OFDM系统同步算法研究及其VLSI实现

针对正交频分复用（OFOM, Orthogonal Frequency Division Multiplex）无线传输系统，提出并设计了一种适用于802．11a标准前导序列的同步算法。首先基于接收基带数据能量判断信道空闲状态，再计算数据归一化自相关值检测帧起始位置，最后利用基带数据与参考训练序列的互相关运算检测OFDM符号的起始位置，实现同步功能。算法的硬件实现采用移位加和流水线技术来提高系统的性能与效率。实践表明，所提算法能有效地实现同步并且硬件实现复杂度低，适合于超大规模集成电路（VLSI，Very LargeScale Integration）的实现。

Synchronization Algorithm and VLSI Implementation for OFDM Systems

Aiming at OFDM （orthogonal frequency division multiplex） wireless communication systems, a synchronization algorithm based on 802.11a preamble structure is proposed. The algorithm, based on calculation of the input baseband data energy, first determines the busy state of the channel, then by using the autocorrelation analysis, detects the start point of a frame, and finally by computing the cross-correlation between the input data and the reference training sequence locates the start point of the OFDM symbols and realizes the synchronization. For hardware implementation of the proposed algorithm, the shift-and-add operations and the pipeline technology are adopted, thus to enhance the performance and efficiency of the system. Experiment indicates that the proposed algorithm could provid efficient frame detection and OFDM symbol detection with low complexity of hardware architecture, and thus is proper for VLSI （Very Large Scale Integration） implementation.