Cognitive Radio Spectrum Sensing 1586 ppt
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Transcript of Cognitive Radio Spectrum Sensing 1586 ppt
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Cognitive Radio Spectrum Sensing
Under the guidance of : Mr. Sandeep Sharma Designation : Research/Faculty Associate
ANUPAM K YADAV 11/IEC/021Gautam Buddha University
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CONTENTS• Introduction• Application• Architecture for CRC Network• Types of spectrum Sensing• Energy Detection Mathematical model• Algorithm Used for Detection of spectrum Holes• Results and simulations• References
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Cognitive Radio : It’s a Radio technique that aims to utilize Radio Spectrum more efficiently by Intelligently exploiting licensed spectrum.
Need to exploit spectrum :
There is increasing number of smartphones & laptops every year which have different QoS requirements :
• Web browsing• Faster Internet• Multimedia downloads
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Applications
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In CR Network we provide services to all users at same time :
• Use of VACANT bandwidth :• STs can use those spectrums which are
not occupied by (primary receivers) PRs.
• SHARING of bandwidth :• STs can share spectrum as long as they do
not interfere with PRs
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There are two types of Radio resources in CR –Network : 1. Radio resource ( licensed band )RR Small bandwidth, Hight Tx power, High reliability.
2. Cognitive Radio resource ( Unlicensed Band) CRRBroad Bandwidth, low Tx Power, low reliability.
Challenge : Is to jointly utilize both the bands to increase system performance.
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Non-Cooperative Architecture (standalone )There are two different interfaces operating at licensed and unlicensed band.
• Power limited C-RR is used for Users near the MACRO Cell BS, while it uses licensed RR for users who are further away.
• Small Cell they use CRR to cover traffic hotspots and bridges the coverage gaps.
They offer High capacity
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Cooperative architectureAlso uses both licensed and CRR .Have longer range of communication as compared to non cooperative.
• Relay is deployed for better coverage & capacity. It can communicate with BS using licensed RR & can provide local coverage using CRR. It works in duplex way.
• It also uses the Cognitive RR to form Virtual Antenna Array.
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Types of spectrum Sensing
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Energy Detection mathematical Model• We calculate energy of receiving signal to find the presence of primary user.
• In spectrum the primary user is present when calculated level of incoming energy level is more than threshold energy level.
• Also we compare the output of energy detector with a threshold which depends on noise floor and signal is detected.
• Energy detection is a non-coherent detection technique which do not need prior knowledge about primary user as required by other filters, so it has relatively less complexity as compared to other spectrum sensing.
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Algorithm Used for Detection of spectrum Holes
• In this paper PSD is used for detection of spectrum holes. Here we can compare values of PSD for different channels and can estimate spectrum holes.
• PSD is also used for modulation of incoming input signals at different channel with different carrier frequencies.
• Then this modulated signal is multiplexed where noise may or may not corrupt the signals. At the receiver end, PSD from different channels is calculated.
• And lastly, the threshold power level is compared with calculated power for the presence of primary user.
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Results and Simulations
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Fig. 1. Fig. 2.
Fig. 3. Fig. 4.
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References• Juan Andrés Bazerque, Georgios B. Giannakis, “Distributed SpectrumSensing For
Cognitive Radio Networks By Exploiting Sparsity”, IEEETransactions On Signal Processing, Vol. 58, No. 3, March 2010.
• S.Haykin, “Cognitive Radio: Brain-Enpowered Wireless Communications,” IEEE JSAC, vol. 23, no. 2, Feb. 2005,pp. 201–20.
• Spectrum Sensing for Cognitive Radio. By Simon Haykin, Life Fellow IEEE, David J. Thomson, Fellow IEEE, and Jeffrey H. Reed, Fellow IEEE
• Takeshi Ikuma and Mort Naraghi-Pour (2008), “A Comparison of Three Classes of SpectrumSensing Techniques”, IEEE GLOBECOM proceedings.
• F. F. Digham, M. S Alouini and M.K Simon, “On the energy detection of unknown signals over fading channels”, in Proc. IEEE International Conference on Communication (ICC003), pp. 3575-3579, May 2003.
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THANK YOU