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The following topics are dealt with : cognitive radio; physical-layer techniques; high-data-rate systems; ad hoc networks; security; energy-aware wireless sensor networks; Web services; user centric network selection; RFID sensor networks; UWB TR receivers; next generation broadband wireless networks; location-based information sharing; and protocols.
Dynamic spectrum management (DSM) is one of the key problems in the design of cognitive radio (CR) networks. It is a time-varying Dynamic spectrum management (DSM) is one of the key problems in the design of cognitive radio(CR) networks. It is a time-varying and location-dependent optimization problem, equivalent to the well-known graph-colouring problem in graph theory. This problem is known to be...
New wireless systems expected to provide access to broadband networks are being considered for operation in the unused channels of the VHF and UHF TV bands. These new systems will have to avoid interference to TV broadcast operation and one way to achieve this will be by sensing the presence of broadcast operation in the area and change their operating frequency accordingly. This article deals with...
A critical issue in wireless sensor networks isrepresented by the limited availability of energy withinsensor nodes. An effective approach for energy conservationis scheduling sleep intervals for extraneous nodes, while theremaining nodes stay active to provide continuous service.Most previous solutions assumed a perfect radio conditionwith a static, circular coverage. However, in real situations,radio...
This paper introduces a collaborative coding algorithm and re-initialized transmission scheme to improve spectral efficiency of two-relay OFDMA networks. By broadcasting the network coded frames through the shared sub-carriers, with specific network coding and frame recovery at each relay node (RN), the proposed algorithm provides 1/3 higher spectral efficiency than the conventional, store-and-forward,...
In this paper we propose a soft output detector for theMIMO-CDMA systems with permutation spreading. Insuch systems, the spreading waveforms of each transmitantennas are dependent on the data to be transmitted. Inthe proposed system, information bits are convolutionallyencoded prior to being used in a MIMO-CDMA systemwith permutation spreading. Reliability of the detectedbits in the receiver is calculated...
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