【摘要】：連續(xù)相位調制(Continuous Phase Modulation,CPM)是一種包絡恒定相位連續(xù)的頻率調制信號。由于這種調制頻譜利用率高,抗干擾性強,因此是一種解決頻帶資源緊張的有效方式。但CPM信號調制參數(shù)眾多,使得調制的復雜度增加,也制約了CPM信號的發(fā)展。所以研究該調制方式下的同步、解調算法有著十分重要的意義。本課題首先從信號數(shù)學模型入手,分別從時域和頻域詳細分析CPM信號的優(yōu)勢以及各個調制參數(shù)對信號性能的影響,為后面同步與解調技術奠定了理論基礎。其次本文研究了CPM信號定時同步算法、載波頻率同步算法和載波相位同步算法。定時同步技術深入研究了基于最大似然理論的前饋NDA定時同步算法和采用牛頓迭代法的遞歸型NDA算法,并給出了算法性能的詳細分析。之后本文在深入分析了基于延遲相乘的頻偏估計算法的基礎上,給出了一種改進算法。與原算法相比,不僅擴大了算法的適用范圍,而且將算法精度提高了4dB左右。相位同步算法重點研究了2P-Power算法,同樣通過理論仿真給出了算法性能的詳細分析。最后本文對CPM信號的解調算法進行了深入研究,并對各個算法的誤碼特性進行了詳細的分析與比較。其中非相干解調算法著重研究了相位差分解調算法與限幅器-鑒頻器解調算法。這兩種算法結構簡單易于實現(xiàn),但誤碼特性劣于相干解調,比較適合高信噪比的信道。相干解調算法則以最大似然理論為核心深入研究了最大似然接收機、Viterbi解調以及基于PAM分解的解調算法。其中最大似然接收機為最佳解調,但是復雜度極高�；诖说腣iterbi算法通過保留幸存路徑降低了最大似然算法的計算量,但在小調制指數(shù)下,計算量仍呈指數(shù)增長。針對Viterbi算法解調復雜度仍然較高的問題本文給出了一種Viterbi的改進算法,將網(wǎng)格搜索運算量降低為原來的1/2,同時性能僅犧牲了0.9dB左右。基于PAM分解的解調算法主要研究了基于PAM分解的最優(yōu)與次優(yōu)接收機并與最大似然接收機的性能進行了比較。基于PAM分解的解調算法極大的降低了接收機的復雜度,而且性能幾乎沒有損失。
[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.
【學位授予單位】：哈爾濱工業(yè)大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TN911.3

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本文編號：2371396