We focus on full-rate, fast-decodable space-time block codes (STBCs) for 2x2 and 4x2 multiple-input multiple-output (MIMO) transmission. We first derive conditions for reduced-complexity maximum-likelihood decoding, and apply them to a unified analysis of two families of 2x2 STBCs that were recently proposed. In particular, we describe a reduced-complexity sphere decoding algorithm suitable for QAM signal constellations. Next, we derive a novel reduced-complexity 4x2 STBC, and show that it outperforms all previously known codes with certain constellations.
@article{arxiv.0708.2804,
title = {On Fast-Decodable Space-Time Block Codes},
author = {Ezio Biglieri and Yi Hong and Emanuele Viterbo},
journal= {arXiv preprint arXiv:0708.2804},
year = {2008}
}