正交频分复用系统的非对称调制星座频域信道盲估计方法

针对频域信道盲估计的相位模糊问题，提出了基于非对称调制星座的频域信道盲估计方法．根据正交频分复用系统子信道的衰落相位等于该子信道调制星座旋转的角度这一特性，通过独立地估计各子信道接收信号的平均功率及调制星座旋转的角度来估计信道的频率响应．相对于预编码频域信道盲估计方法，该方法的信道估计精度高且没有误差底限，具有实现简单、易并行处理等特点．系统的对比仿真实验表明，该方法与预编码频域信道盲估计方法相比，在信噪比超过18dB时可使信道估计误差随信噪比增加线性递减．

Blind Channel Estimation Based on Dissymmetrical Modulation Constellation for Orthogonal Frequency Division Multiplexing Systems

Aiming at the phase ambiguity of the blind channel estimation in frequency domain, a blind channel estimation method in frequency domain based on dissymmetrical modulation constellation was proposed. Sub-channel fading phase in orthogonal frequency division multiplexing systems is equal to the angle that the modulation constellation of the sub-carrier channel was rota- ted. So the scheme could estimate each sub-channel coefficients independently by estimating received signal average power and rotating angles of constellations for each sub-channel. Further- more, compared to pre-coded blind channel estimation scheme in frequency domain, the scheme could eliminate channel estimation error floor and had merits of simple implementation and parallel disposal. Simulation results showed that, compared with the pre-coded blind channel estimation method in frequency domain, the scheme can further linearly reduce channel estimation error for increasing signal-noise-ratio over 18 dB.