一种低复杂度的DFT-S-OFDM系统迭代检测算法

A low-complexity iterative detection algorithm for DFT-S-OFDM systems

针对LTE上行的单载波频分多址系统——离散傅立叶变换扩频的正交频分复用(DFT-S-OFDM)系统,提出了一种低复杂度的迭代检测实现方法。由于传统方法根据发射机与信道级联系统的等效传输矩阵,完成最小均方误差(MMSE)的迭代检测,但非对角矩阵求逆复杂度较高,因此,所提出的新方法对发送端DFT扩频后的信号先进行单点的MMSE检测,然后根据逆离散傅立叶变换(IDFT)解扩后的后验均值和方差等效得到输出外信息比特似然比。仿真结果表明,所提出迭代检测接收算法的性能与传统方法相近,而其实现复杂度则有较大降低。

A complexity reduced iterative detection method for single-carrier frequency division multi-access systems （discrete Fourier transform spread orthogonal frequency division multiplexing （DFr-S-OFDM） systems） is proposed in this paper. For the traditional method, the minimum-mean-squared error （MMSE） iterative detection is implemented based on the equivalent transform matrix, thus resulting the higher complexity for the non-diagonal matrix inversion, therefore, the proposed method first performs the MMSE estimation is for the transmitted signal after DFr spreading, which is characterized by the posterior mean and variance. According to this, the log likelihood ratio （LLR） information is transferred between the detector and the decoder. The simulation results show that the performance of the proposed iterative receiver is as same as the traditional method, while its complexity is greatly reduced.