Diversity-Multiplexing Tradeoff in Selective-Fading Multiple-Access MIMO Channels

TL;DR

This paper determines the optimal diversity-multiplexing tradeoff for selective-fading MIMO multiple-access channels, linking error mechanisms to dominant error events, and validates a recent distributed space-time code construction.

Contribution

It establishes the optimal DM tradeoff for these channels, introduces a relation between DM framework and error event regions, and provides design criteria for space-time codes.

Findings

Optimal DM tradeoff characterized for selective-fading MAC MIMO channels

Error mechanisms linked to dominant error event regions

Distributed space-time codes meet the derived design criteria

Abstract

We establish the optimal diversity-multiplexing (DM) tradeoff of coherent selective-fading multiple-access multiple-input multiple-output (MIMO) channels and provide corresponding code design criteria. As a byproduct, on the conceptual level, we find an interesting relation between the DM tradeoff framework and the notion of dominant error event regions which was first introduced in the AWGN case by Gallager, IEEE Trans. IT, 1985. This relation allows to accurately characterize the error mechanisms in MIMO fading multiple-access channels. In particular, we find that, for a given rate tuple, the maximum achievable diversity order is determined by the error event that dominates the total error probability exponentially in SNR. Finally, we show that the distributed space-time code construction proposed recently by Badr and Belfiore, Int. Zurich Seminar on Commun., 2008, satisfies the code design criteria derived in this paper.