一种新的DFT-S-OFDM软判决检测算法

A new DFT-S-OFDM soft decision detection algorithm

离散傅里叶变换扩频正交频分复用(DFT-S-OFDM)作为一种单载波调制方案,与传统正交频分复用相比具有较小的峰均功率比,并且已被3GPP采用作为其长期演进项目(LTE)的上行调制方案。针对该方案,提出了一种新的基于传统频域最小均方误差(MMSE)均衡器输出信号的DFT-S-OFDM软判决算法,通过对最大比合并以及均衡后信号统计特性的分析,进而依据所得的概率分布计算软判决的输出。仿真结果表明,该算法在高码率情况下能获得2dB左右的增益,而所需的额外计算量很小,并且当信道估计误差存在时仍然有效。

As a single carrier modulation scheme, Direct Fourier Transformer Spread Orthogonal Frequency Division Multiplexing（DFT-S-OFDM） has lower Peak to Average Power Ratio（PAPR） than the conventional OFDM. And it has been adopted as the uplink modulation scheme in 3GPP＇s Long Term Evolution（LTE）. In this work, a new DFT-S-OFDM soft decision algorithm was proposed using the traditional frequency domain linear Minimum Mean Squared Error（MMSE） equalization receiver structure. The statistics of the signal after Maximal Ratio Combine（MRC） and equalization was derived and the output of soft decision was calculated based on the acquired probability distribution. Numerical simulations showed that the proposed method had an approximative 2 dB gain in high code rate scenarios at the cost of little additional computations, and also worked under the non-ideal channel estimation conditions.