Microwave Propagation Characteristics in an Urban Quasi Line-of-Sight Environment under Different Traffic Conditions

概要

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Signal path loss and propagation delay spread were measured at microwave frequencies of 3.35, 8.45, and 15.75 GHz along a straight quasi line-of-sight (LOS) street in an urban environment under different traffic conditions: daytime and nighttime. Comparison between daytime and nighttime measurements reveals that the break points shift toward the base station because of the increase in the effective heights of the road and sidewalk; break points were not seen during the daytime at a mobile antenna height (h_m) of 1.6 m. According to the cumulative probabilities of the delay spreads during the nighttime, frequency dependence is not clearly observed and the delay spreads for h_m=1.6 m were clearly larger than those for h_m=2.7 m. This is because a lower h_m results in stronger blocking of the LOS wave, as was also observed during the daytime. The plot of path losses versus delay spreads is confirmed to be represented by an exponential curve. The exponential coefficients during the daytime were observed to be greater than those during the nighttime. This indicates that a LOS wave is more likely to be blocked during the daytime.
社団法人電子情報通信学会の論文
2001-05-01