯白噪声信道作为信道模型,选取信号高阶累积量和经典统计量作为特征参数,采用引力搜索算法对径向基神经网络基函数中心进行优化,并在引力搜索算法中引入粒子群的信息熵来调节算法执行过程中探索与开采的关系,进一步提高了算法的分类和泛化能力.然后,利用仿真试验测评了该算法对6种卫星常用调相调制信号的识别效果.仿真试验结果表明,没有先验知识的情况下,该算法在调制信号信噪比大于4 d B时就可以达到100%的识别率,从而证明了该算法在低信噪比和贫先验知识条件下的有效性,说明算法满足星上软件通信适配器对物理层调制模式的识别要求.展开更多
自动调制方式识别技术在通信领域有着不可或缺的作用,针对传统的卷积神经网络在信号分类问题中特征提取能力不足的问题,本文研究了一种利用多维度特征的端到端双流膨胀卷积神经网络来对调制信号进行分类的方法。该方法不仅利用原始采样...自动调制方式识别技术在通信领域有着不可或缺的作用,针对传统的卷积神经网络在信号分类问题中特征提取能力不足的问题,本文研究了一种利用多维度特征的端到端双流膨胀卷积神经网络来对调制信号进行分类的方法。该方法不仅利用原始采样信号,还利用输入信号的瞬时幅度和相位信息;原始IQ(In-phase and Quadrature,IQ)数据输入进神经网络后,网络首先通过内置的数据预处理模块对输入的IQ信号进行预处理,提取原始信号的幅度和相位信息,再将原始IQ信号和幅度相位两种特征信息分别通过两个并行的卷积神经网络结构分别进行特征提取;本文所设计的双流卷积神经网络模型中的膨胀残差网络分支利用卷积核的膨胀卷积特性,将膨胀卷积与残差网络结构相结合,在网络参数不变的情况下使得卷积核具有更大的感受野,同时也能够更好地结合上下文信息,另一个网络分支是将卷积神经网络与长短期记忆神经网络相串联,然后将两个并行卷积神经网络的输出特征向量进行矩阵相乘达到两种特征信息融合的目的。整个识别过程是基于端到端的,数据预处理模块内嵌到神经网络内部,由神经网络完成对数据的预处理,只需将原始的IQ数据直接送入神经网络即可;仿真实验结果显示相比较于单分支结构的卷积神经网络模型或者循环神经网络模型,本文所提出的基于残差膨胀卷积的双流网络结构在数据集RML2016.10a上识别准确率有了极大地提升,识别准确率最高能够达到85%,同时对于单分支结构无法识别的16QAM和64QAM两种信号,本文模型也具有一定的分类能力。展开更多
文摘An automatic method for classifying frequency shift keying(FSK),minimum shift keying(MSK),phase shift keying(PSK),quadrature amplitude modulation(QAM),and orthogonal frequency division multiplexing(OFDM)is proposed by simultaneously using normality test,spectral analysis,and geometrical characteristics of in-phase-quadrature(I-Q)constellation diagram.Since the extracted features are unique for each modulation,they can be considered as a fingerprint of each modulation.We show that the proposed algorithm outperforms the previously published methods in terms of signal-to-noise ratio(SNR)and success rate.For example,the success rate of the proposed method for 64-QAM modulation at SNR=11 dB is 99%.Another advantage of the proposed method is its wide SNR range;such that the probability of classification for 16-QAM at SNR=3 dB is almost 1.The proposed method also provides a database for geometrical features of I-Q constellation diagram.By comparing and correlating the data of the provided database with the estimated I-Q diagram of the received signal,the processing gain of 4 dB is obtained.Whatever can be mentioned about the preference of the proposed algorithm are low complexity,low SNR,wide range of modulation set,and enhanced recognition at higher-order modulations.
文摘Automatic modulation classification is the process of identification of the modulation type of a signal in a general environment. This paper proposes a new method to evaluate the tracking performance of large margin classifier against signal-tonoise ratio （SNR）, and classifies all forms of primary user＇s signals in a cognitive radio environment. For achieving this objective, two structures of a large margin are developed in additive white Gaussian noise （AWGN） channels with priori unknown SNR. A combination of higher order statistics and instantaneous characteristics is selected as effective features. Simulation results show that the classification rates of the proposed structures are well robust against environmental SNR changes.
文摘针对联合自适应调制编码(adaptive modulation and coding,AMC),自动重传请求(automatic repeatrequest,ARQ)与包分割传输3种机制的通信系统,提出了一种ARQ多帧动态周期反馈机制,并建立了分析此系统的马尔可夫链模型,得到了包平均时延、平均反馈次数、平均掉包率和系统吞吐量等多种性能指标。在此基础上提出了在服务质量(quality of service,QoS)条件约束下,以最大化系统有效吞吐量为目标的双向链路跨层最优化算法。仿真结果表明,提出的马尔可夫链模型能精确预测系统的性能,与现有的单帧反馈和多帧固定周期反馈相比,提出反馈机制可达到更大的系统有效吞吐量。
文摘在异构卫星网络动态组网时,为了解决星上软件通信适配器对物理层调制模式识别率低的问题,提出了一种适合低信噪比和贫先验知识的自动调制模式识别算法.该算法以高斯白噪声信道作为信道模型,选取信号高阶累积量和经典统计量作为特征参数,采用引力搜索算法对径向基神经网络基函数中心进行优化,并在引力搜索算法中引入粒子群的信息熵来调节算法执行过程中探索与开采的关系,进一步提高了算法的分类和泛化能力.然后,利用仿真试验测评了该算法对6种卫星常用调相调制信号的识别效果.仿真试验结果表明,没有先验知识的情况下,该算法在调制信号信噪比大于4 d B时就可以达到100%的识别率,从而证明了该算法在低信噪比和贫先验知识条件下的有效性,说明算法满足星上软件通信适配器对物理层调制模式的识别要求.
文摘自动调制方式识别技术在通信领域有着不可或缺的作用,针对传统的卷积神经网络在信号分类问题中特征提取能力不足的问题,本文研究了一种利用多维度特征的端到端双流膨胀卷积神经网络来对调制信号进行分类的方法。该方法不仅利用原始采样信号,还利用输入信号的瞬时幅度和相位信息;原始IQ(In-phase and Quadrature,IQ)数据输入进神经网络后,网络首先通过内置的数据预处理模块对输入的IQ信号进行预处理,提取原始信号的幅度和相位信息,再将原始IQ信号和幅度相位两种特征信息分别通过两个并行的卷积神经网络结构分别进行特征提取;本文所设计的双流卷积神经网络模型中的膨胀残差网络分支利用卷积核的膨胀卷积特性,将膨胀卷积与残差网络结构相结合,在网络参数不变的情况下使得卷积核具有更大的感受野,同时也能够更好地结合上下文信息,另一个网络分支是将卷积神经网络与长短期记忆神经网络相串联,然后将两个并行卷积神经网络的输出特征向量进行矩阵相乘达到两种特征信息融合的目的。整个识别过程是基于端到端的,数据预处理模块内嵌到神经网络内部,由神经网络完成对数据的预处理,只需将原始的IQ数据直接送入神经网络即可;仿真实验结果显示相比较于单分支结构的卷积神经网络模型或者循环神经网络模型,本文所提出的基于残差膨胀卷积的双流网络结构在数据集RML2016.10a上识别准确率有了极大地提升,识别准确率最高能够达到85%,同时对于单分支结构无法识别的16QAM和64QAM两种信号,本文模型也具有一定的分类能力。
