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Nowadays, the use of Wireless Sensor Networks (WSN) is gaining popularity especially in dense urban scenarios with a wide range of applications which share the same ISM band of the spectrum frequency, this situation leads to severe congestion problems. Therefore, it is important to define mechanisms that allow the use of their resources in an efficient way maintaining system quality even under harsh...
In recent years, the deployment of wireless short-range devices has increased dramatically, especially in urban settings with high density buildings. This is causing high levels of interference at the ISM bands, thus deteriorating performance. However, there is spectrum being unused and if the devices could make opportunistic use of available channels in other bands (OSA) it will improve their performance...
Nowadays, Cognitive Radio (CR) is projected as the technology that will maximize the utilization of the spectrum resources in next generation wireless systems. Therefore, the Spectrum Sensing (SS) is the key function, which allows CR to know the available spectrum resources of an interest band. Nevertheless, one of the major problems in the SS is the big amount of samples that are processed in the...
Radar systems are widely used for military, transportation and scientific purposes. For radars, the ability of the device to mitigate the effects of noise and interference is of great importance because it will determine its performance. Radars may suffer from attacks aimed to hinder their performance, known as jamming attacks. In this context, noise jamming attacks are a very common type of attack,...
Nowadays the deployment of Wireless Sensor Networks (WSN) is rapidly increasing specially in dense urban scenarios, due to upcoming new technologies based on Internet of things. In this context, the presence of WSN, Wi-Fi and Bluetooth sharing the ISM band, could cause unsuspected interference levels that could deteriorate channel capacity in WSN and consequently deteriorate the performance of WSN...
In this paper, a novel wideband spectrum sensing algorithm based on Compressive Sensing (CS) and reconstruction of second order signal statistics from covariance matrix of the acquired samples for Cognitive Radio (CR) systems is presented. This allows cognitive users to sense the spectrum without apriori knowledge of signal characteristics in the radio environment by minimizing the amount of samples...
Due to the increased demand for internet services, the challenges that large data centers must handle are bigger. Therefore, in recent years the development of networks defined by software (SDN) has caught the attention of the scientific community, mainly because of the flexibility it presents in its model of centralized management, which facilitates the development of solutions according to demand...
Dense urban zones with high concentration of Wireless networks can degenerate in problems such as spectrum scarcity for devices in licensed bands, or high interference levels for devices in unlicensed bands, thus producing QoS problem. A possible solution to deal with this issue is the use of wireless devices to access opportunistically a licensed band. For this reason, this paper evaluates a channel's...
Currently, the number of wireless networks has increased especially in urban zones where the devices concentration is enormous. This fact and the huge bandwidth consumption per device have produced spectrum scarcity in the operation bands assigned for those networks. Consequently, the scientific community has been led to seek new approaches to use the spectrum. In this context, opportunistic spectrum...
Channel allocation problem is a major task, especially in dense deployments of wireless local area networks (WLANs). In such cases, opportunistic spectrum access (OSA) is considered to be a promising approach to diminish congestion of the ISM band in highly dense WLANs scenarios. OSA allows to secondary users, the use of underutilized licensed channels, without affecting legacy users. In this paper,...
Currently, the number of wireless networks has increased especially in urban zones where the concentration is enormous. This fact and the huge bandwidth consumption per device have produced spectrum scarcity in the operation bands assigned for those networks. Consequently, they have induced the search of new approaches to use the spectrum. In this context, Opportunistic Spectrum Access (OSA) has appeared...
In this paper a measurement method of antenna radiation patterns is presented and implemented. For this, it has been built an experimental mechanism that allows acquiring the radiation intensity in different angular positions, based on far-field measurement techniques and probabilistic analysis, which shows a good performance. This technique provides a fast and simple method for verifying antenna...
A promising approach to alleviate ISM band congestion problems in highly dense WLAN scenarios consists of exploiting opportunistic spectrum access (OSA) to underutilized bands under a primary-secondary model. This paper develops a distributed channel assignment algorithm valid for uncoordinated WLAN deployments where access points do not follow any specific planning and they could belong to different...
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