Massive Grant-Free Access With Massive MIMO and Spatially Coupled Replicas

Massive multiple access schemes, capable of serving a large number uncoordinated devices while fulfilling reliability and latency constraints, are proposed. The schemes belong to the class grant-free coded random protocols tailored massive input output (MIMO) base station processing. High is obtained owing an intra-frame spatial coupling effect, triggered by simple device protocol combined with acknowledgements (ACKs) from station. To provide system design guidelines, analytical bounds on error floor also derived. proposed particularly interesting address challenges machine-type communications in framework next generation systems.