采用幅度相移键控调制的分层空间调制算法
A Layered Spatial Modulation Algorithm Based on Amplitude/Phase？？Shift Keying

针对空间调制(SM)算法频谱效率较低的缺陷,提出了一种基于幅度相移键控(APSK)调制的分层SM(LSM)算法。该算法首先对发射天线进行分层,然后分别对每层发射天线进行SM映射,最后根据每层SM映射得到总的天线激活索引号和调制符号。为了进一步降低系统的误比特率,以系统误比特率上界为目标函数给出了APSK内外环幅度比选择准则。此外,为了实现低复杂度的最大似然译码,接收端对激活天线索引号和调制符号进行独立检测。理论分析和仿真结果表明:LSM算法对于任意发射天线数目都适用,并且可以灵活地调节激活天线个数;与分层空移键控算法相比,当频谱效率为8 b/(s？Hz)时,2种算法的性能基本相似,但天线数量节省了12根,从而节约了硬件资源;与广义空间调制算法相比,当发射天线为3、5和6时,频谱效率提高了1 b/(s？Hz)。
A high rate layered spatial modulation algorithm based on amplitude/phase？？shift keying (APSK), called layered spatial modulation (LSM), is presented to improve the spectral efficiency of spatial modulation (SM). The new scheme firstly layers the transmit antennas, then the SM mapping is carried out for each layer of the transmit antennas. According to the mapping of each layer, all the active transmit antennas and the modulated symbols can be obtained. In order to further minimize the bit error rate of the system, a simple and efficient ring of the amplitude levels optimization algorithm is proposed. Moreover, a low？？complexity detection scheme is proposed to detect the active antenna indexes and the modulated symbols separately to reduce the decoding complexity effectively at the receiver. Simulation results show that the LSM algorithm is suitable for any number of active antennas, and the active antennas can be adjusted flexibly. Compared with the layered space shift keying algorithm, when the spectrum efficiency is 8 b/(s？Hz), the performance of the two algorithms is almost the same, but the LSM algorithm can save twelve antennas and hardware resources. And, compared with the generalized spatial modulation, when the number of transmit antenna is three, five or six, the LSM algorithm can improve the spectrum efficiency by 1 b/(s？Hz)