طراحي و تحليل الگوريتم هاي تامين كيفيت سرويس براي كاربران VoIP در يك شبكه راديو شناختگر گسترده

چكيده انگليسي :

Design and Analysis of QoS Provisioning Algorithms for VoIP Users in a Distributed Cognitive Radio Network Ali Bayat a bayat@ec iut ac ir Date of Submission 5 1 2013 Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor Mehdi Mahdavi m mahdavi@cc iut ac ir Abstract Wherever human beings face scarcity of resources they look either for another new resource or for new solutions to increase the utilization of the current resources The idea world spread resource is being under utilized is thoroughly sensible to let the resource be utilized more efficiently The software defined radio development has made the design and implementation of cognitive radios possible A cognitive radio has the ability to sense the radio spectrum in order to find spectrum gaps and exploit them to send its own data so opportunistically that it does not disturb the communication of the licensed users primary users with each other The emergence of cognitive radio brings with itself many challenges Obtaining the best method of sensing the radio spectrum at the physical layer PHY and proposing the most efficient channel allocation algorithms at MAC layer to guarantee a high level of QoS for cognitive radio users secondary users are some of these challenges In this thesis after studying a variety of cognitive radio MAC protocols and the way of allocating channels in them an efficient channel allocation algorithm for secondary users having VoIP traffic will be proposed To the best of our knowledge the channel allocation algorithms proposed in the recent research have not take into account the channel quality concerning the way of allocating available channels to VoIP traffic secondary users The network model in this thesis is a distributed network of unlicensed users having VoIP traffic In this way after declaring analyzing and simulating several channel allocation algorithms for slotted cognitive radio networks with constant transmission capacity and variable transmission capacity an efficient queue based algorithm for the constant transmission capacity network and an efficient queue based channel quality aware algorithm for the variable transmission capacity networks will be proposed In the latter the queue status of the secondary users and the quality of the channel would be considered in addition to the variable behaviour of primary users in occupying their channels By applying these two efficient algorithms in the constant transmission capacity and variable transmission capacity networks respectively the QoS will be provisioned to a proper certain level for the secondary users carrying VoIP traffic At the end the performance of these algorithms in a cognitive radio network will be proved and observed by calculating the mean packet loss rate which is a key performance measure for the VoIP services PDF created with pdfFactory trial version www pdffactory com

بيات، علي

طراحي و تحليل الگوريتم هاي تامين كيفيت سرويس براي كاربران VoIP در يك شبكه راديو شناختگر گسترده

راديو نرم افزار , كاربر ثانويه , تخصيص كانال