Investigation of MIMO Channel Characteristics in a Two-Section Tunnel at 1.4725 GHz

Rongchen Sun,Zhenhui Tan,Tao Zhou,Cheng Tao,David W Matolak,Liu Liu

doi:10.1155/2017/3693149

Abstract

This paper presents results from a wide band single-input–single-output (SISO) and 16 × 16 virtual multiple-input–multiple-output (MIMO) measurement campaign at a center frequency of 1.4725 GHz in a 100-meter long tunnel laboratory which is terminated by a vertical wall with a metallic door. The path loss, root-mean-square delay spread (RMS-DS) characteristics, and power delay profiles (PDPs) are described. In addition, we provide results for the MIMO channel amplitude matrix, which offers a new perspective in understanding MIMO characteristics in tunnel scenarios. Our measurement results are analyzed and compared to ray tracing simulations. The relationships among the angle spread, channel matrix singular values, and MIMO capacity at various link distances are illustrated, and these provide insights into MIMO system deployment.

Highlights

To ease the growing population pressure on urban traffic, major cities in China have accelerated subway construction
As link distance increases, the multipath components (MPCs) of parts B and C come gradually closer to those of part A, which makes it difficult to identify the valid MPCs of part A from the power delay profiles (PDPs)
In cases like the PDP at 25 m in Figure 7, MPCs of parts B and C can be removed completely, but in cases like the PDP at 85 m, we can only remove the signal under the noise floor, in which case some reflections from the rear door cannot be removed completely, and this will have some influence on the subsequent parameter analysis

Summary

Introduction

To ease the growing population pressure on urban traffic, major cities in China have accelerated subway construction. Extensive work has been done on propagation and MIMO channel capacity based on measurements in subway tunnels. The authors of [7, 8] provided some wide band measurement results, including time delay dispersion and Ricean K factors. In [1, 2] the authors noted that antenna alignment and the shape of the tunnel cross section have a great influence on the correlations between antennas, the channel matrix singular values, and MIMO capacity.

Description of the Measurement Campaign

SISO Measurement

Conclusion