Multi-channel Dual Clocks three-dimensional probability Random Multiple Access protocol for Wireless Public Bus Networks based on RTS/CTS mechanism

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1 MATE Wb of onfrncs 44, 00 ( 06 DO: 0.05/ mtcconf/ Ownd by th uthors, publishd by EDP Scincs, 06 Multi-chnnl Dul locks thr-dimnsionl probbility ndom Multipl Accss protocol for Wirlss Public us Ntworks bsd on TS/TS mchnism Shng Ji Zhou, Hong Wi Ding,, Mng Yo Wng, Qin Lin Liu nd Zhi Jun Yng School of nformton, Yunnn Univrsity, Kunming, 65009, hin. Abstrct. A MA protocol for public bus ntworks, clld us MA protocol, dsignd to provid high qulity ntrnt srvic for bus pssngrs. Th ppr proposd multi-chnnl dul clocks thr-dmission probbility rndom multipl ccss protocol bsd on TS/TS mchnism, dcrsing collisions cusd by multipl ccss from multipl pssngrs. Us th TS/TS mchnism incrss th rlibility nd stbility of th systm, rducing th collision possibility of th informtion pckts to crtin xtnt, improvs th chnnl utiliztion; us th multichnnl mchnism, not only nbls th chnnl lod blncing, but lso solvs th problm of th hiddn trminl nd xposd trminl. Us th dul clocks mchnism, rducing th systm idl tim. At lst, th diffrnt slction of th thr-dimnsionl probbilitis cn mk th systm throughput dpt to th ntwork lod which could rliz th mximum of th systm throughput. ntroduction ntllignt Trnsporttion Systms (ntllignt Trffic Systm, rfrrd TS, is th dvncd scinc nd tchnology (informtion tchnology, computr tchnology, dt communiction tchnology, snsor tchnology, lctronic control tchnology, utomtic control thory, oprtions rsrch, rtificil intllignc, tc. to ffctivly pply th intgrtd trnsport, srvic control nd vhicl mnufcturing, to strngthn tis vhicls, rods, mong usrs, crting sfty, improv fficincy, improv th nvironmnt, nrgy consrvtion intgrtd trnsport systm [. With th dvlopmnt of intllignt trnsporttion systms tchnology, intllignt trnsporttion systm will b mor widly usd in th trnsporttion industry. Thrfor, ntrnt ccss by bus chivs growing dmnd. n mjor citis, vry dy bout th millions of popl trvl by bus nd oftn tks svrl minuts or vn on hour in trffic. omprd to othr ntworks, providing ntrnt srvics hv its obvious chnnl for th bus ccss fturs. uss usully hv mor thn on pssngr. Ths pssngrs s group of mobil nod movs nd ch pssngr simultnously produc diffrnt typs of ntrnt srvic rqust, for xmpl, nws browsing, - mil ccss nd strming mdi dt srvics [. ombind bus communiction chrctristics, th ppr proposd multi-chnnl dul clocks thrdmission probbility rndom multipl ccss protocol bsd on TS/TS mchnism. for th sit first snds rqust to snd pckt trnsmission frm TS (qust to Snd to th trgt sit, witing for th rspons from th trgt sit TS (lr to Snd frm ftr, it bgn to trnsfr pckts. f th trnsmitting sttion dos not rciv TS, thn prform binry xponntil bckoff lgorithm dly rtrnsmission TS. n this procss, w listn to th othr nod TS to b dlyd for som tim to snd, in ordr to nsur th snding nod cpbl of succssfully rcivd TS. Us TS/TS hndshk (hndshk mchnism, it cn nsur tht th nxt trnsmission pckt, no collision, sinc th TS/TS frm whil vry smll, so tht th invlid trnsmission ovrhd bcoms smll [3. Abov is th TS/TS mchnism. sd on th thr-dimnsionl probbility rndom multipl ccss protocol, w rsolv th "hiddn trminl" nd "xposd trminl" problm, dcrsing collisions cusd by multipl ccss from multipl pssngrs [4. Also to rduc th systm idl tim, w dopt th dul clocks mchnism. Whn th systm is idl, w us continu-tim control strtgy; whn th systm is busy, w us th discrt-tim control strtgy [5. Lst to chiv th multipl businss ccss nd improv th systm throughput, w join th multi-chnnl mchnism rliztion th chnnl lod blncing, mt th diffrnt prioritis businss with diffrnt QoS rquirmnts by tking dvntg of th priority control of multi-chnnl multi-srvic [6. Th nlysis of th proposd protocol orrsponding uthor: dhw964@63.com This is n Opn Accss rticl distributd undr th trms of th rtiv ommons Attribution Licns 4.0, which prmits distribution, nd rproduction in ny mdium, providd th originl work is proprly citd. Articl vilbl t or

2 MATE Wb of onfrncs. Th nlysis of TS/TS mchnism Th chnnl modl of thr-dimnsionl rndom multipl ccss protocol is shown in Figur. Figur. Th chnnl modl of thr-dimnsionl rndom multipl ccss protocol n this modl, thr will b thr rndom vnts: Evnt tht informtion pckts r snt succssfully (U vnts. Evnt tht informtion pckts collid with ch othr (th collision pprs, vnts. Evnt tht thr r no informtion pckts in th chnnl rriv, th chnnl is idl ( vnts [7. Ths thr vnts r forcd into: th chnnl is idl ( vnts vnt, th chnnl is busy (U vnts nd th chnnl is idl following th U vnts (U vnts; th pckt is snt succssfully or unsuccssfully (combind vnts with U vnt, dnotd by U vnt; forc th U vnts nd th U vnts into vnts [8. According to th nw protocol, if th chnnl is idl, thn th usr dcids to snd n informtion pckt probbility P ; if th chnnl is in trnsmission tim, th usr listns to th chnnl with probbility P nd P 3 rpctivly in tim nd. This control strtgy, P, P nd P by thr-dimnsionl 3 slction nbls th systm utiliztion nd throughput is gurntd undr diffrnt lod. Th chnnl modl of thr-dimnsionl rndom multipl ccss protocol bsd on TS/TS mchnism is shown in Figur. TP NAK U T n AK Figur Th chnnl modl of thr-dimnsionl rndom multipl ccss protocol bsd on TS/TS mchnism Th trnsmission priod is dividd into th following sctions undr th control of th protocol: n intrrogtion signl TS, th rspons signl TS, n informtion pckt trnsmission tim, AK monitoring signl, othr informtion contnt: 9 3, nd th dly tim. Whn thr r n informtion pckts rriving, th procss of chnnl stisfying th Poisson procss, th probbility is n ( Pn ( ( n! n vnts, t idl tim slot, if thr is no informtion pckts to b snt, its possibility is: 0 q p ( n vnts, t idl tim slot, if thr is only on informtion pckt to b snt, its possibility is: q p p (3 At th trnsmission priod, if thr is no informtion pckts to b snt, its possibility is: q { p[ (3 3} 0 p (4 n th trnsmission priod, if thr is only on informtion pckt to b snt, its possibility is: q { p [ (3 (5 { p[ (3 n cycl, th possibility of continuous i idl vnts is: { p[ (3 3} p p i ( ( PN i (6 n cycl, th possibility of continuous j vnts is: { p[ (3 3} ( ( ( p p j PN j (7 n cycl, th possibility of continuous i vnts nd j vntsis: i PN ( in, j ( ( (8 { p[ (3 { p[ (3 3} p j ( Th vrgs numbr of i continuous vnts in cycl is: EN ( ipn ( in, j i j i i ( ( i j { p[ (3 { p[ (3 3} p j ( (9 Th vrg numbr of j continuous vnts in cycl T is: n EN ( jpn ( in, j i j i j ( ( i j { p[ (3 { p[ (3 3} p j (0 ( { p[ (3 To th discrt tim thr-dimnsionl probbility rndom multipl ccss protocol with TS/TS mchnism, th informtion pckts r snt succssfully in two css. Firstly th numbr of informtion pckt trnsmittd succssfully in vnts r: EN ( q p U 0 q ( Th vrg lngth of informtion pckt trnsmittd succssfully in vnts is: p EU ( E( NU ( Scondly th vrg lngth of continuous K U vnts in th TP tim in cycl is: 00-p.

3 EE 06 i EU ( KPN ( in, j i j K0 i i j K0 i ( ( K { p[ (3 { p[ (3 3} p j (3 ( { p [ (3 n cycl, th vrg lngth of tim slot tht informtion pckt hs bn succssfully snt is: EU ( EU ( EU ( (4 p { p [ (3 Th vrg lngth of vnt in is: 3 (5 E ( EN ( 3 { p[ (3 Th vrg lngth of vnt is: E ( EN ( (6 p Th throughput of th thr-dimnsionl probbility rndom multipl ccss protocol with TS/TS mchnism is: EU ( S E ( E ( p { p [ (3 p 3 p { p[ (3. Th nlysis of dul clocks mchnism (7 Whn th systm is idl, th systm uss continuous-tim control strtgy. And if th systm is busy, th systm uss discrt-tim control strtgy. Sinc th numbr of idl slots within th gomtric distribution with th mn: EN (, n p informtion pckt rriv in tim slot with normlizd p probbility: p p, mor thn n informtion p pckt rrivs in tim slot with th normlizd p p probbility: p p. p Thn w gt: p p p p ( p (8 E ( ( p p p ( Th throughput of th dul clocks thr-dimnsionl probbility rndom multipl ccss protocol with TS/TS mchnism is: EU ( S E ( E ( p (9 { { p [ (3 } 3 /[ ( p { p[ (3 p p p p ( p p p (.3 Th nlysis of multi-chnnl mchnism Assuming tht nods hv diffrnt srvic rquirmnt hv diffrnt prioritis, stting N trffic chnnls in th systm, th nod occupis th chnnl ccording to thir businss prioritis. Assum tht ch priority unlimitd th numbr of usrs, th priority from low to high in ordr is priority, priority priority N. Priority occupis th chnnl, priority occupis chnnl nd chnnl priority i occupis chnnl to chnnl i. Th rrivl informtion pckts on th chnnl i subjct to th Poisson distribution with rriving rt i, th rrivl pckts of priority r on th chnnl i subjct to th Poisson distribution with rriving rt i i /( Ni. Th multichnnl mchnism owning N chnnls is showd in Figur 3. Figur 3 Th multichnnl mchnism owning N chnnls n th N chnnls of wirlss communiction systm, bcus this chnnl modl is lod quilibrium modl, so th rrivl probbilitis of ch chnnl r th sm, tht is to sy: 3 i N (0 sing on th bov nlysis nd computtionl formul of th systmic throughput, th systm totl throughput is: ' S NS p N{ { p [ (3 } ( 3 /[ ( p { p[ (3 p p p p ( p p p ( Thn ccording to th bov nlysis, w cn gt th throughput with th priorityl : l Spl ( S i N i l p ( ( { { p [ (3 i N i 3 9 }/[ ( p { p[ (3 p p p p ( p p p ( 3 Exprimntl clssifiction rsults nd nlysis 00-p.3

4 MATE Wb of onfrncs sd on th bov nlysis, with th us of simultion tool: MATLA 00, th simultion rsults r shown s following. During th simultion, trnsmission dly tim: 0., 0., pckt lngth is: 3. Figur 7 Th throughput of th nw protocol with diffrnt. Figur 4 Th throughput of th nw protocol with diffrnt P. Figur 8 Th throughput of nw protocol with diffrnt tr, tc. Figur 5 Th throughput of th nw protocol with diffrnt P. Figur 9 Th diffrnc of systm idl tim btwn th nw protocol nd th trditionl on. Figur 6 Th throughput of th nw protocol with diffrnt P3. 00-p.4

5 EE 06 Figur 0 Th throughput of th nw protocol with 3 chnnls. Figur Th throughput th nw protocol with 5 chnnls. Through th bov simultion rsults, w cn drw th following conclusions:, systm simultion coincids with th thorticl vlu highr dgr of consistncy provd th thorticl drivtion, nd provs th ccurcy of th simultion., through P, P nd P3, w chiv rgultion on th systm throughput. At low lod, P incrss systm throughput cn b improvd; howvr, t high lod, P incrss will rduc th throughput. cus of th low lod incrss th trnsmission probbility my incrs th probbility of succssfully trnsmittd pckts, nd trnsmit high lod incrss th probbility it will cus mor srious conflict. Similrly, whn low lod, P mk smll incrs systm throughput will incrs; high lod, incrsing th probbility P collisions will incrs drmticlly rducs systm throughput. Thrfor, w cn mk th probbility of combintion of P, P nd P3 t optimum circumstncs mntiond in th throughput is grtr. 3, by introducing th dul clock mchnism, it cn rlly rduc th idl rt of th systm, spcilly t low lod, idl rt of th systm is rducd by big mrgin; bcus t high lod, th systm is idl rt lrdy high, so th cpcity of th mchnism t high lod rducing systm idl rt wknd; nd in diffrnt combintions of probbility, idl rt of th systm is rducd rts r not th sm. 4, nd finlly through multi-chnnl mchnism, not only improvs th ovrll throughput of th systm, but lso to chiv th diffrnt prioritis for diffrnt bus pssngrs, providing diffrnt throughput ccss to multipl srvics. 4 onclusions With th dvlopmnt of intllignt trnsporttion systms tchnology, for providing high qulity ntrnt srvic in public buss, combind bus communiction chrctristics, th ppr proposd multi-chnnl dul clocks thr-dmission probbility rndom multipl ccss protocol bsd on TS/TS mchnism. y introduction of th TS/TS mchnism incrss th rlibility nd stbility of th systm, rducing th collision possibility of th informtion pckts to crtin xtnt, improvs th chnnl utiliztion; by th us of th multi-chnnl mchnism, not only nbls th chnnl lod blncing, but lso solvs th problm of th hiddn trminl nd xposd trminl. y introduction of th dul clocks mchnism, rducing th systm idl tim. Th diffrnt slction of th thr-dimnsionl probbilitis cn mk th systm throughput dpt to th ntwork lod which could rliz th mximum of th systm throughput. At lst, systm simultion coincids with th thorticl vlu highr dgr of consistncy provd th thorticl drivtion, nd provs th ccurcy of th simultion. Acknowldgmnts This work ws supportd by th Ntionl Nturl Scinc Foundtion of hin (646053, , ; Nturl Scinc Foundtion of Yunnn Provinc (00D0; Th Finncil Support of Yunnn Univrsity (No.XT4004. frncs. Shngji Zhou, Hongwi Ding, Yifn Zho, Zhijun Yng nd Qinlin Liu. srch on th discrt tim thr-dimnsionl probbility csm protocol in dhoc ntwork [J. ntrntionl Journl of cnt Scintific srch, 05, 6(5: Xuming. srch nd dvlopmnt of mobil Ad Hoc ntwork [J. Dt ommunictions, 003 (4: onti M, iordno S. Mobil d hoc ntworking: milstons, chllngs, nd nw rsrch dirctions [J. ommunictions Mgzin, EEE, 04, 5(: ndhi, Ary V. A Survy of Enrgy-Awr outing Protocols nd Mchnisms for Mobil Ad Hoc Ntworks [M. ntllignt omputing, Ntworking, nd nformtics. Springr ndi, 04: Xioping Wu. srch on th hiddn nd xposd trminl problm in th Ad Hoc ntwork [J. Microcomputr nformtion, 006 (0X: Jysuriy A, Prru S, Ddj A, t l. Hiddn nd xposd trminl problm in d hoc ntworks[d. ATNA Wng L, Wu K, Hmdi M. Attchd-TS: Eliminting n Exposd Trminl Problm in Wirlss Ntworks [J. EEE Trnsctions on Prlll nd Distributd Systms, 03, 4(7: Dongfng Zho. Study on A Nw Mthod for ontinuous-tim Systms of ndom Accss hnnl [J. Journl of Elctronics, 999, (: p.5