基于BICM-ID系统的优化符号映射方案  

Optimization of Symbol Mapping for BICM-ID

作　　者：方伟伟[1] 李建平[1] 王威[1] 

机构地区：[1]中国传媒大学信息工程学院,北京100024

出　　处：《中国传媒大学学报（自然科学版）》2013年第2期19-23,共5页Journal of Communication University of China：Science and Technology

基　　金：教育部科学技术重点项目(106042);教育部留学归国人员科研启动基金项目(2007[24])

摘　　要：比特交织编码调制迭代译码(bit-interleaved coded modulation with iterative decoding,BICM-ID)技术能够在带宽受限的条件下增加时间分集,继而提高编码增益。由星座点和比特映射确定的符号映射方案是决定BICM-ID系统性能的关键因素。然而,以往的符号映射方案并未最大程度地利用信号空间。本文构造了一种基于BICM-ID系统的符号映射方案。该映射方案是由两个具有不同半径和相位的QPSK星座组成,并具有MSP(Mixed Separated Participation,MSP)映射的高分集特性,命名为交叉均衡8PSK准MSP映射(cross equalization-8PSK-quasi-MSP,CE-8PSK-QM)。在平均功率相同的前提下,该映射方案相比BICM-ID的传统映射方案具有更大的最小欧式距离,因此可以提高接收机的性能。仿真结果显示,当BER为10-4时,所提映射方案在瑞利信道下至少提高0.4分贝的编码增益。Bit-interleaved coded modulation with iterative decoding （BICM-ID） is a technique to increase the time diversity and achieve larger coding gain for bandwidth efficient transmission. Symbol mapping, defined by the signal constellation and the bit labeling,is the crucial design parameter to achieve a high coding gain for BICM-ID. However, conventional mapping schemes cannot take full advantage of the signal constellation. In this paper, an improved symbol mapping scheme is proposed for BICM-ID, which com- bined of two QPSK constellations with different radius and phases, and combined of Mixed Separated Par- ticipation （MSP） mapping with large diversity, called Cross Equalization-8PSK-quasi-MSP （ CE-8PSK- QM）. Simulation results show that, under the premise of same average power, the proposed scheme can in- crease the minimum squared Euclidean distance （MSED） and then improve the receiving performance of BICM-ID compared with the conventional symbol mapping schemes. At BER = 10 -4,the improved scheme can achieve more than 0. 4dB code gains over Rayleigh fading channels.

关 键 词：BICM ID 符号映射 功率有限 CE-8PSK—QM 

分 类 号：TN919[电子电信—通信与信息系统]