OFDM系统中一种改进的快衰落信道估计算法

在OFDM系统中,由于无线信道的随机性,在一个OFDM符号帧内,信道特性会发生明显的变化,OFDM符号会产生子载波间干扰,并且一个OFDM符号边缘的子载波受到的影响比较大,正交频分复用系统中导频符号由于采用了均匀分布的方案,造成信道估计算法的误码率较大。本论文提出了一种非均匀分布的导频分布方案,利用牛顿插值算法分别计算导频符号边缘和中央的间距,再进行信道估计算法。并且在仿真参数相同的条件下,在均匀分布和本论文提出的非均匀分布的方案的基础上,对信道估计算法进行了matlab仿真,结果表明:改进后的方案与原来方案相比,具有更好的估计性能,尤其在移动台高速移动时候更有优越性,表明了改进后的方案更适合第四代移动通信的高速要求。

Analysis of an improved fast-fading algorithm in OFDM system

In the OFDM system, the channel characteristic had changed because of the randomicity of wireless channel. At the same time, the intercarrier interference had existed among the OFDM signals. The brim of the carriers in the OFDM system had been influenced more deeply than the one in the center of the system. In the system, the bit error rate was higher as the pilot signals was arranged symmetrically. The asymmetric pilot arrangement was adopted instead of the former one, the values of the distance of the center and the brim pilot signals are found by Newton interpolation algorithm, then the channel characteristic was estimated. Based on the same simulation parameters, the algorithms of the former and advised signal arrangement were analyzed. The matlab software were used in the analyzing process, and the simulation results demonstrated that the estimation veracity of the asymmetric arrangement is much preciser, especially in the speedy environment, it was a preferable choice for the OFDM system.