A Proxy Based Indirect Routing Scheme for Ad Hoc Wireless Networks

Transcription

1 A Proxy Bs Inirt Routin Shm or A Ho Wirlss Ntworks Wook Choi n Sjl K. Ds Cntr or Rsrh in Wirlss Moility n Ntworkin (CRWMN Dprtmnt o Computr Sin n Eninrin Th Univrsity o Txs t Arlinton Arlinton, TX Astrt Th mjority o th xistin ho wirlss ntwork routin protools hs tnny to us th shortst sinl pth rom th sour to th stintion. Howvr, in onstntly hnin topolois suh s thos in moil ho ntworks, th shortst sinl pth is quit unstl or rhility n lso or tri lo quilirium. In this ppr, w propos novl shm, ll Applitiv Inirt Routin (, to ontrol ntwork tri onstion n rin th rout vilility y opin with unrlil links quikly. Th propos shm, tin s protiv routin protool, utilizs itionl inormtion out th nihors shr (in s proxis y th snr n rivr to in onmn n ltrntiv or th oriinl pth with unrlil links. Th itionl nwith us in to otin th inormtion out shr nihors is so miniml tht th nwith vilility or t pkts is not siniintly t. In our shm, it is possil or th nos to ynmilly rrout inomin pkts into ltrntiv pths so th pkts will rh thir stintions vn whn th il routin pth ils. Th onut simultion xprimnts show tht ls to muh improv systm prormn in trms o pkt livry rtio, vr n-to-n pkt ly, n ntwork rliility s ompr with onvntionl protiv protool, nmly Dstintion-Squn Distn Vtor (. is lso omptitiv protool in trms o pkt livry rtio s ompr with two xistin rtiv protools; nmly A ho On Dmn Distn Vtor ( n Dynmi Sour Routin (. Inx Trms A Ho Wirlss Ntworks, Altrntiv Pth, Constion Control, Proxy Bs Routin I. INTRODUCTION An ho wirlss ntwork is ynmi ntwork without ny ix inrstrutur n ntrliz ontrol systm. In ll omponnts (nos o this ntwork r potntilly moil without ny wir onntion twn thm, n ny no n t s routr. This rom o moility, howvr, rsults in rqunt link isonntions twn th omponnts sin thy hv limit ommunitin istn trmin y thir rio rn. A ho wirlss ntworks r normlly us or spii strti purposs, suh s militry ploymnt, mrny tsk or oprtion or tmporry spil usinss tivity whr it is not possil to hv ix inrstrutur. Du to th onstntly vryin topoloy in moil ho ntworks, it is quit iiult to mintin th ntir ntwork s routin inormtion urtly n urnt th mss livry. Thror, ynmi multihop pths r onstrut to rout msss whil moil nos ooprt wnrin. Bs on th onstrution o multihop pths, xistin ho ntwork routin protools n roly toriz into protiv n rtiv protools [1]. A protiv protool, lso ll tl-rivn protool, is l to or routin inormtion on th spot. For xmpl, th Dstintion-Squn Distn Vtor ( [1] n Wirlss Routin Protool (WRP [1] lon to th lss o protiv protools. On th othr hn, rtiv protool, lso ll sour-initit on-mn protool, ors routin inormtion with som ltny sin it usully ns to lunh th rout isovry pross i it hs no pr-isovr rout. For xmpl, th A ho On Dmn Distn Vtor ( routin [1], Tmporlly-Orr Routin Alorithm (TORA [13], n Dynmi Sour Routin ( [] lon to th lss o rtiv protools. Compr to th rtiv protools, th protiv protools inur smllr ly in snin out pkt, plus thy kp th ntir ntwork topoloy inormtion. Howvr, thy us up mor nwith sin thy n to prioilly rost th routs or ll nos in th ntwork. Th nwith us or ontrol msss is proportionl to th siz o th ntwork. Du to this prormn tr-o or oth th ov toris, hyri n orphil routin protools hv n propos in th litrtur. A hyri protool, suh s Zon Routin Protool (ZRP [7], is omintion o protiv n rtiv shms. It uss protiv shm or lol r routin n rtiv shm or rmot r routin. On th othr hn, orphil protools suh s Distn Routin Et Alorithm or Moility (DREAM [1], Gry Primtr Sttlss Routin (GPSR [], n Lotion-Ai Routin (LAR [11] utiliz lotion inormtion o th nos in th ntwork to in th rout, thus ruin ontrol mss ovrh. Th lotion inormtion is usully or y xtrnl mns suh s lol positionin systm (GPS. Most o th prin protools us sinl (shortst pth rom th sour to th stintion to livr msss n prorm no lo lnin or th ntwork tri, lthouh som o thm [], [1] kp th multipth inormtion. Du to th hrtristis o th wirlss mium (suh s hih it rror rt n low nwith n unpritl no moility, it is not wis to pn only on on pth to stintion or iint or sussul routin. This is us tht sinl pth miht out o t or onst unr hvy tri whn it ns to us, n hn my not lwys urnt th rhility to th stintion //$17. ( IEEE.

2 < A. Our Contriutions In this ppr, w ous on th prolm o rokn links n onstion o protiv routin protools. As mntion, th rokn links n onstion r, rsptivly, u minly to th no moility n th us o sinl (shortst pth mhnism. To tivly op with this prolm, w propos nw protiv routin shm, ll Applitiv Inirt Routin (, whih ls with ntwork rliility n lo lnin sin th hih prnt o pkts ropp rom unrlil links nnot inor to improv systm prormn in ynmi ntwork topoloy. rovrs rom unrlil links y orin ltrntiv pths throuh th ooprtion o intrmit nos (ll proxis on pth rom sour to stintion. Th shm is hrtriz s ollows. Applitiv: It limits th itionl us o nwith sin it os not rost inpnnt ontrol pkts. It os not lso mintin multipth inormtion twn sour n stintion to ln tri n rovr rom rokn links, nor os it pn only on on primry irt pth to orwr pkts whn n intrmit no is unr onstion or hs rokn links. Inirt: It ins n ltrntiv n inirt pth with th hlp o th shr nihors o two ommunitin nos. Ths shr nihors r not on th primry irt pth to th inl stintion. Th nihorin nos inirtly ui pkts to th primry irt pth tht is on or mor hops wy, or to th nw irt pth to th stintion y llowin thm to ypss unrlil links. Atr prsntin th tils o th propos shm n its proprtis, w rport rsults rom our xtnsiv simultion xprimnts usin ntwork simultor ns. A omprison o our rsults with th protiv protool monstrt tht th shm inrss totl throuhput n ntwork rliility y improvin th pkt livry rtio up to mximum o 3% n pkt orwrin ilur rtio up to mximum o 9%. As rsult o proviin ltrntiv pths to th onst tri whih lks vli links, th lso improvs th vr nto-n pkt ly. A omprison with th rtiv protools, n, shows tht th hs hihr pkt livry rtio n hn it is vry omptitiv s protiv protool. Th rminr o this ppr is orniz s ollows. Stion II introus som si initions. In Stion III, w xplin th lorithms or rroutin pkt y inin n ltrntiv pth. Stion IV sris how n hiv lo lnin n nhn orwrin pility, whil Stion V isusss th simultion nvironmnt n omprison rsults. Finlly, Stion VI onlus th ppr. II. APPLICATIVE INDIRECT ROUTING ( SCHEME In this stion w prsnt our propos shm, ll th Applitiv Inirt Routin (, or rroutin pkts lon ltrntiv pths to rh th inl stintion. Th is s on th protiv routin mhnism suh tht it ynmilly ontrols th ntwork tri n pths th rokn links with n ltrntiv pth. Th is quit tiv n st in rovrin rom rokn links n in rlivin onstion sin it rirts th tri to rlil link in n ltrntiv pth. Finin n ltrntiv pth is possil with lol rio onntivity inormtion (i.., with th hlp o nihors whn no tmporrily ontins inorrt routin inormtion or xprins onstion. This is us ll nos in n ho wirlss ntwork n t s iniviul routrs; mnin vry no n hn th irtion o th n-rout pkt. As mttr o t, th onpt o n ppli to ny xistin ho routin protool with tl-rivn strutur ut th prormn is likly to vry, s on th hoi o spii protool us. Lt us irst introu som si initions n trminoloy, n thn mov on to onrt sription o. A. Bsi Dinitions A ho wirlss ntworks onsist o nos n wirlss links rprsntin th irt ommunition twn no pirs within th rio rn. Nos in this ntwork isrn trnsint topoloy t th momnt whn thy r in tion throuh wirlss links, suh s orwrin pkts. W shll in this ho wirlss ntwork topoloy s n unirt wiht rph, whr n r th st o nos n wirlss links, rsptivly. A rtin proility (wiht is ssin to h. Th proility is msur o link vilility. Th squn o s in orms pth, #, ' * n This is onsir s multihop routin pth n h no in pth ts s n iniviul routr. Eh * hs its spii rio rn with rius 7. Lt 9 ; th r o rio rn o. W in A C D E 9 ; H 9 > ( K M s shr zon twn no n N. Th nos in A C D r ll shr nihors o no n N, n it is not y C D Q S T A U V. Lt W X 9 ; \ N 3 _ i N. 7 K M n whr 3 W X 9 ; p q, th st o lol nihors o no. Thus, < C D Q S T A U V W X 9 ; H W X 9 >. Whn n i * is inlu in routin pth,, two nos ormin th, i, shoul th rivr n snr. With th i o this t, lt 9 ; S x y z 9 ; th hl r o 9 ; whih s towr th rivr. Thn w in A C D E A C D 9 ; H S x y z s or zon o no n N, rsptivly th snr n rivr. Th < C D Q S T A U V in A C D r ll proxis o no n N. III. DESCRIPTION OF ALGORITHM Th nos in moil ho ntwork usully mk nlss movmnts tr th ntwork is ploy. Thy prioilly or on-mn xhn ontrol inormtion with lol nihors within thir trnsmission rn to pt with th ntwork ynmiity. Howvr, it is hllnin tsk to urnt th quisition o th nihors lotion inormtion in timly mnnr. To minimiz th rror o no s lotion quir in, w st up tim prio prmtr or th vliity o in nihor, s on th prioi ontrol mss intrvl. Th lorithm onsists o thr su-lorithms: proxy isovry n mintnn proxy no sltion, n rroutin lorithm. Th proxy no sltion is th min su-lorithm. Its worst-s runnin tim is } //$17. ( IEEE.

3 whr is th numr o nihors. Th stor sp rquirmnt or proxy tl is}. A. Proxy Disovry n Mintnn Alorithm To op with th unrlil link prolm, th rquirs inormtion out th nihors o th nxt hop no whih is rivr n ors n ltrntiv pth rsultin rom th sltion o proxy no. Th rquir inormtion is ollt with th hlp o routin upt pkts without snin out ny inpnnt ontrol pkts. Nmly, no ronizs its lol nihors whil ths nihors rost thir routin upt pkts, trwr th no rosts its routin upt pkt whih ontins its lol nihor inormtion. Tl I rprsnts th ormt o two tls or h no in th ntwork: routin tl n proxy tl. Mtri is rout lnth to stintion rom no. Distn is physil istn twn no n its nihor. Rport tim is th tim t whih no is roniz s nihor. Intrvl is th intrvl tim or l or rroutin. Th proxy isovry n mintnn prour is til low. TABLE I ƒ ;ˆ Š Œ;ˆ Ž ;ˆ ;ˆ Š (A ROUTING TABLE,(B PROXY TABLE ; Œˆ Ÿ š ; œˆ Œž š ; š ; ; Œˆ œˆ Œž Th nos st up th Proxy ino il o thir nihors in th routin tl with routin ontrol pkts rost y th nihors. LtM n lmnt o th stw X, n lt N not th istn twn nos nm. Rll thtw X is th st o lol nihors o no. Th istn twn th two ommunitin nos n msur y th tim o rrivl mtho []. EhM * W X rosts its routin ontrol pkts whih r riv y no M urin th prioi rout upt intrvl,. Whn rivs th ontrol pkt o, it msurs N n sts up th Proxy ino om in its routin tl. No rosts its ontrol pkt with th ollt Proxy ino to ll nihors in vry. EhM * W X is l to roniz th urrnt on hop nihors o no y hkin i Proxy ino.istn o h no in th ontrol pkt rost y no. Bs on tht Proxy ino n th Rport tim, h nom uils or upts its own proxy tl. Th proxy tl inormtion n upt prioilly n synhroniz with th routin tl, sin it is s on th rost routin ontrol pkts. Th proxy tl onstrution-mintnn lorithm is sri in Fiur 1. B. Proxy No Sltion Alorithm Fiur pits th si onpts o proxy no sltion n Fiur 3 sris th orrsponin lorithm. Hr nos no UD9 n7 r th snr n rivr, rsptivly; whil is prvious snr whih orwr th pkt to no. Furthrmor,ª is th st o nihors«in th shr zon. Th ooln ovrlo no (w rturns th onstion sttus o rivr«(s til in Stion 3; is th inl Fi. 1. i UD D9DV x TUAx xv UA C Q x ±D thn msur istn to th snr prour trl pkt rivr in upt routin tl invok UA²³ xc xqdu n prour; prour proxy mnr in xtrt UA² upt UA² ³ ³ xtyd C z A z UA TUAx xv x ±D n prour; Proxy tl onstrution-mintnn lorithm st o th proxy no nitsµ in th or zon. n slt romª y msurin th nl (shr nihor«, snr, rivr7. Tht nl shoul lss thn or qul to.cdqs UD9 TAUV o UD9 is th st s nihors. Th omprison o 7 UD9 with µ 7 UD9 hlps pkt to low towr th oriinl orwrin irtion s iintly s possil. Any nl rquir in th lorithm n msur y usin th lw o osin untion n th invrs osin untion in trionomtry. An xmpl is: ¹ # º «¼ 7 p 7 «- «7 À «7 X Y Fi.. ( h Shr Zon Cor Zon X Y ( h Rn or Sltin No or Rroutin or xyyê Á  ÄÆ S Ç È ÄÆ Ì Â ÄÊ ËÎ Ï Á Ê =V=U S ÇÑ ÒÓÔ untion slt proxy (no s, no r, no È A9DUyAx D sš in C A D Ê Õ (U z xyvd Ç Ë ÄÆ S š n or; i Ç or (ll± (Ï Ë Ì È ÄÆ Ì V=U=Vš Â Ì S š # ± Ï ± Ç i =U=Vš (Ì Õ n i n or n i i Ø thn ls VÂrturnC  UxC x² V 9DyA ³ yyvvac UxC QD rturn Â Ä x² ± ÙUD AU D D Ú # ± Ù V xc D ÜV α Ë Ì Ç n untion; Fi. 3. Proxy No Sltion Alorithm Thr r two possil snrios s sri in Fiur or proxy no sltion. Lt snr ný rivr, n th irtion twn ný is th oriinl orwrin irtion o th mss in oth snrios. Two sts //$17. ( IEEE.

4 ª z Q Ù x E W X H W X z n ª z Q Ù T E W X H W X z r onsir s < C = D z Q S T A U V o nos n Ý in Fiurs ( n (Þ, rsptivly. Thus, ª z Q Ù x \, n n ª z Q Ù T \,,, hn. Not tht Ý is th nxt hop o no to rh th stintion. Howvr, ronizs tht th link to Ý is rokn. Th sltion o no or to rrout th mss n on y hoosin no rom th nihor sts o A= zc D, ª z Q Ù x n ª z Q Ù T. W shoul not hoos ny no hin th snr to rstrit th mss rom lowin kwr n throuh ny no unr onstion (s xplin in Stion 3. Thus, in Fiur, th shr nihors tht lon only to A= zc D r onsir s nits or sltin proxy no or rroutin pkt. Bs on th ov prour, th inl sts o proxy nos r thror z Q Ù x \, n n z Q Ù T \,, hn.bsis onstion sttus, s shown in th lst two vrils (i.., o Fiur 3, th istn twn two nos n th rport tim r onsir to th ky omponnts in inlizin th proxy no sltion. C. Rroutin Alorithm A pkt is l to rh th stintion throuh th nihors in V A= U C D whr n 7 r rsptivly th snr n th rivr who is th nxt hop no sin thy r in los proximity o th pth to th stintion. Whn th pkt is orwr to ny on o thos nihors, it is just on hop wy rom th nxt hop no whr th pkt ws oriinlly suppos to o i th link to th nxt hop ws vill. Whn no ns to orwr pkt, it irst hks th orwrin pth in th routin tl. Dpnin on th vilility o routin inormtion in th routin tl n th urrnt link tri sitution, it ins n ltrntiv pth on mn y sltin proxy no rom th proxy tl. Howvr, th proility o inin n ltrntiv pth pns on th numr n lotion o th nihors in th proxy tl. Thr r two rsons or rroutin: rokn links n onstion. In th ollowin, w sri th rroutin u to rokn links. In Stion IV, th rroutin u to onstion will sri in til. Fiur illustrts th onpt o th rroutin lorithm o whih is sri in Fiur. In Fiur (, th s- ( ( Fi.. ( ( Rroutin u to Brokn Links tlish pth throuh th rost routin inormtion is prour in i U D D 9 D V x x ± D thn z C V S D U A C Q C z A z U A S D U A C Q x T y D i ((no rout xists à (rout xists ut rokn or ovrlo thn i ( proxy no lry stup thn orwr pkt to proxy no ls ll slt proxy V D C D U = U D D 9 D U = U D 9 V D C D U i ( proxy no xists thn stup (proxy no, routin tl z A U Ê x U x ± D A U A ² ³ C A D ls Ê x C y C D Ê x S C z A x U U 9 D V ls z A U Ê x U x ± D = T x V D A C S D A U Q C x y U A D C z A i C D ² S A V x T U A ± D C y C ± thn i ( proxy no lry stup thn pur (proxy no, routin tl upt proxy tl ll slt proxy V D C D U = U D D 9 D U = U D 9 V D C D U i ( proxy no xists thn stup (proxy no, routin tl ls Ê x C y C D Ê x S C z A x U U 9 D V n prour; Fi.. Rroutin Alorithm â Þ â â i â å whr is th sour n å is th stintion. As pkt rrivs t no, it knows i is th nxt hop to rh th stintion. Howvr, it ronizs tht th link to i is rokn sin no i movs rthr thn mx istn(,, th trnsmission rn o. In Fiur (Þ, ins no _ * \ W X H W X D n. In no _, th pth to th stintion is _ â i â å ut i is not rhl rom _. In Fiur (, ins no Ý * \ \ W X H W X D n p \ W X H W X D n n. In Fiur (_, no Ý ins th stintion å within its trnsmission rn, thus th inl pth is otin s â Þ â â _ â Ý â å. Aorin to th ntwork tri n th vilility o th shortst sinl pth to th stintion, th rroutin prour oul invok in vry hop until pkt rhs th stintion. Thus rstilly rlivs th roppin rt prou rom th tmporry lk o orrt pth inormtion y quikly prouin n ltrntiv pth. Th ov isussion rsults in th ru trnsmission ly o pkts irt to rokn link n th inrs pkt livry rtio. IV. PROPERTIES OF Th propos shm ors lo lnin n improvs th pkt orwrin vilility. Thus, thr is lss possiility o stllin n roppin pkts u to onst tri n rokn links. W irst prsnt th proprty o lo lnin n thn th improvmnt on orwrin vilility whn th link oms unrlil u to no moility or onstion. A. Approh to Lo Blnin Th tri towr th stintion throuh onst no î oul rrout throuh on o th nihors o î tr tts th onstion. Sin onstion is usully not prsnt on th ntir pth, th tri ns to ynmilly ontroll t vry hop. In, h no on pth to th stintion rrouts th tri, whn it nountrs onstion in th nxt hop no N ( K M, y inin n ltrntiv pth with th //$17. ( IEEE.

5 ý > ý ý C 9 ; D = 9 > Q S T A U V (proxis A C D. Th onstion ontrol hlp o < lorithm is sri in Fiur. In wht ollows, w sri how n tt n llvit onstion in no usin impliit n xpliit mthos. Th nottions n trminoloy us in th lorithm r lso isuss. prour tri rirt Õ in i (tt mo xpliit thn ñ > ; Â rroutin tim (ò ls ñ > ; Â EM.sttus i (j = proxy no upt (ñ ; >, proxy tl thn ll slt proxy (snr, rivr, prv snr i ( proxy no xists thn upt (nw proxy no, routin tl ls pur (ol proxy no, routin tl ls ll slt proxy (snr, rivr, prv snr i ( proxy no xists thn stup (proxy no, ñ > ;, routin tl ls stup (ñ > ;, routin tl n prour; untion ovrloõ no (no j in i (tt mo xpliit thn i (ñ > ; ó urrnt tim thn rturn tru ls rturn ls ls rturn ñ ; n untion; untion rroutin tim (ò in ö ô ; õ> Â proption ly rom i to j > Â prossin ly o j D Â ò # ø ô ; õ> # ö > Ú urrnt tim rturn R tim n untion; Fi.. Constion Control Alorithm As prt o th impliit mtho, th nos on pth lult th pproximt witin tim o th pkt to orwr whn th nxt hop no is unr onstion. This is on y usin knowlmnt (ACK o th pkt whih is trnsmitt rlir. W in th on-hop totl ly, ú, s th tim twn th prtur o pkt rom th ntwork lyr n th rrivl o th ACK o tht pkt to th link lyr. Th link lyr notiis o ú i it xs rtin prin thrshol. Th on-hop totl ly, ú, ontins quu ly, prossin ly n proption ly []. Th quu ly, onsir s ominnt omponnt in ú, is th tim tht lpss or pkt is orwr. It vris orin to th intrvl o il hnnl quisition n th mount o tri. For instn, suppos thr r numr o nos within th rio rn o rtin no î n lt 7 th vr intrvl tim whn thr is no ontntion or n il hnnl. In this s, i nos simultnously ompt or th sm il hnnl to orwr pkts to no î, th vr intrvl tim oms 7 û p q n th proility o th hnnl quisition oms C, hn, th tim lps in th quu will proportionlly inrs. Th pproximt orwrin ly is riv s ¹ 7 «7 _ i ÿ ú p =N û - p N whr, M r th snr n rivr, rsptivly n, r rsptivly th vr proption n prossin lys. I thr is no rtrnsmission, ý ¹ 7 «7 _ i ÿ is qul to th quuin ly in no. As prt o th xpliit mtho, onst no rosts two xpliit msss (EM only to lol nihors whn it is unr onstion n out o onstion. Thry, lol nihors n roniz th onstion sttus o th no throuh thos two EMs. W in N s th intrvl tim or th l in no or rroutin inomin tri irt to no M n or rtril o orwrin pkt to M. To i onstion sttus in no, th ly ú or th EM is us pnin on th wy o ttin onstion. I no ý tts onstion throuh th impliit mtho, sts up ¹ 7 «7 _ i ÿ ¼ { 7 7 i i s N whr CurrntTim is th tim whn quirs Forwr- Dly(i. In th s o xpliit mss, th EM.sttus (onstion sttus, whih ontins ooln vlu, is st up s N. As N is in st up, stlishs n ltrntiv pth to rrout th pkts irt to no M y sltin proxy no s sustitut or no M. Thrtr, whn no rivs pkt n th nxt hop is no M, it hks th onstion sttus prmtr N o M. For instn, i th urrnt tim is N o M, thn inrs tht no M still xprins onstion n rrouts th pkt to th ltrntiv pth. Othrwis, rtris orwrin th pkt to th oriinl routin pth. smllr thn Fi. 7. Rroutin u to Constion As n xmpl, Fiur 7 illustrts th rroutin onpt to llvit onstion unr. In this iur, is th sour no n X is th stintion. Lt no i xprinin hvy tri. Whil pkts rriv t no, this no tts onstion in no i. Thus rrouts inomin tri whih woul othrwis o throuh no i. No irst uils th nit st = \ _, Ý n n thn slts proxy no rom. Lt _ * hosn s th proxy no sin _ hs lowr tri thn Ý. Th with (olnss o lin in Fiur 7 rprsnts its tri sttus. No å * \ \ W X H W X D n p n is slt s th proxy no or th nxt hop in no _, sin i is still unr onstion whil th pkts r rrout to _. No å inlly orwrs th pkt to th stintion X. Thus, th oriinl pth o â Þ â â i â X rsults in th pth â Þ â â _ â å â X. Th totl orwrin ly o pth n riv s Ë h ¹ 7 «7 _ i ÿ, whr < is th st o nos without th stintion on th pth n is tim unit. Unr th onstion ontrol shm o, th prmtr F(t n ru y splittin th tri lo into ltrntiv pths //$17. ( IEEE.

6 ± X Howvr, pnin on th r o onstion, th r o onntivity o th ntwork, n trnsmission mi (sinl or multipl hnnl, ý oul lonr sin multipl rroutin is n until it ins n ltrntiv pth. B. Improvmnt o Forwrin Avilility Unr th onvntionl routin lorithms, nos mintin th shortst sinl pth routin inormtion ompos o multipl hops. I ny hop on th pth is rokn, th whol pth oms unvill sin vry hop hs only on link to orwr pkt towr th stintion. Th protool n ovrom this limit orwrin ility o h hop. Not tht th wiht ntwork n rprsnt y 3 3 û 3 3 mtrix,, whos lmnts N r ivn y th non-ntiv proility o link vilility twn two nos n M, orin to th prtiiption o nos on th pth vill rom sour to stintion. W will now riv th ntwork rliility o ivn pth with th hlp o vr hop orwrin vilility o tht pth otin rom th mtrix. Whn no sns or rivs pkt, it ns to orwr th pkt i it is not th stintion. Tht no my not hv th link to th nxt hop to orwr th pkt. W ssum tht link xists with rtin vilility, N, whn two ommunitin nos n M r within h othrs trnsmission rn, i.., istn(i,j. rius o rn. I thr is no link to th nxt hop, th inomin pkt nnot orwr n hn will ly or ropp. W lult th vr hop orwrin ilur proility o pth, not s 7 z x y, whih is th omplmntry proility o th vr hop orwrin vilility. First, w n to onsir th orwrin ilur proility Ý o no in h hop in trms o th omplmntry proility q p N, whr is th snr n M is th rivr. Pkt orwrin will il whn no possil links r vill in no to rh th stintion. Thror, th orwrin ilur proility or no in h hop is: Ý y Õ q p N y (1 whr µ quls th numr o links vill in no to orwr pkt towr th stintion. W n trmin µ rom th numr,, o possil pths rom no to th stintion. Clrly, n otin rom th mtrix y rplin non-zro N with q.lt_ th ntwork imtr. Thn, ¼ ¼ ¼ ¼ ivs ll possil pths o lnth. _ twn ny pir o nos. Thus, or ivn o possil pths pth, w n trmin th numr µ. to th stintion rom ny no on th pth rom. In th protool, µ quls th numr o < C 9 ; D = 9 > Q S T A U V in 9 A; C= 9 D> n in th sinl shortst pth (SSP shm, µ simply quls 1. Lmm 1. Forwrin pkt to on o th shr nihors is vli or th pkt to rh th sm stintion. Proo: All nos s on th protiv routin protool in n ho ntwork kp th ntir ntwork routin inormtion. Thus, thortilly vry no hs on pth to ny stintion onnt to th ntwork, n it is l to orwr th pkt to rh th sm stintion. Bs on Formul (1, th vr hop orwrin ilur proility o pth is ivn y 7 z x y S Õ Ý whr X is th numr o hops in pth rom sour to stintion. From Formuls (1 n (, w n onlu tht 7 z x y. 7 z x y < < whih implis tht th vr hop orwrin vilility, q p 7 z x y, in th propos shm is hihr thn q p 7 z x y < <. Hn hs lowr proility o ilin to orwr pkt. Tht ls to hihr ntwork rliility. V. SIMULATION RESULTS W vlut th propos routin shm usin isrt tim vnt ntwork simultor ns []. As mntion rlir, is lssii s protiv routin protool. Thror, or prormn omprison, w simult rprsnttiv protiv lorithm, whih hs lry n vlut in [], [9] usin ns. Sin rtiv protools hv n shown to prorm ttr in trms o most mtris [], [9], w lso simult two rtiv protools, nmly, n, to msur th omptitivnss o. For simultin,, n w us th sm prmtr vlus s in [], whil th prmtr vlus or is th sm s. Espilly, w st up th prioi rout upt intrvl s tim prmtr or th vliity o in proxy nit in th proxy tl o. A. Simultion Environmnt Th prormn o truly pns on th numr n lotion o proxis (shr nihors in th or zon [3]. Thus, w run th simultion in two irnt ntwork sizs, û n û. Sin h o thm ontins nos, th simultion is run or two irnt nsitis, suh s 1 no/, n 1 no/, so tht w n msur th t o nsity on th prormn o. A uniqu proprty o ho wirlss ntworks is th ynmiity o topoloy. Th vloity o nos is th min omponnt o th ntwork ynmiity. A ho routin lorithms r sin to op with this proprty, thus, w hoos st mximum vloity m/s (7km/hr. Th vloity hs smll mounts o pus tim rnin rom to 1 sons with 3 son intrvl (i..,, 3,, 9, 1. Th rnom moility nrtor s on th rnom wypoint lorithm [] is us or th no movmnt pttrn in th ntworks. Th no movmnt is rstrit to lt trrin without ny ostls. Th no strts movin towr point inpnntly n rnomly hosn t sp rnin twn n m/s. It puss or prin mount o tim (i..,, 3,, 9, 1 on rrivin in th point. For th ommunition pttrn, w us onstnt it rt (CBR tri mol. Th numr o sours o CBR in th simultion is. Eh sour sns out pkts/s or low tri lo n 1 pkts/s or hih tri lo usin yt ( //$17. ( IEEE.

7 TABLE II SIMULATION PARAMETER VALUES Ntwork Siz # $ & & & *, & &, & & *, & & Ntwork Dnsity 1 no/, / 1 no/, / Numr o Nos Trnsmission Rn - Movmnt Sp - /s Pus Tim (son, 3,, 9, 1 Tri Typ / Sours CBR / Pkt Siz yt Trnsmission Rt pkts/s n 1 pkts/s Numr o snrios /pus tim Simultion Tim ss # o pkts snt on rokn link / # o snt pkts x 1 1 Pus Tim (s Fi.. Pkt Forwrin Filur Rtio ( with pkts/s pkts. W run th simultion usin iv snrios t h pus tim. Th simultion lsts sons. Tl II summrizs th prmtrs hosn or this simultion nvironmnt. W vlut th prormn o in this simultion, s on th ollowin thr mtris: ( pkt orwrin ilur rtio, ( pkt livry rtio, n ( vr n-to-n pkt ly. B. Pkt Forwrin Filur Rtio W hos only th protool to ompr th orwrin ilur rt sin th min purpos o is to rovr rom unrlil links quikly s protiv protool. W n pproximtly msur th ntwork rliility y vlutin this mtri. With th st rovry o unrlil links, rstilly rss th numr o pkts snt ovr th unrlil links, whn ompr to th protool. Th rsults r shown in Fiurs, 9,, n 11. Th lowr th nsity o th ntwork (1 no/,, th lowr th numr o nihors o no. In othr wors, th low nsity ntwork hs lowr proility o inin proxy no to rrout pkt. Fiurs n show hihr rovry rtio thn Fiurs 9 n 11 whih hv rltivly lowr nsity. Not tht th link rk ttion rom th MAC (mium ss ontrol protool is not us in simultion sin it is mntion in [] tht th prormn o is lowr usin th link lyr rk ttion. In ontrst, lunhs th proxy sltion lorithm s soon s it ins out tht th link is unrlil with th link rk ttion rom MAC protool. I proxy no xists tmporrily sts up tht proxy no s th nxt hop no to rh th stintion until it rivs nw rost routin inormtion. Bs on th ov isussions, w osrv tht inrss th ntwork rliility y sustitutin ltrntiv pths quikly or th unrlil links t ll pus tims. In othr wors, rus th proility o orwrin pkts on th rokn links y llowin th pkts to orwr on ltrntiv pths. C. Pkt Dlivry Rtio Fiurs 1 n 1 show how mny pkts r sussully riv t th stintion in th û ntwork, n Fiurs # o pkts snt on rokn links / # o snt pkts x Pus Tim (sons Fi. 9. Pkt Forwrin Filur Rtio ( Ó with pkts/s 13 n 1 show rsults in th û ntwork. Fiurs 13 n 1 monstrt tht improvs out % in th pkt livry rtio in onstnt movmnt, (i.., pus tim is, s ompr to. llows mor pkts to rh th stintion y rovrin th unrlil links quikly. This implis tht th mor th links rk, th hihr th livry rtio o. Consquntly, shows hihr livry rtio thn in ll ss. In th s o protiv protools, th lonr th pus tim, th lss ynmi is th ntwork. Hn thr is lowr proility or th link in th routin tl to rokn. Thus, th irn o livry rtio twn th two protools - n - rss, s th pus tim inrss. Th ov proprty o kps th pkt livry rtio ov 9% in ll ss t low tri lo ( pkts/s, s in th rtiv protools n. At hih tri lo (1 pkts/s, th pkt livry rtio shows th lst pkt rop, styin ov % mon ll simult protools. Tht is us only ttmpts to rliv onstion y splittin th inomin tri o onst nos into som propr proxis whil ll othr protools xprin onstion. Th prormn o,, n is quit stti in ll ss sin n quir th pth on mn whrs rovrs rom rokn links quikly y usin th pr-ollt nihorin no inormtion. This n osrv rom Fiurs 1, 13, 1, n //$17. ( IEEE.

8 # o pkts snt on rokn links / # o snt pkts x Pus Tim (sons Fi.. Pkt Forwrin Filur Rtio ( with 1 pkts/s # o Riv Pkts / # o Snt Pkts Pus Tim (sons Fi. 1. Pkt Dlivry Rtio ( with pkts/s # o pkts snt on rokn links / # o snt pkts x 1 Pus Tim (sons Ó Ó Ó Fi. 11. Pkt Forwrin Filur Rtio ( ø Ó Ó with 1 pkts/s # o riv pkts / # o snt pkts Pus Tim (sons 1 Ó Ó Ó Fi. 13. Pkt Dlivry Rtio ( ø Ó Ó with pkts/s D. Avr En-to-En Pkt Dly Th vr n-to-n pkt ly t low tri lo is shown in Fiur 1 or m û m siz ntwork n in Fiur 17 or 1,m û m ntwork. Fiur 1 xhiits th vr n-to-n pkt ly t hih tri lo or m û m n Fiur 19 or 1,m û m ntwork. Not tht link oms unrlil whn it is rokn n/or sturt with hvy tri. Whn link is unrlil, th no ils to orwr pkts, usin pkt rops or lonr lys. At low tri lo, th nos rrly xprin onstion ut otn xprin rokn links. Thry th n-rout pkts, whih lk vli links, n to quu until thy r orwr n hn lonr lys r prou. To ovrom it, our shm ors n instnt ltrntiv pth usin proxy nos in orr to ru th vr n-to-n pkt ly. In Fiurs 1 n 17, w lrly osrv tht th protool xprins mor ly thn th protool sin os not hv ny othr mhnism to voi th sitution (unrlil links xplin ov, xpt or witin or nw routin inormtion. At hih tri lo, howvr, th nos rop pkts spit th prsn o pths sin th orwrin rt is r lowr thn th rivin rt. Th propos shm ttmpts to rliv th onstion y inin n ltrntiv pth n rirtin th tri lo. Th ltrntiv pth oul oun with multipl rroutin trils sin th nihors o th onst # o Riv Pkts / # o Snt Pkts # o riv pkts / # o snt pkts Pus Tim (sons Fi. 1. Pkt Dlivry Rtio ( with 1 pkts/s.. Pus Tim (sons Ó Ó Ó Fi. 1. Pkt Dlivry Rtio ( ø Ó Ó with 1 pkts/s //$17. ( IEEE.

9 intrmit no hv lss o hn to orwr pkts u to low il hnnl quisition rt us y hih tri lo. Evntully it ls to onstion in ths nihors n th onstion rsults in nothr rroutin tril. Howvr, ll othr xistin protools just rop th pkts so tht it os not t th vr n-to-n ly o sussully livr pkts. Aorinly, Fiur 19 shows hs th hihst ly. Howvr, hs th hihst livry rtio (s Fiur 1 mon ll th simult protools. At hih moility rt, th nihors o th onst no hv lss o hn to hv th quu ull sin th routs r otn rnw with nwly isovr nihors. Thus, th ins ltrntiv pths with lss rroutins thn t low moility rt (i.., pus tim is lon. Bs on th ov isussion, t hih tri lo shows hihr ly t th ost o lowr pkt rop thn, n protools. Also prous rltivly lowr ly t hihr moility rt s osrv rom Fiurs 1, 1, 1, n 19. In s o CBR (onstnt it rt low tri lo, n show rltivly short ly n shows th lonst ly. Av. En to En Pkt Dly x (sons Av. n to n pkt ly x 1 1 Pus Tim (sons 1 Fi. 1. Av. En-to-En Pkt Dly ( with pkts/s Pus Tim (sons Fi. 17. Av. En-to-En Pkt Dly ( Ó with pkts/s VI. CONCLUSIONS In this ppr, w hv ous on th prolm o onst tri in ho wirlss ntworks n th sprs orwrin vilility whn th no with th sinl (shortst pth nountrs n unrlil link. Th sinl (shortst pth shm Av. En to En Pkt Dly x (sons Av. n to n pkt ly x (sons Pus Tim (sons 9 7 Fi. 1. Av. En-to-En Pkt Dly ( with 1 pkts/s 3 Pus Tim (sons Fi. 19. Av. En-to-En Pkt Dly ( Ó with 1 pkts/s is xtrmly voltil u to th onstntly hnin topoloy rsultin rom no moility in ho wirlss ntworks. Thus th sinl (shortst pth otn rsults in rokn links, n hn inrss pkt rop rt n pkt lys sin th no kps only sinl link to orwr pkt to th nxt hop no. Furthrmor, th sinl link rris ll inomin tri, n th prtiiptin nos xprin onstion with hih tri lo. W hv prsnt nw routin shm s on protiv routin protool, ll (pplitiv inirt routin, or ho wirlss ntworks to op with ths prolms. Th propos protool utilizs th nihors shr y two nos, th snr n th rivr, to in n ltrntiv pth. It is s on th t tht th nxt hop no whih is onnt to rokn or sturt link, is not r rom its lol nihors in trms o th lst rost position. Th rrouts th pkt towr th irtion o th stintion s iintly s possil y hoosin proxy no rom th st o shr nihors. Th ltrntiv pth is rthr in trms o th istn to th stintion. On th othr hn, it is str in trms o th n-to-n ly whil nos xprin th lk o routin inormtion n onstion on th pth to th stintion. Howvr, it miht lonr in trms o oth th istn n th ly sin ltrntiv pths oul oun with multipl rroutins pnin on th r o onstion, th r o onntivity o th ntwork, n th trnsmission mi (sinl or multipl hnnls //$17. ( IEEE.

10 In nrl, protiv routin protools tk up lr mount o th limit wirlss nwith u to routin ontrol inormtion rostin in quirin th ntir ntwork topoloy n in kpin it urt. Th onvrts this rwk into n vnt y usin th inormtion ollt y th rost mss to in n ltrntiv pth whn th no surs rom th prolms lry mntion. Our simultion rsults show improv prormn in trms o shortr n-to-n ly n mor rsistn to link ilur, s ompr with th protool. Comprin with two rtiv protools, n, th xprimntl rsults lso monstrt tht th is omptitiv protiv protool. [1] L. Wn, L. Zhn, Y. Shu n M. Don, Multipth Sour Routin in Wirlss A Ho Ntworks, Cnin Conrn on Eltril n Computr Eninrin, volum: 1, pp. 79-3,. ACKNOWLEDGMENTS This work ws in prt support y NSF rnt EIA-, EIA-11, Nortl Ntworks, n Txs Tlommunitions Eninrin Consortium (TxTEC. REFERENCES [1] S. Bsni, I. Chlmt n V. R. Syrotiuk, A Distn Routin Et Alorithm or Moility (DREAM, In Proins o th th Intrntionl Conrn on Moil Computin n Ntworkin, ACM MOBI- COM 9, pp. 7-, Ot [] D. Brtsks n R. Gllr, Dt Ntworks, son ition, Prnti Hll, 199. [3] W. Choi n S. K. Ds, Applitiv Inirt Routin Shm or Fst Rovry rom Unrlil Links in A ho Wirlss Ntworks, Mstr Thsis, Computr Sin n Eninrin, Univrsity o Txs t Arlinton, My 1. [] J. Broh, D. A.Mltz, D. B.Johnson, Y-C. Hu, J. Jthv, A Prormn Comprison o Multi-Hop Wirlss A Ho Ntwork Routin Protools, In Proins o th th Intrntionl Conrn on Moil Computin n Ntworkin, ACM MOBICOM 9, pp. -97, Ot [] S. Cpkun, M. Hmi, n J.-P Huux, GPS-r positionin in moil A-Ho ntworks, In Proins o th 3th Annul Hwii Intrntionl Conrn on Systm Sins, HICSS, Jn. 1. [] K. Fll n K. Vrhn, ns nots n oumnttion, Th VINT projt, UC Brkly, LBL, USC/ISI, n Xrox PARC, Frury. [7] Z. J. Hs n M. R. Prlmn, Th Zon Routin Protool (ZRP or A Ho Ntworks, IETF Intrnt rt, rt-it-mnt-zon-zrp-1.txt, 199. [] D. B. Johnson n D. A. Mltz, Th Dynmi Sour Routin in A-Ho Wirlss Ntworks, In Moil Computin, it y T. Imilinski n H. Korth, hptr, pp , Kluwr, 199. [9] P. Johnsson, T. Lrsson, N. Hmn, B. Milzrk, n M. Drmrk, Snrio-s Prormn Anlysis o Routin Protools or Moil A-ho Ntworks, In Proins o th th Intrntionl Conrn on Moil Computin n Ntworkin, ACM MOBICOM 1999, pp [] B. Krp n H. T. Kun, GPSR: Gry Primtr Sttlss Routin or Wirlss Ntworks, In Proins o th th Intrntionl Conrn on Moil Computin n Ntworkin, ACM MOBICOM, pp. 3-. [11] Y-B Ko n N. H. Viy, Lotion-Ai Routin (LAR in Moil A Ho Ntworks, In Proins o th th Intrntionl Conrn on Moil Computin n Ntworkin, ACM MOBICOM 9, pp. -7, Ot [1] S. Murthy n J.J. Gri-Lun-Avs, An Eiint Routin Protool or Wirlss Ntworks, ACM Moil Ntworks n App. J., Spil Issu on Routin in Moil Communition Ntworks, Ot. 199, pp [13] V. D. Prk n M. S. Corson, A Hihly Aptiv Distriut Routin Alorithm or Moil Wirlss Ntworks, In Proins o 1997 IEEE Conrn on Computr Communitions, INFOCOM 97, Apr. 1997, pp [1] C. E. Prkins n P. Bhwt, Hihly Dynmi Dstintion-Squn Distn-Vtor Routin ( or Moil Computrs, In proins o ACM SIGCOMM 9 Conrn on Communitions Arhitturs, Protools n Applitions, Au. 199, pp. 3-. [1] C. E. Prkins n E. M. Royr, A-ho On-Dmn Distn Vtor Routin, In proins o n IEEE Workshop. Moil Computin Sys n Apps., pp. 9-, F //$17. ( IEEE.