空间调制系统中一种低复杂度比特映射算法

空间调制(spatial modulation,SM)通过激活发射天线的索引在空间域中传输信息比特,将比特到符号映射技术引入到SM系统中,可以提高SM系统的性能.一般而言,在判决准确率一定的情况下,采用相邻SM符号汉明距离较小的映射方式将获得较优的系统性能.提出一种低复杂度的比特到符号映射算法,称为符号最近法(symbol nearest method,SNM).该算法从具有最小距离的符号对开始对SM符号进行排序,寻找下一个最近的SM符号,直到所有SM符号排序结束为止,将格雷编码的比特映射分配给排序后的SM符号.分析和仿真结果表明,SNM算法在发射端使用全信道状态信息(channel state information,CSI)时,其系统性能接近于SM和空间移位键控(space shift keying,SSK)误码率(bit error rate,BER)性能的下界,并且所提出的算法复杂度为O(K2),其复杂度也较低.

A low complexity bit mapping algorithm in spatial modulation system

Spatial modulation (SM) can transmit information bits by activating the index of the transmitting antenna in the spatial domain. Introducing bit-to-symbol mapping technology into SM system will improve the performance of SM system.Generally speaking, when the decision accuracy is fixed, the mapping method with smaller Hamming distance between adjacent SM symbols will obtain better system performance. In this paper, we propose a bit-to-symbol mapping algorithm with low-complexity called symbol nearest method (SNM). In this algorithm, firstly, the SM symbols are sorted from the symbol pair with the smallest distance, and then the next nearest SM symbols are searched until the sorting of all SM symbols is completed. Finally, the Gray-coded bit mapping is assigned to the sorted SM symbols. Analysis and simulation results show that when full channel state information (CSI) is applied at the transmitter, the system performance of SNM algorithm is close to the lower bounds of SM and space shift keying (SSK) BER performance, and the complexity of the proposed algorithm is o(K²), where K is the number of symbol, and the complexity of the proposed algorithm is low.