Generalized Space-Time Super-Modulation for Headerless Grant-Free Rateless Multiple Access

摘要

This work introduces Generalized Space-Time Super- Modulation (GSTSM), a generalization of the recently proposed Space-Time Super-Modulation scheme that enables the transmission of additional, highly-reliable information on the top of conventionally transmitted symbols, without increasing the corresponding packet length. GSTSM jointly exploits the spatial and temporal dimensions of multiple-antenna systems but, in contrast to the initially proposed approach, it does not require the use of space-time block codes. Instead, GSTSM jointly elaborates on the concepts of spatial modulation and spatial diversity, while intentionally introducing temporal correlation to the transmitted symbol sequence. In the context of machine-type communications, GSTSM enables one-shot and grant- free medium access without transmitting additional headers to convey each machines ID. As a result, we show that GSTSM can provide throughput gains of up to 2.5× compared to conventional header-based schemes, even in the case of colliding packets.