Hard and Soft Spherical-Bound Stack decoder for MIMO systems

TL;DR

This paper introduces the SB-Stack decoder, a novel MIMO decoding algorithm that combines stack and sphere decoding strategies to reduce complexity and improve soft-output detection performance.

Contribution

The paper presents the SB-Stack decoder, a new algorithm that reduces complexity of MIMO decoding and extends to soft-output detection, outperforming existing methods.

Findings

SB-Stack decoder reduces decoding complexity for large MIMO systems.

Soft SB-Stack decoder outperforms other MIMO soft decoders in performance.

The proposed decoder effectively handles lattice and large constellation decoding.

Abstract

Classical ML decoders of MIMO systems like the sphere decoder, the Schnorr-Euchner algorithm, the Fano and the stack decoders suffer of high complexity for high number of antennas and large constellation sizes. We propose in this paper a novel sequential algorithm which combines the stack algorithm search strategy and the sphere decoder search region. The proposed decoder that we call the Spherical-Bound-Stack decoder (SB-Stack) can then be used to resolve lattice and large size constellations decoding with a reduced complexity compared to the classical ML decoders. The SB-Stack decoder will be further extended to support soft-output detection over linear channels. It will be shown that the soft SB-Stack decoder outperforms other MIMO soft decoders in term of performance and complexity.