Large Intelligent Surface-Assisted Wireless Communication Exploiting Statistical CSI

TL;DR

This paper evaluates the performance of large intelligent surface-assisted wireless systems using statistical CSI, proposing an optimal phase shift design and quantization requirements to maximize ergodic capacity.

Contribution

It introduces a tight ergodic capacity approximation for LIS-assisted systems and develops an optimal phase shift scheme based on statistical CSI.

Findings

Optimal phase shift design maximizes ergodic capacity.

A 2-bit quantizer suffices to limit capacity degradation to 1 bit/s/Hz.

Proposed methods improve LIS-assisted communication performance.

Abstract

Large intelligent surface (LIS)-assisted wireless communications have drawn attention worldwide. With the use of low-cost LIS on building walls, signals can be reflected by the LIS and sent out along desired directions by controlling its phases, thereby providing supplementary links for wireless communication systems. In this study, we evaluate the performance of an LIS-assisted large-scale antenna system by formulating a tight approximation of the ergodic capacity and investigate the effect of the phase shifts on the ergodic capacity in different propagation scenarios. In particular, we propose an optimal phase shift design based on the ergodic capacity approximation and statistical channel state information. Furthermore, we derive the requirement on the quantization bits of the LIS to promise an acceptable capacity degradation. Numerical results show that using the proposed phase shift design can achieve the maximum ergodic capacity, and a 2-bit quantizer is sufficient to ensure capacity degradation of no more than 1 bit/s/Hz.