Ramy H. Gohary and Timothy N. Davidson.
Non-Coherent MIMO Communication:
Grassmannian Constellations and Efficient Detection
IEEE Transactions on Information Theory,
55(3):1176-1205, March
2009.
This paper considers the design of both a transmitter and a receiver for noncoherent communication over a frequency-flat, richly scattered multiple-input multiple-output (MIMO) channel. The design is guided by the fact that at high signal-to-noise ratios (SNRs), the ergodic capacity of the channel can be achieved by input signals that are isotropically distributed on the (compact) Grassmann manifold. The first part of the paper considers the design of Grassmannian constellations that MIMIC the isotropic distribution. A subspace perturbation analysis is used to determine an appropriate metric for the distance between Grassmannian constellation points, and using this metric, greedy, direct and rotation-based techniques for designing constellations are proposed. These techniques offer different tradeoffs between the minimum distance of the constellation and the design complexity. In addition, the rotation-based technique results in constellations that have lower storage requirements and admit a natural "quasi-set-partitioning" binary labeling.
A preliminary version of this work appeared in the Proceedings of the International Symposium on Infomration Theory, Chicago, July 2004.
We have developed a BICM-IDD scheme for non-coherent MIMO that uses the constellations in this paper and a soft-output demodulator that uses similar insights to the detector in this paper.
We have also developed lablelling schemes for the Grassmannian constellations developed in this paper.
Some details regarding one approach to optimization over the complex Grassmannian manifold are available here.
Unfortunately, a few distracting typos were added into the paper after our review of the galley proof. Although none of these are critical, they can be distracting. They are corrected below.
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