Explore the Capacity of Near Field Channel using Gaussian Beams

TL;DR

This paper introduces a Gaussian beam domain approach using Hermite Gaussian modes to efficiently approximate near field MIMO channels, enabling accurate capacity estimation with reduced overhead.

Contribution

It develops a novel method to approximate near field channels in the Gaussian beam domain, improving estimation efficiency and capacity calculation.

Findings

The method accurately estimates channel capacity in near field MIMO systems.

It converges rapidly and reduces channel estimation overhead.

Hermite Gaussian modes effectively represent dominant channel singular modes.

Abstract

Channel capacity lies at the core of wireless communication, yet determining it typically requires detailed channel information between the transmitter and receiver. For near field MIMO systems, obtaining the detailed native channel is often difficult or expensive. This paper develops a scheme to approximate the near field channel in a Gaussian beam domain. Hermite Gaussian (HG) modes are used to approximate the channel between a pair of square antenna arrays in a free space line of sight (LOS) environment. We show that HG modes efficiently represent the dominant singular modes of the native channel, enabling accurate channel estimation and capacity computation in the HG beam space. An iterative algorithm is proposed to approach the maximal channel capacity by gradually expanding the beam space dimension. Simulation results demonstrate that the method converges rapidly and significantly reduces channel estimation overhead.