| 摘要: |
| 符号定时同步是正交频分复用（Orthogonal Frequency Division Multiplexing,OFDM）系统中最为关键的同步之一。针对现有的基于数据辅助类的同步算法中帧头存在持续时间长、抗噪声性能差和对载波频偏敏感等问题，提出了一种可变长度的同步帧结构，采用滑动差分相关算法完成符号定时同步。仿真结果表明，提出的同步帧结构持续时间短于一个OFDM符号周期，并且训练序列长度可以通过估算信噪比大小而灵活控制。同时，所提算法在归一化载波频偏为12（远远超过晶振的误差范围 ±10-5）的情况下正常工作；在高斯白噪声和多径衰落信道中都有较好的性能，且其流水线结构易于硬件实现。 |
| 关键词: 正交频分复用 符号定时同步 可变同步帧 训练序列 差分相关 |
| DOI： |
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| 基金项目:国家自然科学基金资助项目(11672293) |
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| An OFDM Timing Synchronization Algorithm Using Variable Synchronization Frames |
| ZHANG Yufeng,CHEN Qingyue,LI Jionghui,WANG Zhugang,XIONG Weiming |
| (1.Key Laboratory of Electronics and Information Technology for Space Systems,National Space Sciences Center, Chinese Academy of Sciences,Beijing 101400,China;2.University of Chinese Academy of Sciences,Beijing 100049,China;3.Beijing Institute of Spacecraft System Engineering,Beijing 100094,China) |
| Abstract: |
| Timing synchronization is one of the most critical synchronizations in orthogonal frequency division multiplexing(OFDM) systems.In most data-aided timing synchronization algorithms,the training sequence features a long duration.Besides,these algorithms generally have a poor synchronization performance in noisy environment,and are sensitive to carrier frequency offsets(CFO).To deal with those problems,a new sliding differential correlation algorithm using a variable-length training sequence is proposed.Simulation results show that the duration of the proposed training sequence is less than an OFDM symbol,and can be modified after evaluating the signal-to-noise ratio.Moreover,the proposed algorithm can still work when the normalized CFO is 12,which is far beyond the frequency tolerance of the crystal oscillator(±10-5).Besides,the proposed algorithm has a good synchronization performance in the additive Gaussian noise channel and multi-path fading channel,and its pipelined structure makes it easily be implemented in hardware. |
| Key words: OFDM timing synchronization variable synchronization frame training sequence differential correlation |
