86 IJCSNS Intenational Jounal of Copute Science an Netwok Secuity, VO. No.6, June 0 at oss opagation Moel fo Gobi own Aaawa State Nigeia +Salangwa, D. A. & Jeoe, G. +Depatent of ysics, Aaawa State Univesity, Mubi Nigeia. Depatent of Mateatics an Copute Science, Aaawa State Univesity, Mubi Nigeia Suay e esie in tis wok is to evelop a oel tat can elp in planning bette Global syste fo obile counication GSM netwok an to aess te coplains of te poo quality of GSM netwok sevices in Gobi town by te custoes. Measueents wee conucte to pecision, te oveall aveage pat loss etecte wee 44.93, 43.76 an 47.76 fo MN, ZAIN an GO an te ean squae eo obtaine wee,.5 an 3 espectively, tese iffeences ay be attibute to te natue of te envionents o te location o eigt of te ase stations Ss. e new oifie Equations wee evelope using Hata oel tat can elp in planning an optiization of te investigate envionent. Key wos: Netwok quality, subscibes, envionent, epiical easueent an oel.. Intouction Gobi epeience api gowt of global syste fo obile counication GSM telepone subscibes igt fo te ay te GSM opeatos cae into opeation in Gobi, as te nube of subscibes of GSM pone use inceases te spectal efficiency becoes oe citical because te fequency allocation is liite esouces. e salle te fequency euse te geate te netwok capacity [], ig spectal efficiency eans geat acieveent by eusing, fequency ove iegula teain suc as tees, builing an ote geogapical featues. Gobi epeience soe call ifficulties oe especially fo 006 to ate Fiel suvey 0. e GSM eception suffes te following; fequent call op, netwok busy, oo inta an intes connectivity, coss talk, uing convesion. Accoing to ay MClanan 000 attenuation fo tees o builings/tees ae usually of oe of 0.05M/, since Gobi use 900MHz as te caie fequency te iniu epecte attenuation ay be of oe of 0.5/ tis epen stictly on istance wee te powe ensity is etecte o eceive o te copleity of te envionent ee ae any factos tat affects GSM signal stengt wic ay inclue ainfall, snow, fog, eflection, iffaction, fee space loss, vegetation an ote geogapical featues but tis wok epases on oeling of fee space loss, eflection an iffaction effects wic appene to be te ajo effect tat coul significantly cause pat loss o ape effective counication. is wok ai at eveloping oels fo eac GSM opeatos wic ay aesse soe of te ponounce effect on te GSM signal stengt. is wok is also oganize in te following anne teoetical oeling of te tee coponents consiee in tis eseac followe by te epiical oel ten esults, iscussion an conclusion.. eoetical opagation Moel e popagation oels ae ivie into tee basic types tese ae, fee space popagation, flat o soot eat popagation oe an iffaction effect popagation.. Fee Space opagation Moel e popagation oel stats wit fee space popagation, in fee space popagation te wave is not eflecte o absobe but ieal popagation iplies equal aiation in all iections fo te aiating souce an popagation to an infinite istance wit no egaation [5]. Fee space attenuation inceases as te fequency goes up fo a given unit of istance tis occus because ige fequencies ave sote wave lengts [ 3], an cove a given istance, consequently te ige te fequency te sote te wave lengt. y aving ientifie te powe flu, te powe ensity at any point at a istance fo te aiato, if te eceive antenna is place at tis point te powe eceive by te antenna can be calculate. Consie a tansitte wit t couple to an antenna wic aiates equally in all iections at a istance fo te tansitte wee te powe ensity is etecte, Manuscipt eceive June 5, 0 Manuscipt evise June 0, 0
IJCSNS Intenational Jounal of Copute Science an Netwok Secuity, VO. No.6, June 0 87 ten te aiate powe is istibute unifoly ove an aea of 4π tat is te suface aea of a spee of aius so tat te powe ensity is given by s 4 en te pat loss epens on ow uc of tis powe is captue by te eceiving antenna. If te captue aea, o te effective apetue is given by A, te powe wic can be elivee to te eceive assuing no isatc o fee line losses, is siply SA Fo ypotetical isotopic eceiving antenna, we ave 4 A 3 Wee λ is te wave lengt of te popagation [], cobining Eq. an 3, we ave 4 4 Wile Eq. 5 illustate te pat loss, given by 5 p Substituting Eq. 4 into 5, it yiel Eq. 6 0log 4 0log 0log 6 Consieing λ in k an ationalizing te Eq. 6 pouces te geneic fee space pat loss foula, tis is state in Eq. 7 3.4 0log 0log 7 f As ealy state popagation pat loss is a function of istance. Accoing appapot et al 997 popagation pat loss is given by an epession 8 Epession of Eq. 8 is fute siplifie in tes of logaitic fo as log 9 Wee p is now te popagation constant known as te fee space loss.3 Flat o soot eat popagation oel. e fee space popagation oel oes not consie te effects of popagation ove goun. Wen a aio wave popagate ove flat o soot eat suc as eset, wate o wet goun soe pat of te powe woul be eflecte ue to te pesence of te flat o soot eat an ten eceive by te eceive. If te effect of te eflecte powe is eteine ten we can say te fee space oel is oifie tis is efee to as flat o soot eat eflection popagation oel. e vecto su of te flat o soot eat oel an iect signal fo te ain souce now foe te oifie equation of te flat o soot eat eflection tat base escibe te pat loss popagation. fse 3.4 60log 0log f 0log 0log M.4 Diffaction effects e fee space popagation oel an flat o soot eat popagation oes not consie te effect of iffaction. A Fesnel zone is a siple concept to unestan iffaction effect, it is just te volue space enclose by an ellipsoi wic as two antenna at te ens of te aio link at its foci. A signal tat ay be eceive by te eceive ay not be copletely fee fo iffaction since te popagation pat tavels acoss quite a nube of iffeent geogapical featues suc as builing, tees an ote geogapical featues, tis can cause significant pat loss. e electic fiel eceive by te eceive ay be escibe by te cobination of te iect signal pat popagation cause by iffaction, fee space loss an te flat o soot eat eflecte wave ay be sue togete to give te actually pat loss. E a 7.0 cos.5.5 sin sin j60 cos j60 cos Wee, is te elative ielectic constant, λ is te wave lengt in ete, δ is te conuctivity in Sieens/ete an β is te angle of incience. eefoe te powe equivalent of te electic fiel ay be epess as p E 30G e j Wee is te powe eceive by te eceive, G θ is te iecte antenna gain an is te popagation pat lengt in ete [4], te pat loss ay be witten as fo epession 5
88 IJCSNS Intenational Jounal of Copute Science an Netwok Secuity, VO. No.6, June 0 e E 30G e j 3 te istance between te S an MS in k an C H is te antenna eigt coection facto..5 Epiical opagation Moel e tee basic popagation oel iscusse in te teoetical oel above suc as fee space, flat o soot loss an te iffaction loss woul equies etaile knowlege of te location, iension an constitutive paaetes of evey builings, tees an ote geogapical featues in te investigation aea o cell to be covee. is is fa cople, teious an cubesoe to be pactical an efinitely it woul yiel unnecessay aount etails o it is ifficult to gain an accuate bill of te coponents in te investigation aea but one obvious way fo eteining tese cople effects is toug epiical popagation oel, tee ae actually any types of epiical peiction aong few ae Okuua Hata oel, Sakagai - Kuboi oel, Walfisc Ikegai oel an Hata noel [5] tese oels can solve te pobles of te copleity effects, aong te ention oels Hata is cosen because of its suitability of te geneal caacteistics of te investigation aea..6 Hata - Moel Hata oel is caacteize by te following paaetes; caie fequency 50 500MHz, te istance fo te base station anges fo K to 0KM, te eigt of te base station antenna anges fo 30 to 00 an eigt of obile station anges fo t0 [7, 8]. ase on fiel test esult peicte, Hata ceate a nube of epesentative pat loss ateatical oel fo iffeent types of clustes as follows U 69.55 6.6log 44.9 6.55log log f 3.8log C 4 een Mubi is a eiu size city, te antenna coection facto ay be consiee as C H.8.log f 0.7.56log 5 0 M f Substituting 5 into 4, it yiel 69.55 6.6log f 3.8log.56log f ] 44.9 6.55log log [0.8.log H 0.7 6 Wee u is te pat loss fo uban aea, is te pat loss fo eiu size city like Mubi, is te eigt of base station S antenna, M is te eigt of obile station MS antenna, f is te opeating fequency, is M. Investigation Aea an Meto of Data Collection Gobi falls witin te suan savanna belt of Nigeian vegetation zone in te not east of te county, te zone is ae of y lan wees intespace by subs an wooy plants, te plants ae ivie into two categoies; inigenous an eotic wooy plants. e inigenous wooy plants ae aain, Sea butte, ocust bean, aasus aetiopus Giginya tei eigt anges between 7 an eotic wooy plants ae Nee, Maogany, casew an Guava alost of te sae eigt []. Gobi as ills of appoiately 0 5 ig above te sea level in te easten pat of te town wic is ougly KM away fo te ain settleent an steas also 5KM away fo te ain settleent. ee ae only 3 GSM base station S plante in te town in iffeent locations of iffeent GSM Opeatos naely ZAIN, MN an GO. e Ss wee installe at 35, 30 an 35 above te sea level fo ZAIN, MN an GO espectively. In te aea wee te easueent was conucte te igest builing is about.5, te tees an te builing ae scattee oun te settleents. o geneate easueents of signal stengt powe ensity level fo te uplink an te own link at te coveage aea fo a cell EM instuent was use. In te easueent aiu open aeas wee note fist an ecoe wic efe to as fee space pat loss witout any fo of obstacle an soe easueent wee taken bein te tees an te builing in te investigation aea, te fee space pat loss was etecte at 0, 75 an fo ZAIN, MN an GO espectively wile te subsequent easueents wee taken at 500 up to 5000 fo eac of te GSM Opeatos. 3. esults an Discussion e esults of te easueents ae sown in able-. e easueents wee taken at an inteval of 500, ties fo eac of te GSM Ss. e nees fo ig quality an ig capacity netwok, estiating coveage accuately as becoe eteely significant, teefoe fo oe accuate esign coveage of oen cellula netwoks te signal stengt easueents ust be taken into consieation in oe to povie an efficient an eliable coveage aea [5].
IJCSNS Intenational Jounal of Copute Science an Netwok Secuity, VO. No.6, June 0 89 able : Measue pat loss in MN [0.8.log 67.3 6.6 log [44.9 6.55log f 0.7 ]log f 3.8 log.56 log f ] 9 GO 66.4 6.6 log [0.8.log [44.9 6.55log f 0.7 ]log f 3.8 log.56 log f ] 0 e new oifie Equations of Hata oel in 8 0 ae ten copae wit Hata oel Eq. 6 to see wic one is suitable fo planning an optiization of te investigate aea as epicte in Fig.. e fee space loss easue at 0, 75 an wee copute as 30.9, 7.5 an 9.0 fo ZAIN, MN an GO espectively using Eq. 7, te ean squae eo of able wee eteine using epession 7 E N 7 Wee E is te ean squae eo, σ is te stana eviation an N is te nube of tes. e aveage ean squae eos E of te popagation pat loss easue fo te tee GSM opeatos wee eteine using te Eq. 7 as,.5 an 3. e aveage ean squae eo is ten subtacte fo te Eq. 6 of Hata oel an te oifie Equations fo eac GSM Opeatos now becoes ZAIN [0.8.log 67.83 6.6 log [44.9 6.55log f 0.70 ]log f 3.8 log.56 log f ] 8 Fig. : at loss veses istance Fig., pesents te pactical an te teoetical pat loss against istance fo all te tee GSM opeatos, afte eteining te pat loss of te easue values fo eac istance, te stuy ten copae te easue an teoetical values. Fo te plot, te esults clealy sow tat te pat loss fo all te easue values is less tan te teoetical pat loss altoug it vaies fo eac GSM Ss, tis ay be attibute to te location o eigt of te Ss an te copatibility of te envionent an tees in te investigation aea.
90 IJCSNS Intenational Jounal of Copute Science an Netwok Secuity, VO. No.6, June 0 Fig. : opagation pat loss Fig., pesents te oveall aveage aount of popagation pat loss easue fo te GSM Opeatos. GO as te igest pat loss geate tan tat of MN wit.73 an tat of ZAIN wit.7 wile ZAIN is te least, te oveall aveage of te pat loss easue fo all te GSM Opeatos lies between 8., fo MN te aiu iffeence easue fo S to 5000 is 3.93, fo ZAIN is 3.4 wile fo GO is 8. tis witin te acceptable ange, since te acceptable ange lies between < 0 [9]. 4. Conclusion e esie in tis wok is to evelop a oel tat can elp in planning bette Global syste fo obile counication GSM netwok an to aess te coplains of te poo quality of GSM netwok sevices in Gobi town by te custoes. e oveall aveage pat loss peicte wae 44.93, 43.76 an 47.76 fo MN, ZAIN an GO an te ean squae eo obtaine wee,.5 an 3 espectively, base on tese esults te new oifie Equations was evelope using Hata oel tat can elp in planning an optiization of te investigate envionent. intepolation fo issing ata fo Oan, oceeing of te wol congess on engineeing. onon Uk. 6 [6] appapot,. S., lankensip, K. an Xu, H. 997: opagation an aio syste esign issues in obile aio systes fo Gloo poject, obile an potable aio goup, Viginia olytecnic Institute an State Univesity. [7] Saune,. S. an Hata, M 980: Epiical foula fo popagation loss in lan obile aio sevice, IEEE tansaction on veicula tecnology, 9. 4-9 [8] Seybol, J. S. 005: Intouction to F popagation. Jon Wiley an Sons [9] Wu, J. an Yua, D. 998: opagation easueent an oeling in Jinan city, IEEE intenational syposiu on pesonal inoo an obile counication, boston MA USA, 3. 57-59 [] Yu Huei,. Wen Syang, H. an Ce Kuen, S. 009: te influence of popagation in a live GSM netwok, Jounal of electical engineeing. 7 p 7 Salangwa, D. A. on in Gakia Gobi GA Aaawa State Nigeia. eceive. Eng Electical an Electonic at Univesity of Maiugui 000 an M. Eng Electonic an elecounication at Univesity of enin Nigeia 006, e is cuently lectuing at Aaawa State Univesity Mubi Nigeia. He secue aission to stuy. D elecounication at Dnepopetovsk s National Univesity, Ukaine wit special inteest in wieless counication an obile syste Jeoe, G. eceive. Eng Electical an Electonic at Univesity of Maiugui an M. Eng Contol syste at afawa alewa Univesity auci Nigeia. He is at te avance stage of is. D poga at te sae Univesity. efeences [] Aebayo, A. A. 004: Mubi egion a Geogapical syntesis, st eition aaclete ublises t, Nigeia. p 3 7 [] etoni, H.., Honcaenko, W., Maciel.. an Xia, H. H. 994: UHF popagation peiction fo wieless pesonal poceeing of te IEEE 89. 333 359 [3] Fank, J. J. 00: Funaental eleents of aio link engineeing. Jounal of aio Engineeing, 7. p 03 3 [4] Helel, S. Ozen, S. an Goksu, H. 008: Investigation of GSM signal vaiation y an wet eat effects., p 47-57. [5] Nai, Z., Elfail, N. an ouati, F. 008: at loss eteination using Okuua Hata oel an spline