基于信道线性滤波估计的迭代解调及译码技术

Linear filter iterative differential DPSK demodulation and decoding

为了提高衰落信道下基于判决反馈的差分迭代译码 (Turbo DPSK)系统的性能 ,针对系统的特点 ,提出了一种基于信道增益线性滤波估计的解调 /译码算法。与传统的基于信道增益线性预测估计的 Turbo DPSK解调 /译码算法相比 ,新算法在根据判决反馈进行信道增益 hi 的估计时 ,不仅利用了时刻 i以前的波形值和判决反馈 ,而且还利用了 i时刻本身的波形值和判决反馈 ,因而能更有效地消除噪声干扰 ,获得更准确的信道估计 ,从而提高了系统的性能。仿真结果表明 ,该算法对系统性能确有明显的提高 ,在误码率为10 - 4时 ,性能增益大约为 0 .6 d B。

A novel decision aided linear filter algorithm for iterative demodulation and decoding of DPSK signals is proposed to improve system performance using the properties of decision aided Turbo DPSK over Rayleigh flat fading channels. Compared with conventional decision aided linear prediction algorithms for Turbo DPSK, the new linear filter based algorithm, which utilizes not only the decision feedback bits before step i but also the decision feedback bits at step i to estimate the channel coefficient h i , improves the channel estimation accuracy and the system performance. Simulation results show that a considerable improvement in the performance can be achieved by the new algorithm which gives a 0.6 dB SNR gain at P b=10 -4 .