Multi-h CPM同步及序列检测技术研究

发布时间：2018-10-05 17:13

【摘要】：多调制指数连续相位调制(Multi-h Continuous Phase Modulation, Multi-h CPM)由于高效的带宽效率和功率效率,将成为新一代无线通信中一项核心技术,在未来遥测领域也有巨大的潜在优势。但是同步困难、序列检测复杂度高,一直是限制Multi-h CPM广泛应用的短板。本文围绕遥测中Multi-h CPM同步及序列检测技术开展了深入的研究,取得了如下主要研究成果：首先,提出了一种适用于Multi-A CPM的非数据辅助的(Non Data-Aided,NDA)载波频率同步算法。从最大似然估计理论入手,引入调制指数同步误差概念,利用其离散且等概分布的性质,通过对边缘联合似然函数化简得到载波频偏误差估计。该算法能适用于全响应和部分响应Multi-h CPM,而且在中低信噪比下具有良好的估计性能。在此基础上,引入量化函数将算法中的滤波器冲激响应量化为矩形,降低了实现复杂度且性能损失较小。为了界定算法性能,推导了Multi-h CPM的载波频偏估计MCRB限；研究了一种适用于Multi-hCPM的基于PAM分解的面向判决的载波相位同步算法,并对载波相位估计的MCRB限进行了理论推导。利用波形能量占优的PAM波形,进行载波相位误差估计,使算法能以较小的性能损失获得复杂度降低。其次,提出了一种适用于Multi-h CPM的NDA定时同步算法。通过对边缘联合似然函数化简得到定时误差估计。该算法没有假锁现象,而且对多进制L3信号,定时恢复性能逼近理想同步。多进制L=3信号的码间串扰严重,针对该问题,提出了一种粗定时同步辅助细定时同步的解决方案,通过组合两种定时同步算法的各自优势,在以一定的复杂度代价实现了精确的定时同步；研究了一种NDA调制指数同步算法,该算法不需要矢量参数估计,简化了实现结构。同时,为了改善估计性能,研究了一种基于后处理细估计的两级级联调制指数同步算法,通过设置合理的后处理门限值,对粗估计值进行估计保护,改善了粗估计算法似然函数对噪声敏感而造成的性能恶化。然后,提出了一种适用于Multi-h CPM的差分非相干序列检测算法。该算法利用符号差分和参考相位信号,实现载波频偏的消除与校正,通过多符号差分增加欧式距离,改善误比特率性能。在此基础上,引入逐幸存处理技术,利用判决反馈的思想,研究了一种减少网格状态的差分非相干序列检测算法,该算法能以较小的信噪比损失,获得显著的复杂度降低。另外,研究了一种调制指数自同步的方法,利用序列检测自身的分支度量信息获得调制指数序列的估计,从而简化了接收机结构。最后,设计了一套Multi-h CPM中频收发信机系统,在该系统上对提出的部分算法进行了验证,该系统为Multi-h CPM在遥测领域实用化、工程化提供了初步的解决方案。
[Abstract]:Multi-Modulation exponential continuous Phase Modulation (Multi-h Continuous Phase Modulation, Multi-h CPM), due to its high bandwidth efficiency and power efficiency, will become a core technology in a new generation of wireless communication, and it will also have great potential advantages in the future telemetry field. However, the difficulty of synchronization and the high complexity of sequence detection have been the limitations of Multi-h CPM applications. In this paper, the Multi-h CPM synchronization and sequence detection techniques in telemetry are deeply studied, and the main research results are as follows: firstly, a non-data-assisted (Non Data-Aided,NDA) carrier frequency synchronization algorithm for Multi-A CPM is proposed. Based on the theory of maximum likelihood estimation, the concept of modulation exponent synchronization error is introduced, and the carrier frequency offset error estimation is obtained by simplifying the edge joint likelihood function by using its discrete and equal distribution properties. The proposed algorithm can be applied to both full and partial response Multi-h CPM, and has good estimation performance in low and low signal-to-noise ratio (SNR). On this basis, quantization function is introduced to quantize the impulse response of the filter into a rectangle, which reduces the complexity of the implementation and reduces the performance loss. In order to define the performance of the algorithm, the MCRB limit of carrier frequency offset estimation for Multi-h CPM is derived, and a Decision-oriented carrier phase synchronization algorithm based on PAM decomposition for Multi-hCPM is studied, and the MCRB limit of carrier phase estimation is derived theoretically. The carrier phase error is estimated by using the PAM waveform with the dominant waveform energy, so that the complexity of the algorithm can be reduced with less performance loss. Secondly, a NDA timing synchronization algorithm for Multi-h CPM is proposed. The timing error estimation is obtained by simplifying the edge joint likelihood function. The algorithm has no false lock phenomenon, and the timing recovery performance is close to ideal synchronization for multiary L3 signals. In view of the serious inter-symbol crosstalk of the multi-ary LN3 signal, a solution of coarse timing synchronization assisted fine timing synchronization is proposed, which combines the respective advantages of the two timing synchronization algorithms. Precise timing synchronization is realized at a certain cost of complexity, and a NDA modulation exponential synchronization algorithm is studied, which does not require vector parameter estimation and simplifies the implementation structure. At the same time, in order to improve the estimation performance, a two-stage concatenated modulation exponential synchronization algorithm based on post-processing fine estimation is studied. By setting reasonable post-processing threshold, the coarse estimation is protected. The performance deterioration of likelihood function caused by noise sensitivity in rough estimation method is improved. Then, a differential incoherent sequence detection algorithm for Multi-h CPM is proposed. The algorithm uses symbol difference and reference phase signal to eliminate and correct carrier frequency offset and increase Euclidean distance through multi-symbol difference to improve bit error rate performance. On the basis of this, a differential incoherent sequence detection algorithm with reduced grid state is studied by using the idea of decision feedback, which can reduce the SNR loss and reduce the complexity significantly. In addition, a self-synchronization method of modulation exponent is studied, and the estimation of modulation exponent sequence is obtained by using the branch metric information of the sequence detection, which simplifies the receiver structure. Finally, a set of Multi-h CPM intermediate frequency transceiver system is designed, and some of the proposed algorithms are verified on the system. The system provides a preliminary solution for the practicality and engineering of Multi-h CPM in the field of telemetry.
【学位授予单位】：中国工程物理研究院
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TN919.34

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