Turbo Packet Combining for Broadband Space-Time BICM Hybrid-ARQ Systems with Co-Channel Interference

TL;DR

This paper introduces a turbo packet combining method for broadband MIMO hybrid-ARQ systems with unknown co-channel interference, improving decoding efficiency and robustness.

Contribution

A novel frequency domain soft MMSE-based signal combining technique with recursive implementation insensitive to ARQ delay, enhancing performance in interference-limited channels.

Findings

The proposed scheme is not interference-limited under certain conditions.

Simulation results show significant performance gains.

Complexity and memory are insensitive to ARQ delay.

Abstract

In this paper, efficient turbo packet combining for single carrier (SC) broadband multiple-input--multiple-output (MIMO) hybrid--automatic repeat request (ARQ) transmission with unknown co-channel interference (CCI) is studied. We propose a new frequency domain soft minimum mean square error (MMSE)-based signal level combining technique where received signals and channel frequency responses (CFR)s corresponding to all retransmissions are used to decode the data packet. We provide a recursive implementation algorithm for the introduced scheme, and show that both its computational complexity and memory requirements are quite insensitive to the ARQ delay, i.e., maximum number of ARQ rounds. Furthermore, we analyze the asymptotic performance, and show that under a sum-rank condition on the CCI MIMO ARQ channel, the proposed packet combining scheme is not interference-limited. Simulation results are provided to demonstrate the gains offered by the proposed technique.