DVB-T2系统中同步算法研究

发布时间：2018-12-14 23:22

【摘要】：欧洲电信标准委员会(ETSI)于1997年颁布了第一个采用OFDM传输技术的地面广播标准DVB-T,为了进一步改善频谱利用效率,ETSI又提出了第二代标准DVB-T2。DVB-T2相比DVB-T,帧结构有了很大变化,尤其是P1符号的引入使得系统具有了快速同步和对抗大载波频偏的能力。传统的OFDM同步算法不适用于P1符号的同步,因此针对P1符号结构特点需提出一些特定的同步算法。论文主要在充分利用DVB-T2帧结构特点以及分析了系统同步要求的基础上围绕系统的同步算法展开了研究,主要工作包括以下方面:1.首先介绍了DVB-T2系统的物理层模块、系统帧结构、同步资源等,重点分析了在DVB-T2系统中同步偏差造成的影响。说明了DVB-T2同步算法研究的必要性以及系统的同步要求。2.主要研究了基于P1符号的DVB-T2系统同步算法。在分析了P1符号结构特点、子载波分布特点和数据生成过程的基础上研究了检测算法、定时同步算法、载波频率同步算法和解码算法。在FFT之前进行了检测,粗定时同步和小数倍CFO估计算法的研究,粗定时同步性能不能满足解码要求。在FFT之后又进行了整数倍CFO估计算法和精定时同步算法研究。整数倍CFO估计精度高,范围广。精定时同步将定时准确率大幅提升,为解码做好准备。在完成同步的基础上进行了P1解码,同步后的解码性能和理想同步下的解码性能基本一致。3.研究基于DVB-T2导频序列的频率同步算法。帧头符号P1不能进行采样频偏估计,因此研究了基于系统连续导频的SFO估计算法。发射机和接收机的本地振荡器频率不匹配时,会产生频偏,随着时间的推移就会形成系统无法容忍的频偏,因此必须对频偏进行同步跟踪。研究了基于连续OFDM符号中连续导频相位增量的频偏跟踪算法。对CFO和SFO的跟踪,在系统工作的最低信噪比下可以快速收敛,稳定后估计偏差在系统容忍范围内。4.对论文中的多种DVB-T2系统同步算法进行了深入的仿真研究。仿真表明本文设计的同步方案能够满足DVB-T2系统解调解码的要求。
[Abstract]:The European Telecommunication Standards Committee (ETSI) issued the first terrestrial broadcasting standard DVB-T, using OFDM transmission technology in 1997. In order to further improve spectrum efficiency, ETSI proposed the second generation standard DVB-T2.DVB-T2 compared with DVB-T,. The frame structure has changed greatly, especially the introduction of P1 symbol makes the system have the ability of fast synchronization and anti-large carrier frequency offset. The traditional OFDM synchronization algorithm is not suitable for P1 symbol synchronization. On the basis of making full use of the DVB-T2 frame structure and analyzing the system synchronization requirements, this paper focuses on the synchronization algorithm of the system. The main work includes the following aspects: 1. Firstly, the physical layer module, system frame structure and synchronization resource of DVB-T2 system are introduced, and the influence of synchronization error in DVB-T2 system is analyzed. The necessity of the research of DVB-T2 synchronization algorithm and the synchronization requirements of the system are explained. 2. This paper mainly studies the synchronization algorithm of DVB-T2 system based on P1 symbol. Based on the analysis of P1 symbol structure, subcarrier distribution and data generation process, the detection algorithm, timing synchronization algorithm, carrier frequency synchronization algorithm and decoding algorithm are studied. Before FFT detection, coarse timing synchronization and fractional CFO estimation algorithms are studied. The coarse timing synchronization can not meet the decoding requirements. After FFT, the integer multiple CFO estimation algorithm and precision timing synchronization algorithm are studied. The CFO estimation accuracy of integer times is high and the range is wide. Precision timing synchronization will greatly improve the timing accuracy, ready for decoding. On the basis of complete synchronization, P1 decoding is carried out. The decoding performance after synchronization is basically the same as that under ideal synchronization. 3. 3. Frequency synchronization algorithm based on DVB-T2 pilot sequence is studied. The frame header symbol P1 can not estimate the sampling frequency offset, so the SFO estimation algorithm based on the system continuous pilot is studied. When the frequency of the transmitter and receiver is mismatched, the frequency offset will be produced, and the frequency offset will be intolerable with time, so it is necessary to track the frequency offset synchronously. Frequency offset tracking algorithm based on continuous pilot phase increment in continuous OFDM symbol is studied. The tracking of CFO and SFO can converge rapidly at the lowest SNR of the system, and the estimation deviation after stabilization is within the tolerance range of the system. In this paper, several synchronization algorithms for DVB-T2 systems are simulated. Simulation results show that the proposed synchronization scheme can meet the requirements of demodulation and decoding in DVB-T2 system.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN919.34

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