7 research outputs found

    Long term evolution of the surface refractivity for arctic regions

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    YesIn this paper, local meteorological data for a period of 35 years (from 1979 to 2013) from Kuujuaq station have been used to calculate the surface refractivity, N and to estimate the vertical refractivity gradient, dN1, in the lowest atmospheric layer above the ground. Monthly and yearly variations of the mean of N and dN1 are provided. The values obtained are compared with the corresponding values from the ITU maps. The long-term trend of the surface refractivity is also investigated. The data demonstrate that the indices N and dN1 are subject to an evolution which may have significance in the context of climate change (CC). Monthly means of N show an increasing departure from ITU-R values since 1990. Yearly mean values of the dN1 show a progressive decrease over the period of study. Seasonal means of dN1 show a decrease over time, especially for summer. Such a trend may increase the occurrence of super-refraction. However, currently available ITU-R recommendations for microwave link design assume a stationary climate, so there is a need for a new modelling approach

    An indoor path loss prediction model using wall correction factors for wireless local area network and 5G indoor networks

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    A modified indoor path loss prediction model is presented, namely, effective wall loss model. The modified model is compared to other indoor path loss prediction models using simulation data and real-time measurements. Different operating frequencies and antenna polarizations are considered to verify the observations. In the simulation part, effective wall loss model shows the best performance among other models as it outperforms 2 times the dual-slope model, which is the second best performance. Similar observations were recorded from the experimental results. Linear attenuation and one-slope models have similar behavior, the two models parameters show dependency on operating frequency and antenna polarization
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