LogMAP译码算法量化方法研究.pdf

　　 25 　 12 　　　　 2008 12　　 :1006 -9348(2008)12 -035 1-04 LogMAP 1 2 1 姚如贵, 尹武涛 , 王永生 (1., 7 10072; 2., S7N5A9) : Turbo, , , LogMAP, Turbo 、、, ;“3σ”, ; (ModifiedVribleShiftnormliztion, MVS), ; LLR, 。 , , ( 0.3 dB), Turbo, 。 :;;; :TN9 11.7　　:A QuntifictionTechniquesofLogMAPDecodingAlgorithm 1 2 1 YAORu-gui, YINWu-to, WANGYong-sheng (1.SchoolofElectronicsndInform tion, NorthwesternPolytechniclUniversity, XinShnxi7 10072, Chin; 2.DeprtmentElectriclndComputerEngineering, UniversityofSsktchewn, Ssktoon, S7N5A9, Cnd) ABSTRACT:Mostofturbodecodingperformncenlysispresentedinthelitertureisbsedonflotingpointrith- metic.Howeve,riffixedpointrithmeticisemployed, BERperformncedegrdtionisexpected.Theeffectsof quntifictionhvebeendiscussedindetiluponLogMAP lgorithm nd ppropritequntifictiontechniquesre proposed.Thepperproposes novel3σ-ruletoccurtelydecidetherngendprecisionforthequntifictionof thereceivedsymbol.sAndmodifiedvribleshiftnorm liztion lgorithmisintroducedtoreducethedynmicrnge ofpthmetric.Beside,s windowedLLR lgorithm issetforthtoreducetheinternldtwidthfurthermore.The smiultionresultshveshowedthttheproposedfixedpointlgorithm cngretlydecreseLogMAP lgorithmsmi- plementtioncomplexity tthecostoflittledegrdtioninBERperformnce.CompringtotheflotingpointLogMAP decodingsystem, theproposedfixedpointlgorithmsoverllBERperformncedegrdtionisonly0.3 dB.Conse- quently, thesetechniquescnbeesilyusedfortheengineeringppliction. KEYWORDS:Dynmicrnge;Fixedpoin;tQuntifiction;WindowedLLR , Turbo 1　 , 。