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An Intelligent Spectrum Management Framework in Cognitive Radio Networks

Abachi, Taha | 2010

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 41019 (19)
  4. University: Sharif University of Technology
  5. Department: Computer Engineering
  6. Advisor(s): Hemmatyar, Afshin
  7. Abstract:
  8. Cognitive radio is a tool for optimal use of radio spectrum, not used by the primary users all the time. Two main features of a cognitive radio are cognitive capability and reconfigurability. An intelligent cognitive radio uses its cognition ability to identify the environmental parameters and makes future decisions based on this information. Then the reconfigurability is used to set the sending parameters to the calculated values in the cognition phase. Cogition phase consists of major steps; spectrum sensing, decision, mobility and handoff. Throughout this thesis we first propose a cooperative sensing scheme using algorithmic techniques based on sensors’ spatial information through modeling the environment as a unit disc graph. This solution solves the important problem hidden terminal. The method also adds a new dimension to the spectrum map by taking the sonsors’ spatial information into account and leads to finding more spectrum opportunities. Next a new scheme for optimal spectrum decision is presented using the Analytic Hierarchy Process (AHP). Due to the several criteria influenceing the decision such as power, signal-to-noise- ratio, delay, bit error rate, etc, the problem of selecting a channel is a multi-criteria decision making problem. One approach for solving such problems is the AHP method where the problem is divided into a hierarchy of mutual comparisons. A weight vector for is obtained containing the priorities of different options. The option receiving the highest weight, in terms of mutual comparisons has been the most important one. The AHP method is very efficient both in terms of time complexity and taking all the influencing objectives into account. Software simulation using NS2 proves that using the AHP method leads to a more effiecient use of spectrum opportunities and increases the total throughput of the network
  9. Keywords:
  10. Analytical Hierarchy Process (AHP) ; Cognitive Radio ; Cooperative Spectrum Sensing ; Graph Modeling

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