The effects of antenna directivity on UWB propagation in an underground mining environment
ARP '07 The Fourth IASTED International Conference on Antennas, Radar and Wave Propagation
A holistic approach to wireless sensor network routing in underground tunnel environments
Computer Communications
Wireless Personal Communications: An International Journal
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This paper presents comprehensive experimental results obtained from narrowband and wideband radio-channel measurements in an underground mine with narrow veins at 2.4 GHz. From continuous-wave (CW) measurement data, large-scale distance-power curves and path-loss exponents of the environment are determined. Other relevant parameters, such as the mean excess delay, the maximum excess delay, the root-mean-square (rms) delay spread, and the coherence bandwidth are extracted from the wideband-measurement data. Results show a propagation behavior that is specific for these underground environments with rough surfaces. The rms delay spread does not follow a dual-slope relation with respect to distance, as in environments with smooth surfaces. Moreover, the dependence of the rms delay spread on the bidimensional position of the user is found to be very significant. For the majority of locations, the rms delay-spread values are less than 60 ns.