Half Spatially Coupled Turbo-Like Codes

TL;DR

This paper introduces half spatially coupled turbo-like codes with simplified coupling structures that achieve near-capacity performance with small coupling memory, addressing previous threshold loss issues.

Contribution

The paper proposes a new class of half spatially coupled turbo-like codes with deterministic coupling, improving decoding thresholds and performance over existing spatially coupled codes.

Findings

Achieve near-capacity performance with coupling memory as small as 2

Simpler, deterministic coupling structure reduces threshold loss

Theoretical and numerical results demonstrate performance advantages

Abstract

This paper presents a new class of spatially coupled turbo-like codes (SC-TCs), namely half spatially coupled braided convolutional codes (HSC-BCCs) and half spatially coupled parallel concatenated codes (HSC-PCCs). Different from the conventional SC-TCs, the proposed codes have simpler and deterministic coupling structures. Most notably, the coupling of HSC-BCCs is performed by re-encoding the whole coupling sequence in the component encoder of one time instant, rather than spreading the coupling bits to component encoders of multiple time instants. This simplification not only addresses the window decoding threshold loss issue in existing BCCs, but also allows the proposed codes to attain very close-to-capacity performance with a coupling memory as small as 2. Both theoretical and numerical results are provided to demonstrate the performance advantages of the proposed codes over existing spatially coupled codes.