基于训练序列与数据叠加的ACO-OFDM无线光通信系统时间同步方法

摘要

A new synchronization method for asymmetrically clipped optical orthogonal frequency division multiplexing (ACO-QFDM)-based optical wireless communications systems with the superimposed m sequence is proposed. The pseudo-noise (PN) sequence modulated by ACO-OFDM as training sequence is sent with a data symbol in the same symbol cycle. Receiver by using local sequence and the received signal correlation operation,accumulates the energy of the superimposed training sequence in order to achieve timing synchronization. Via simulation, both in LOS channel and diffuse channel, the proposed method has better synchronization accuracy, lower timing offset estimator variance, and the flexibility of time and power allocation, improves the bandwidth efficiency.%提出了一种适用于ACO-OFDM无线光通信系统的基于时域叠加训练序列的时间同步方法.该方法将经过ACO-OFDM调制后的伪随机序列作为训练序列,并将其在一个符号周期内与数据同时发送.接收端利用本地序列与接收信号进行相关运算,对所叠加训练序列的能量进行积累,从而实现时间同步.仿真表明,在多种信道模型下,该方法能够有效改善同步准确率和定时偏移方差,同时极大地提高了带宽效率,使得时间功率分配具有较强的灵活性.