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In recent years, novel spectrum access schemes have increased the need to further explore and exploit radio propagation dynamics. One proposed approach is to use spectrum sensing nodes for propagation environment estimation, and particularly to allow shadowing field extraction. In general there is a tendency to develop techniques that allow the automated and localized estimation of the spatial correlation...
We study the propagation dynamics of a typical European forest by calculating and modeling shadowing fading correlations. This work relies on highly accurate propagation measurements that are able to capture the dynamics of such environment in detail. We also describe how such propagation measurements should be conducted to provide reliable results. These types of measurements are important for military,...
In the recent years there has been an effort for the wireless systems to become more efficient in terms of power consumption and coverage planning. One aspect of this effort was the proposal of using spatial estimation approaches, that exploit the spatial correlation of the shadowing and received power, to improve propagation prediction. In this demonstration, we present a software tool that implements...
In this paper we propose the application of spatial decomposition methods for improving the prediction accuracy of linear regression models when used for establishing radio environment maps through large-scale pathloss estimation. We discuss two basic decomposition schemes, namely square and radial decomposition, and apply them in a reference scenario for a high-power TV transmitter. Our results show...
We present the results of an extensive, high spatial density measurement campaign made for investigating the shadowing correlations on two different frequency bands, namely 485MHz and 2600MHz in an urban propagation environment. In particular, we report results using different analysis procedures and tools. Our results show that the signal detector has only a small impact on the extracted data, given...
Localization errors can play an important role in measurements of radio propagation or spectrum utilization, especially in urban environment where GPS localization accuracy is highly varying. In this paper we present a low cost and simple method for mitigating the impact of localization errors, based on multiple GPS receivers. The presented results are based primarily on performance evaluation of...
We report results from extensive measurements based study to understand the shadow fading correlations. We have particularly studied and analyzed common assumptions done in literature for shadow fading, which is typically modeled as a spatially correlated Gaussian random process in the logarithmic scale. We show that these assumptions, starting from the Gaussianity of the radio propagation environment,...
We report, based on extensive propagation measurements, cases where typical assumptions regarding shadow fading do not hold. These assumptions include universally assumed Gaussian marginals and exponentially decaying uniform spatial correlation structure. Our results are based on measurement campaigns conducted on three different environments, namely in urban, suburban and forest areas. We discuss...
In this paper we describe the effects of the radio propagation model on the spatial characteristics of the radio environment. For this study we have conducted a dedicated propagation measurement campaign focusing on the three different frequency bands of 485MHz, 1700 MHz and 2600MHz in order to capture the impact of the used frequency on the radio propagation. The presented results are coming from...
Wireless network deployments are becoming increasingly complex in order to cope with the exponential growth in mobile data traffic. Multi-tier technologies capable of supporting spatially dense networks enable high data rates, but require timely and accurate models of the radio environment, particularly for scenarios that incorporate dynamic access to spectrum. However, network planners, algorithm...
A growing demand for bandwidth in wireless data networks has motivated policy makers to consider opening underused frequencies, e.g. in the TV broadcasting bands, to opportunistic secondary access. To support secondary network operations in these TV whitespaces (TVWS), centralized databases are envisioned that employ radio propagation models to derive the spectrum usage of the primary system. Precise...
In this paper we propose a general model to estimate the maximum allowed transmit power of a secondary node based on the measured signal from the primary transmitter that is willing to share its downlink spectrum. The transmit power should satisfy primary constraints related to the minimum required Signal to Interference and Noise Ratio (SINR) of its users. The model can be used by secondary nodes...
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