Adaptive Resource Allocation in Multiuser OFDM SystemsIntroductionSubcarrier GainAlgorithm for [Jang and Lee]Subcarrier allocationAlgorithm for [Prof. Evans et al]Algorithm for [Prof. Evans et al] Conti..ImplementationResultsResults Conti…Future WorkAdaptive Resource Allocation in Multiuser OFDM SystemsMalik Meherali SalehEE 381-14May 05, 2005(05/05/05)Introduction•Future Generation (4G) systems to provide high data rates •Issue: Inter-Symbol Interference (ISI)•Multiple Input Multiple Output (MIMO) and Orthogonal Frequency Division Multiplexing (OFDM) to the rescue…•Resource Allocation−Margin Adaptive [Wong, Cheng, Letaief and Murch, 1999]−Rate Adaptive [Jang and Lee, 2003]−Rate Adaptive + proportional fairness [Shen, Andrews and Evans, (Draft) 2004]Subcarrier Gain14 16 18 20 22 240.050.10.150.20.250.30.3514 16 18 20 220.050.10.150.20.250.30.35Channel MagnitudeChannel MagnitudeTonesTonesUser 2User 1These figures have been created for better understanding of algorithm. They are NOT results from simulationsAlgorithm for [Jang and Lee]•Initialization −Set Rk = 0 for k=1~K•For n = 1 to N {−Find the user k having higher channel gain−Update Rk−}•For Power Allocation −Water-filling−Equal power allocation (Ptotal/N)Subcarrier allocation 6 8 10 12 14 160.050.10.150.20.250.30.350.4User 16 8 10 12 14 1600.20.40.60.811.2User 2Channel MagnitudeChannel MagnitudeTonesTonesThese figures have been created for better understanding of algorithm. They are NOT results from simulationsAlgorithm for [Prof. Evans et al]Initialization•Set Rk = 0, Wk = {0} for k = 1 to K and A = {1,2,…,N}•Y1:Y2:…:YKFor k = 1 to K•Find n satisfying h(k,n) > h(k,j) for all j ε A•Let Wk = Wk U {n}, A = A-{n} and update RkAlgorithm for [Prof. Evans et al] Conti..While A != empty•Find k satisfying Rk/Yk <= Ri/Yi for all I, 1<=i<=K•For the found k, find n satisfying h(k,n) >= h(k,j) for all j ε A•For the found k and n, let Wk = Wk U {n}, A=A-{n} and update RkImplementation•For Non Fair System−Code Development in progress•For Fair System−‘A Low Complexity Algorithm for Proportional Resource Allocation in OFDMA Systems’ – Ian Wong et al−Linearizes power allocation−Approximates rate proportionalityResults0 5 10 15 20 2500.020.040.060.080.1GammaLINEARROOT-FINDING8.5 9 9.5 10 10.5 110.080.0850.090.095GammaLINEARROOT-FINDINGUser Number (k)Normalized Rate Proportions0 5 10 15 204.54.554.64.654.74.754.84.85number of userscapacity (bit/s/Hz)LINEARROOT-FINDINGResults Conti…0 5 10 15 2010-410-310-2number of usersAve CPU time (s)Average CPU time comparisonLINEARROOT-FINDINGFuture Work•Implement code for first method•Compare the two methods on the following −Total Capacity−Normalized data rate for individual
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