Characterization of a 60 GHz scattered wireless channel with different antenna polarizations for underground multimedia applications

Abstract

Large scale (i.e. <10 m) and small scale (i.e. 1 � 1� 1 cm) measurements and characterization of a scattered wireless channel with different antenna polarizations and configurations in the underground mine galleries at 60 GHz are addressed. Results show that the rough surface scattering and the gallery dimensions affect the path loss (PL) exponent and it becomes smaller than the free space. Vertically polarized antennas give a lower value of the PL exponent and root mean square (RMS) delay spread compared to the horizontal one. The small scale 3D measurement results show that the power loss of around 1-5 dB within a small scale cubical area. Results also show that the channel is less time dispersive in a wider gallery and observed a higher value of the RMS delay spread compared to a smaller gallery. The statistical results of the small scale multipath amplitude fading provide a better fit with the Rician distribution. The effects such as scattering, polarization, antenna radiation patterns, and waveguide which caused increase and decrease of the value of PL exponent and delay spread are also analysed. Results revealed that a directional narrow beam dualpolarized antenna configuration might be a good candidate in this environment. | INTRODUCTIONNowadays, short-range wireless communications offer huge possibilities to provide seamless multimedia services. Recently, the 60 GHz band has generated significant interest because of its high data rate (i.e. >1 Gbps) capability within a short-range communication in indoor environments [1]. However, the utility of wireless communications is also essential for safety and productivity particularly in an underground mine environment [2,3]. Besides the multimedia services (voice, video, and data), wireless communications are used for geolocalization of miners and equipment, speedy rescue operation of trapped miners under debris etc. In the mining industry, the well-known Through The Earth communication systems are used for vehicle tracking, monitoring, and controlling. Other systems such as radio-frequency identification, Zigbee, wireless sensor networks, and Wi-Fi systems are also convenient to use in underground mine. The use of the Internet of Things and This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.