Diversity-Multiplexing Tradeoffs in MIMO Relay Channels

TL;DR

This paper analyzes the fundamental tradeoff between diversity and multiplexing in MIMO relay channels, showing how different protocols perform under full-duplex and half-duplex constraints.

Contribution

It characterizes the optimal diversity-multiplexing tradeoff for MIMO relay channels and compares the performance of various relaying protocols.

Findings

DF relaying achieves optimal DMT in full-duplex scenarios.

DDF protocol is necessary for optimal DMT in half-duplex relays.

Static protocols have quantifiable DMT performance in half-duplex cases.

Abstract

A multi-hop relay channel with multiple antenna terminals in a quasi-static slow fading environment is considered. For both full-duplex and half-duplex relays the fundamental diversity-multiplexing tradeoff (DMT) is analyzed. It is shown that, while decode-and-forward (DF) relaying achieves the optimal DMT in the full-duplex relay scenario, the dynamic decode-and-forward (DDF) protocol is needed to achieve the optimal DMT if the relay is constrained to half-duplex operation. For the latter case, static protocols are considered as well, and the corresponding achievable DMT performance is characterized.