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1.WhyCQI ?Some meQuest i onsanswer ed 2.WhyCQI Se v er a lt i me swe ’ v eas k edou r s e l v e st h es equ es t i o ns : Q:WhydowegetpoorEc/ Nowhenconduct i ngHSDPADr i veTest ? Q:Wh ati st h ec a l c u l a t i o nsb eh i n dEc / Nogo i n gl o w wh enHSDPAs e ss i o ni si n i t i a t e d? Q:Wh yd owec on s i d e rCQIa saQu a l i t yMe Me t r i cwh e nc o n d uc t i n gHSDP ADr i v eT e s ti n s t e a do fEc / No ? T ak eal ookatt hef ol l o wi wi ngs l i des 3.WhyCQI No t et h eCQIv a l u ei s2 7( g oo d)wh i l eEc Noi sa bo utt oe xp l o de( 1 2d b) 4.L et ss t a r tb ye st a bl i s hi n gs omeb as i c s : Ec / Nof o rmo sto fy oui saQu al i t y&Ca pa ci t yme mea su r i ngMe Me t r i c .I tg en er a l l ygi v esust h ei d eaho wg oodorb adt h el i n kQu al i t yi s .Ho we v er , b ydefi ni t i on,i t squi t ec onf us i ng– CPI CHEc / No=Pi l o tc ha nn el qu al i t yen er g yp erc hi pov ert o t al r e ce i v edpo we rs p ec t r a ld en si t y OR RSCP=RSSI+Ec/ No EcNo=RSCP-RSSI L et ’ sgob ac kt od ev e l o pi n gBa s i c s WHAT?! ?! ? Ok …. . 5.RSCP:Th eRe c ei v e dSi g na lCo dePo we r :Th at ' st h ep owe rl e v el t h ep i l o tc h an ne lo fac e l l i sr e ce i v e dwi t han du s ua l l ye xp r e s se di ndBm ( mW o nal o ga r i t h mi mi cs c al e ) . Wi t ht h i spa r a me me t er ,d i ff er e ntc el l su si n gt hes ameca r r i e rc a nb ec omp ar e da ndhan do v ero rc e l l r e se l e ct i o n d ec i s i o nsc a nb et a k en . RSSI :I nUMTSt h at ' st h es i g na lp owe ro v e rt h ec o mp mp l e t e5MHzc ar r i e rwh i c hi n c l u de sa l l c o mp mp on en t sr e c ei v e d,i n c l u di n gt h es i g na l sf r o m t h ec ur r e nta ndne i gh bo r i ngc el l so nt hes amef r e que nc y .I nani s ol a t e dc el l ha v i ngon l yCPI CHpo wert ot r a ns mi mi tan dwi t hno neoft heot h er c h an ne l su t i l i z e d,t h ee ff ec t i v eRSSIa ss ee nb yt h eUEwo ul dbe( f r a c t i o no f )PCPI CHp owe r .Ho we v e r ,t h eRSSIc h an ge swh ent h e5 Mh Mh z c ar r i e rwi l lc ar r ypo werf o ro t h erd ed i c at e do rc o nt r ol c han ne l s .I nt ha tc as e,t hee ffe ct i v epo werpe r c e i v edb yt h eUEwo ul db et h e t r a ns mi mi t t e dpo we ro ft h es er v i n gc el l +t h epo we rt r an smi t t e db yn ei g hb orc el l sov ert h es amec ar r i e rf r e qu en cy . Ec No :Th at ' st h er e ce i v edene r g ype rc h i p( Ec )o ft h ep i l o tc ha nn el d i v i d edbyt het o t al n oi s epo we rd en si t y( No ) .I not h erwo r d st h eEc Noi s t h eRSCPd i v i d edbyt h eRSSI .An da ga i ni not he rwo r d s :Th eb et t e rt h i sv al u et h eb et t e rc a nasi g na lo face l l b ed i s t i n gu i s hedf r o mt h e o v er al l n oi s e.TheEc Noi sus ua l l yex pr e ss edi nd Ba si t ' sar e l a t i v ev a l u e.Thev al uei sne ga t i v ea st h eRSCPi ss mal ma l e rt h ant h et o t a l r e ce i v e dp owe r .Ast h eRSCPt h i sv al u ec a nb eu s edt oco mp mp ar edi ff er e ntc el l so nt h es a meca me r r i e ra n dh an do v ero rc e l l r e se l e c t i o n
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d ec i s i o nsc a nb et a k en . L et ’ sgob ac kt od ev e l o pi n gBa s i c s 6.I ti sbel i ev edt hatEc / Noi sanex pr es si onofs i gnal t onoi s er at i oandi st her ef or e,ani ndi c at orofs i gnal qual i t y . I TI SNOT( j us tt hat ) ! The“ N0”c ons i s t soft hr eet hi ngs :i nt er f er i ng( n onor t hogonal )power ,t her mal noi s e,and,noni nt er f er i ng( or t hogonal )power . I ns i t u at i on swh er eN0co ns i s t sma i n l yof" i n c e l l "p owe r( e . g . ,d ur i n gHSDSCHbu r s t s ) ,Ec / N0c anbe" l o w" ,wh er e ast heob j e ct i v es i g na l qual i t yi shi gh.Thi swi l l bes howni nt hef ol l owi ngs l i des Mi s c o nc e pt i o nsa b ou tEc / No 7.F ur t h er ,Eci sa ne x pr e s si o no fp owe ri nt h eCPI CH,n oti nt h ed own l i n kDPx CH. Th ou ght h ed y na mi cr a ng eo fd own l i n kDPx CHp owe ri sof t e ne x pr e s se dr e l a t i v et ot h eCPI CH,d own l i n kp owe rc o n t r o lwi l l d oi t sb es tt o en su r et h atd own l i n kSNRi swh at e v eri tn eed st ob et ome ett het r a ns po r tc han ne lq ua l i t yt a r g et . Th ep oi n tb ei n g:Th et r a fficc h an ne lSNRh asa l mo s tn ot h i n gt odowi t hpi l o tEc / N0 . I ti sal s ot obeno t edt h atUEi son l yc ap ab l eofr e cei v i n gPi l o tRSCPa ndRSSIo nt heca r r i er .Ec Noi sc al c ul a t e db yt h eUEb yt hef o r mul a ( RSCPRSSI )a n ds e n ti nt h eUL . Mi s c o nc e pt i o nsa b ou tEc / No 8.Do n’ tbes h y .Ik no w we ’ r es t i l l Co nf u sed…. .ϑ Bas i c s ……. 9.Th en , Ec / Nof o raUEi s Th eme as u r eofPCPI CH( c o depo we r )o v e rT o t a lWi d eb an dPo we ro nt h atp ar t i c u l a rc a r r i e r Measur eofPCPI CH=RSCPdBm ( r i ght ?) Measur eofTot alWi debandpower=RSSIdBm Soou rEc / Nowi l l b ec o meEc / No=RSCP/RSSI( c a nn o td i v i d ed Bm v a l u ess oweha v et oap pl yl o ga r i t h mi cr u l e s ) Ec/ No=RSCP–RSSI( db)( dBm –dBm =val uei ndB) Fort hes ak eofs i mpl i c i t y ,j us ti magi net haty ou’ r ei nat es t bed,bei ngs er v edb yas i ngl ec el l 10.Hopeyou’ r eabl et omakeapi ct ur eofhow Ec/ Nowor ks……. I fy e s ,p r o c e edf u r t h ert ofin dwh ath ap pe nswh enanHSDPAs e ss i o ni si n i t i a t e d I fno t ,Is ug ge sty oud i s c us st h i sc on cep tfi r s tb ef o r epr o ce edi n g. Ar ey o ut h e r ey e t …? 11.L et ’ st a k eal o oka th o wt h ePOWERo faCEL Li sd i s t r i b ut e da mo ngdi ff e r e n tc h an ne l s Fo rs i mp l i c i t y ,c he ckt h ed i ag r a mb el o w. No t i c et h a tHSDP Au s e st h eREMAI NI NG p o we ro ft h ec e l l a f t e rp o we ri sa l l o c a t e dt oCo mmo na n dDe d i c a t e dc h a nn e l s( c h e c kmo r e de t a i l edfi gur ei nt hene xts l i de) HSDPA
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Cel l PowerDi s t r i but i on De di c a t e dc h an ne l s( p o we rc o nt r o l l e d) T ot al a vai l abl ec el l power Co mmo nc ha nn el s( n o tp owe rc o nt r o l l e d) 12.Cel l Po werDi s t r i but i on Thefi gur eshi ghl i ghtt hef ol l owi ngpoi nt s : Co mmo nCh an ne l sh av et h eh i g he s tp r i o r i t yf o rPo we r .Th ei rp owe ri sfi x e d DCHc o mes e co ndi np r i o r i t y–Po we rc o nt r o li sap pl i c a bl e Al l t h atr e ma i n saf t e rDCHu t i l i z at i o nc a nb eu se du pf o rHSDPAp owe r Soi fac el li sl e s sl o ad ed ,as i n gl eUEHSs e s si o nc a nu t i l i z et h ewh ol eHSDPAp owe rs p a cewh i c hi sl y i n gu nu s ed . 13.No wi ma gi n ey ou r s e l fc o nd uc t i n gat e s ti nT es tBe donac el l h a v i n gZERO DCHo rHST r a ffic . As s u mi n go n l y1 0 %c e l lp o we ri sd e di c a t e dt oCPI CH( 3 3 dBm =2 wa t t ) Cel l MAXTXPOWER i s2 0W or43 dBm I d eal l y ,i fy ouha v eNO t r a fficont hi sc el l ,y ou rUEwi l l c al c ul at et h eCPI CHEc / Noi nt h ef o l l o wi n gma nn er Ec / No=1 0l o g( CPI CHp owe r/T o t a lT r a ns mi tp owe r ) Ec / No=1 0l o g( 2 w/ 2 w)=10l o g( 1 )=0d B( VERYh i g h,b utt h at ’ sI DEAL ! ! ! ) OR( i ndBm) Ec/ No=RCSP–RSSI Ec/ No=33( dBm)–33( dBm)=0* Ec/ NoComput at i on–NoLoad 14.Ec/ NoComput at i on–OneHSDPAuse r No wa s s u mey o us t a r ta nHSs e s s i o n . Si n c et h e r ei sn oDCHt r a ffic ,a l lt h eREMNANTpo we ri sg i v e nt oHSDP A Ce l l T r a n s mi tp o we ri sn o w2 Wf o rCPI CHa n dREMNANTp o we r( 1 8 W)f o rHSDP A–s oi d e al l y ,Ce l l i su t i l i z i n ga l mo s t1 0 0% p o we r SoUEwi l l me as u r et h eEc / Noi nt h ef o l l o wi n gma nn er Ec / No=1 0l o g( CPI CHp owe r/T o t a lT r a ns mi tPo we r ) Ec/ No=10l og( 2W /20W) Ec / No=1 0l o g( 0 . 1 )=1 0d B( Ve r yl o w –ag ai nv er yI DEAL ! ) OR( i ndBm) Ec/ No=RCSP–RSSI Ec/ No=33( dBm)–43( dBm)=10dB 15.WhyCQI Fr o ma bo v ec o mp ut a t i o ns ,wee s t a bl i s ht h ef o l l o wi n g: I nI d l emo dean dwi t hnor e s ou r c e sal l o c at e d,aUEwi l l me as u r easl o wa s0d BEc / No I nHSMo dean dwi t hnor e s ou r c e sal l o c at e do nDCH,aUEwi l l me as u r easl o wa s1 0d B.I tc a nn o tr e po r t ANYb et t e rt h an1 0d B
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He nc e,t h atme an s ,i nal i v en et wo r kwh er er e so ur c e so fc e l l a r es h ar e db et we enma nyus er s ,a ndI n t e r f e r e nc ef r o mo t h erc e l l sal s op l a y s i t spa r t ,t h eEc / Nowi l l a l wa y sgi v eaF AL SEv a l u ef o ra nHSDPAu s er .An di twi l l s h owav e r yp oo rv a l u e Wh aty o us h ou l dbeas k i n gy o ur s e l f : Whathappenswhenmor euser sj oi ni nt oshar et heREMNANTpower ? Wi l l Ec / Noi mp r o v eo rd e gr a def u r t h erwi t had di t i o no fDCHo rHSu se r ? 16.So,wees t abl i s ht hat , Th eCPI CHEc / Nome as u r e me nt sc o l l e c t e ddu r i n gHSDP AT r a ns mi s s i o nc ou l dma s kt h et r u er a d i oc o nd i t i o ns T oa v oi dt h i s ,weh av et omo ni t o rt h eEc / Noi nI DL Emo deo nl y , wh i c hi sat r u er e fle c t i o no fI n t e r f e r e nc ea ndc o v er a gepr o bl e ms HSDPAs e ss i o na dd st ot h eo v er a l l l o ado ft h ec el l wh i c hi st a k eni n t oc o ns i d er a t i o nd ur i n gc o mp ut i n gEc / No .Asca l c u l a t i o nsab ov ep r o v e d t h att h i sdoe sn ot ,ne ce ss ar i l y ,d ep i c tt h eTRUEr a di oCo nd i t i on s. So ,wh a ti st h eAL T ERNA TI VEt oEc / Noi nHSs e s s i o n ? I t sc al l edChannel Qual i t yI ndi c at i on CQI WhyCQI 17.Whati sCQI HSDPAu t i l i z esl i n ka dap t a t i o nt e chn i q ue st os ub st i t ut epo we r c on t r o la ndv ar i a bl es pr e ad i n gf a ct o r Th eHSDSCHl i n k a da pt a t i o na l g or i t h ma tt h eNo de Bi sv e r yd y na mi c ,a ndad j u s t st h et r a ns mi tb i tr a t eont h eHSDSCHe v er y2 msTTI . Th eUEp er i o di c a l l ys en dsaCQIt ot h es e r v i n gHSDSCHc e l l o nt h eu pl i n kh i g hs p ee dd ed i c a t e dp h y s i c a lc o nt r o lc h an ne l( HSDPCCH) Th eCQIt e l l st h eNo de Bs c he du l e r ,t heda t ar a t et h eUEe x pe ct st obeab l et or e c ei v ea tagi v enpo i n ti nt i me . NOTE:Th eHSDP As y s t e md efi n esadi ff e r e ntCQIma pp i n gt a bl ef o rd i ff e r e ntc a t e go r i e sofUEs .Th ec a t e go r yi sd et e r mi n edac c o r d i n gt o t hec apabi l i t yofUE I naddi t i ont oCQI ,UEal sosendsHARQ onHSDPCCH 18.Be l o wfi gu r esh owst h es t e psho w CQIh el p si nde t e r mi n i n gt h ei n i t i a lt h r o u gh pu tt h ataUEt e r mi n al d ema nd sf r o mt h es y s t e m STEPS SI NRi sus e dt oe v al u at et h ec ha nn el q ua l i t yasob s er v e db yt h er e c ei v e r ,wh er eas t a nd ar ds i n gl ea nt e nn aRa k ei sus e db ec a us ei ti st h e most commoni nt heSI SO HSDPAt er mi nal s. CQIv a l u ef o ragi v e nSI NRi sd on ev i aal i n ea rma pp i n g,a ss ho wni nfi gu r e Cont d…. . HSDPA–CQIi nv ol v ement 19.HSDPA–CQIi nv ol ve ment STEPS Th eCQIv a l u esar eus e db yt h el i n ka da pt a t i o na l g or i t h ma tt h eNo de B.Ev e r yCQIv a l u er e po r t e dc o r r e s po nd st ot h eT r a ns p or tBl o c kSi z e ( TBS)t h atc a nb eg r a n t e do napa r t i c u l a rMo du l a t i o nt y p ea ndNu mb ero fc o de s
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Ex a mp l eofaUEc at e go r y1 0CQIv a l u esf r o m 0t o30ar es ho wni nt h efi g ur e .Ot h erUEc a t e go r i e sar es ho wni nt h ef o l l o wi n gs l i d e Th eCQIi sf u r t h e rd e fi n e da st h eT BSt h a tc a nb es u p p or t e dwi t haBL ERn og r e a t e rt h a n1 0 %20.STEPS Wh i l eCQIi ss e nd i n gUE’ sr e qu i r e me ntt ot h es y s t e mi nUL ,t h er ei sBL ERc a l c u l a t i o ng oi n go na ndULHARQ ( Hy b r i dAu t oRe pe at Re qu es t )me c ha ni s mi sh el p i n gi nma i n t a i n i n gt h eBL ERt obe l o w1 0%. Sot h es y s t e m( No de B)i se ss e nt i a l l yc a l c u l a t i n gt h eDa t aRa t et obes ch ed ul e dt ot h eu s erb as edonCQIr e po r t sa ndBL ERwh i c hi t r e ce i v e sf r o mt h eUE SoDA T ARA TE( b p s )=TBS( b i t s ) /TT I( s e c )*( 1 BL ER) HSDPA–CQIi nv ol v ement 21.HSDPA–UECat egor i es112 22.Th an ky ouf o rr e ad i n g
