Characterization of a NLOS Off-Body Channel at 2.45 GHz Using Patch Antenna Inside a Mine

In underground environments, the safety of the miners depends on the quality of the used communication systems. Currently, wireless underground communications suffer from small-scale and large-scale fading, compromising the propagation quality and limiting the achieved bit rate. In this paper, the performance of a patch antenna set in off-body channels under None Line of Sight (NLOS) conditions is evaluatedat a frequency of 2.45 GHz. Measurement campaigns were performed in a gold mine in order to determine the channel parameters for NLOS configurations and compare them with previously published Line Of Sight (LOS) results. Hence, the channel parameters were determined from the measured frequency responses. The off-body channel is characterized in terms of the impulse response, path loss, RMS delay spread, coherence bandwidth, and channel capacity.