GESE: A Tplgy Gnratr Fr Ral Wirl Snr twrk Dplymnt Tiag Camil, Jrg Sá Silva, Anré Rrigu, Frnan Bavia Dpartmnt f Infrmatic Enginring, Univrity f Cimbra Pl II, Pinhal Marrc, -9 Cimbra, Prtugal {tanr, ailva, ar, bavia}@i.uc.pt Abtract. twrk Simulatr ar imprtant tl in ntwrk rarch. A th lct tplgy ftn influnc th utcm f th imulatin, ralitic tplgi ar rquir t pruc ralitic imulatin rult. Th tplgy gnratr prnt in thi cumnt, GnS, wa crat ba n th authr knwlg frm vral xprinc. GnS i a tl capabl f gnrating ralitic tplgi f wirl nr ntwrk an, aitinally, aut-cnfiguring imprtant charactritic f nr n, uch a nrgy paramtr. Th tl wa valiat by cmparin with ral plymnt tratgi an xprinc. Kywr: Wirl Snr twrk, Simulatr, Snr Dplymnt. Intructin Du t tchnlgy avanc in tlcmmunicatin, micrprcr an mnitring, it i nw pibl t ign ntwrk with pcial fatur, uch a Wirl Snr twrk (WS) []. Such ntwrk hav pcific rquirmnt uch a ruc nrgy availability, lw mmry an ruc prcing pwr. A WS cnit f a numbr f nr (.g. frm ~ up t ~) pra acr a ggraphical ara. Each nr i quipp with a wirl cmmunicatin ytm, an m lvl f intllignc fr ignal prcing an ntwrking f th ata. Althugh thy can b cnir a hc ntwrk, WS ar in fact quit itinct frm th ntwrk in th plymnt pha. In typical a hc ntwrk, vic ar mbil an thir lcatin i a ranm factr, inc ur f uch quipmnt nrmally cannt prict th plac an tim whr th ntwrk will b tabl. On th thr han, in WS th plymnt pha i critical an may rquir carful planning, u t th ingular charactritic f nr n. A th authr mntrat [], th crrct itributin f nr vic vr th targt mnitring ara affct th ntir WS plymnt, frm th chic f th crrct nr n, t th crrct ntwrk prtcl, an th architctur/tplgy t u. Whn a WS lutin i ign, it i imprtant t fin th main valuatin critria that, in th n, will b u t valiat th btain rult. Liftim, latncy, fault-tlranc, calability an prciin ar m f th paramtr u t valuat WS lutin.
In ptimal cnitin, whr rai intrfrnc nt xit, th trrain i plan an n btacl ar prnt, th mt ffctiv plymnt tratgy wul b th gri tratgy, whr all vic ar in rang an vnly plac t cvr th whl mnitring ara. Hwvr, u t thir vat applicability, WS ar cmmnly ply in unuual lcatin, whr human accibility i limit (.g. ini a vlcan). In uch nvirnmnt it i ncary t plac nr n uing iffrnt tratgi (.g. rpping nr n frm a plan). Thrfr, it bcm crucial t vlp th ncary tl t tuy uch variabl in a imulatin nvirnmnt, bfr th tt in th final nvirnmnt bgin. In [] th authr intifi m rarch iu / irctin that influnc th WS MAC layr vlpmnt. On f thm wa th n t imprv th imulatin tl with bttr rprntatin f th rality (namly bttr rai ml that accunt fr trrain, antnna lcatin, fliag typ, tc). Thi papr, ba in ata frm [,8], tri t ar m f th prblm by vlping a nw WS tplgy gnratr fr twrk Simulatr (S-). Th rmainr f thi papr i rganiz a fllw: Sctin prnt th rlat wrk rgaring tplgy gnratr. Spcial fcu i givn t th tp_gn, which i th nly pcific tl that cvr WS. Sctin intifi th main prblm rgaring th plymnt f WS an prnt ix iffrnt plymnt tratgi. In Sctin th GnS i intruc. Spcial attntin i givn t th input an t th utput paramtr f th gnratr. Rult takn frm th tplgy gnratr ar icu in Sctin. Finally, cncluin an futur wrk ar ar in th lat ctin. Rlat Wrk Th vlpmnt f tplgy gnratr that mulat ral nvirnmnt fatur i a prblm that attract an till attract th attntin f th cintific cmmunity. waay thr ar a numbr f cmpting apprach t th cntructin f ranm ntwrk tplgi, fr wir an wirl nvirnmnt. On f th mt ppular gnratr availabl i BRITE []. It i a flxibl tl that upprt flat rutr an hirarchical tplgi, allwing th cnfiguratin f vral imprtant paramtr uch a banwith an lay. GT-ITM [], anthr tplgy gnratr, fcu n rprucing th hirarchical tructur f th tplgy f th Intrnt. Finally, th Int [] i a ntwrk gnratr aiming t rpruc th cnnctivity prprti f Intrnt tplgi, aigning n gr frm a pwr-law itributin. Hwvr, th rfrr apprach ar pcially ign t buil wll knwn Intrnt ntwrk tplgi, which prnt ignificant iffrnc whn cmpar t WS. Th Tp_gn [] i a tplgy gnratr ign by th ISI Labratry fr Emb twrk Snr Exprimntatin, which intn t b a tl t gnrat ranm nr n lcatin. Althugh it wa riginally ign t b u in irct iffuin xprimnt, it i an aaptabl tl that can b aily prt t
upprt thr prtcl. Tp_gn ha m cnfigurabl paramtr uch a map imnin, urc an ink cunt. It allw th cratin f tplgy fil fr S- an EmSim []. nthl, thi tplgy gnratr nt tak in accunt ral nr ntwrk placmnt, inc it nly allw ranm r clutr n itributin. Charactritic uch a nr n plymnt tratgi ar nt cvr. Wirl Snr twrk Dplymnt WS iffr frm typical a hc ntwrk by rquiring a plymnt pha, in cntrat with a hc ntwrk, which ar knwn t grup pntanuly an mv in a ranm way. Snr n ar nrmally plac in pcial nvirnmnt withut guarant f pitin. Thi i why th plymnt pha in a WS prjct i xtrmly imprtant t th final xprimnt utput. Du t it charactritic, th WS can b ply in nvirnmnt whr th accibility by human i ifficult, an whr ambint cnitin can ignificantly vary. Th minimal numbr f nr n rquir t mnitr a pcific ara (A), i prvi by Equatin, whr r rprnt th ning rang f ach nr n [6]. A. π S= () r 7 Hwvr, thi apprach cnir that all n hav th am mnitring capabiliti, which man that it cannt b appli t WS with iffrnt typ f nr n. Mrvr, it nt tak int accunt th xitnc f btacl, uch a tr r wall. A mntin bfr, in rr t ptimiz nr n placmnt, nr n mut b ply a a gri, whr all vic ar mticululy an vnly pac accring t thir mnitring/tranmitting rang. Such mth minimiz th numbr f n n t mnitr a pcific ara, with full phnmnn cvrag. Hwvr, uch cnari can nly b appli whn ial rai nvirnmnt charactritic ar prnt (i.. n rai intrfrnc xit, th trrain i flat an thr i n vgtatin). Mrvr, nr n plymnt i ftn ma in inhpitabl lcatin, whr it bcm impibl t ply a unifrm itributin. In plac uch a th can b, it i nt faibl t ply nr n in a gri arrangmnt. On th thr han, applicatin uch a mnitring a cycln rquir a fat plymnt pha, inc thi kin f phnmnn i nt prictabl, an it i ncary t itribut nr n a quick a pibl t maximiz th cvrag ara, cnnctivity, tc. Fr thi ran, it i ncary t cnir iffrnt plymnt tratgi, which cul b u in inhpitabl ara r cul b mr uitabl t iffrnt nr ntwrk applicatin. Thrfr th authr uggt ix iffrnt plymnt tratgi in a prviu pic f wrk [], ach n lit blw: Gri: in thi tratgy it i imprtant t crat a ntwrk f nr imilar t th n illutrat in Fig., whr ach nr vic i vnly parat frm nighbring vic by r, which i th cmmunicatin/mnitring rang f ach nr. An pratr i rpnibl t plac ach nr facing up (antnna pint
up). A ribbn-mtric i u that th nr lcatin i trmin a xactly a pibl; Fig. Snr n plac a a gri On-by-On: thi tratgy cnit in plying ach nr iniviually, but withut uing mtric tl. Th pratr i rpnibl t thrw ach n uing nly hi knwlg rgaring th avrag itanc btwn n, nt rlying n th n pitin; Tw-by-tw: th nly iffrnc btwn thi tratgy an th prviu n, i th fact that th pratr, in thi ca, thrw nr n in pair; Thr-by-thr: th tchniqu i imilar t that in th n-by-n an tw-by-tw tratgi, but in thi ca th pratr rp th nr n in grup f thr lmnt; Cliff: in thi tratgy th pratr rp th n frm a highr pint, mr prcily frm a mtr crag. Such tratgy intn t imulat a WS xprimnt wr th phnmnn i lcat far bllw th pratr, r vn t imulat th plymnt frm ini a hlicptr; Prpllant: in thi final tratgy th nr ar pra in th ara t mnitr thrugh th hlp f a prpllant. All nr ar pra at th am tim. Th prpllant i calibrat t n th nr n t th mil f th mnitr ara. Th iffrnt plymnt tratgi wr cmpar uing a ral WS implmntatin [8]. In a 6 m mnitring ara (6 pr mtr), a t f Emb Snr Bar (ESB) nr vic frm th ScattrWb [9] platfrm wr u. Th nvirnmnt wa tratgically chn: plain, ry an with n natural r human ma btacl. Each nr wa plac at grun lvl. Fr ach tratgy, th plymnt tim, ct an ntwrk cnnctivity wr analyz. By iviing th rctangl ara in quar th authr fun th avrag n lcatin pr quar, n ach plymnt tratgy; th rult can b fun in []. Frm thi tuy it wa pibl t cnclu that th bt rult wr btain by th gri tratgy, inc it la t an ptimal n itributin, (ach f th rgin wa cvr by n n). Stratgi uch a cliff an prpllant, which hav ruc plymnt tim, tn t cncntrat th n in th cntr f th cnari, craing th ara cvr by th nr. Anthr imprtant iffrnc in WS plymnt i th fact that it i nt pibl t guaranty th crrct n (antnna) rintatin, cntrary t nrmal a hc ntwrk bhaviur. Whn a n i pra (.g. by a prpllant), pning n th vic (th ESB prmit ix iffrnt antnna rintatin), it can b facing iffrnt pitin: antnna up, antnna wn, tc. A prnt in [], uch charactritic can b crucial fr WS, inc a ba nr n pitin can cra th rai rang by %.
GnS: A Gnratr fr Snr twrk Th n fr a ralitic WS tplgy gnratr ha lng bn rcgniz by nr ntwrk rarchr. Such tl, aciat t a ntwrk imulatr, i th firt intrumnt t unrtan th bhavir f nw prtcl prttyp. Th xiting apprach, a crib in Sctin, ar nt aquat t th WS charactritic (a hc ntwrk tplgy gnratr), r nt cntmplat ralitic n itributin (TpGn). Th GnS i a tplgy gnratr built in C++ that i pcifically ign t wrk with S- [7]. It i ba n ral WS plymnt prfrm by th authr, an crib in Sctin. Thi gnratr ha th capability t imulat th bhaviur f th prnt plymnt tratgi: gri, n-by-n, tw-by-tw, thr-by-thr, cliff, an prpllant. It prnt vral input paramtr which ar u t charactriz ach nr n (Fig. ). Fig. GnS Tplgy Gnratr Architctur A utput, GnS prvi a tcl frmat fil cntaining th cnfiguratin f ach nr an al it pitin in th mnitring ara. Th fllwing ub-chaptr prvi a tail xplanatin n th input an utput paramtr prvi by GnS.. GnS Input GnS prvi variabl input paramtr, ach n u in th charactrizatin f ach nr vic. A illutrat in Fig. th firt paramtr t b intruc i th mnitring ara imnin. Unfrtunatly S- nt yt prvi a triimninal cnari. Fr thi ran nly x an y paramtr ar u. In th nxt tp it i ncary t ch which will b th plymnt tratgy t u in th nr itributin. Th ur ha th fllwing ptin: - Gri (u n t t th itanc) - Ranm (DEFAULT) - On-by-n - Tw-by-tw - Thr-by-thr
6 Prpllant 7 - Cliff Th ur ha th pibility t ch any f th plymnt tratgi prnt in th prviu ctin, plu th ranm n itributin, which i in fact th fault ptin. Thi lattr ptin will ranmly itribut th nr thrughut th fin mnitring ara. Such ptin hul b u in ca th ur nt knw which plymnt tratgy will b u in th final WS implmntatin. In th gri altrnativ th ur mut t th minimal itanc btwn th n. Such itanc hul b t t th mallt f tw itanc: th rai rang an th ning cp. Th n lcatin ar trmin by th prbabilitic rul larnt frm []. Rgaring th n pitin, GnS nabl th ur t cnfigur th numbr f pibl n rintatin (rgaring th antnna). Th ur hul lct hw many pibl pitin th nr n vic will hav. A an xampl, th vic u in [], th ESB, nly upprt fur pibl rintatin-tag, cntrary t th Mica family (Mica, Micaz), which prnt nly tw. A fault, nly n pitin i cnir: - On Pitin (DEFAULT) - Tw Pitin - Thr Pitin - Fur Pitin GnS will ranmly ch th n pitin, which thn will affct th tranmitting an rciving nrgy fr ach n. Du t rtrictin in S-, it i nt pibl t pcify iffrnt rai prpagatin cnitin in th am imulatin. Thrfr, it wa ncary t mulat uch capability. Thi wa achiv by mifying th lvl f tranmitt nrgy in ach n, althugh all th n hav th am tranmitting rang. In trm f nrgy cnfiguratin, GnS allw t t th fllwing paramtr: initial nrgy, il nrgy, tranmitting nrgy an rciving nrgy. Mrvr, it upprt th cnfiguratin f fur iffrnt lvl f nrgy, maning GnS can gnrat iffrnt initial nrgy lvl pr nr n. T allw uch bhavir, th ur n t ch n f th fllwing ptin: - All n with am nrgy (DEFAULT) - Tw nrgy lvl - Thr nrgy lvl - Fur nrgy lvl Fr ach n, GnS will ranmly ch th initial nrgy ba n th ptin (initial nrgy) prvi by th ur. In ach itratin, GnS gnrat iffrnt rult whn cmpar t prviu itratin, inc it ranm factr ar aciat t a variabl. Hwvr, th gnratr nabl th ur t cnfigur it wn, allwing bugging pratin. Finally, it i al pibl t pcify th final tcl utput fil.
. GnS Output GnS i S- ba, maning it wa crat t pruc a WS tplgy which can b u in a imulatin xprinc in thi imulatr. A uch, GnS utput tw tcl cript fil. On f th fil av th infrmatin rgaring th n lcatin (x an y), which i crat a rult f th chn plymnt tratgy. Th cn fil utput th n cnfiguratin, namly th nrgy paramtr f ach iniviual n. Finally, GnS calculat th timat tim rquir t prfrm th plymnt f th ntir nr ntwrk which, nc again, pn n th plymnt tratgy chn by th ur. Th valu ar ba n th n achiv by th authr in [8]. Rult In rr t tuy th bhaviur f GnS, thi ctin prnt th rult pruc by thi tplgy gnratr, an brifly valiat thm with th rult achiv by th authr in []. Th main gal f thi tuy i t cmpar th n itributin fr th iffrnt plymnt tratgi. Uing a mnitring ara f 6 m ( m pr 6 m), a ttal f nr n wr pra uing vn plymnt tratgi: gri, ranm, nby-n, tw-by-tw, thr-by-thr, cliff, an prpllant, a crib in Sctin. Th nvirnmnt ara wa virtually cut int 6 qual quar, ach n with 7 m. Th numbr f n itribut n ach quar wa rgitr an it i illutrat in figur -9. Sinc thr ar nr n, it wul b xpct that th bt lutin wr t ply vic pr rgin. Such rult wa achiv nly by th gri tratgy (Fig. ). Thi lutin prnt th bt rult in trm f cnnctivity an ning cvrag. Fig. prnt th rult pruc by th ranm itributin f n. Thi tchniqu i th mt u by th cintific cmmunity whn imulating nw prtcl. Hwvr, th rult ar nt vry ncuraging, inc thr xit nrmu iffrnc in trm f ara cvrag pr vic, an it al nt rally rflct a ral plymnt tratgy. Fig.. pr rgin fr th Gri Dplymnt Stratgy Fig.. pr rgin fr th Ranm plymnt tratgy
On th thr han, th lutin prnt in Errr! Rfrnc urc nt fun., hw a bttr placmnt whn cmpar t that f Figur. In Figur th maximum numbr f n pr quar i, an all th quar ar cvr by at lat n vic. Fig.. pr rgin fr th On-by-n plymnt tratgy Fig. 6 an Fig. 7 prnt th tw-by-tw an thr-by-thr tratgy plymnt, rpctivly. Th tratgi la t prr rult whn cmpar t th n-by-n tratgy. In th ca f th thr-by-thr tratgy, n f th quar ara n up with n vic at all. On th thr han, a ingl rgin n up with vic. Fig. 6. pr rgin fr th Tw-by-tw plymnt tratgy Fig. 7. pr rgin fr th Thr-bythr plymnt tratgy Finally, Fig. 8 an Fig. 9 hw th wrt nr itributin rult, mainly u t th charactritic f th u tratgi. It i ntriu that thr i an xciv n nity in th cntr f th nvirnmnt ara, cntrary t th g, whr vral rgin withut nr n xit. Lking at th prnt rult in trm f ning cvrag, thr i a hug iffrnc btwn plymnt tratgi. Thi i why it i imprtant t cnir ralitic ml whn vlping nw ntwrk prtcl. All th rult ar chrnt with th n achiv in []. Th tratgi that rquir human intrvntin in th mnitring ara achiv th bt rult, a pp t th lat tw apprach whr th n appar irganiz.
Fig. 8. pr rgin fr th Cliff plymnt tratgy Fig. 9. pr rgin fr th Prpllant plymnt tratgy Cncluin In a WS prjct, it i imprtant frm an arly tag t fin th plymnt tratgy t u. Dciin uch a which architctur t u r what kin f n t ply, hav t b in cnnanc with th plymnt tratgy. A an xampl, in an nvirnmnt whr th human prnc i nt af (.g. bilgical cntaminatin) it bcm impibl t achiv th rult frm th gri plymnt tratgy. Architctur that aum a rigi tplgy (.g. n hp cmmunicatin) bcm impibl t ply. In thi papr w prnt a nw tl t gnrat ralitic ntwrk tplgi, GnS. It allw th ur t crat nw WS cnfiguratin, ba n ralitic knwlg achiv in prviu wrk prfrm by th authr. All th rult pruc by thi tplgy gnratr ar ba n ral plymnt xprinc; ach placmnt tratgy rflct m f th pibl lutin whn prparing a WS cnari. Ba in S- cnfiguratin fil, GnS utput tw tcl cumnt, which can irctly b u a part f a ntwrk cnfiguratin cript. GnS allw th pcificatin f vral paramtr, uch a iffrnt nrgy lvl. A futur wrk, it wul b imprtant t xtn th upprt plymnt tratgi. Slutin uch a watr nvirnmnt ar crucial fr crtain nr ntwrk applicatin. Anthr imprtant xtnin wul b th upprt f D nvirnmnt. Hwvr uch xtnin i mr ifficult t achiv inc th S- cr al nt upprt uch fatur. Acknwlgmnt. Th wrk prnt in thi papr wa partially financ by th IST FP6 COTET twrk f Excllnc (IST-FP6-89).
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