基于有限字符特性的空时OFDM系统决策反馈信道估计
doi: 10.3724/SP.J.1146.2006.01116
Finite-Alphabet and Decision-Feedback Based Channel Estimation for Space-Time Coded OFDM Systems
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摘要: 该文提出了一种适用于空时编码正交频分复用(STC-OFDM)系统盲信道估计算法，利用信号的字符有限特性获取粗信道估计，进而利用映射星座先验知识，采用决策反馈方法得到信道精估计。充分利用了信号的先验知识，以较高的计算复杂度为代价，提高了盲信道估计精度，因此能较好地适用于具有慢时变频率选择性较强的信道，且子载波数不大的系统。与基于子空间盲信道估计算法比较验证了该算法性能。Abstract: A novel blind channel estimation scheme is presented for Space-Time Coded OFDM (STC-OFDM) systems. This scheme is composed of rude channel estimation by exploiting the finite-alphabet property of information signals and fine channel estimation by using decision-directed method, which employs the priori knowledge of the transmitted signals other than the finite-alphabet property of mapping constellation. At the cost of a little more computational complexity, it achieves better performance than the competitive one, hence it is suitable for STC-OFDM systems with a small number of subcarriers in slowly time-varying and not severely frequency selective channels. The scheme is tested with simulations and also compared with the subspace-based channel estimation.
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