In this letter, we propose a novel scheme extending index dimension with two distinct signal constellations, named as generalized spatial modulation with multi-index modulation (GSM-MIM). Through this scheme, which exploits the spatial domain and index domain, more extra information bits are transmitted by the spatial indexes as compared with the traditional GSM system. More specifically, with the aid of a vector index bit, a transmitted spatial vector (TSV) is derived by combining two spatial vectors, one of which is obtained by mapping $M$ -ary pulse amplitude modulation ( $M$ -PAM) symbol on an antenna index (AI) vector with the aid of both a key index bit and a group of AI bits, and the other one of which is obtained by mapping $L$ -quadrature amplitude modulation ( $L$ -QAM) symbol on another AI vector with another group of AI bits. Furthermore, the modified $M$ -PAM ( $M$ -MoPAM) is designed for increasing the squared minimum Euclidean distance (SMED) between the TSVs, the average bit error probability (ABEP) and the SMED are provided and analyzed. Finally, simulation results using Monte Carlo demonstrate that the GSM-MIM scheme has a significantly lower bit error ratio (BER) than other MIMO schemes.

中文翻译：

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具有多指数调制的广义空间调制

在这封信中，我们提出了一种使用两个不同信号星座扩展索引维度的新方案，称为具有多索引调制的广义空间调制 (GSM-MIM)。通过这种利用空间域和索引域的方案，与传统的GSM系统相比，空间索引传输了更多的额外信息比特。更具体地说，借助向量索引位，通过组合两个空间向量得到传输空间向量（TSV），其中一个是通过映射获得的 百万美元 -ary 脉冲幅度调制 ( 百万美元 -PAM) 符号在一个天线索引 (AI) 向量上，借助一个关键索引位和一组 AI 位，另一个是通过映射得到的 $L$ -正交幅度调制（ $L$ -QAM) 符号与另一组 AI 位在另一个 AI 向量上。此外，修改后的 百万美元 -PAM ( 百万美元 -MoPAM) 旨在增加 TSV 之间的平方最小欧几里得距离 (SMED)，提供并分析平均误码率 (ABEP) 和 SMED。最后，使用蒙特卡罗的仿真结果表明，GSM-MIM 方案的误码率 (BER) 明显低于其他 MIMO 方案。