Approximately-Universal Space-Time Codes for the Parallel, Multi-Block and Cooperative-Dynamic-Decode-and-Forward Channels

TL;DR

This paper constructs explicit space-time codes that achieve optimal diversity-multiplexing tradeoff in cooperative relay channels, using simple building blocks and proving universality across various fading distributions.

Contribution

It introduces a new class of approximately-universal space-time codes for multiple channel types, including cooperative, parallel, and MIMO-OFDM channels, with simple constructions.

Findings

Codes achieve the DMT of cooperative-relay channels under dynamic decode-and-forward.

Proves existing codes are approximately universal for block-fading and parallel channels.

First DMT-optimal code construction for the general MIMO-OFDM channel.

Abstract

Explicit codes are constructed that achieve the diversity-multiplexing gain tradeoff of the cooperative-relay channel under the dynamic decode-and-forward protocol for any network size and for all numbers of transmit and receive antennas at the relays. A particularly simple code construction that makes use of the Alamouti code as a basic building block is provided for the single relay case. Along the way, we prove that space-time codes previously constructed in the literature for the block-fading and parallel channels are approximately universal, i.e., they achieve the DMT for any fading distribution. It is shown how approximate universality of these codes leads to the first DMT-optimum code construction for the general, MIMO-OFDM channel.