突发OFDM信号定时同步估计算法的改进和实现

Improved timing recovery for burst OFDM signal receive

突发OFDM信号的接收需要快速准确的定时同步。Schmidl和Cox提出的同步方法(SCA)得到的估计值方差比较大,准确度不高。这里以SCA得到的结果为基础,在FFT运算后进行路径延迟时间估计,根据得到的结果对前面的粗估计值进行修正,使得估计准确度提高。仿真结果和相应的DSP硬件电路实际测试证明该方法大大改善了定时同步的性能。

Fast and accurate timing recovery is important for OFDM receiver. The Schmidl and Cox algorithm （SCA） gives a low accurate result. We present an improved timing scheme based on SCA. At first, the OFDM receiver acquires coarse timing offset estimation through SCA. Secondly it uses path time delay estimation method to modify the coarse estimation value after the FFT. Then, accurate of estimation is improved. The simulation results and field experiment on the correspondent DSP hardware circuit in the actual wireless environment show that the improved algorithm performs better than the original one.