连续相位调制同步及解调技术研究
发布时间：2018-12-10 23:19
【摘要】：连续相位调制(Continuous Phase Modulation,CPM)是一种包络恒定相位连续的频率调制信号。由于这种调制频谱利用率高,抗干扰性强,因此是一种解决频带资源紧张的有效方式。但CPM信号调制参数众多,使得调制的复杂度增加,也制约了CPM信号的发展。所以研究该调制方式下的同步、解调算法有着十分重要的意义。本课题首先从信号数学模型入手,分别从时域和频域详细分析CPM信号的优势以及各个调制参数对信号性能的影响,为后面同步与解调技术奠定了理论基础。其次本文研究了CPM信号定时同步算法、载波频率同步算法和载波相位同步算法。定时同步技术深入研究了基于最大似然理论的前馈NDA定时同步算法和采用牛顿迭代法的递归型NDA算法,并给出了算法性能的详细分析。之后本文在深入分析了基于延迟相乘的频偏估计算法的基础上,给出了一种改进算法。与原算法相比,不仅扩大了算法的适用范围,而且将算法精度提高了4dB左右。相位同步算法重点研究了2P-Power算法,同样通过理论仿真给出了算法性能的详细分析。最后本文对CPM信号的解调算法进行了深入研究,并对各个算法的误码特性进行了详细的分析与比较。其中非相干解调算法着重研究了相位差分解调算法与限幅器-鉴频器解调算法。这两种算法结构简单易于实现,但误码特性劣于相干解调,比较适合高信噪比的信道。相干解调算法则以最大似然理论为核心深入研究了最大似然接收机、Viterbi解调以及基于PAM分解的解调算法。其中最大似然接收机为最佳解调,但是复杂度极高。基于此的Viterbi算法通过保留幸存路径降低了最大似然算法的计算量,但在小调制指数下,计算量仍呈指数增长。针对Viterbi算法解调复杂度仍然较高的问题本文给出了一种Viterbi的改进算法,将网格搜索运算量降低为原来的1/2,同时性能仅牺牲了0.9dB左右。基于PAM分解的解调算法主要研究了基于PAM分解的最优与次优接收机并与最大似然接收机的性能进行了比较。基于PAM分解的解调算法极大的降低了接收机的复杂度,而且性能几乎没有损失。
[Abstract]:Continuous phase modulation (Continuous Phase Modulation,CPM) is a frequency modulated signal with constant phase envelope. Because of its high spectral efficiency and strong anti-interference, this modulation is an effective way to solve the shortage of frequency band resources. However, the complexity of CPM signal modulation is increased because of its numerous modulation parameters, which restricts the development of CPM signal. Therefore, it is very important to study the synchronization and demodulation algorithm in this modulation mode. This paper starts with the mathematical model of the signal and analyzes the advantages of the CPM signal in time domain and frequency domain respectively and the influence of each modulation parameter on the signal performance, which lays a theoretical foundation for the subsequent synchronization and demodulation techniques. Secondly, this paper studies CPM signal timing synchronization algorithm, carrier frequency synchronization algorithm and carrier phase synchronization algorithm. In this paper, the feedforward NDA timing synchronization algorithm based on maximum likelihood theory and the recursive NDA algorithm based on Newton iteration are studied in detail, and the performance of the algorithm is analyzed in detail. Then, based on the analysis of the frequency offset estimation algorithm based on delay multiplication, an improved algorithm is proposed. Compared with the original algorithm, it not only expands the application range of the algorithm, but also improves the accuracy of the algorithm about 4dB. The phase synchronization algorithm focuses on the 2P-Power algorithm, and the performance of the algorithm is also analyzed by theoretical simulation. Finally, the demodulation algorithm of CPM signal is deeply studied, and the error characteristics of each algorithm are analyzed and compared in detail. The non-coherent demodulation algorithm focuses on the phase difference decomposition modulation algorithm and the limiter-frequency discriminator demodulation algorithm. These two algorithms are simple and easy to implement, but the error performance is inferior to coherent demodulation, which is more suitable for the channel with high signal-to-noise ratio (SNR). Based on the maximum likelihood theory, the coherent demodulation algorithm has studied the maximum likelihood receiver, Viterbi demodulation and demodulation algorithm based on PAM decomposition. The maximum likelihood receiver is the best demodulation, but the complexity is very high. The Viterbi algorithm based on this algorithm reduces the computational complexity of the maximum likelihood algorithm by preserving the survival path, but the computational complexity increases exponentially in the case of small modulation exponents. In order to solve the problem that the demodulation complexity of Viterbi algorithm is still high, this paper presents an improved Viterbi algorithm, which reduces the grid search operation to 1 / 2 of the original, and only sacrifices the performance of 0.9dB at the same time. The demodulation algorithm based on PAM decomposition mainly studies the optimal and suboptimal receiver based on PAM decomposition and compares the performance of the receiver with the maximum likelihood receiver. The demodulation algorithm based on PAM decomposition greatly reduces the complexity of the receiver and has little loss of performance.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN911.3
本文编号：2371396
[Abstract]:Continuous phase modulation (Continuous Phase Modulation,CPM) is a frequency modulated signal with constant phase envelope. Because of its high spectral efficiency and strong anti-interference, this modulation is an effective way to solve the shortage of frequency band resources. However, the complexity of CPM signal modulation is increased because of its numerous modulation parameters, which restricts the development of CPM signal. Therefore, it is very important to study the synchronization and demodulation algorithm in this modulation mode. This paper starts with the mathematical model of the signal and analyzes the advantages of the CPM signal in time domain and frequency domain respectively and the influence of each modulation parameter on the signal performance, which lays a theoretical foundation for the subsequent synchronization and demodulation techniques. Secondly, this paper studies CPM signal timing synchronization algorithm, carrier frequency synchronization algorithm and carrier phase synchronization algorithm. In this paper, the feedforward NDA timing synchronization algorithm based on maximum likelihood theory and the recursive NDA algorithm based on Newton iteration are studied in detail, and the performance of the algorithm is analyzed in detail. Then, based on the analysis of the frequency offset estimation algorithm based on delay multiplication, an improved algorithm is proposed. Compared with the original algorithm, it not only expands the application range of the algorithm, but also improves the accuracy of the algorithm about 4dB. The phase synchronization algorithm focuses on the 2P-Power algorithm, and the performance of the algorithm is also analyzed by theoretical simulation. Finally, the demodulation algorithm of CPM signal is deeply studied, and the error characteristics of each algorithm are analyzed and compared in detail. The non-coherent demodulation algorithm focuses on the phase difference decomposition modulation algorithm and the limiter-frequency discriminator demodulation algorithm. These two algorithms are simple and easy to implement, but the error performance is inferior to coherent demodulation, which is more suitable for the channel with high signal-to-noise ratio (SNR). Based on the maximum likelihood theory, the coherent demodulation algorithm has studied the maximum likelihood receiver, Viterbi demodulation and demodulation algorithm based on PAM decomposition. The maximum likelihood receiver is the best demodulation, but the complexity is very high. The Viterbi algorithm based on this algorithm reduces the computational complexity of the maximum likelihood algorithm by preserving the survival path, but the computational complexity increases exponentially in the case of small modulation exponents. In order to solve the problem that the demodulation complexity of Viterbi algorithm is still high, this paper presents an improved Viterbi algorithm, which reduces the grid search operation to 1 / 2 of the original, and only sacrifices the performance of 0.9dB at the same time. The demodulation algorithm based on PAM decomposition mainly studies the optimal and suboptimal receiver based on PAM decomposition and compares the performance of the receiver with the maximum likelihood receiver. The demodulation algorithm based on PAM decomposition greatly reduces the complexity of the receiver and has little loss of performance.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN911.3
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