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A wireless sensor network equipped with microphones can be used for context awareness by classifying sound events in the target environment. This classification will become less accurate when more than one sound can be heard at the same time. We conduct a series of experiments in which we mix different sound types in order to see how high this influence is. We conclude, that in most cases, the classifier...
In cognitive sensor networks, the first cognitive task preceding any form of dynamic spectrum management is the sensing and identification of spectrum holes in wireless environments. Research in the physical and medium access control layers for DSA (Dynamic Spectrum Access) and DSS (Dynamic Spectrum Sharing) is currently at its early development. Aspects such as spectrum sensing and spectrum management...
Cognitive radio is based on dynamic spectrum sharing in order to increase spectrum efficiency. In this approach, which is opposite of the current spectrum allocation, a secondary user (unlicensed) shares a frequency band with designated primary users (licensed) without causing interference or performance degradation to the primary users. Cognitive radio needs reliable spectrum sensing techniques to...
The effect of man-made noise in wireless microphone operation has been studied in this paper. Man-made noise measurements were taken in different locations in Vienna, VA and the amount of interference from man-made noise in potential wireless microphone channels were analyzed. Data collection results show that man-made noise levels can be up to 30 dB above the thermal noise floor. Our results show...
The FCC recently issued the regulatory rules for cognitive radio use of the TV white space spectrum. These new rules provide an opportunity but they also introduce a number of technical challenges. The challenges require development of cognitive radio technologies like spectrum sensing as well as new wireless PHY and MAC layer designs. These challenges include spectrum sensing of both TV signals and...
Spectrum sensing in the context of wireless microphone (WM) signals is considered in this paper. The spectrum sensing algorithm developed in this study makes use of the property that the bandwidth of the WM signal is narrow compared with the bandwidth of a digital television (DTV) channel. As a result, the power of the WM signal is highly concentrated in the frequency domain and there are apparent...
Ever since the Federal Communications Commision (FCC) announced that it would open the television (TV) spectrum for opportunistic access, there has been an increased interest in industry as well as academia to come up with proposals that would fit the criteria laid by FCC. To this end, IEEE 802.22 Working Group (WG) is formulating the first worldwide standard for cognitive radio to operate in the...
Recent advances in wireless communications and micro-electro-mechanical systems have fostered the development of wireless sensor networks (WSNs) which consist of tiny, low-cost and low-power sensor nodes. Individual sensor nodes only have local views of the environment, but global views can be obtained by collaborative processing between densely deployed sensor nodes. Energy efficiency is critical...
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