A Signal Characteristic Based Cluster Scheme for Aeronautical Ad Hoc Networks

Transcription

1 KSII TRANSACTIONS ON INTERNET AND INFORMATION SYSTEMS VOL. 8, NO. 10, Ot Copyght 2014 KSII A Sgnal Chaatest Based Cluste Sheme fo Aeonautal Ad Ho Netwos Yu Tan, Lnhua Ma, Le Ru, Hong Tang and Bo Song Shool of Aeonauts and Astonauts Engneeng, A Foe Engneeng Unvesty X an, Chna [e-mal: labyahoo@126.om] *Coespondng autho: Yu Tan Reeved Apl 7, 2014; evsed July 26, 2014; aepted August ; publshed Otobe 31, 2014 Abstat Clusteng s an effetve method fo mpovng the pefomane of lage sale moble ad ho netwos. Howeve, when the movng speed s vey fast, the topology hanges quly, whh leads to fequent luste topology updates. The dastally neasng ontol oveheads seveely theaten the thoughput of the netwo. SCBCS (Sgnal Chaatest Based Cluste Sheme) s poposed as a method to potentally edue the ontol oveheads aused by luste fomaton and mantenane n aeonautal ad ho netwos. Eah node peodally boadasts Hello paets. The Hello paets an be eplaed by data paets, whh peseve bandwdth. The haatests of the eeved paets, suh as the Dopple shft and the powe of two suessve Hello paets, help to alulate the elatve speed and deton of moton. Then, the ln onneton lfetme s estmated by the elatve speed and deton of moton. In the lusteng fomaton poedue, the node wth the longest estmated ln onneton tme to ts one-hop neghbos s hosen as the luste head. In the luste mantenane poedue, e-afflaton and e-lusteng shemes ae desgned to eep the lustes moe stable. The e-lusteng phenomenon s edued by lmtng the pple effet. Smulatons have shown that SCBCS polongs the ln onneton lfetme and the luste lfetme, whh an edue the topology update oveheads n hghly dynam aeonautal ad ho netwos. Keywods: Moble Ad Ho Netwos, Clusteng algothm, Moblty, Dopple shft, Powe Ths wo was suppoted n pat by the Pojet of Natonal Foundaton 9140A JB

2 3440 Tan et al : A Sgnal Chaatest Based Cluste Sheme fo Aeonautal Ad Ho Netwos 1. Intoduton Clusteng s an effent netwo topology management method, and the heahal stutue obtaned usng the lusteng algothm an lagely mpove the pefomane of moble ad ho netwos. Many dffeent lusteng shemes have been poposed. Some detaled suveys of exstng lusteng shemes an be found n [1]-[3]. Nodes n the same luste an exhange messages detly, whle nodes n dffeent lustes ae able to ommunate though luste heads o gateway nodes. Compaed wth the nomal ad ho netwos, the aafts n aeonautal ad ho netwos move at a vey hgh speed, typally fom 700 m/h to l000 m/h [4]. Thus, the ommunaton n aeonautal ad ho netwos an be extemely unstable, as the netwo topology fequently hanges. To mantan stable lustes n aeonautal ad ho netwos, moblty paametes must be taen nto aount fo luste fomaton and mantenane. The luste shemes that ae detemned by the moblty behavo of the moble entty ae alled moblty-awae lusteng shemes. The man motvaton behnd the moblty-awae lusteng sheme s to goup moble enttes wth smla speeds nto the same luste [1]. Then, the nta-luste lns an beome moe tghtly onneted. Futhemoe, the e-afflaton and e-lusteng ate an be deeased. Ths pape fouses on the development of a moe stable lusteng sheme fo hghly moble aeonautal ad ho netwos. The poposed lusteng sheme, SCBCS, uses the sgnal haatests of eeved paets to auately alulate the elatve movng speed and movng deton, povdng auate nfomaton fo the fomaton and mantenane of lustes. Futhemoe, SCBCS s a speally desgned dstbuted lusteng sheme, fo whh the loal e-eleton of one luste head wll not affet the stutue of many lustes and aouse the luste head e-eleton ove the whole netwo. In Seton 2, we evew the pevous wo that has been onduted on lusteng algothms. Seton 3 ntodues the moblty model used n ths pape. Seton 4 alulates the elatve speed usng sgnal haatests. Seton 5 estmates the ln onneton lfetme usng elatve speed and sgnal powe. In Seton 6, the lusteng fomaton and mantenane algothm s pesented n detal. In Seton 7, the smulaton esults of ou study ae pesented. Fnally, Seton 8 onludes ths pape. 2. Related Wo Thee have been some moblty-awae lusteng algothms that have been pevously poposed n [5]-[18]. The lusteng sheme poposed n [5] has a smple luste fomaton and uses asynhonously event tggeed luste mantenane, whh elmnates the "pple effet" and nus muh less ovehead. Howeve, as the luste heads ae pedefned n [5], ths sheme s not patal fo andomly deployed moble ad ho netwos. A well nown moblty met-based lusteng sheme alled MOBIC [6] uses the powe of two suessvely eeved paets to evaluate the elatve moton between two moble enttes. MOBIC does not alulate the auate dstane o speed usng the haatest of the eeved sgnal beause on ty steets the sgnal s lely to suffe fom hgh attenuaton. MOBIC s moe feasble and effetve n the senao that the nodes move wth smla speed and deton. If moble nodes move andomly and hange the speeds fequently, MOBIC s pefomane may be geatly degaded [1]. The lusteng sheme poposed n [7] taes nto aount the speed dffeene among vehles as well as the poston and deton dung the

3 KSII TRANSACTIONS ON INTERNET AND INFORMATION SYSTEMS VOL. 8, NO. 10, Otobe luste fomaton poess, but ts moblty model s only applable fo a hghway envonment. MWC (Mult-paamete Weghted Clusteng) [8] onsdes esdual powe, onnetvty, and aveage moblty n lusteng fomaton and mantenane. Its ompehensve pefomane s good, but MWC s not speally desgned fo a hghly dynam netwo. The algothm n [9] fnds lustes that mnmze both the elatve moblty and the dstane fom eah luste head to ts luste membes. Howeve, t wll not luste vehles movng n opposte detons; ths sheme s not neessay when the node s deton of moton hanges fequently. MCFA [10] uses the leanng automaton theoy [11] to hoose an optmal lusteng sheme fom a fnte set of allowed atons though epeated nteatons. MCFA s sutable fo the senao that the deton of moton and moblty speed s assumed to be andom vaables wth unnown dstbutons. Howeve, t does not esolve the poblem of how to effently exhange moblty nfomaton. The lusteng sheme n [12] mpoves the seah effeny and salablty of MANETs by lusteng nodes based on the tust mehansm. In [12], lustes efe to node goups whee nodes ae tghtly onneted based on a tust elatonshp and shae the same ontext of tust. The lusteng sheme n [12] s sutable fo the hghly dynam haatest of MANETs. Howeve, t assumes that a node an always obtan the nteaton hstoy of othe nodes by seahng the whole netwo; when the luste sze neases, the ontol ovehead wll nease dastally. In most moblty-awae lusteng shemes, the luste head s assumed to now the uent moblty nfomaton (poston, speed and movement deton) of eah of ts membes. Due to the hgh movng speeds and fequently hangng deton of moton, the netwo topology may hange fequently. If the membe moblty nfomaton s not updated n tme, the lusteng pefomane deays damatally. Howeve, t wll ost exta bandwdth to exhange ontol nfomaton to update the luste membe table and luste head table n eah luste head. So t s mpotant and neessay to develop an effent way to obtan the moblty nfomaton wthout fequently exhangng ontol paets, nludng explt poston, speed o movng deton nfomaton. Thee ae seveal lusteng shemes that use sgnal haatests suh as powe and Dopple shft to obtan poston o speed nfomaton. The advantages of these shemes ae: (1) They an be used n the ase that GPS o othe satellte navgaton systems ae not avalable. (2) The Dopple shft and powe an be obtaned fom the data paets, whh edues the amount of peodally boadasted topology ontol paets. In [13], an teatve Dopple shft estmato s poposed that s nsenstve to SNR at a wde ange of velotes and SNR, patulaly n the vey low SNR ases. We assume that the Dopple shft and powe ae measued wthout mstaes. In [14], the staton handoff n alway ommunaton s mplemented based on the eeved aveaged sgnal stength fom the adjaent base staton and the Dopple shft fom the sevng base staton. SECA (Sgnal Effent Clusteng Algothm) [15] hooses the nodes wth low moblty, moe neghbos, hgh esdual battey enegy and hgh sgnal stength as luste heads. In SECA, sgnal stength s an mpotant lusteng teon, but sgnal stength does not fully eflet the moblty of the movng enttes. DDVC (Dynam Dopple Veloty Clusteng) [16] s a stable lusteng sheme usng Dopple shft to estmate elatve veloty. DLDC (Dynam Ln Duaton Clusteng) [16] s also a stable lusteng sheme that s based on the estmated ln expaton tme. Howeve, both DDVC and DLDC only apply to the moble entty that moves n a elatvely lnea path wthout fequently hangng ts deton and speed. DSRC (Dedated Shot-Range Communatons) [17] measues the Dopple shft of the ae of DSRC sgnals. Dopple-based ange-atng s vefed n pate usng DSRC tanseves. Based on the speed alulated by Dopple shft, an mpovement of up to 48% ove the GPS auay s aheved. In MPBC (Moblty Pedton-Based Clusteng) [18], the Dopple shfts of

4 3442 Tan et al : A Sgnal Chaatest Based Cluste Sheme fo Aeonautal Ad Ho Netwos peodally exhanged Hello paets between neghbong nodes ae used to estmate the elatve speeds. The nodes that have the smallest elatve moblty n the neghbohoods ae seleted as the luste head. Howeve, the speed alulaton s not pese n [18]. If fomula (7) n [18] s satsfed, by law of osnes, we fnd that any two nodes n the netwo should move at a same beelne wthn the tme between two suessve Hello paets. Ths assumpton s not patal n most aeonautal ad ho netwos. Although the smulaton esults n [18] show that MPBC an adapt to hghly dynam ad ho netwos, the mpatal assumpton onstans ts pefomane. 3. Moblty Model The Refeene Regon Goup Moblty (RRGM) model [19] s a gene moblty model that an be used fo both entty moblty and goup moblty. In the RRGM model, goup patton and mege wll ou dynamally and andomly. A goup may splt nto multple smalle goups o a numbe of goups may mege nto a lage one. In ths pape, we modfy the PRGM model to adapt t to a hghly dynam senao wthn whh both sngle entty moblty and goup moblty exst. The new moblty model s expessed as follows: (1) In the ntal stage, all the nodes ae deployed andomly n the smulaton egon. Seveal ula egons whose adus s equal to the ommunaton ange R ae deployed andomly n the smulaton egon, too. The ula egons ae not ovelapped to eah othe. All the nodes n the same ula egon fom a goup. Eah node that does not loate n the ula egons s seemed as a goup. (2) Evey goup s assoated wth a efeene egon. The membes n the same luste wll andomly selet a loaton wthn the oespondng efeene egon as ts taget and move towads ths pont wth vayng speeds. One a node aves at the efeene egon, t wll move aound wthn the egon watng fo the aval of othe nodes. Afte all the nodes of a luste ave at the efeene egon, a new efeene egon s assgned to the goup. (3) At a onstant tme nteval, a new destnaton s geneated. The goup that s losest to the new destnaton s hosen to splt nto two smalle goups. A numbe of nodes n the ognal goup ae andomly seleted to fom a new goup. Then, eah goup s assgned a new efeene egon. (4) At a onstant tme nteval, a same efeene egon s assgned to two goups, whose efeene egons ae losest to eah othe. Afte the two goups ave at the fome egons, they mege nto a new goup and a new efeene egon s assgned to the new goup. Befoe the mege, f a goup aves eale than anothe goup, ts membes move aound wthn ts oespondng egon watng fo anothe goup s aval to the oespondng egon. 4. The Relatve Speed Calulaton The attenuaton model adopts the Fee-Spae Path Loss model [20] as follows: 2 P PG t tg ( ) (1) 4 d P s the eeved powe, P t s the tansmttng powe, G t s the tansmttng antenna gan, G s the eevng antenna gan, s the wavelength, d s the dstane between the tansmtte and the eeve.

5 KSII TRANSACTIONS ON INTERNET AND INFORMATION SYSTEMS VOL. 8, NO. 10, Otobe a n b n j v Fg. 1. Relatve moblty n j Fg. 1 llustates the elatve moblty of n and n j. In fat, node n and node n j ae both moble, but we see n as stat and n j as moble fo onvenene. When node n j moves fom b to wth a elatve speed v, we all t a eedng senao. When node n j moves fom to b wth a elatve speed v a, we all t an appoahng senao. n j sends a Hello paet at b and, espetvely. n eeves the paets. t s the tme nteval between two Hello paets. By (1), the eeved powe of the sgnal sent at b s b 2 2 P PG t tg ( ), the eeved powe of the sgnal sent at s P PG t tg ( ). d ab s 4 dab 4 da the dstane between a and b, d a s the dstane between a and. Then, d ab and d a an be expessed as: PG t tg dab (2) b 4 P d a PG t tg (3) 4 P Suppose f s ognal ae wave fequeny at sende n j, f s the eeved ae wave fequeny at eeve n. If f f ', t means that the tansmtte n j and the eeve n ae eedng fom eah othe. Contaly, f f f ', t means that the tansmtte n j and the eeve n ae appoahng to eah othe. Aodng to Dopple effet, n eedng senao the followng expesson s obtaned: f V v os ab f (4) V ' In (4), V s the speed of lght and v s the elatve speed n eedng senao. By (4), the eedng speed s obtaned: V ( f f ') v f osab Fom the law of osnes, we an obtan the followng: da db dab os ab (6) 2d d In (6) b d s the dstane between b and. We assume that n the tansmsson tme nteval t, n j would not hange ts movng deton, then the dstane fom b to an be expessed as: a b (5)

6 3444 Tan et al : A Sgnal Chaatest Based Cluste Sheme fo Aeonautal Ad Ho Netwos db v t (7) Substtutng (7) n (6) and then substtutng (6) n (5), the followng expesson s obtaned: v 2 d V ( f f ') d d f t t 2 2 a ab a 2 (8) Tae (2) and (3) nto (8), and we obtan the followng: v 2 V ( f f ') PG t tg PG t tg b 2 f t P 16 t P P ( ) (9) In the appoahng senao, n j fst loates at, and then t moves to b. Le the speed alulaton n eedng senao, the elatve movng speed an be alulated as: v 2 V ( f ' f ) PG t tg PG t tg 1 1 a 2 2 b 2 f t P 16 t P P ( ) (10) 5. The Ln Conneton Lfetme Estmaton Moblty pedton of movng enttes plays a majo ole n effent lusteng of aeonaut ad ho netwos. Ths wll allow fo bette plannng and mpoved oveall QoS n tems of ontnuous seve avalablty and less topology ontol oveheads. We an estmate the maxmum ln onneton lfetme based on the pesent elatve speed and the Dopple fequeny shft. The ommunaton ln nteupton happens unde the ondton that the two nodes ae at the maxmum ommunaton ange. If the two nodes eep the pesent elatve speed and deton, the maxmum ln onneton tme an be alulated. Of ouse, f the nodes wll hange the speed and deton of moton andomly and quly, the estmated maxmum ln onneton lfetme s not lely to be auate. The estmated tme s just used as a met to measue the ln stablty at a spef tme. 5.1 Reedng senao In Fg. 2, le the despton of Fg. 1, we assume that n s stat and loated at a; n j s fst loated at b and then t moves to. If n j wll not hange ts pesent speed and deton of moton, the maxmum ln onneton tme n the eedng senao s alulated as: t d d d d bd b (11) v v d s loated at the edge of the ommunaton ange, d d s the dstane between and d, dbd s the dstane between b and d.

7 KSII TRANSACTIONS ON INTERNET AND INFORMATION SYSTEMS VOL. 8, NO. 10, Otobe b d a R In Fg. 2. Estmaton n the eedng senao ab, fom the law of osnes, we an obtan the followng: dab db da os ab (12) 2dabdb Tae (9) nto (7), and we get the dstane between b and : d 2 V ( f f ') t PG t tg PG t tg 1 1 b 2 b 2 f P 16 P P ( ) (13) Tae (2), (3) and (13) nto (12), and we get: 4 V ( f f ') t 1 1 b f P PG t tg P P osab (14) 1 8 V ( f f ') t 1 1 b b P f P PG G P P In abd t t, fom the law of osnes, we an obtan the followng: dab dbd dad os abd (15) 2d d As llustated n Fg. 2, d bd s the dstane between b and d, d ad s the dstane between a and d. Atually, dad s the adus of the luste, so (15) an be ewtten as: dab dbd R os abd (16) 2dabdbd In (16), R s the maxmum ommunaton ange. (16) an be tansfomed as: dbd 2dabdbd os abd dab R 0 (17) Solve the quadat equaton (17), and d bd s obtaned as: The value of dbd bd ab ab ab bd d d os abd R d sn abd (18) s sngle, so the ndetemnaton n (18) should be elmnated.

8 3446 Tan et al : A Sgnal Chaatest Based Cluste Sheme fo Aeonautal Ad Ho Netwos If d os abd R d sn abd, the followng expesson an be obtaned: ab ab d os abd R d sn abd (19) 2 2 ab ab ab ab os ab sn By (19), we obtan that d d abd d abd R. Howeve, dab s defntely shote than the ommunaton ange R. So (19) wll neve be ght. Then, dab os abd R dab sn abd s the fnal ght expesson. At last, the defnte answe of quadat equaton (17) s: d d osabd R d sn abd bd ab ab d osabd R d d os abd 2 ab ab ab Atually, abd and ab ae the same angle, so: os abd os ab (21) Tae (20), (21), (14) and (2) nto (11), the maxmum ln onneton lfetme n the eedng senao s alulated as: dbd dbd t t v v M W 16 R 1 ( M W) 2 b 2M W PG t tg P 2M W [ 1] t 2M t W 4 V ( f f ') t 1 1 In (22), M, W. b f P PG G P P t t 5.2 Appoahng Senao In Fg. 3, we assume that n s stll stat and loated at a, n j s fst loated at and then t moves to b. If n j wll not hange ts pesent speed and deton of moton, the maxmum ln onneton tme n the appoahng senao s alulated as: dbd dd db ta (23) v v d bd s the dstane between b and d n Fg. 3. d a a (20) (22) b a R Fg. 3. Pedton n the appoahng senao

9 KSII TRANSACTIONS ON INTERNET AND INFORMATION SYSTEMS VOL. 8, NO. 10, Otobe In appoahng senao, the dstane fom b to an be expessed: db va t (24) Tae (2), (3), (24) and (10) nto (6), os ab n Fg. 3 s obtaned as: os ab V ( f ' f ) t (25) 2 2 fv ( f ' f ) t PG t tg f PG t tg 1 1 ( ) 2 b 2 P 16 P P In ad, fom the law of osnes, we an obtan the followng: da dd dad os ad (26) 2d d It s pesented n Fg. 3 that os ab os ad, and dad R. We an alulate d d by (25) and (26), whh adopts the same way that uses (14) and (16) to alulate d bd. 2 d a a a a d d d os ab R d d os ab (27) Tae (3), (25), and (27) nto (23), the maxmum ln onneton lfetme n the appoahng senao s alulated as: v a s obtaned fom (10). t a PG G V ( f ' f ) 16 RP V ( f ' f ) [ 1] t (28) 4v P fv PG G f v t t a a t t a 5.3 Ln Conneton Lfetme Update By (22) and (28), the estmated ln onneton lfetme of node n towad n j s: t, f f ' 0 Tj t, f f ' 0 a If n j and n ae n the appoahng senao, the ln onneton lfetme between them s t a. If n j and n ae n the eedng senao, the ln onneton lfetme between them s t. If n j and n ae stat elatvely, the ln onneton lfetme s nfnte. All nodes n the netwo peodally boadast the Hello paets and buld the neghbo lsts based on the eeved Hello paets fom eah othe. When the netwo s fst establshed, all the nodes ae n the ophan state. Afte two suessve Hello paets fom the same neghbo n j ae eeved, node n estmates the ln onneton lfetme between n and n j to eate an enty of n j n n s neghbo lst. The ln onneton lfetme s updated eah tme when a new Hello paet s eeved fom node n j. (29) 6. Clusteng Sheme The SCBCS lusteng algothm ams to fnd the luste head that has the longest ln onneton lfetme to ts one-hop membes. Suppose N s a set of nodes whose dstane to n s appoahng to the maxmum dstane R and the estmated ln onneton lfetme towad n s appoahng to zeo. Any node n j N p s not lely to be a membe of n. So thee s no need to onsde any node nj Np when alulatng the met to measue the degee that n s appopate to be a luste heade. Table 1 shows some notatons and the oespondng defnton used n Seton 6. p

10 3448 Tan et al : A Sgnal Chaatest Based Cluste Sheme fo Aeonautal Ad Ho Netwos Table 1. The notaton defntons Notaton Defnton t mn The mnmum allowed ln lfetme between a heade and ts membe d max The maxmum allowed dstane between a heade and ts membe β A onstant fato and 0<β<1 t x The ln lfetme theshold n the luste mege stage γ The degee delne that H s sutable to be a luste head T The tme nteval to alulate the degee that H s sutable to be a luste head N The numbe of the nodes n a luste W The degee that luste head H s stll sutable to be a heade H The dstane of these nodes to n s longe than d max, and the estmated ln onneton lfetme towad n s shote than t mn. Suppose N n s a set of n 's one-hop neghbos. Any node n n the netwo gathes ts one-hop neghbos' dstane, moblty and ln stablty nfomaton by the method shown n Setons 4 and 5 of ths pape. When n alulates ts degee to beome a luste head, t hes ts one-hop neghbo lst and exludes any node nj Np fom measung the degee that n s appopate to be a luste heade. n 's degee to be a luste at tme t s alulated as the sum of ts one-hop neghbos estmated ln lfetme: W ( t) mn( T, T ) (30) n j s njnn and n j N p In (30) Ts s the tme theshold. The lage W () t s, the moe n s appopate to beome a n luste head. In (29), the estmated ln lfetme may appoah nfnte when the veloty of n and n j ae vey smla. Thus, f the estmated ln lfetme T j s longe than T s, we thn that t s equal to T s n (30). 6.1 Cluste Fomaton When the netwo s fst establshed, all the nodes ae n the ophan state. The luste fomaton poedue should follow the followng ules: (a) Any node n alulates ts Wn () t and boadasts t to ts one-hop neghbos n the Hello paet. Wn () t s updated based on the latest neghbo nfomaton. Upon eevng Wn () t fom ts neghbos, node n ompaes them wth ts own Wn ( t '). If ts Wn ( t ') s the longest, node n beomes a luste head and boadasts an announement. Othewse, node n wats fo the luste head announements fom the othe nodes. (b) n must be loated at the edge of two dffeent goup of nodes wth dffeent goup moblty. When n fnds that most of the elatve speeds of ts one-hop neghbos sepaately appoah two dffeent speeds, n wll not patpate n the ompetton to beome a luste head. Ths sheme helps to aeleate the fomaton of a luste. () If node n eeves moe than one luste head announement, n selets the node that an povde t wth the longest ln onneton lfetme as ts luste head.

11 KSII TRANSACTIONS ON INTERNET AND INFORMATION SYSTEMS VOL. 8, NO. 10, Otobe (d) If node n does not eeve any luste head announement, n beomes a luste tself. 6.2 Cluste Mantenane In the luste mantanng stage, the lusteng-elated ontol ovehead an be edued by lmtng e-afflaton and e-lusteng events though the estmated moblty nfomaton pesented n Setons 4 and 5 of ths pape Re-afflaton sheme When a luste membe moves out of ts luste head's ommunaton ange o an ophan node jons an establshed luste, e-afflaton ous. Due to the lmted ommunaton ange and dynam node moblty, an establshed assoaton between a luste membe and ts luste head may be nteupted afte the luste fomaton stage. Some luste membes may eeve the announement of seveal luste heads; they hoose the optmal luste head usng the sheme desbed n Seton 6.1. These luste membes eep the luste head nfomaton they have head f the neghbong luste head an povde an estmated ln onneton lfetme longe than t mn. The estmated ln onneton lfetmes ae updated when the oespondng Hello paets ae eeved. When a luste membe n fnds the followng phenomenon n ts luste, t nfoms ts pesent luste head that t s leavng. a) n fnds that ts estmated ln onneton lfetme towad ts pesent luste head s shote than t mn. b) n s on the edge of the luste. The dstane between n and ts luste head s longe than d max. If n s loated n the ommunaton oveage of othe luste heads, t sends a jon equston to the neghbong luste head that an povde the longest estmated ln onneton lfetme. Befoe n moves off of the pesent luste, t wll not be a membe of anothe luste. If n annot fnd a bette luste head, t wll stay an ophan and eep boadastng Hello paets whle watng fo Hello paets fom the othe heads Re-lusteng sheme Thee ae thee man easons that an lead to e-lusteng: luste patton, luste mege and head-membe status otaton. 1) Cluste Patton If the luste head of C fnds ts membes have the followng thee haatests, t boadasts a message to ts membes that the ognal luste C no longe exsts. a) Some of ts membes have a smla moblty patten, suh as smla elatve speeds and smla dstanes to the heade. The membes that have the smla moblty ae alled a goup. b) Thee exsts at least a goup, and ove half of ts membes' estmated ln onneton lfetme towad the heade s shote than t mn.

12 3450 Tan et al : A Sgnal Chaatest Based Cluste Sheme fo Aeonautal Ad Ho Netwos ) Eah goup at least ontans moe than N enttes, whee * means the mnmum ntege that s lage than *. Then, the lusteng fomaton stage desbed n Seton 6.1 of ths pape s begun. Nodes n luste C an jon othe lustes o send speal luste head announements to fom new lustes themselves. When a node n luste C alulates ts aveage ln onneton lfetme, t only alulates ts one-hop neghbos n C. Only the nodes n luste C an jon the luste of whh the luste head s also a node n luste C. Ths sheme deeases the pple effet that an be aused by loal e-lusteng. 2) Cluste Mege When a luste head eeves othe lustes' announements o Hello paets, t means that the luste head moves nto anothe head's ommunaton ange. If ths phenomenon only lasts fo a shot tme, the e-lusteng wll not happen. Eah luste head alulates the estmated ln onneton lfetme towad othe luste heads and some of the luste membes. If the head H of luste C fnds the followng ondton s satsfed, t boadasts a message to ts membes and neaby lustes that a new luste s geneatng and e-lusteng should be pefomed. a) The estmated ln onneton lfetme towad anothe head H j s longe than t x. b) Thee ae moe than half of H j 's membes whose estmated ln onneton lfetme towad H s longe than t x. The lusteng fomaton stage desbed n Seton 6.1 of ths pape s begun. When a node n the pevous two o moe lustes alulates ts aveage ln onneton lfetme, t only alulates ts one-hop neghbos n the pevous lustes. Only the nodes n pevous lustes an jon the luste of whh the luste head s also a node n pevous lustes. Ths sheme deeases the pple effet aused by the loal e-lusteng. 3) Head-Membe Status Rotaton The moblty of the luste membes and the luste head hanges wth tme. A luste head may no longe be appopate fo beng a head when ts aveage ln onneton lfetme deeases dastally and t moves to the edge of the luste. In ths senao, a new luste head should be geneated to eep a stable lusteng elatonshp ove the long tem. Afte a luste s establshed, the luste head stll updates ts membe lst and the elatve speed to the membes based on the nfomaton nluded n the eeved Hello paets. When a luste head H fnds the followng phenomenon n ts luste, t boadasts an announement to abandon the luste head status. a) The degee that H s sutable to be a luste head s alulated peodally wth tme nteval T aodng to (30). The delne between two suessve degees that H s sutable to be a luste head s lage than. WH ( t T) W ( ) H t (31) N N b) Thee ae moe than half of ts membes whose dstane to the head s longe than d max. Then, the luste fomaton poedue stats.

13 Aveage ln onneton lfetme(s) KSII TRANSACTIONS ON INTERNET AND INFORMATION SYSTEMS VOL. 8, NO. 10, Otobe Smulaton and Analyss We onsde an aeonautal ad ho netwo, whee N = 100 nodes ae dstbuted n a 100 R R m 100 m aea. dmax 0.8R, tmn, tx, 0.2, 30 s. The ntal 5vmax vmax postons of the nodes ae andomly dstbuted, and the movements follow the model desbed n Seton 3 of ths pape. The mnmum speed s 200 m/s. The smulatons ae aed out based on an open soue Matlab paage alled Weless Netwo Smulato [21]. The MAC potool s based on the CSMA/CA mehansm. The modulaton type s BPSK. The ae fequeny s 1GHz and the tansmsson ate s 500bt/s. We hange the tansmsson powe to ontol the ommunaton ange. The hannel fadng adopts the fee-spae path loss model and the hannel nose s negletable. To assess the pefomane of the poposed SCBCS sheme, we mae smulatons and ondut a ompaatve analyss of MOBIC [6], DLDC [16], MPBC [18], SECA [15], MWC [8] and SCBCS. In the above algothms, only SECA and MWC onsde the esdual battey enegy n the luste head eleton. In ou study, we assume that the enegy s suffent dung the smulaton tme. Thus, we do not onsde the effet of esdual battey enegy and set the weghtng fato of the esdual battey enegy to zeo n [15] and [8] to hoose a luste head. MWC has two types of algothms, so we hoose type b to smulate MOBIC 140 DLDC MPBC SCBCS 120 SECA MWC vmax (m/s) Fg. 4. Aveage ln onneton lfetme vesus maxmum speed As shown n Fg. 4, the SCBCS sheme povdes a longe aveage ln onneton lfetme than MOBIC, DLDC, MPBC, SECA and MWC when ommunaton ange R=20 m. Ths ndates that SCBCS s moe adaptable to a hghly dynam moblty senao. It an be noted that the aveage onneton lfetme of MOBIC expeenes a elatvely shap delne when the maxmum speed v max neases. Ths s beause MOBIC s desgned fo netwos wth obvous goup moblty behavo. Smlaly, the aveage DLDC onneton lfetme expeenes a elatvely shap delne when v max neases. That s beause DLDC s desgned only fo a pseudolnea moblty senao. SECA s lable to hoose the node wth low moblty and hgh onnetvty to be the luste head. The ln lfetme of SECA s between that of

14 Aveage luste head lfetme(s) 3452 Tan et al : A Sgnal Chaatest Based Cluste Sheme fo Aeonautal Ad Ho Netwos DLDC and MOBIC. SCBCS, DLDC and MWC ae desgned fo hghly dynam netwos, so the delne ate of the onneton lfetme s slowe than the lfetmes of the othe thee shemes. Although MPBC alulates the elatve speed usng Dopple shft and sgnal powe, ts alulated speed s not as pese as that of SCBCS. MWC selets a node wth a stong speed oelaton to the goup and hgh onnetvty to be the luste head. The speed nfomaton of MWC s detly tansmtted, so ts aveage ln lfetme s longe than that of MPBC. SCBCS has a stte ule to geneate and mantan a luste, whh hooses moe stable membes to fom a luste. Thus, SCBCS has the longest aveage ln onneton lfetme among all of the above shemes MOBIC DLDC MPBC SCBCS SECA MWC vmax (m/s) Fg. 5. Aveage luste head lfetme vesus maxmum speed The ommunaton ange R s 20m n Fg. 5. As shown n Fg. 5, the lfetme of all the shemes deeases as maxmum speed neases. Ths s beause hghe speed leads to moe dynam elatve loaton hanges between any two nodes n the netwo. When v max s small, luste heads ae not lely move to eah othe's oveage aea. Addtonally, an establshed luste s not lely to dvde nto seveal pattons. Theefoe, e-lusteng s not often tggeed n a senao nvolvng a elatvely low maxmum speed. When v max neases, the luste heads ae moe lely to move nto eah othe's oveage aea, and the hane of luste mege neases. Thus, the ndene of e-lusteng neases when v max neases, whh edues the luste head lfetme. Due to SCBCS's sevee luste fomaton and mantenane ules and the auate alulaton of the elatve speed, SCBCS s the most sutable sheme fo a hghly moble senao.

15 Aveage luste head lfetme(s) Aveage ln onneton lfetme(s) KSII TRANSACTIONS ON INTERNET AND INFORMATION SYSTEMS VOL. 8, NO. 10, Otobe MOBIC DLDC 150 MPBC SCBCS SECA MWC Communaton ange R (m) Fg. 6. Aveage ln onneton lfetme vesus ommunaton ange Fg. 6 shows the aveage onneton lfetme of the shemes fo a vayng ommunaton ange R when vmax 300 m/s. As R neases, the nodes ae less lely to move out of the oveage aea of the assoated luste heads, and theefoe, the onneton lfetme s longe. SCBCS s aveage ln onneton lfetme s longest; ths s beause SCBCS uses the estmated ln onneton lfetme as the met to fom a luste and exludes the unsutable nodes to jon a luste MOBIC DLDC MPBC 400 SCBCS SECA MWC Communaton ange R (m) Fg. 7. Aveage luste head lfetme vesus ommunaton ange Fg. 7 shows the aveage luste head lfetme vesus node ommunaton ange R fo dffeent shemes when vmax 300 m/s. The SCBCS sheme shows bette aveage luste head lfetme pefomane than MOBIC, DLDC, MPBC, SECA and MWC. When R neases, the pefomane gap between any pa of the above shemes beomes small. That s beause the neased R edues the effet of hgh moblty, whh dmnshes the advantage o dsadvantage of one sheme to anothe.

16 Aveage numbe of membes pe luste Aveage numbe of membes pe luste 3454 Tan et al : A Sgnal Chaatest Based Cluste Sheme fo Aeonautal Ad Ho Netwos MOBIC DLDC 14 MPBC SCBCS 13.5 SECA MWC vmax (m/s) Fg. 8. Aveage numbe of membes pe luste vesus maxmum speed In Fg. 8, the ommunaton ange R s 20 m. It an be noted that when the maxmum speed neases, the aveage numbe of nodes pe luste deeases slghtly. Ths s beause when maxmum speed neases, thee ae moe hanes that a node an move out of a luste, whh esults n moe ophan nodes and slghtly less aveage membes pe luste. SECA and MWC have the lagest numbe of membes. Ths s beause both SECA and MWC hoose the node wth hgh onnetvty as the luste head. The aveage numbe of membes pe luste of DLDC and SCBCS s lowe than MOBIC's and MPBC's. That s beause both DLDC and SCBCS follow stt ules to fom and mantan a luste. SCBCS has the sttest ules so t podues fewe membes pe luste ompaed wth MOBIC, DLDC, MPBC, SECA and MWC. 35 MOBIC DLDC MPBC SCBCS SECA MWC Communaton ange R (m) Fg. 9. Aveage membes pe luste vesus ommunaton ange

17 KSII TRANSACTIONS ON INTERNET AND INFORMATION SYSTEMS VOL. 8, NO. 10, Otobe Fg. 9 shows that the aveage numbe of membes pe luste neases when the ommunaton ange neases. The maxmum speed s v max 300 m/s n Fg. 9. SECA and MWC ae lely to hoose the node wth hgh onnetvty as the luste head so the aveage numbes of membes pe luste ae lagest. MOBIC and MPBC have nealy the same aveage membes pe luste, and the aveage numbe of membes pe luste s slghtly smalle than SECA and MWC when the ommunaton ange s shot. The numbe of nodes n the smulaton egon emans onstant. Thus the dffeenes among MOBIC, MPBC, SECA and MWC delne when the ommunaton ange neases. MOBIC and MPBC have moe membes n a luste than SCBCS beause they do not have a ule to exlude the unsutable nodes fom jonng a luste. SCBCS has the sttest ule to fom a luste, so ts aveage numbe of membes pe luste s smallest. 8. Conluson We have poposed an SCBCS sheme fo hghly dynam aeonautal ad ho netwos. The poposed lusteng sheme uses the Dopple shft and the powe of the eeved sgnal to estmate ln onneton lfetme. Then, we used the estmated lfetme to detemne the appopate nodes fo a luste to mantan the establshed lustes. The poposed lusteng sheme an enhane the netwo stablty by enhanng the ln onneton lfetme and the luste lfetme. In the futue, we would le to study the luste-based outng algothm. Routng algothms and lusteng algothms an shae the same Hello paets, whh mpoves the whole netwo pefomane. Refeenes [1] Jane Y. Yu and Pete H. J. CHONG, A suvey of lusteng shemes fo moble ad ho netwos, IEEE Communatons Suveys & Tutoals, vol. 7, no. 1, pp , Fst Quate, Atle (CossRef Ln) [2] Suhsmta Chnaa and Santanu Kuma Rath, A suvey on one-hop lusteng algothms n moble ad ho netwos, Jounal of Netwos and Systems Management, vol. 17, no. 1-2, pp , June, Atle (CossRef Ln) [3] Sheetal Mehta, Pyana Shama and Ketan Koteha, A suvey on vaous luste head eleton algothms fo MANET, n Po. of 2011 Nma Unvesty Intenatonal Confeene on Engneeng, pp. 1-6, Deembe 8-10, Atle (CossRef Ln) [4] Jnhua Zhou, Lele, Weang Lu, and Jamn Tan, A smulaton analyss of nodes moblty and taff load awae outng stategy n aeonautal Ad ho netwos, n Po. of Poeedngs of th Intenatonal Bhuban Confeene on Appled Senes & Tehnology, pp , Januay 9-12, Atle (CossRef Ln) [5] Janbo L and Shan Jang, A salable lusteng algothm n dense moble senso netwos, Jounal of Netwos, vol. 6, no. 3, pp , Januay, Atle (CossRef Ln) [6] P. Basu, N. Khan and T.D.C. Lttle, A moblty based met fo lusteng n moble ad ho netwos, n Po. of Dstb. Comput. Syst, pp , Apl 16-19, Atle (CossRef Ln) [7] Zaydoun Y Rawashdeh and Syed Masud Mahmud, A novel algothm to fom stable lustes n vehula ad ho netwos on hghways, EURASIP Jounal on Weless Communatons and Netwong, vol. 2012, no. 15, pp. 1-13, Januay, Atle (CossRef Ln) [8] Wenjang Feng, Gaxa Lu, Yuxang Lao, and We Zhao. A mult-paamete weghted lusteng algothm fo moble ad ho netwos, Jounal of Infomaton & Computatonal Sene, vol. 10, no. 17, pp , Novembe, Atle (CossRef Ln) [9] B. Hassanabad, C. Shea, L. Zhang, and S. Valaee, Clusteng n vehula ad ho netwos usng

18 3456 Tan et al : A Sgnal Chaatest Based Cluste Sheme fo Aeonautal Ad Ho Netwos affnty popagaton, Ad Ho Netwos, vol. 13, no. PART B, pp , Febuay, Atle (CossRef Ln) [10] Javad Aba Toestan and Mohammad Reza Meybod, A moblty-based luste fomaton algothm fo weless moble ad-ho netwos, Cluste Computng, vol. 14, no. 4, pp , Febuay, Atle (CossRef Ln) [11] M.A.L. Thathaha and B.R. Hata, Leanng automata wth hangng numbe of atons, IEEE Tans. Syst. Man and Cyben., vol. 17, no. 6, pp , Novembe, Atle (CossRef Ln) [12] We Wang, Guosun Zeng, Jng Yao, Hanl Wang, and Dazhong Tang, Towads elable self-lusteng moble ad ho netwos, Computes and Eletal Engneeng, vol. 38, no. 3, pp , May, Atle (CossRef Ln) [13] Jngyu Hua, Junhua Bao, Zhjang Xu, Lmn Meng, and Gang L, Dopple shft estmaton fo low sgnal-nose-ato envonment n moble ommunaton systems, n Po. of Intenatonal Confeene on Weless Communatons, Netwong and Moble Computng, pp. 1-4, Otobe 12-14, Atle (CossRef Ln) [14] Duanpo Wu, Xnyu Jn, and Luong Jang, Analyss of handoff algothm-based on Dopple effet and RSSI measuements n GSM-R netwo, Jounal of the Chnese Insttute of Engnees, vol. 37, no. 3, pp , Apl, Atle (CossRef Ln) [15] Xaoln Tan, Zhongyang Xong and Yun He, Sgnal attenuaton-awae lusteng n weless moble ad ho netwos, Jounal of Netwos, vol. 8, no. 4, pp , Apl, Atle (CossRef Ln) [16] Ehssan Sahaee and Abbas Jamalpou, Stable lusteng and ommunatons n pseudolnea hghly moble ad ho netwos, IEEE Tansatons on Vehula Tehnology, vol. 57, no. 6, pp , Novembe, Atle (CossRef Ln) [17] Nma Alam, Asgha Tabatabae Balae, and Andew G. Dempste, A DSRC Dopple-based oopeatve postonng enhanement fo vehula netwos wth GPS avalablty, IEEE Tansatons onvehula Tehnology, vol. 60, no. 9, pp , Novembe, Atle (CossRef Ln) [18] Mnmng N, Zhangdu Zhong, and Dongme Zhao, MPBC: a moblty pedton-based lusteng sheme fo ad ho netwos, IEEE Tansatons on Vehula Tehnology, vol. 60, no. 9, pp , Novembe, Atle (CossRef Ln) [19] J. M. Ng and Y. Zhang, A moblty model wth goup pattonng fo weless ad ho netwos, n Po. of IEEE Intenatonal Confeene on Infomaton Tehnology and Applatons, pp , July 4-7, Atle (CossRef Ln) [20] Andea Goldsmth, Weless Communaton, Cambdge Unvesty Pess, Cambdge, [21] Welss Netwo Smulato n Matlab. [Onlne]. souefoge.net/pojets/weless-matlab/.

19 KSII TRANSACTIONS ON INTERNET AND INFORMATION SYSTEMS VOL. 8, NO. 10, Otobe Yu Tan eeved the B.E. and M.E. degees n Communaton and Infomaton System fom A Foe Engneeng Unvesty n 2008 and 2011, espetvely. He s uently wong towad the Doto s degee n A Foe Engneeng Unvesty. Hs eseah nteests nlude hannel odng and Ad Ho netwos. E-mal: labyahoo@126.om Lnhua Ma eeved the B.E. and M.E. degees fom A Foe Engneeng Unvesty n 1988 and 1991, espetvely. He eeved the D.E degee fom Xdan Unvesty. He now s a pofesso of A Foe Engneeng Unvesty. Hs eseah nteests nlude hannel odng, mage poessng, and weless netwos. E-mal: land_max@126.om Le Ru eeved the B.E. degees fom A Foe Engneeng Unvesty n 1999 and 2002, espetvely. He eeved the D.E degee fom Xdan Unvesty. He now s a assoate pofesso of A Foe Engneeng Unvesty. Hs eseah nteests nlude ant-jammng ommunaton and weless netwos. E-mal: Hong Tang eeved the B.E. and M.E. degees fom A Foe Engneeng Unvesty n 1989 and 1992, espetvely. He now s a seno expementalst of A Foe Engneeng Unvesty. Hs eseah nteest s ant-jammng ommunaton. E-mal: haetang11@126.om Bo Song eeved the B.E. and M.E. degees fom A Foe Engneeng Unvesty n 1990 and 1993, espetvely. He now s a assoate pofesso of A Foe Engneeng Unvesty. Hs eseah nteest s ant-jammng ommunaton. E-mal: songb21@126.om