Browsing by Author "Koudelka, Otto"

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    Frequency analysis and selection for cognitive radio using fuzzy logic system
    (Pensee Journal, 2014) Muhammad Tahir Mushtaq; Muhammad Saleem Khan; Sarwar Ehsan; G.Jaffar; I.Khan; S.B.Nasir; Koudelka, Otto
    The spectrum scarcity is a great challenge in the future development of wireless communication devices. The idea of Cognitive radio was proposed for the solution of this problem. The research work presented in this paper addresses the Frequency Analysis and Selection for Cognitive Radio (CR) using Fuzzy logic based Adaptive Control System. Fuzzy logic controller FLC is designed for this purpose to optimize the use of available radiofrequency (RF) spectrum resources while minimizing the chances of interference due to primary users. The FLC is used to deal with the incompleteness, uncertainty and heterogeneity of a cognitive radio scenario. Two cascaded fuzzy logic controllers are used. The first fuzzy inference system takes four inputs i.e. environment condition, distance between primary user and the secondary user, speed of secondary user and signal power received at SU (Psu). The only one output of FLC-1 is Psu, which is the signal power of secondary user (SU). The second fuzzy inference system FLC-2 will take four inputs i.e. transmission power of SU (Psu), signal to noise ratio (SNRpu), used frequency spectrum and duration of used frequency. The result of FLC-2 is appeared in the form of available frequency hole.
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    Spectrum scheduling: the key factor for maximum throughput and optimal resource utilization in cognitive radio netwok
    (Science International Lahore, 2014) Muhammad Tahir Mushtaq; Muhammad Shoaib Hanif; Muhammad Saleem Khan; Koudelka, Otto
    The problem of spectrum scarcity becomes with the new devices and applications of wireless communication. The solution of this problem is the cognitive radio Networks. This paper presents the different scheduling techniques for the secondary user and evaluated the results of maximum throughput and optimal resource utilization based on evaluation results of different scheduling techniques introduced at that time for cognitive radio networks. The research proposes one of the key challenges in spectrum sharing that is spectrum scheduling. And on the base of these results we evaluated that spectrum scheduling for secondary user is the key factor for maximum throughput and optimal resource utilization in cognitive radio networks.