Adaptive Processing Gain Data Services in Cellular CDMA in Presence of Soft Handoff with Truncated ARQ

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1 I. J. Communaton, Netwok and Sytem Sene, 009,, Publhed Onlne May 009 n SRe (htt:// Adatve Poeng Gan Data Seve n Cellula CDMA n Peene of Soft Handoff wth Tunated ARQ Dta DAS (Chaudhu), Sumt KUNDU + Deatment of Eleton & Communaton Engg, D. B. C. Roy Engg College, Dugau, Inda + Deatment of Eleton & Communaton Engg, Natonal Inttute of Tehnology, Dugau, Inda Emal: [email protected], [email protected] Reeved Otobe 7, 008; eved Deembe 8, 008; aeted Febuay 11, 009 ABSTRACT An adatve data tanmon heme baed on vaable eadng gan (VSG) tuded n ellula CDMA netwok n eene of oft handoff (HO). The oeng gan vaed aodng to taff ntenty meetng a equement on data bt eo ate (BER). The oveall efomane movement due to oeng gan adataton and oft HO evaluated and omaed wth a fxed ate ytem. The nfluene of oft HO aamete on ate adataton and thoughut and delay efomane of data ndated. Futhe tunated automat eeat equet (T-ARQ) ued n lnk laye to move the efomane of delay entve eve. The jont mat of VSG baed tanmon n eene of oft handoff at hyal laye and T-ARQ at lnk laye evaluated. A vaable aket ze heme alo tuded to meet a ontant on aket lo. Keywod: Adatve Sytem, Vaable Seadng Gan, Soft Handoff, ARQ 1. Intoduton Multmeda eve ae beomng neangly motant n wele netwok. The demand fo hgh ate aket data tanmon and qualty of eve (QoS) n wele netwok gowng at a ad ae. Code Dvon Multle Ae (CDMA) vey omng to meet the demand fo hgh data ate and qualty of eve (QoS) n wele netwok. The ellula aaty of CDMA ytem lmted n the ulnk by maxmum toleable ntefeene at the bae taton (BS). The ellula aaty ndate that thee a atal numbe of admble ue whh hould not be exeeded n ode to enue QoS (qualty of eve) of the admtted ue. Howeve fo a fxed data ate ytem, thee wll be edundant magn on ytem aaty when taff level muh lowe than the maxmum allowed numbe. Adatve tanmon heme utlze the ytem eoue moe effently ove a fxed ate heme whee the data tanmon ate ontolled deendng on geneated ntefeene o hannel taff ntenty [1-3]. Paket data tanmon ganng motane n CDMA netwok. Vaable oeng gan (VSG) and mult-ode (MC) ae two nteetng aoahe fo neang tanmon ate of data n CDMA [4]. CDMA ue oft handoff (HO) whee the handoff moble nea a ell bounday tanmt to and eeve fom two o moe BS- multaneouly [5]. Soft HO ovde a eamle onnetvty, edue ng-ong effet a eent n had HO, lowe obablty of lot all and eae owe ontol [5,6]. It extend the oveage and neae the evee lnk aaty [6,7] by edung oveall ntefeene. Seveal eeah ae have analyzed adatve tanmon baed on VSG [1-4] wthout ondeng the effet of oft HO. Sne oft HO affet the geneated ntefeene, t exeted to have gnfant mat on eadng gan eleton and ueful tanmon of aket data, whh ondeed n the eent ae. Howeve efomane of data eve lmted by ntefeene and hannel fadng. Adatve modulaton and odng (AMC), adatve antenna aay ovdng ae dvety and eveal eeve algothm at hyal laye [8,9] ae ued to enhane the thoughut efomane of aket data oented ytem. Altenately Coyght 009 SRe. I. J. Communaton, Netwok and Sytem Sene, 009,,

2 156 D. DAS ET AL. hannel fadng an be mtgated by automat eeat equet (ARQ) otool at the data lnk laye whh enue etent etanmon of aket aoated wth a atula meage untl t eeved oetly. ARQ effetve n movng ytem thoughut elatve to only fowad eo oeton (FEC) [9]. Futhe ARQ an be ombned wth FEC n a hybd ARQ heme. To mnmze delay and buffe ze n ate, tunated ARQ ha been adated to lmt the numbe of etanmon. Futhe the tanmon of vdeo/mage eque the delay to be bounded.e. a aket to be doed f t not eeved oetly afte a fnte numbe of etanmon [8]. Seveal eeah ae have tuded the ombned effet of hyal laye ue wth the lnk laye ue lke ARQ [8,9]. Howeve the ue of oft handoff at hyal laye not ondeed n [8,9]. In the eent ae we onde VSG baed data tanmon meetng a ontant on ue lmt of BER n eene of oft handoff. A mulaton tudy aed out to evaluate efomane of aket data n tem of thoughut and delay ondeng the jont effet of VSG and oft handoff. Two ae of etanmon namely nfnte ARQ and tunated ARQ at lnk laye ae alo ondeed. Ft the efomane of data ha been mulated n VSG wth oft HO ondeng nfnte ARQ. Next T-ARQ ondeed at lnk laye fo eal tme eve along wth oft HO at hyal laye. Jont effet of oft HO and tunated ARQ on thoughut and delay efomane of a aketzed data ae evaluated fo an mefet owe ontol CDMA. The efomane n eah ae omaed wth fxed ate. Effet of oft HO aamete on eadng gan adataton and data efomane n tem of thoughut, delay and aket lo aoated wth tunaton ae ndated. Futhe a vaable ze aket tanmon alo ondeed to meet a ontant on aket lo ate. Thu t ha been oble to atfy the BER ontant, delay ontant and the aket level QoS uh a aket lo ate a well. Seton and 3 befly debe the ellula enao and ou mulaton model. Reult and duon ae eented n Seton 4. Fnally we onlude n Seton 5.. Sytem Model A lute of thee etoed ell wth unfomly dtbuted moble data ue (MS) and equal numbe of MS- ( N d ) e eto ae ondeed. All data ue tanmt at the ame ate ung a ngle ode. Fo fxed ate ytem the ue tanmt on ngle ode at a fxed ate R b whle n adatve ytem the tanmon ate R b (l) vaable deendng on taff load (l) whh Poon dtbuted wth mean (). The oeng gan ( g ) of all ode ae equal; whee g(l) =W/ R b (l) ; W ead bandwdth. Poeng gan g(l) (hene data ate R b (l) ) eleted deendng on taff load (l) atfyng a BER teon. A ontnuouly atve data taff model a n [10] ondeed whee eah ue geneate a equene of fxed length aket. A new aket geneated a oon a the eedng aket ethe delveed uefully o doed due to tunaton n ARQ. The oft HO egon defned baed on the dtane fom the bae taton (BS) a n Fgue 1. An MS loated outde the handoff bounday R h ondeed to be unde oft HO wth thee neghbong BS-. Eah eto dvded nto two egon, oft HO egon (B, C, D) and non-ho egon (A, E, F) of ell #0,1and eetvely n Fgue 1. BS 0, BS 1 and BS ae the BS- of ell #0, 1 and eetvely. The oagaton ado hannel modeled a n [7]. The lnk gan fo a loaton (, ) G (, ) d (, ) 10 S /10 (1) whee d (, ) the dtane between the MS and /10 BS, the ath lo exonent and 10 the log-nomal omonent wth wth 0 mean and vaane BS [7] and nomally dtbuted. The hadow fadng at -th a b wth a b 1 () ae ndeendent Gauan andom vaable wth zeo mean and vaane. Out-ell ntefeene ont of ntefeene due to MS- fom egon (E,C,G,H) of ell #1 and (D,F,I,J) of ell #. MS- n futhet eto (G,H,I,J) ae aumed to be owe ontolled by eetve BS-. The efeene ue loated n non-ho egon of efeene eto.e. n egon A. Total n-ell ntefeene n ell # 0 I n I 1 I (3) whee I 1 due to all MS- n A and thoe n B onneted to BS 0, I due to MS- n B but onneted to BS 1 and BS. The out-ell ntefeene I out I o I H ( I E I 1 I I o I G I ) (4) I E the ntefeene due to MS- n E and onneted to BS 1. Smlaly I 1 and I ae due to MS- n egon C and owe ontolled by BS 1 and BS eetvely. due to MS- n C and ontolled by BS 0. and ae the ntefeene due to MS- n G and I G H. MS- n thee fathet eto ae aumed to be owe ontolled by eetve BS.e. BS 1. A multlaton fato of two ued n Equaton (4) to nlude H Coyght 009 SRe. I. J. Communaton, Netwok and Sytem Sene, 009,,

3 ADAPTIVE PROCESSING GAIN DATA SERVICES IN CELLULAR CDMA 157 IN PRESENCE OF SOFT HANDOFF WITH TRUNCATED ARQ ontbuton of ell #. The atual eeved owe fom S deed ue U S R e, whee S a Gauan.v. wth mean 0 and vaane S e. The BER ( P e ) fo data ue mulated a debed n late eton n the above oft HO envonment ondeng det equene eadng and BPSK data modulaton havng ead b.w of W. The maxmum allowed bt ate of data ue ( l) fo taff ntenty adjuted uh that ( ), R b P e g (l) the oeondng oeng gan eleted a. The etanmon obablty P gven a [11] P = 1 ( 1 P ) (5) whee L the length of the aket n bt and the FEC ode ate. Fo ontnuouly atve data ue, the aveage aket delay the ame a the aket tanfe tme T a thee no watng delay n the queue. The tme equed fo tanmttng a aket of length L by a data ue tanmttng at a ate of : T e L R b (l) L L g ( l) R ( l) R (6) b whee R the h ate. We aume that aknowledgement fom the eeve ntantaneou and efetly elable. In ae of tunated ARQ the maxmum numbe of etanmon n ARQ ha to be bounded ne only fnte delay and buffe ze an be affoded n ate. If T max the maxmum allowed aket delay, the maxmum numbe of etanmon gven a N max T max /T. Thu wth tunated ARQ f a aket not eeved oetly afte N max etanmon, t doed and delaed a a aket lo. The aveage delay wth tunaton L D ( 1). g ( l) R N t 1 P 1 P The aveage thoughut defned a the aveage numbe of nfomaton bt uefully tanfeed e e and gven a L.. R (1 P ) G ( N 1) D g ( l) (1 P t (8) ) Some eve may eque mantanng aket lo (aket QoS) below a ebed lmt ( ). A vaable aket length heme ued whee the aket ze adjuted unde dffeent taff and oft HO ondton o a to mantan aket lo below a deed lmt ( ). The length of the aket ( Plo : L (7) ) eleted atfyng L N t 1 Pe t T max / T.e. {1 (1 ) }, N (9) whee T L / R (10) found by multaneouly at- The aket ze fyng (9) and (10). b L Howeve wth nfnte etanmon.e. nfnte ARQ, thee no aket lo. In uh tuaton the aveage delay [11] D= T L g ( l) = 1 P ) R (1 P ) ( (11) and the aveage thoughut (G) gven a L R (1 P ) G (1) D g ( l) In the next eton we eent ou mulaton model fo both nfnte and tunated ARQ ae. 3. Smulaton Model The mulaton develoed n MATLAB ung the followng aamete: PR h ndate the degee of oft HO, hadowng oelaton (a ), e e, taff ntenty. he oft HO egon bounday gven a Rh Ro 1 PRh whee R o the adu of the ell, nomalzed to unty and hexagonal ell aoxmated by a ula one wth adu R o. Ue ae aumed to be unfomly dtbuted Geneaton of Ue Loaton and Intefeene 1) The numbe of ue ( N d ) geneated by geneatng a Poon dtbuted.v wth mean. ) Loaton (, ) of all ( N d ) ue ae geneated and ue ae dvded nto non-ho ( N h ) and oft HO ( N ) egon baed on the loaton. Aumng the deed ue n non-ho egon, let the emanng ntefeng ue n non-ho ae ( N h -1). Numbe of ue n oft HO egon: N N d N h. 3) Fo eah of thoe n oft HO egon ( N ), the lnk gan oeondng to eah of thee BS- nvolved n oft HO ae geneated a G (, ) e, =0,1,. whee a Gauan.v wth mean 0 and vaane b, the dtane fom -th BS. The ue owe ontolled by the BS fo whh the lnk gan maxmum.e. t owe ontolled by BS f G maxmum; 0,1,. R h Coyght 009 SRe. I. J. Communaton, Netwok and Sytem Sene, 009,,

4 158 D. DAS ET AL. 4) The ntefeene eeved at efeene BS G0 I= S R ex( n ) ( ) G (13) f onneted to BS, whee 0, 1,. Hee n a nomal.v. wth 0 mean and tandad devaton e. S R the equed eeved owe at the eetve BS whh nomalzed to unty n the mulaton ne SIR unaffeted by agnng S R =1. 5) Next ntefeene due to ( N h -1) MS- n non_ho egon (A) of efeene ell, eah owe ontolled by BS 0 ondeed a Nh 1 n, I S R e (14) 1 6) Now the ntefeene due to MS- n adjaent eto.e. (egon E,C,D and F) of ell#1 and # ae found n mla manne. The numbe of MS- n E and F ae ( N d N ) eah. Let I 3 I E I C and I 4 I D I F 7) Intefeene fom MS- n G,H, I and J egon ae geneated followng te 4. Let I 5 I G I H and I 6 I I I J. 6 I k k 1 8)Total ntefeene I= (15) 9) Sgnal fom deed ue x U S d e, SIR U / I (16) x Gauan wth mean 0 and vaane 3.. BER Smulaton A Gauan noe amle n g e wth 0 mean and vaane g 1./( g. SIR ) added to eah bt of a tanmtted equene and eeved bt ae omaed wth the tanmtted bt. Hee SIR found followng te A(1) to A(8) fo a gven g Seleton of Poeng Gan 1. An ntal low value of R b hoen and BER mulated a debed above.. nemented n te, the hghet value of Rb R b fo whh oeng gan g = W R b BER, hoen and oeondng eleted Paket Lo and Vaable Paket Length 1) Fo tunated ARQ ae: A amle of Gauan noe a n (B) added to eah tanmtted bt of a aket of L( L ) nfomaton bt. The eeved L bt of a aket ae heked wth the oeondng tanmtted bt to ae aket eo. If the eeved aket noet, the ame aket (.e. the ame bt atten) e-tanmtted N t tme, whee N t = 1,, N max. A aket lo ou f t not eeved oetly afte Nt e-tanmon. Aveage delay (D) etmated a: (( N etx _ ount )./ ) T whee T a n (6), N N : numbe of tanmtted aket, etx _ ount : total etanmon of aket (eah aket etanmtted maxmum u to The thoughut : N N max L / tme. G D (17) An ntal mall aket ze hoen and t nemented n te ( =) tll aket lo jut exeed. The hghet aket length fo whh P lo L. Now thoughut, delay and aket lo ae etmated by mulaton followng te a mentoned above whee g hoen a g ( l ) and L hoen a L. ) Fo nfnte ARQ ae: If the eeved aket noet, the ame aket etanmtted untl the aket fnally eeved oetly ntead of lmtng the etanmon to N max a n ae of T-ARQ. Then delay and thoughut n th ae ae etmated n the ame manne a debed above. Total numbe of eoneou aket ounted out of a lage numbe of tanmtted aket to etmate the aket eo ate (PER). 4. Reult and Duon The aamete aumed n mulaton ae lted n Table 1 a hown. Fo the ae of tunaton we aume Tmax =350 me and Nt = N / max whee N max maxmum etanmon oeondng to. Sead BW (W) T max Table 1. Paamete fo mulaton. Ch ate R Fxed PG Fxed L SIR thehold th e (db) 5.0 MHz 5.0 M db 1 and Shadowng Degee of Path lo Max allowed (db) oelaton oft HO ( a ) PR h aket lo and , 0.7 5% Taget BER T max me e Coyght 009 SRe. I. J. Communaton, Netwok and Sytem Sene, 009,,

5 ADAPTIVE PROCESSING GAIN DATA SERVICES IN CELLULAR CDMA 159 IN PRESENCE OF SOFT HANDOFF WITH TRUNCATED ARQ Fgue 1. Cellula Layout fo oft HO. A, E, F ae non HO egon. B, C, D ae oft HO egon. Cell # 0 efeene ell. Fgue how the effet of oft HO on BER efomane of fxed ate and adatve tanmon. In adatve tanmon, the BER alway mantaned a P e g fo the ente ange of taff by adjutng the.e. tanmon ate edued wth neae n 10 3 BS 0 taff a n uve (v,v). Whle n fxed ate (PG=31), the BER neae wth neae n taff ntenty due to neaed ntefeene a n uve (, and ). Hghe degee of oft HO edue BER n fxed g ae a een n uve () and () due to edued level of ntefeene. In ae of adatve tanmon, a the tanmon ate adjuted (vayng the g) keeng BER fxed, a hghe degee of oft HO wll lead to neae n data ate.e. lowe oeng gan alloaton fo ame BER ontant of P 10 3 e. Two ae of adatve g wth dffeent level of oft HO have been 3 hown n uve (v, v) whee BER 10 n both the ae. Howeve the data ate (alloated g) fo thee ae wll be gnfantly dffeent a een n next fg. Fgue 3 how the effet of oft HO on alloaton of oeng gan n VSG baed adatve tanmon. The oeng gan ( g) ae hoen atfyng BER 10 3 unde dffeent ondton of oft HO. A the taff ntenty () neae, data ate edued by neang g o a to edue the ntefeene level fo mantanng BER ontant. Hghe degee of oft HO edue BER fo fxed data ate. A BER ket fxed, hghe degee of oft HO wll allow hghe data ate o lowe value of alloated g n uve ( and ). Thu t een that a PR neae fom 0.3 to 0.7, alloated g fo BER 10 3 edue fom 339 to 60 at =8. Hghe hadowng oelaton h BS 1 ( a ) a well a lowe e alo edue BER fo fxed PG. Thu n a mla manne a n ae of PR h, th wll alo neae data ate (o edue oeng gan) fo a taget BER a een n uve (,) and uve (,v). The thoughut efomane wth T-ARQ deted n Fgue 4. Adatve g baed tanmon een to aheve a hghe thoughut a omaed to a fxed one fo mot ange of taff n uve (,). Th beaue BER mantaned below a lmt n adatve ae wheea t neae wth taff n ae of fxed g. Futhe movement n thoughut aheved wth hghe degee of oft handoff n uve (,). Howeve a een n Fgue 4 vde uve (,), ove a ange of taff ay u to =7, adatve g and fxed g yeld loe thoughut efomane. Th beaue ou abtay hoen value of fxed g.e. PG=31 loe to adatve g- found (atfyng P 10 3 e ) ove th taff ange. Fo examle at =7, alloated adatve g =304. Effet of oft HO aamete on aket delay ae deted n Fgue 5. Tunaton alway mantan aket delay below a etan level, hee 0.5 tme of T max = 350 me, a numbe of etanmon N t = N max /. Adatve tanmon yeld le delay a omaed to fxed ae fo mot ange of taff. Adatve tanmon alway mantan a fxed BER hene a fxed level of PER (aket eo ate) whle BER neae wth taff n ae of fxed g. Howeve aound 7 the efomane of fxed and adatve ae loe a ou hoen fxed g of 31 beome loe to found value of adatve g. Hghe degee of oft handoff found to lowe delay futhe a een n uve (,). Fgue 6 how the aket lo aoated wth T-ARQ v taff ntenty fo fxed and adatve g baed tanmon. Adatve g alway mantan a fxed level of aket eo. Thu adatve g yeld lowe aket lo a omaed to fxed ate fo modeate taff n uve (,). The aket lo eahe a floo fo adatve ae whle t neae wth hghe taff n ae of fxed ate. Futhe the aket lo ket below 5% ung vaable aket ze a een n uve (v). Hghe oft handoff edue aket lo a n uve (, ). Fgue 7 how the vaaton of aket ze wth taff ntenty. The aket ze vaed n ode to enue that aket lo alway 5%. Hghe taff ntenty eque malle ze of aket. Futhe hghe degee of oft handoff ( PRh ) an tanmt lage aket a een n uve (,). Hghe hadowng oelaton alo allow lage aket whle meetng the lo ontant a n uve (,). Table how the maxmum numbe of etanmon allowed v taff unde two dffeent oft handoff ondton. A the taff ntenty neae, the allo- Coyght 009 SRe. I. J. Communaton, Netwok and Sytem Sene, 009,,

6 160 D. DAS ET AL. Table. Maxmum numbe of etanmon v taff (mean aval ate) fo adatve g baed tanmon (1) N max () N max (1) a 0.3, PRh 0.3, e db T =350 me () a 0.3, PRh 0.7, e db T =350 me ated data ate edued (.e. alloated g neae). Thu the aket tanfe tme neaed whh n tun edue the maxmum numbe of etanmon fo a ebed maxmum allowed delay. Hghe oft HO allow moe numbe of etanmon. Fgue 8 how the effet of tunated ARQ on delay. We have hoen tunaton n etanmon a N t = N / max to enue a maxmum delay of 0.5 tme of Tmax =350me.e. maxmum allowed delay of 175 me n th ae. It een that n ae of nfnte e- max max tanmon, the delay neae adly wth taff ntenty. T-ARQ alway yeld lowe delay a omaed to nfnte ARQ (uve,). Futhe n ae of T-ARQ, though delay neae wth taff, t alway mantaned below a hoen deed lmt of 175 me (.e. 0.5 Fgue 4. Thoughut (Kb) v mean aval ate. Mean aval ate Fgue. BER v mean aval ate ( ue/e) e eto. Fgue 5. Delay (me) v mean aval ate. Fgue 3. Poeng gan v mean aval ate ( ue/ e) e eto. Fgue 6. Paket lo obablty v mean aval ate. Coyght 009 SRe. I. J. Communaton, Netwok and Sytem Sene, 009,,

7 ADAPTIVE PROCESSING GAIN DATA SERVICES IN CELLULAR CDMA 161 IN PRESENCE OF SOFT HANDOFF WITH TRUNCATED ARQ T max ). Wth nfnte etanmon the delay exeed deed lmt of 175me fo =10 onwad n ae of a =0.3 and =6 onwad fo a =0 n uve (,). Thu T-ARQ atfe delay ontant at the ot of aket lo. Futhe hghe hadowng oelaton lowe the delay n uve (,). Fgue 9 how the effet of tunated ARQ and hadowng oelaton on thoughut. In eent wok thoughut ndate the aveage numbe of nfomaton bt uefully tanfeed e e. Sne a aket delveed uefully wth n a gven tme lmt n tunaton (o doed f not ueful), tunaton yeld hghe thoughut a omaed to nfnte etanmon a n uve (,). Alo hghe hadowng oelaton move thoughut a n uve (,). 5. Conluon Fgue 7. Effet of oft HO and hadowng oelaton on aket length fo adatve g baed Tanmon. Fgue 8. Effet of tunaton n ARQ on delay. Pefomane of aket data evaluated n eene of oft handoff unde adatve tanmon baed on vaable oeng gan and omaed wth a fxed ate ytem. The oeng gan vaed aodng to taff ntenty o a to enue an ue lmt on hannel BER. Tunated ARQ ued to enue a ebed maxmum lmt on aket delay. Soft handoff aamete, hadowng oelaton, e and T-ARQ ae found to have gnfant mat on oeng gan alloaton and data efomane. Adatve tanmon outefom fxed tanmon n tem of thoughut, delay and aket lo. Adatve tanmon enhane thoughut by 19% and edue aket lo by 16% fo a taff ntenty of 10 ue/e unde a gven oft handoff enao. Hghe degee of oft handoff and hghe hadowng oelaton move the tuaton futhe. An neae n degee of oft handoff by 133% futhe enhane thoughut by 6% and edue aket lo by 1 % fo a taff ntenty of 10 ue/e. Ung a vaable aket length tanmon the aket lo ould be mantaned below a lmt. Thu data BER, delay ontant and aket QoS uh a aket lo ae multaneouly atfed ung vaable oeng gan, vaable aket length and T-ARQ. Hghe degee of oft handoff and hghe hadowng oelaton allow tanmon of lage aket ze. An neae n degee of oft handoff by 133% allow 0% neae n aket ze fo a taff of 10 ue/e atfyng a aket lo ontant. 6. Refeene Fgue 9. Effet of tunaton n ARQ on thoughut. [1] K. Cho, S. Km, Shn, and K. Cheun, Adatve oeng gan CDMA netwok ove oon taff hannel, IEEE Communaton Lette, Vol. 6, No. 7, , July 00. [] K. Cho, Y. Chae, and J. Pak, Thoughut-delay efomane of ntefeene level adatve tanmon n voe/data ntegated CDMA netwok wth vaable eadng gan, IEE Poeedng on Communaton, Vol. 151, No. 3,. 17-0, June 004. Coyght 009 SRe. I. J. Communaton, Netwok and Sytem Sene, 009,,

8 16 D. DAS ET AL. [3] L. L. Yang and L. Hanzo, Adatve ate DS-CDMA ytem ung vaable eadng fato, IEEE Tanaton on Vehula Tehnology, Vol. 53, No. 1,. 7-81, Januay 004. [4] S. Kuma and S. Nanda, Hgh data ate aket ommunaton fo ellula netwok ung CDMA: Algothm and efomane, IEEE Jounal on Seleted Aea n Communaton, Vol. 17, No. 3, , Mah [5] D. Wong and T. Lm, Soft handoff n CDMA moble ytem, IEEE Peonal Communaton,. 6-17, Deembe [6] H. Jang and C. H. Dav, Coveage exanon and aaty movement fom oft handoff fo ellula CDMA, IEEE Tanaton on Wele Communaton, Vol. 4, No. 5, , Setembe 005. [7] J. Y. Km and G. L. Stube, CDMA oft HO analy n the eene of owe ontol eo and hadowng oelaton, IEEE Tan on wele Communaton, Vol. 1, No., , Al 00. [8] Q. Lu, S. Zhou, and G. B. Gannak, Co laye ombnng of adatve modulaton and odng wth tunated ARQ ove wele lnk, IEEE Tanaton on Wele Communaton, Vol. 3, No. 5, , Setembe 004. [9] B. Lu, X. Wang, and J. Zhang, Thoughut of CDMA data netwok wth mult-ue deteton, ARQ and aket ombnng, IEEE Tanaton on Wele Communaton, Vol. 3, No. 5, , Setembe 004. [10] J. Km and M. Hong, Reoue alloaton fo multle la of DS-CDMA taff, IEEE Tanaton on Vehula Tehnology, Vo. l49, No., , Mah 000. [11] S. Kundu and S. Chakabat, Pefomane of hgh ate data n wdeband CDMA wth oelated ntefee, n GESTS Intenatonal Tanaton on Communaton & Sgnal Poeng, Vol. 7, No. 1, , June 006. Coyght 009 SRe. I. J. Communaton, Netwok and Sytem Sene, 009,,