Performance analysis of high-rate generalized space code index modulation system

Traditional code index modulation (CIM) systems only carry information through spreading codes and constellation symbols, with low energy efficiency and spectral efficiency. However, adding phase as a unique modulation symbol to carry information has the advantage of low transmission power consumption. To fully utilize the multi-antenna lead to improve spectral efficiency, a high-rate generalized space code index modulation (HR-GS-CIM) system with low-power design was proposed. The traditional modulation symbols were replaced with the additional phase by the HR-GS-CIM system, and the genetic algorithm (GA) was used to optimize the design of the additional phase, which could acquire high energy efficiency advantage and performance advantage. At the same time, the methods of generalized and spatial indexing were introduced to jointly map select the additional phase, spreading code, and antenna lead, and a low-complexity joint mapping selection algorithm was adopted to greatly improve the system’s spectral efficiency. Furthermore, the theoretical performance of the HR-GS-CIM system was analyzed and the consistency between the theoretical and simulated performance was verified. Finally, compared with traditional CIM systems, the simulation results show that the proposed HR-GS-CIM system has significant performance gain.