Diversity-Multiplexing-Delay Tradeoffs in MIMO Multihop Networks with ARQ

TL;DR

This paper investigates the tradeoffs between diversity, multiplexing, and delay in multihop MIMO relay networks with ARQ, proposing an optimal ARQ allocation strategy that balances error probabilities and queueing delay to optimize network performance.

Contribution

It formulates the ARQ allocation as a convex optimization problem considering queueing and ARQ errors, providing a novel approach to optimize multihop MIMO network performance.

Findings

Optimal ARQ allocation balances link performance and queue delay.

The problem is formulated as a convex optimization problem.

Numerical examples demonstrate the effectiveness of the proposed allocation.

Abstract

Tradeoff in diversity, multiplexing, and delay in multihop MIMO relay networks with ARQ is studied, where the random delay is caused by queueing and ARQ retransmission. This leads to an optimal ARQ allocation problem with per-hop delay or end-to-end delay constraint. The optimal ARQ allocation has to trade off between the ARQ error that the receiver fails to decode in the allocated maximum ARQ rounds and the packet loss due to queueing delay. These two probability of errors are characterized using the diversity-multiplexing-delay tradeoff (DMDT) (without queueing) and the tail probability of random delay derived using large deviation techniques, respectively. Then the optimal ARQ allocation problem can be formulated as a convex optimization problem. We show that the optimal ARQ allocation should balance each link performance as well avoid significant queue delay, which is also demonstrated by numerical examples.