Hybrid Precoding Architecture for Massive Multiuser MIMO with Dissipation: Sub-Connected or Fully-Connected Structures?

TL;DR

This paper compares sub-connected and fully-connected hybrid precoding structures in massive multiuser MIMO systems, considering hardware dissipation and quantization effects, and finds that sub-connected structures often outperform fully-connected ones under certain conditions.

Contribution

It introduces a realistic hardware model with dissipation into hybrid precoding analysis and demonstrates the advantages of channel correlation-based codebooks over traditional RVQ codebooks.

Findings

Sub-connected structures outperform fully-connected ones in low SNR scenarios.

Channel correlation-based codebooks outperform RVQ codebooks.

Increasing signal power mitigates quantization performance loss.

Abstract

In this paper, we study the hybrid precoding structures over limited feedback channels for massive multiuser multiple-input multiple-output (MIMO) systems. We focus on the system performance of hybrid precoding under a more realistic hardware network model, particularly, with inevitable dissipation. The effect of quantized analog and digital precoding is characterized. We investigate the spectral efficiencies of two typical hybrid precoding structures, i.e., the sub-connected structure and the fully-connected structure. It is revealed that increasing signal power can compensate the performance loss incurred by quantized analog precoding. In addition, by capturing the nature of the effective channels for hybrid processing, we employ a channel correlation-based codebook and demonstrate that the codebook shows a great advantage over the conventional random vector quantization (RVQ) codebook. It is also discovered that, if the channel correlation-based codebook is utilized, the sub-connected structure always outperforms the fully-connected structure in either massive MIMO or low signal-to-noise ratio (SNR) scenarios; otherwise, the fully-connected structrue achieves better performance. Simulation results under both Rayleigh fading channels and millimeter wave (mmWave) channels verify the conclusions above.