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On Dynamic Spectrum Access in Cognitive Radio NetworkingRutabayiro Ngoga, Said January 2013 (has links)
The exploding increase of wireless communications combined with the existing inefficient usage of the licensed spectrum gives a strong impetus to the development and standardization of cognitive radio networking and communications. In this dissertation, a framework for Dynamic Spectrum Access (DSA) is first presented, which is the enabling technology for increasing the spectral efficiency of wireless communications. Based on that, Cognitive Radio (CR) can be developed as an enabling technology for supporting the DSA, which means that the wireless users are provided with enhanced capability for sensing the operating radio environment and for exploiting the network side information obtained from this sensing. The DSA concept means that the users of a wireless system are divided into a multi-tiered hierarchy with the primary users (PUs) entitled to protection and with cognitive radio capable secondary users (SUs). The improved spectrum efficiency is obtained by means of a medium access control protocol with knowledge about the statistical properties or available local information of the channels already occupied by PUs as well as knowledge about the interference tolerance within which the interference to PUs is kept to a given level. Related to this, emphasis is laid on the protocol capability to determine the efficiency of the secondary sharing of spectrum. Based on the type of available local information, the capacity of opportunistic communication is investigated for three models. These are: with dynamic, distributed channels information; with dynamic, parallel channels information; and under a dynamic sub-channels allocation scheme. The results indicate that this capacity is robust with reference to the uncertainty associated with localized sensing of distributed dynamic channels and with timely sensing of parallel dynamic channels. The extension to dynamic parallel sub-channels enables resource allocation to be carried out in sub-channels. The analytical results on the performance of sub-channel allocation indicate a robust traffic capacity in terms of blocking probability, drop-out probability and delay performance as function of PUs traffic loads.
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Web based system for radio planning in WRAPShakya, Nabin Raj January 2009 (has links)
<p>Radio planning is designing of network structure and elements under various design requirements. With the increasing shortage of frequencies, radio planning has become more and more complex. Hence, to maintain accuracy and optimization computerized planning tools are needed.</p><p>This thesis focuses on developing a simplified and economical solution on web for radio planning tool using WRAP- the software for spectrum management and radio planning developed by WRAP International AB, Linköping, Sweden. In order to make WRAP calculations available for remote users it had developed APIs. The web-based WRAP needs to communicate with WRAP API server, for exchanging API messages in order to perform calculation. To make the system user friendly and interactive, latest web technologies are implemented.</p><p>In this thesis, we started development process right from requirements gathering to find out required components that need to be analyzed to find suitable web-based conversion. Further, we designed and implemented a software solution. The final part is evaluation to discover if requirements are fully implemented or not as well as to gather the performance result of the new system. It is found, the performance of web based WRAP is equally fast as desktop version for smaller coverage areas whereas, for larger coverage areas, web-based WRAP is slower than desktop version</p>
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Web based system for radio planning in WRAPShakya, Nabin Raj January 2009 (has links)
Radio planning is designing of network structure and elements under various design requirements. With the increasing shortage of frequencies, radio planning has become more and more complex. Hence, to maintain accuracy and optimization computerized planning tools are needed. This thesis focuses on developing a simplified and economical solution on web for radio planning tool using WRAP- the software for spectrum management and radio planning developed by WRAP International AB, Linköping, Sweden. In order to make WRAP calculations available for remote users it had developed APIs. The web-based WRAP needs to communicate with WRAP API server, for exchanging API messages in order to perform calculation. To make the system user friendly and interactive, latest web technologies are implemented. In this thesis, we started development process right from requirements gathering to find out required components that need to be analyzed to find suitable web-based conversion. Further, we designed and implemented a software solution. The final part is evaluation to discover if requirements are fully implemented or not as well as to gather the performance result of the new system. It is found, the performance of web based WRAP is equally fast as desktop version for smaller coverage areas whereas, for larger coverage areas, web-based WRAP is slower than desktop version
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