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The ability of adapting to the environment in the most efficient way is a crucial issue in Cognitive Radio (CR) networks. For this purpose, an accurate estimation of the characteristics and activity of the Primary Users (PUs) is required. A system that takes into account heterogeneous PUs with several features is developed. A new scheme is integrated in the system to exploit these motleys and to improve...
The detector proposed in this paper tries to address the challenge of low signal-to-noise ratio signal detection in low-complexity MB-OFDM UWB receivers. The idea is to exploit the 128-point FFT of the UWB receiver to carry out frequency-domain energy detection. The main advantage of the proposed detector is that it only requires a memory buffer the size of the UWB receiver FFT, which makes it lighter...
Cognitive radio (CR) is viewed as a novel approach for improving utilization of the precious radio spectrum. Spectrum sensing is one of the most important technologies in cognitive radio. A general presentation of OFDM technology and cooperative spectrum sensing are given in the first instance. In order to improve detection probability and reduce equipment complex and computation complex, to combine...
This paper discusses an interference DAA (Detection And Avoidance) technique for coexisting pulse based UWB and OFDM systems when the both systems are operated in the same frequency band. In a UWB transmitter-receiver, utilization of the OFDM system is detected by correlating with the GI (Guard Interval) signals. And also timing of the GI period is detected for interference mitigation. The UWB signal...
Orthogonal frequency division multiplexing (OFDM) is the modulation scheme of choice for digital video broadcasting-handheld (DVB-H), which is required to operate under high mobility conditions resulting in significant Inter-carrier Interference (ICI). To mitigate ICI, several cancellation schemes have been proposed but they require reliable channel information at the receiver which is quite challenging...
Orthogonal frequency division multiplexing (OFDM) is the modulation scheme of choice for digital video broadcasting-handheld (DVB-H) which is required to operate under high mobility conditions resulting in significant Inter-Carrier Interference (ICI). Under these conditions, the conventional one-tap per subcarrier channel estimation and equalization is suboptimal since it does not account for ICI...
Ultra-wideband (UWB) systems possess several distinct features such as very high data rate, large multipath or frequency diversity and improved ranging precision while requiring low-power low-complexity transceivers. Among the different modulation schemes, differential PSK is an attractive option because it does not require channel estimation, and hence reduces implementation complexity. This paper...
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