一种适用于DCO-OFDM系统的DFT信道估计算法

针对直流偏置光正交频分复用系统中传统离散傅里叶变换(DFT)信道估计算法运算复杂度高和循环前缀(CP)内存在非有效信道系数的问题,提出厄米特对称的DFT(H-DFT)阈值改进信道估计算法。首先,根据信道时域响应变换到频域满足厄米特对称的性质,只需对有效子载波的信道频域响应做厄米特对称即可获得全部子载波的信道频域响应;其次,根据CP外噪声的平均功率对CP内的信道抽头数据设置阈值来滤除CP内的噪声。仿真结果表明:与传统DFT信道估计算法相比,H-DFT阈值改进信道估计算法有效降低了运算复杂度,在误比特率和均方误差方面也得到了明显的改善。

DFT channel estimation algorithm for DCO-OFDM system

Aiming at the problems of high computational complexity of traditional discrete Fourier transform(DFT)channel estimation algorithm and inefficient channel coefficients in cyclic prefix(CP)in direct-current biased optical orthogonal frequency division multiplexing system,an improved channel estimation algorithm based on Hermite symmetric DFT(H-DFT)threshold is proposed.Firstly,according to the property that the time domain response of the channel is transformed to the frequency domain to satisfy the Hermite symmetry,the frequency domain response of all the subcarriers can be obtained by only making Hermite symmetry for the frequency domain response of the effective subcarriers.Secondly,according to the average power of the noise outside the CP,the threshold value is set for the channel tap data inside the CP to filter the noise inside the CP.Compared with the traditional DFT channel estimation algorithm,the simulation results show that the H-DFT threshold improved channel estimation algorithm can effectively reduce the computational complexity,and improve the bit error rate and mean square error.