인지무선시스템에서의 효과적인 무선자원관리 기법 연구 Efficient Radio Resource Management Schemes for Cognitive Radio 200801140 운봉영 Contents • Cognitive Radio • Main Issues • Environments • Outputs • System Model • Problem Formulation • Time Schedule • References Cognitive Radio • Cognitive Radio • Improves the bandwidth efficiency by exploiting temporarily available frequency bands of licensed users not heavily occupied [1]. But the shortage of the current frequency The actual frequency of the spectrum there are inefficiencies in the use of the band 동기 – 현재 주파수 부족 현상이 있으나 실제 주파수에서는 스펙트럼 대역 사용의 비효율성이 있다. Main Issues • Unused spectrum bands allocated to Secondary (Unlicensed) user. • Secondary (Unlicensed) user to access temporarily spectrum hole. So, consider Intelligent way without causing harmful interferences with primary users • The price of each allocated a frequency band is considered. 1.사용하지 않는 스펙트럼 대역을 SU에게 할당. 2.SU는 일시적으로 스펙트럼 홀에 접근해야 하는데 이 때, PU에게 피해를 주지 않는 방법을 사용. 3. 각각의 주파수 대역의 가격을 고려한다. Environments • • • • • • Perfect Spectrum Sensing Perfect Information Exchange (No error, no delay) Multiple transmission channels/users Variant numbers of the channels/users Simulation tool : MATLAB , C++ Performance Evaluation • Metric : total (system) throughput, individual (user) throughput • Factors : the number of channels, the number of users Outputs • Allocation algorithms/protocols for cognitive radio • Program source code for performance evaluations • Paper, etc. The same LAN, but there is more than one base station. CBS is to find an empty space to allocate gives SU. And assume that Price is different for each frequency LAN. 같은 랜이지만 여러 개의 기지국이 존재 한다. CBS는 빈공간을 찾아 SU에게 할당해 준다. 그리고 랜마다 주파수 가격이 다르다. System Model • System Scenario SU is as shown in the same LAN, or between the LAN and the LAN will use the empty space. • Spectrum Utilization Scenario SU는 그림과 같이 랜과 랜 사이 또는 같은 랜 안에서의 빈공간을 사용하게 될 것이다. Problem Formulation • Objective • Maximize System Utility • System Utility : sum of user utility(satisfaction) • User utility : log (avg. throughput/cost) • Optimization Problem for Spectrum Band Allocation Utility of currently available 현재 가능한 Utility Just before the average Utility 직전 평균 Utility Time Schedule (Tentative) Item Month 3 Survey/Analysis of state of art System Model/Problem formulation Suggestion of algorithms/protocols Development of performance evaluation tool, Final report /Paper submission/presentation 4 5 6 7 References • [1] I. F. Akyildiz, W. Y. Lee, M. C. Vuran, and S. Mohanty, “Next generation / dynamic spectrum access/cognitive radio wireless networks: A survey,” Computer Networks, vol. 50, no. 13, pp. 21272159, May 2006. • [2]Tian Bu , Li (Erran) Li , Ran Ramjee, «Generalized Proportional Fair Scheduling in Third Generation Wireless Data Networks” 409 - 413 Vol. 1 , pp. 8427096,Sept. 2004 • [3] Taewon Park, “Proportional fair scheduling for wireless communication with multiple transmit and receive antennas” , 1573 - 1577 Vol.3, pp. 8107771 ,Oct. 2003 • [4] Hoon Kim, “A Proportional Fiar Scheduleing for Multicarrier Transmission Systems”, Vol.9, NO.3,pp.221, March 2005 • My theme is efficient Radio Resource Management Schemes for Cognitive Radio •
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