Adaptive Playout Adjustment Algorithm to Improve QOS for Voice Streaming over Wireless Ad-hoc Networks

Transcription

1 Adtve Plyout Adjutment Algorthm to Imrove QOS for Voce Stremng over Wrele Ad-hoc Network M. Sleh, M. Dehghn Dertment of Comuter Engneerng, Amrkbr Unverty of Technology, Tehrn, Irn Abtrct Provdng ervce wth good qulty for trnmon nd lyng rel-tme voce converton (voce tremng over wrele d-hoc work lwy bg chllenge. Bufferng nd djutng the lyout tme of cket one of the method ued to overcome th chllenge whch cn be deloyed n recever de. In th er, new dtve lyout djutment lgorthm to trem the voce converton over wrele d-hoc work rooed. Th lgorthm lwy tre to be wre of work' condton, dt telf wth thee condton nd djut the lyout tme of voce cket good oble. So, not only mot of the cket mut be receved before ther lyout tme whch cheduled n recever, but lo the lyout tme mut not be too long much tht h bd effect on the nterctvty between ender nd recever. The mn feture of the reented method re: Frt, djutng the threhold dtvely wth reect to vrnt condton of work, n order to determne the tte of ytem. Second, clcultng the men work jtter nd eeclly lh rmeter dynmclly bed on the current condton of work, n order to clculte the lyout dely of current cket. Thrd, beng otmtc bout the future tte of work nd not ung the htory of dely, n order to clculte the men work dely. The reult of multon how tht the rooed lgorthm dt telf wth the work' dynmc condton nd djut the lyout dely of voce cket better thn the other lgorthm. Keyword- Wrele moble d-hoc Network, Voce tremng, Adtve lyout lgorthm, Qulty of ervce I. INTRODUCTION A moble d-hoc work (MANET collecton of moble node tht cn communcte wth ech other over rdo n the bence of ny nfrtructure. In fct, nde MANET ll node ct router nd forwrd receved cket to node wthn rdo rnge. Indeed, moble d-hoc work re chrcterzed by moblty of ll node, bndwdth-lmted chnnel, unrelble wrele trnmon medum, etc. The MANET' roerte mke the rovon of cket-bed convertonl lcton uch cketbed voce converton chllenge. Indeed, uch lcton requre bounded end-to-end dely nd jtter, but cn llow lmted cket lo rto. The trnmon of voce over cket-wtched work dffer from conventonl crcut-wtched work n tht ech VoIP cket wll exerence vrton n dely. Th knd of jtter vrton n nherent chrctertc of cket-wtched work. To ddre th roblem, lyout jtter buffer t the recever de ued to hold ncomng voce cket for hort erod of tme (jtter buffer dely, to ynchronze the cket trem before ther cheduled lyout tme. Pcket tht re not receved before ther cheduled lyout tme re condered lot (jtter buffer cket lo. Imroved ynchronzton qulty wll be gned when the jtter buffer cheduler moe longer dely. However, th wll lo reult n ncreed overll dely to the voce trem tht my be erceved by the uer. The trnmon of voce cket over IP work hown n Fg. 1. From the work trnort erectve, VoIP eech qulty rmrly mred by cket lo, totl end-to-end dely (mouth-to-er dely nd the jtter. The lo of ome cket wll generte g n the contnuou voce trem, reultng n degrded voce qulty. The totl cket lo nclude work trnmon lo due to work congeton nd jtter buffer lo due to cket rrvl ltene. There re vrou trtege my be emloyed to fll thee g uch, reetng the lt receved cket, nerton of lence, nerton of noe nd nterolton. The totl cket end-to-end dely doe not cue reducton n voce qulty but t ffect the nterctve nture of converton. A work rogton dely of le thn 100m not notceble to uer, where dely over 200 m begn to cue ome degree of wkwrdne between lterntng eker durng converton. The ntroducton of the VoIP lyout jtter buffer ffect both the totl end-toend dely tme nd the totl cket lo rte. Wth mll jtter buffer ze, more lte rrved cket re lkely to be droed, o tht correondngly the jtter buffer cket lo ncree, reultng n ncreed totl cket lo rte. When the jtter buffer ze ncree, fewer cket wll be droed due to rrvl ltene, reultng n mroved ynchronzton voce qulty. However, lrge buffer ze wll ncree the totl end-to-end dely. Both the ncreed cket lo rte nd ncreed totl end-to-end dely reult n the degrdng of converton qulty. Fndng the trdeoff between the totl end-to-end dely nd the totl cket lo rte the key ue for degnng the VoIP lyout jtter buffer cheduler. A good lyout lgorthm hould be ble to mnmze bufferng dely nd lte cket lo, thu mrovng the lodely trdeoff. Fgure 1. VoIP cket' trnmon over IP work [2] In th er, we rooed new dtve lyout djutment lgorthm to trem the voce converton over wrele d-hoc work. Th lgorthm lwy tre to be wre of work' condton, dt telf wth thee condton nd djut the lyout tme of voce cket good oble. The ret of the er tructured /09/$ IEEE

2 follow. Secton II Clfe lyout djutment lgorthm degned for rel-tme cket-bed voce converton. Secton III decrbe the rooed lgorthm, degned ecfclly to ly voce cket trnferred over MANET. The multon cenro nd erformnce reult re gven n Secton IV. Secton V conclude the er. II. RELATED WORKS Mny technque from dfferent ngle hve been rooed to mrove the QoS for voce trnmon over wrele IP-bed work. Thoe technque cn be clfed nto the followng four tye: 1 Technque to mrove bndwdth utlzton; nclude lterntng dfferent voce CODEC, lence ureon nd Reducng the IP/UDP/RTP overhed heder. 2 Mechnm to mrove the underlyng work rotocol effcency for rel-tme voce cket; nclude gvng hgher rorte to the rel-tme voce cket, ung dmon control cheme nd mrovng the bndwdth nd throughut for wrele LAN. 3 Mechnm to recover nd concel the lot cket. 4 Algorthm to remove cket' jtter nd voce lyout mrovement. The forth technque condered n th er nd lterture octed to th technque re urveyed n th ecton. The further nformton nd lterture urvey bout the three other technque re gven n [4]. Rel-tme cket-bed voce converton requre bounded end-to-end dely nd dely jtter. To th end, lyout jtter buffer nd lyout djutment lgorthm re ued n recever. A hown n Fg. 2, the degn of the VoIP lyout jtter buffer cn be clfed nto two tye: ttc lyout buffer degn nd dtve jtter buffer lyout degn. Snce the fxed-ze jtter buffer lyout lgorthm do not dt to the dynmc work condton, ther erformnce re uully not dequte. Thu, n rctce, mot current VoIP lyout jtter buffer cheduler cn be dtve to work trffc chnge to ome extent. Adtve lyout lgorthm dynmclly djut the lyout dely throughout vocl converton. It very common to hve burt or ke n the work cket dely ere. A ke men tht there udden nd very lrge ncree of dely vlue n the cket dely ere. The norml dtve lyout lgorthm do not work well n the reence of uch ke. Thu, mot of the current dtve lyout lgorthm rovde ome ke detecton mechnm o tht the lgorthm cn wtch between ft dtton mode for ke nd the regulr workng mode for norml condton. Alo Adtve roche fll nto two ctegore: Inter tlkur djutment lgorthm nd Per-tlkurt djutment lgorthm. Both of thee two knd of lgorthm dt the lyout dely ccordng to the meured erformnce metrc, nd conder the feture of the lyed gnl uch tlkurt n the ce of voce converton nd tye of frme n the ce of vdeo converton. But they hve dfference. VOIP lyout djutment Sttc Fgure 2. Inter-tlkurt Adtv Per-tlkurt Clfcton of lyout djutment lgorthm 1Per-tlkurt lyout djutment lgorthm: thee dtve lgorthm clculte nd djut the lyout dely only t the begnnng of the tlkurt. The erformnce of er-tlk-urt lyout lgorthm re hghly relted to everl confgurton rmeter. Indeed, the dtrbuton of tlkurt trongly relted to the CODEC ued whch tyclly nclude bult-n VAD (voce ctvty detector functonlty. The VAD lgorthm enble the detecton of the tlkurt occurrence to effcently chedule the cket trnmon nd to t the lyout lgorthm. In [1], Rmjee et l. rooed n dtve lyout jtter buffer lgorthm whch recently becme tndrd dtve lyout mechnm for VoIP ytem. Th dtve lyout lgorthm bed on Jcobon work [3] on TCP roundtr tme etmton (n exonentlly weghted movng verge etmtor. Th lgorthm etmte two tttc: the cket dely nd the dely vrnce, nd then ue thoe two etmte to clculte the lyout tme. T = T + Tˆ + β Vˆ, (1 Vˆ Tˆ = αvˆ = α Tˆ + (1 α T + (1 α T, Tˆ where T nd T rereent, reectvely, the lyout nd endng tme of th cket, nd Tˆ the weghted verge of work dely uon the rrvl of th cket Vˆ the men dely vrton whch udted for ech receved cket, nd coeffcent nd re condered to be 4 nd reectvely. However, the rctclty of Rmjee dtve lyout lgorthm hndered by the entvty of the erformnce to the roer tunng of t rmeter. In [5], Nrbutt et l. dd exerment wth dfferent vlue of under dfferent work condton nd found out tht t not feble to tune rmeter to n otml vlue o tht the dtve lgorthm work well for ll work condton. Thu, Nrbutt rooed dynmc lyout lgorthm bed on Rmjee cheme. The electon of bed n emrcl functon derved from exerment on lrge et of work trce. In the dynmc lgorthm, dynmclly djuted ccordng to the oberved dely vrton. When thee vrton re hgh, the rmeter et low, nd vce-ver. Performnce evluton of th extenon how tht the dtve lyout lgorthm wth reect to enble chevng better lo-dely trde-off thn conventonl lyout lgorthm. Bede Rmjee tndrd dtve lyout lgorthm nd t vrnt, other reercher hve rooed dtve lyout lgorthm bed on the cket-dely htogrm nted of ung lner recurve flterng for the etmton of cket dely. In [6], Moon et l. rooed clcultng gven ercentle ont q n the dtrbuton functon of the cket dely for the ltet w cket, nd then ue t the lyout dely for the new tlkurt. The dvntge of th htogrm-bed etmton roch tht the uer cn ecfy the ccetble cket lo rte, nd the lgorthm utomtclly djut the dely ccordngly. Thu, the trdeoff between the bufferng dely nd the lte-rrvl lo rte cn be controlled exlctly. However, the htogrm-bed etmton cn only rovde the dtrbuton nformton nd cnnot rovde nformton bout the dynmc reltonh between the conecutve cket dely. Tht to y, the, (2 (3

3 htogrm bed etmton gve the me tretment for the entre t cket dely wthout conderng tht the ltet cket dely my be more correlted wth next cket dely. Th my reult n low dtton to the dynmc work condton, eeclly for the non-ttonry wrele Inter envronment. Indeed ll Per-tlkurt lyout djutment lgorthm djut the jtter buffer ze only t the begnnng of the tlkurt. Wth th tye of er-tlkurt mechnm, ny vrton n the lyout dely wll ntroduce rtfclly comreed or exnded lent erod between conecutve tlkurt. Th knd of er-tlkurt mechnm effectvene lmted when tlkurt re long nd the work dely vrton wthn them hgh. In order to overcome thee roblem, Inter-tlkurt lyout lgorthm wll tudy follow. 2 Inter-tlkurt lyout djutment lgorthm: thee knd of dtve lgorthm clculte nd djut the lyout dely not only t the begnnng of the tlkurt, but lo throughout tlkurt nd even for ech cket. Snce lyout dely djutment cn be done wthn tlkurt. In th wy, the lgorthm cn be more rectve to the chnge of work condton, nd better trdeoff between the bufferng dely nd lte-rrvl lo rte cn be cheved. In [7], Lng et l. rooed n dtve lyout lgorthm whch cn djut the jtter buffer ze wthn tlkurt. Proer recontructon of contnuou lyout eech cheved by clng ndvdul voce cket ung tmecle modfcton technque bed on the Wveform Smlrty Overl-Add (WSOLA lgorthm. Ther ubjectve ltenng exerment howed tht the voce cket could be cled from 50 ercent to 200 ercent of the orgnl ze wthout degrdng ound qulty. In Lng dtve lyout cheme, the cket dely redcton w lo bed on htogrm roch. In [2], Lu rooed novel lyout buffer djutment lgorthm bed on dynmc etmton of work dely ung tme ere modelng technque. One of the mjor contrbuton n h lgorthm cheme to ue tme-ere nly method to model nd forect the dynmc of nonttonry WLAN end-to-end cket dely nd the jtter ere. Th lgorthm rovde n exlct reltonh between the cket lte-rrvl lo rte nd the lyout bufferng dely. Thu, the lgorthm cn rovde mnmum lyout buffer dely whle gurnteeng tht the cket lo rte wll be le thn certn level. In [8], Jel rooed n dtve lyout lgorthm whch djut the lyout dely ccordng to node moblty. Th lgorthm oerte n two oble mode: Durng the occurrence of th lo due to moblty, the lyout dely clculted on er-cket b, whle mng to mxmze the ercetul qulty nofr oble. But durng norml erod, t ly voce cket ccordng to belne ertlk-urt lyout lgorthm. One of the dvntge of th lgorthm gnorng cket receved lte f the ntroduced g below 80 m. In contrt, when the g bove 80 m, t wll ly the lte cket nd the lyout dely ncreed conequently. Then t reduce the mount of ntroduced dely durng the lt tlk-urt n the next lence erod. In our rooed lgorthm we ue of thee uerorty. Though jel' lgorthm h ome dvntge nd erform well over MANET, but t h ome wekne tht wll tudy follow: Although th lgorthm y tht to clculte work men dely ue the thrd lgorthm rooed by Rmjee[1], but n fct t clculte work men dely wthout conderng f cket tht re ued to clculte men dely, re receved on tme nd before t lyout tme or not. Snce work men dely tht clculted n th wrong wy led to determne cket' lyout dely, o th lgorthm could not clculte nd djut the rght lyout dely for cket. In ddton th lgorthm ue (3 to clculte work men jtter nd conder fxed vlue for. whle uge of th ttc n order to clculte men jtter n dhoc work tht re chrcterzed by moblty of node nd vrble work condton, re not reonble. On the other hnd, th lgorthm ue the contnt threhold to determne the mount of work ctvty nd do not chnge t n vrble condton. So th lgorthm doe not hve otml erformnce nd cn not trce work' vrble condton roerly. To olve thee roblem, rooed lgorthm wll be ntroduced n next ecton. III. PROPOSED ALGORITHM In th er novel lgorthm rooed to mnge the lyout buffer nd djut the lyout dely of voce cket tht re belongng to rel-tme voce converton nd receved to the recever. Th lgorthm trce the work condton nd behve ccordng to the current tte of work roerly. To th end, t lwy montor qulty of ervce rmeter lke jtter nd then dt t mnner n conder to current tte of work nd djut cket' lyout tme well oble. Snce the node moblty nd vrnt work toology re the mn chrctertc of wrele d-hoc work, nd hown n [8] tht jtter nd cket out of order re the bet metrc to be wre of work condton, o the reented lgorthm tre to gther mount of jtter (dely vrton nd cket out of order nd determne the work' current tte by them. The rooed lgorthm run n ctve mode when both reltvely hgh jtter (nter cket dely dfference: IDD vlue nd hgh cket out of order (POR vlue detected. IDD vlue re gven by: IDD = (T T (T T (4 POR clculted bed on the cket' equence number. The occurrence of n out-of-order cket detected once cket reche the ource hvng equence number mller thn mx. Otherwe, the vlue of gned to mx. The mx rereent the mxml equence number receved untl now. Otherwe the lgorthm work n norml mode. The further exlnton bout the lgorthm' mnner wll be reented n the next rt. After clcultng IDD nd POR metrc the tte of work hould be detected. So t necery to judge f thee mled vlue re hgh or not. For th uroe, we ue n [9], the reltve mle devton (RSD method. RSD tttcl lgorthm ued to judge the level of mle vlue reltve to the recent htory of record [9].The RSD lgorthm return vlue lyng between 0 nd 1, whch ued to clfy the level of mle HIGH or not. RSD

4 cn be ummrzed follow: ume mle vlue x vry n the rnge [0, R]. RSD dvde the rnge R nto N ntervl I 1, I 2,..., I N where the ntervl I hold mle vlue wthn [( - 1R/N, R/N. Denote the totl number of mle S nd the number of mle wthn ntervl I (I. Gven x, t correondng ntervl I x = x/[r/n] + 1. To decde how HIGH x, RSD clculte the rto of mle vlue below x over the totl number of mle: RSD( x x = = 1 ( I / S Th correond to the CDF dtrbuton t x. Gven RSD(x, we cn tell wht ercentge of mle vlue lower thn x. An RSD vlue cloe to one mle tht x HIGH wth reect to the htory record. In th wy, the RSD(IDD nd the RSD(POR re clculted. Then they hould be comred to ther correonded threhold. In th er they re denoted to IDD-threhold nd POR-threhold reectvely. Thu the work' current condton determned. Fg. 3 how the tte determnton functon of rooed lgorthm. A t cn be een, to IDD-threhold nd POR-threhold re regulted dynmc wth conderng to the vrnt tuton of work. Th one of contrbuton of rooed lgorthm. It men tht, n crtcl tuton when the work n ctve tte for long tme, threhold re decreed. Converely, when the work n norml mode for long tme, threhold re ncreed. The htory of work' tte mntned by ung globl vrble denoted ct. Another contrbuton of reented lgorthm bout clcultng the men work jtter. Uully lyout djutment lgorthm etmte the men jtter by ung (3 nd conder tht the contnt vlue. Whle uge of th ttc, n order to clculte men jtter n d-hoc work tht re chrcterzed by moblty of node nd vrble work condton re not reonble. In th er, the lgorthm ue (3 n order to clculte the men jtter, but t regulte dynmclly the lh rmeter bed on current condton of the work; becue there no otml fxed vlue of when work condton vre n tme. Idd-threhold & POR-threhold 0.2 Ye Stte = norml Strt < 0 > 0 ct Idd = RSD(jtter POR = RSD(cket out of order Idd < Idd-threhold && POR < POR-threhold Stte = ctve End Idd-threhold & POR-threhold 0.1 Fgure 3. Stte determnton functon (5 Tˆ = T + T TH SIL,Tˆ INC T = Mx(T Ye T = T T INC = 0 New Tlkurt + T ck + T = Mx(T,T GAP = T T T = T + T + T ck Ye GAP < 80 T = T T = Mn( 0.4,T T INC = INC + ( T + T T T ctve Ye T < T tte= StteDetermnton (,T,T Act ++ ctve tte Act -- norml End Strt tte Act -- T = norml = T tte= StteDetermnton (,T,T T = Tˆ = α Tˆ Vˆ = αvˆ mn T T = Mx( T Ye Fgure 4. Prooed lgorthm ctve + (1 α T + (1 α T Tˆ Ye T < T mn SIL = T T T = Tmn + βvˆ + T tte Act ++ ck norml Idd= RSD(jtter Idd < _threhold && dely_chnge> d_threhold Ye = 0.7 New Tlkurt + THR SIL T,T T = Mn(0.4,T T A t hown n [5] when jtter mll nd fluctuton n the end-to-end dely re lrge, the bet reult re cheved when mll. On the other hnd, when jtter lrge but verge work dely contnt, the bet reult re cheved when = So the rooed lgorthm djut the lh rmeter ccordng to verge dely nd jtter. It cn be hown follow. If (jtter mll nd (fluctuton n the end-to-end dely re lrge { α = 0.7;} Ele {α = ;} The other contrbuton of rooed lgorthm relted to clculte the men work dely. Commonly, lyout djutment lgorthm whch re reented u to now, etmte the men work dely bed on (2. Whle ung the htory of work nd clcultng the men work dely n d-hoc work where work dely vrton re unredctble, not reonble. So the rooed lgorthm doe not ue th equton, but t otmtc bout the future tte of work. It ue the mnmum work dely tht h been occurred n lt tlkurt the men work dely n the next tlkurt. It elect the mnmum dely vlue of cket whch re receved on tme nd before t lyout tme. It cn be hown n Fg. 4. The reult of multon whch wll be hown n the next rt llutrte tht the rooed lgorthm dt telf wth the work' dynmc condton nd djut the lyout dely of voce cket better thn the other lgorthm. IV. PERFORMANCE EVALUATION Uully there re two wy to evlute the rooed lgorthm: mthemtcl nly nd multon. The frt method more relble but t more comlex nd lo n mny ce t not oble to model the current condton

5 wth mthemtcl equton. So the econd method elected nd the multon h been ued to verfy the reented lgorthm. We ued NS2 runnng on Lnux to multe cket-bed voce converton over MANET. In th work we ue Gu Mrkov (GM moblty model to generte work toology. GM model node movement ccordng to eed nd drecton vlue whch re udted t dcrete tme ntervl. Th model vod unnturl brut movement of node nd ure unform dtrbuton of node over the multed re. Ech multed cenro nvolve 25 moble node romng freely,.e., wthout obtcle, over rectngulr re of 900 m 300 m. The trnmon rnge of ech node et to 250 m. de velocte re rndomly elected n the rnge 1 5 m/ to mmc node moblty n n urbn envronment. A the work trffc ttern, fve bdrectonl voce converton were etblhed durng the multon run. Ech voce converton lted for rndomly elected durton ccordng to n exonentl dtrbuton wth men 3 mn. The trt tme of ech eon w choen unformly. The generted voce cket trem of ech eon h men ctve nd lence erod of 1 nd 1.5 reectvely. In the ctve erod, one cket trnmtted every 20 m, ech of length 160 byte. We only conder dely trce hvng cket lo rto below 10% n ech drecton of voce eon. The other multon rmeter re ummrzed n Tble I. TABLE I. MAC Protocol Routng Protocol Trnort Protocol Smulton durton Wrele lnk bndwth CODEC SIMULATION PARAMETERS IEEE b DSR UDP Mb G.711 ITU-T E-Model n led method to vldte the rooed lgorthm. In Fg. 5 dfferent cheme of verfyng the qulty of voce converton hown. ITU-T E-Model n objectve, non-ntruve nd rmeter-bed method tht ued to evlute the voce qulty. In th er the convertonl qulty of voce ervce etmted through rtng fctor denoted R. The rtng fctor bed on ITU-T E-Model whch clr rngng from 0 to 100 correondng reectvely to the wort nd bet trnmon qulty. The rtng fctor vlue mller thn 60 correond to n untfctory trnmon qulty. cheme of verfyng the voce qulty Subjectve Prmeter-bed Fgure 5. n-intruve Objectve Intruve Sgnl-bed Method clfcton to verfy the qulty of voce converton The reduced formul to derve the dequte rtng fctor R eng VoIP converton gven by [10]: R = 93.2 I (T I ( CODEC, lr A, (6 + d e Where I d model the mrment ffectng the nterctvty uch the bolute rogton dely nd echoe, I e model the mrment ffectng the ntellgblty of voce converton uch low bt-rte CODEC nd cket loe, nd A rereent n dvntge fctor tht ccount for uer wllngne to ccet ome qulty degrdton n return for ee of cce (e.g., cell hone. T nd lr correond reectvely to the men bolute rogton dely nd cket lo rte. The dtorton effect of I d cn be gven by the followng equton: I (T = 0.024T ( T H(T 77.3, (7 d H( x = 1 f x < 0 where H( x = 0 f x 0 Where T rereent the men bolute rogton dely nclude frmng, bufferng, nd work dely. In contrt to I d, model of I e hould be develoed nd clbrted ecfclly for ech CODEC. Tyclly, rooed model n the lterture hve the followng form: I e ( CODEC, lr = + b ln(1+ c lr, (8 Where lr correond to the end-to-end cket lo rte, nd the contnt coeffcent, b, nd c re elected ccordng to the behvor of ech CODEC [11,12]. For ntnce, the dequte coeffcent of the G.711 CODEC wth cket lo concelment (PLC cblty re = 0, b = 30, nd c = 15. Snce the condton of MANET dynmc nd vrble durng the converton nd n order to clculte the rtng fctor more ccurtely, n [8] recommended to dvde the converton durton nto fxed ntervl whch re eed ndeendently (e.g., 10. The roduced rtng fctor termed "ntntneou rtng fctor". Then clculte the rtng fctor t the end of ech converton whch termed "overll rtng fctor". Reult- To evlute the erformnce of the rooed lgorthm, t necery to do the multon nd montor the lgorthm' behvor n dfferent condton over MANET nd comre t to the other lyout djutment lgorthm. To th end, the rooed lgorthm contrted wth two mortnt djutment lgorthm. The frt one the bet one whch uggeted n [1] (the thrd one nd the econd one recently reented n [8] whch re djuted the lyout tme n wred IP-bed work nd n wrele d-hoc work, reectvely. The reult of multon nd the behvor of mentoned lgorthm re hown n the followng fgure. The dfferent behvor of rooed lgorthm nd the other lgorthm n fce to the dely vrton over MANET re hown n Fg. 6. Fg. 6. how tht the rooed lgorthm trck work dely vrton more cloely durng th wtchng occurrence nd h fter dtton of the lyout dely to trck work dely vrton thn the other lgorthm. In Fg. 7. the exerenced one-wy work dely over the multed MANET durng the 7th voce converton hown nd the ntntneou rtng fctor of cted lgorthm whch re octed to th converton hown n Fg. 8. A hown n Fg. 8., the reented lgorthm outerform ll other wth reect to the ntntneou rtng fctor. Snce

6 the rtng fctor clculted from dely nd cket lo (ccordng to Eq. (6, o t mrove trdeoff between the totl end-to-end dely nd the totl cket lo rte. Dely (ec Network Dely Prooed Algorthm [8] [1] of the roceed cll nd t cn be mroved the erformnce 10% to 14%. Indeed the clculted rtng fctor llutrte tht the reented lgorthm cn mnmze both the end-to-end dely nd cket loe due to lte rrvl. On the other hnd, the clculton outcome demontrte the lo-dely trdeoff exlctly. They hown tht the "Men end-to-end Dely" octed to the 10 rel-tme multed voce converton 183 mllecond, whle ther "Men cket lo rte" 18.2 ercent Arrvl Tme (ec Fgure 6. The dfferent behvor of lgorthm n fce to the dely vrton over MANET Dely (ec Intntneou Rtng Fctor Fgure Tme (ec Fgure 7. The 7th voce converton Perod Identfer Prooed Algorthm [8] [1] Intntneou rtng fctor of cted lgorthm octed to the 7th converton TABLE II. Algorthm' Nme The [1]' 2nd lgorthm The [1]' 4th lgorthm The [1]' 1t lgorthm The [1]' 3rd lgorthm The[8]' lgorthm The Prooed Algorthm THE OVERALL RATING FACTORS end of cll In order to generlly evlute the lgorthm' erformnce, the "overll rtng fctor" tht re correonded to the ll of 10 multed voce converton re hown n Tble II. It how tht rooed lgorthm cheve the hghet etmted ercetul qulty t the end R V. CONCLUSION In th rtcle, we degned nd develoed new dtve lyout djutment lgorthm to trem the voce converton over wrele d-hoc work. The degned lyout lgorthm djut the lyout dely ccordng to node moblty nd tlk-urt. The mjor contrbuton of th er frt, novel lyout buffer djutment lgorthm bed on djutng the threhold dtvely wth reect to vrnt condton of work n order to determne the tte of ytem, econd, clcultng the men work jtter nd eeclly lh rmeter dynmclly bed on the current condton of work n order to clculte the lyout dely of current cket nd thrd, beng otmtc bout the future tte of work nd not ung the htory of dely n order to clculte the men work dely. Thu, the lgorthm rovde mnmum lyout buffer dely whle gurnteeng tht the cket-lo rte le thn certn level. The rooed lyout buffer djutment done wthn tlkurt, o t cn be more rectve to the chnge of work condton, eeclly when burt or ke rrve. The reult of our multon exerment how tht the rooed dtve lyout lgorthm dt telf wth the work' dynmc condton nd djut the lyout dely of voce cket better thn the other lgorthm nd outerform two current dtve lyout bufferng cheme ([1] nd [8] for ll of the teted trce. The lgorthm cheved erformnce mrovement of 14% nd 10% n term of the E-model R-fctor reectvely comred to [1] nd [8] lgorthm. Further, we ln to mrove the erformnce of the tte determner functon. REFERENCES [1] R. Rmjee, J. Kuroe, D. Towley, H. Schulzrnne, "Adtve lyout mechnm for cketzed udo lcton n wde re work," n: Proceedng of IEEE INFOCOM, Toronto, Cnd, vol. 2, , [2] M. Lu, "QOS Imrovement for Rel-tme wrele Vo," PhD. The, Arzon Unverty, [3] V. Jcobon, M. J. Krel, "Congeton Avodnce nd Control," n: Proceedng of ACM SIGCOMM Conference, Stnford, [4] M. Sleh, "QOS mrovement for voce trnmon over wrele LAN work," MSc. The, Amrkbr Unverty of Technology, [5] M. Nrbutt, L. Murhy, "VOIP lyout buffer djutment ung dtve etmton of work dely," n: Proceedng of 18th Interntonl Teletrffc Congre (ITC-18, Berln, Germny, , Setember [6] S. Moon, J. Kuroe, D. Towley, "Pcket udo lyout dely djutment: erformnce bound nd lgorthm," ACM/Srnger Multmed Sytem, vol. 6, , [7] Y. Lng, N. Frber, B. Grod, "Adtve Plyout Schedulng nd Lo Concelment for Voce Communcton over IP Network," IEEE Trncton on Multmed, vol. 5, no. 4, , December [8] S. Jel, H. Youef, "Adtve lyout chedulng lgorthm tlored for rel-tme cket-bed voce converton over wrele d-hoc work," n: Proceedng of Elever Comuter Network, vol. 52, , [9] Z. Fu, X. Meng, S. Lu, "TCP frendly rte dtton for multmed tremng n moble d hoc work," n: Proceedng of IEEE Interntonl Conference on Mngement of Multmed Network nd Servce (MMNS 03, Belft, rthern Irelnd, UK, , Setember [10] M. Nrbutt, M. Dv, "Predctng the mct of lcton-lyer dtton mechnm nd MAClyer rmeter tunng on eech trnmon qulty n VoIP ytem," Avlble on-lne t htt:// vted on Jnury [11] R.G. Cole, J.H. Roenbluth, "Voce over IP erformnce montorng, comuter communcton revew," ACM SIGCOMM, vol. 31,. 2, [12] L. Sun, E. Ifechor, "New model for erceved voce qulty redcton nd ther lcton n lyout buffer otmzton for VOIP work," n: Proceedng of IEEE Interntonl Conference on Communcton (ICC 04, vol. 27,. 1, June 2004.