OFDM中基于有限字符集特性的半盲信道估计

Semi-blind Channel Estimation Based on Finite Alphabet in OFDM System

由于基于有限字符集特性的盲估计方法最短距离(MD)计算量大、收敛速度慢、消耗时间长,而修正后的MMD方法,计算量下降的同时精度也降低了很多,提出了一种基于有限字符集特性的半盲估计方法。该方法通过导频结合有限字符集特性,利用最小距离准则快速辨识出所有子载波上频率响应的相位。仿真结果表明,该算法的信道估计性能优于修改后的最小距离(MMD)算法,与MD相等,而计算复杂度大大低于MD和MMD算法。

In OFDM system, because Minimum Distance （MD） algorithm which is blind channel estimation based on the finite alphabet property of information symbols has deficiencies of large qualities of calculation, slow convergence rate and long computing time. And the Modified Minimum Distance （MMD） algorithm has lower computation complexity and lower channel estimation accuracy. In this paper, a semi-blind channel estimation based on finite alphabet is proposed. The algorithm, which employs characteristics of finite alphabet and pilot, resolves phase ambiguities of each subcarrier quickly. Simulation results show that the channel estimation accuracy of the semi-blind algorithm is better than the MMD algorithm, and it have lower computation complexity than MMD and MD.