Geosphere: An Exact Depth-First Sphere Decoder Architecture Scalable to Very Dense Constellations

This paper presents the algorithmic design, experimental evaluation, and very large scale of integration (VLSI) implementation of Geosphere, a depth-first sphere decoder able to provide the exact maximum-likelihood solution in dense (e.g., 64) and very dense (e.g., 256, 1024) quadrature amplitude modulation (QAM) constellations by means of a geometrically inspired enumeration. In general, linear detection methods can be highly effective when the...