基于星座修正聚类的双模式盲均衡算法  

Dual-Mode Blind Equalization Algorithm Based on Clustering

作　　者：王成[1] 杨宾[1] 王大磊[1] 

机构地区：[1]解放军信息工程大学信息工程学院,河南郑州450002

出　　处：《信号处理》2012年第8期1194-1199,共6页Journal of Signal Processing

摘　　要：针对时变信道下,调制类型未知的MPSK/MQAM类信号快速均衡问题,本文提出了一种新的基于星座聚类的双模式均衡算法。初始阶段均衡器采用稳健的恒模算法,一段时间后,用低复杂度的减法聚类算法处理缓存的均衡器输出。然后利用MPSK/MQAM类信号星座图的几何旋转不变性,采用C均值模糊聚类算法修正初次聚类的结果,恢复信号星座,由此获得精确符号信息。最后依据修复后的聚类效果选择切换时机,均衡器切换到符号匹配算法,完成信号均衡。与已有算法相比,本文提出的新算法克服了调制类型未知的不利因素,具有收敛速度快,剩余码间干扰小,均衡器模式切换时性能平稳等优点。仿真验证了新算法对4PSK和16QAM信号的有效性。The paper introduces a new dual-mode blind equalization algorithm for the MPSK/MQAM signals without mod- ulation types identified under the time-varying channel. At the beginning, the constant modulus algorithm （CMA） is adopt- ed in equalization for its robust performance. After a while, we get the cluster values of the equalized signal by subtraction clustering method. Notice that nearly all of the MPSK/MQAM signals＇ constellations have geometrical rotary symmetry, so the fuzzy c-means algorithm is introduced to modify the former cluster values for the signals＇ constellation rebuilding. There- fore we can get the signal＇s precise alphabet information from the modified constellation. Finally, the equalization switches to alphabet-matched algorithm （AMA） to obtain better performance, what＇s more the switching time depends on the cluster validity index. The new dual-mode algorithm can effectively overcome the difficulty that the modulation types are unknown. Compared with the existing methods, this new algorithm converges fast with few inter symbol interference and enable equali- zation switch smoothly from CMA to AMA. Simulation results have proved the efficiency of the proposed algorithm for 4PSK and 16QAM inputs.

关 键 词：双模式均衡 星座聚类 旋转修复 

分 类 号：TN929.5[电子电信—通信与信息系统]