SC-FDE系统中一种改进的MMSE-RISIC均衡算法

单载波频域均衡(SC-FDE)系统中的最小均方误差残留码间干扰消除(MMSE-RISIC)均衡算法对最小均方误差(MMSE)均衡后的残留码间干扰(RISI)进行了估计并消除,但判决数据中仍存在噪声干扰,而且RISI估计的偏差会造成额外干扰,影响了均衡的精度。为此详细分析了MMSE-RISIC算法存在的问题,并针对帧结构基于特殊字(UW)的SC-FDE系统提出一种改进的MMSE-RISIC均衡算法,该算法增加了噪声预测模块,利用UW估计噪声和数据估计噪声的相关性,由UW噪声预测和抵消MMSE-RISIC均衡后数据的噪声,由此RISI的估计精度也会提高。最后利用我国华北地区300km的9径散射链路参数进行仿真,结果表明:改进的MMSE-RISIC均衡算法在低信噪比(SNR)下相比MMSE-RISIC均衡算法误码率(BER)有所降低,当BER为10-3时SNR大约有2dB的性能增益。

An Improved MMSE-RISIC Equalization Algorithm in SC-FDE System

This article analyzes the problems existed in the MMSE-RISIC algorithm in detail and proposes an improved MMSE-RISIC equalization algorithm for SC FDE whose frame structure applied Unique Word (UW). This algorithm adds a noise prediction module to utilize the correlation between the estimated noise in UW and the estimated noise in date. The noise in data after MMSE equalization is predicted and eliminated by the estimated noise in UW. The estimation accuracy of RISI will also improve. Finally, the parameters based on the 300 km troposcatter channel in north China are utilized for making a simulation. The results show that the improved MMSE-RISIC equalization can lower a bit of error rate (BER) under condition of low signal to noise ratio (SNR). And SNR gains about 2 dB when BER=10 -3 compared with the MMSE RISIC equalization.