A New Approach to UEP-HARQ via Convolutional Codes

TL;DR

This paper introduces a novel UEP-HARQ scheme using pruned convolutional codes that enhances error protection for important bits and improves overall reliability compared to existing methods.

Contribution

It proposes a new type-II HARQ scheme based on pruned convolutional codes supporting unequal error protection with a retransmission strategy for important bits.

Findings

Strong protection for important bits achieved

Improved reliability for standard bits

Outperforms existing UEP schemes in simulations

Abstract

This paper presents a novel type-II hybrid automatic repeat request (HARQ) transmission scheme which is based on pruned convolutional codes (CCs) and supports unequal error protection (UEP). The data to be transmitted is assumed to consist of important bits (IB) and standard bits (SB). In the proposed scheme, all the bits are first encoded using a single mother CC and transmitted over the channel. If a decoding error is detected in the IB, then retransmission of {\em only} the IB takes place using a CC, typically with a better error correction capability. Next, taking advantage of the properties of pruned CCs, the decoded IB are used to increase the decoding reliability for the SB. Numerical simulations indicate that the proposed scheme offers strong protection for the IB along with improved reliability for the remaining bits compared to other UEP schemes.