Low-Complexity Zero-Forcing Precoding for XL-MIMO Transmissions

TL;DR

This paper introduces two low-complexity zero-forcing precoding schemes tailored for XL-MIMO systems, addressing the challenges of high complexity and unique propagation conditions in beyond-5G massive MIMO deployments.

Contribution

The paper proposes novel precoding schemes that leverage plane-wave approximation and user grouping to reduce complexity while maintaining performance in XL-MIMO systems.

Findings

Proposed schemes significantly reduce computational complexity.

Performance close to traditional ZF precoding in simulations.

Effective in handling XL-MIMO propagation characteristics.

Abstract

Deploying antenna arrays with an asymptotically large aperture will be central to achieving the theoretical gains of massive MIMO in beyond-5G systems. Such extra-large MIMO (XL-MIMO) systems experience propagation conditions which are not typically observed in conventional massive MIMO systems, such as spatial non-stationarities and near-field propagation. Moreover, standard precoding schemes, such as zero-forcing (ZF), may not apply to XL-MIMO transmissions due to the prohibitive complexity associated with such a large-scale scenario. We propose two novel precoding schemes that aim at reducing the complexity without losing much performance. The proposed schemes leverage a plane-wave approximation and user grouping to obtain a low-complexity approximation of the ZF precoder. Our simulation results show that the proposed schemes offer a possibility for a performance and complexity trade-off compared to the benchmark schemes.