一种新型的正交频分复用载波频偏相偏联合估计算法

A New Joint Estimation Algorithm of OFDM Carrier Frequency Offset and Phase Offset

正交频分复用 ( OFDM)对载波频率偏差很敏感 ,因此要求精确地估计载频偏差 .本文提出一种载波频偏、相偏联合估计新算法 ,结合相干判决反馈算法对频偏、相偏同时进行估计 .仿真结果表明 ,对于 1 2 8个子载波正交移相键控 ( QPSK)调制的 OFDM系统 ,在多径衰落信道中 ,信噪比为1 5 d B、频偏小于 0 .1 2、相偏小于 0 .0 5 π时 。

OFDM is sensitive to carrier frequency offset, so the frequency offset estimation must be accurate. A new joint estimation algorithm of OFDM frequency offset and phase offset was proposed. The new algorithm combines with a coherent demodulation decision feedback algorithm, estimates the frequency offset and phase offset simultaneously. An OFDM system with 128 sub carriers, QPSK modulation, a multi path fading channel and SNR=15dB was simulated. The result indicates that the frequency offset and phase offset can be estimated accurately, when the frequency offset is less than 12% and the phase offset is less than 0.05 π.The joint estimation algorithm can be used to keep the track of frequency offset and phase offset effectively for OFDM systems.