A Unified Implementation Framework for Index Modulation Assisted MIMO Backscatter Communication

In this letter, a unified hardware implementation framework is designed for index modulation (IM) assisted multi-input multi-output (MIMO) backscatter communication, including space shift keying (SSK), spatial modulation (SM), SM assisted vertical bell labs space-time (SM-VBLAST), as well as SM assisted space-time block code (SM-STBC) schemes. Specifically, the concepts of SM-VBLAST and SM-STBC architectures are successfully applied into backscatter communication to balance an elegant tradeoff between spatial multiplexing and diversity gain. Then the coupled channel estimation and interference-cancellation-based signal detection algorithms are designed for hardware implementation. Furthermore, a unified IM-MIMO-based backscatter hardware prototype and experimental platform are designed. Experimental results verify that the proposed IM-MIMO implementation framework works efficiently and we can choose one proper IM-MIMO backscatter communication based on the required throughput, diversity gain as well as implementation complexity.