Hybrid Vector Perturbation Precoding: The Blessing of Approximate Message Passing

TL;DR

This paper proposes a hybrid vector perturbation precoding framework that combines lattice reduction, zero forcing or SIC, and an approximate message passing algorithm to enhance performance in multiuser MIMO systems.

Contribution

It introduces a novel hybrid precoding scheme that integrates approximate message passing with lattice reduction aided precoding, improving symbol error rates.

Findings

AMP algorithm enhances SER performance of LR precoding.

Hybrid scheme effective for massive MIMO data detection.

Low-complexity AMP significantly boosts precoding performance.

Abstract

Vector perturbation (VP) precoding is a promising technique for multiuser communication systems operating in the downlink. In this work, we introduce a hybrid framework to improve the performance of lattice reduction (LR) aided precoding in VP. First, we perform a simple precoding using zero forcing (ZF) or successive interference cancellation (SIC) based on a reduced lattice basis. Since the signal space after LR-ZF or LR-SIC precoding can be shown to be bounded to a small range, then along with sufficient orthogonality of the lattice basis guaranteed by LR, they collectively pave the way for the subsequent application of an approximate message passing (AMP) algorithm, which further boosts the performance of any suboptimal precoder. Our work shows that the AMP algorithm can be beneficial for a lattice decoding problem whose data symbols lie in integers $\mathbb{Z}$ and entries of the lattice basis may bot be i.i.d. Gaussian. Numerical results confirm the low-complexity AMP algorithm can improve the symbol error rate (SER) performance of LR aided precoding significantly. Lastly, the hybrid scheme is also proved effective when solving the data detection problem of massive MIMO systems without using LR.