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Cognitive radio is an emerging wireless technology that is capable of efficiently coordinating the use of the currently scarce spectrum resources, and spectrum sensing constitutes its most crucial operation. This paper proposes wideband multichannel spectrum sensing methods utilizing fast Fourier transform or filter-bank-based methods for spectrum analysis. Fine-grained spectrum analysis facilitates...
We study the physical layer design of a distributed time-division multiple access (TDMA) protocol for wireless body area networks (WBAN). The distributed TDMA scheme is derived from a bio-inspired algorithm known as Pulse-Coupled Oscillator (PCO), in which each node in the network updates its state based on its knowledge of the neighborhood. ON-OFF ultra wide band (UWB) modulation is used by the sensors...
Cognitive radio (CR) is regarded as an emerging technology to utilize the scarce RF (radio frequency) spectrum in opportunistic manner to increase the spectrum efficiency. However, major challenge to successful operation and realization of CR system is the identification and detection of primary user signals in the wide band regime to identify spectrum opportunities reliably and optimally. Several...
Ultra wide band (UWB) is an appropriate candidate used into the physical layer of the wireless body area networks (WBAN). In this paper, a novel UWB transreceiver structure is presented, where a Miller encoder is adopted in the transmitter side and a non-coherent detection scheme is used in the receiver side. Since the power spectral density (PSD) of the UWB signal plays a major role in the coexistence...
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...
Ultra-wideband (UWB) has become one of the key technologies in wireless communication industries. In this paper we discuss and evaluate the performance of UWB under different channel conditions when it is applied for wireless sensors. The simulation was carried out for various detection and modulation schemes. Simulation results confirm that UWB with coherent detection outperforms the noncoherent...
In emerging cognitive radio (CR) networks, the first cognitive task preceding any dynamic spectrum management is the sensing and identification of spectrum holes in wireless environments. This paper develops a distributed compressed spectrum sensing approach for (ultra-)wideband CR networks. First, compressive sampling is performed at local CRs to scan the very wide spectrum at practical signal-acquisition...
Wireless sensor networks consist of a large number sensors spread across a given geographical area. Each sensor has its own communication capability as well as certain level of intelligence for signal processing and networking. As the sensor nodes are densely populated, communication range requirement for these nodes is smaller. After signal detection, a number of sensor nodes communicate over the...
In this paper, we propose a cognitive radio-based multi-user resource allocation framework for mobile ad hoc networks using multi-carrier DS CDMA modulation over a frequency-selective fading channel. In particular, given pre-existing communications in the spectrum where the system is operating, in addition to potential narrow-band interference, a channel sensing and estimation mechanism is provided...
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