改进型算法在LTE系统主同步中的应用.docVIP

 改进型算法在 LTE 系统主同步中的应用 ** 5 10 摘要：本文介绍了 LTE 系统帧同步的完整过程，包括主同步和辅同步。主同步采用粗同步 和细同步结合的方法。在粗同步过程中，可以适当降低接收序列的采样频率来减小相关运算 滑动窗的大小，从而降低运算的复杂度。细同步则是在粗同步结果的基础上进行原始采样率 的相关运算。另外在性能方面，主同步过程采用了 Massey 提出的最大似然判决算法，考虑 了主同步序列周围数据的带来的影响，在传统相关算法的基础上引入了加权修正项。实验仿 真结果表明，在高斯白噪声信道中，采用 Massey 算法的主同步过程比采用传统相关算法的 主同步过程具有更好的捕获率，最大增益可达到 3~4dB。 关键词：信号与信息处理；帧同步；Massey 算法；捕获率 中图分类号：TN929.53 15 Improved algorithm in the LTE main synchronization system MA Junlong, BIE Zhisong (School of Information and Communication Engineering,Beijing University of Posts and 20 25 30 35 40 Telecommunications, Beijing 100876) Abstract: This paper describes a complete LTE system frame synchronization process, including the main Synchronization and Secondary Synchronization. The main synchronization using coarse synchronization and fine synchronization method. In the coarse synchronization process, it is possible to appropriately reduce the sampling frequency of the received sequence to reduce the size of the correlation operation of a sliding window, thereby reducing the complexity of the operation. Fine synchronization is the correlation calculation of the original sampling rate based on the coarse synchronization results. Moreover, in terms of performance, the main synchronization process using the maximum likelihood decision made by Massey algorithm, consider the impact of primary synchronization sequence surrounding data, introducing a weighted correction term based on the traditional correlation algorithm. Simulation results indicate that, in the white Gaussian noise channel, the main synchronization process using the Massey algorithm has a better capture rate of the main synchronization process than traditional algorithm, wih the maximum gain up to 3 ~ 4dB. Key words: Signal and Information Processing; frame synchronization; Massey algorithm; capture rate 0 引言 同步问题是所有通信系统中的关键问题，对于 3GPP 长期演进 LTE（Long Term Evolution）[1]这样的多载波系统，同步问题更加关键，我们应该尽量减小定时偏差，所以帧 同步成为了接收机的首要任务。广泛用作实现帧同步的措施是在一个连续的数据流中周期性 地插入一个同步序列 FF