Uru rupapuro rusobanura ibyingenzi nubwoko bugenda bugabanuka mubitumanaho bidafite umugozi.Ubwoko bwa Fading bugabanijemo ibice binini bigenda bishira kandi bito bigenda bishira (gutinda kugwira gukwirakwira no gukwirakwiza doppler).
Kugabanuka kwa Flat hamwe ninshuro zo gutoranya kuzimangana ni igice cyo kugabanuka kwinshi aho kugabanuka vuba no gutinda buhoro ni igice cya doppler ikwirakwizwa.Ubu bwoko bugenda bugabanuka bishyirwa mubikorwa nkuko Rayleigh, Rician, Nakagami na Weibull bikwirakwizwa cyangwa moderi.
Iriburiro:
Nkuko tubizi sisitemu yitumanaho idafite umugozi igizwe na transmitter hamwe niyakira.Inzira iva kuri transmitter yerekeza kubakira ntabwo yoroshye kandi ibimenyetso byanyujijwe bishobora kunyura muburyo butandukanye harimo gutakaza inzira, kugabanuka kwinshi nibindi. Ibimenyetso byerekana inzira binyuze munzira biterwa nibintu bitandukanye.Nigihe, radio inshuro ninzira cyangwa umwanya wa transmitter / yakira.Umuyoboro uri hagati ya transmitter nuwakiriye urashobora kuba umwanya utandukanye cyangwa ugenwa bitewe nuburyo bwohereza / kwakira neza cyangwa kwimuka kubireba.
Kugabanuka ni iki?
Igihe cyo gutandukana kwakiriwe ibimenyetso byimbaraga bitewe nimpinduka zoherejwe hagati cyangwa inzira bizwi ko bishira.Kugabanuka biterwa nibintu bitandukanye nkuko byavuzwe haruguru.Mugihe cyagenwe, kuzimangana biterwa nikirere cyikirere nkimvura, imirabyo nibindi Mugihe kigendanwa, kugabanuka biterwa nimbogamizi zinzira zinyuranye zijyanye nigihe.Izi mbogamizi zitera ingaruka zo kwanduza ibimenyetso byanduye.
Igishushanyo-1 cyerekana amplitude hamwe nimbonerahamwe yerekana intera yo kugabanuka gahoro kandi byihuta bigenda tuzabiganiraho nyuma.
Ubwoko bugenda bugabanuka
Urebye imiyoboro inyuranye ijyanye nubumuga hamwe numwanya wa transmitter / uwakiriye bikurikira nubwoko bugenda bugabanuka muri sisitemu yitumanaho ridafite umugozi.
ScIbipimo binini bigabanuka: Harimo gutakaza inzira n'ingaruka zo kugicucu.
➤Ibipimo bito bigabanuka: Igabanijwemo ibyiciro bibiri by'ingenzi ni.gutinda kugwira gukwirakwira no gukwirakwira.Gutinda gukwirakwira kugabanijwe kugabanijwe no kugabanuka kugabanuka no guhitamo kugabanuka.Gukwirakwiza Doppler bigabanijwemo kugabanuka vuba no kugenda buhoro.
Models Kugabanuka: Hejuru yubwoko bugenda bushyirwa mubikorwa muburyo butandukanye cyangwa kugabura birimo Rayleigh, Rician, Nakagami, Weibull nibindi.
Nkuko tubizi, ibimenyetso bizimangana bibaho bitewe no gutekereza ku butaka no ku nyubako zikikije kimwe n'ibimenyetso bitatanye biturutse ku biti, abantu n'iminara igaragara mu gace kanini.Hariho ubwoko bubiri bwo gushira.nini nini igenda ishira kandi ntoya irashira.
1.) Ibipimo binini bigenda bishira
Ingano nini igenda ibaho iyo inzitizi ije hagati ya transmitter niyakira.Ubu buryo bwo kwivanga butera umubare munini wibimenyetso byo kugabanya imbaraga.Ni ukubera ko EM wave igicucu cyangwa igahagarikwa nimbogamizi.Bifitanye isano nihindagurika rinini ryibimenyetso hejuru.
1.a) Gutakaza inzira
Gutakaza umwanya wubusa inzira irashobora kugaragazwa nkibi bikurikira.
T Pt / Pr = {(4 * π * d)2/ λ2} = (4 * π * f * d)2/c2
Aho,
Pt = Kohereza imbaraga
Pr = Akira imbaraga
λ = uburebure
d = intera iri hagati yo kohereza no kwakira antene
c = umuvuduko wumucyo ni ukuvuga 3 x 108
Uhereye ku kuringaniza bisobanura ko ibimenyetso byanyujijwe byiyongera intera uko ikimenyetso gikwirakwizwa ahantu hanini kandi hanini kuva ihererekanyabubasha ryerekeza ku iherezo.
1.b) Igicucu
• Biboneka mu itumanaho ridafite umugozi.Igicucu ni ugutandukana kwakiriwe imbaraga za EM ibimenyetso uhereye kubiciro byagereranijwe.
• Ni ibisubizo by'inzitizi hejuru yinzira yohereza no kwakira.
• Biterwa na geografiya kimwe na radiyo yumurongo wa EM (ElectroMagnetic).
2. Umunzani muto ugabanuka
Gitoya igenda ishira ihindagurika ryihuta ryibimenyetso byakiriwe mugihe gito cyane kandi mugihe gito.
Bishingiyegutinda kugwira gukwirakwirahari ubwoko bubiri bwurwego ruto rugenda rugabanuka.kugabanuka no guhindagurika guhitamo guhitamo.Ubwoko bwinshi bwo kugabanuka buterwa no gukwirakwiza ibidukikije.
2.a) Kugabanuka
Umuyoboro udafite insinga bivugwa ko ugenda uzimangana niba ufite inyungu zihoraho hamwe nicyiciro cyicyiciro gisubiza hejuru yumurongo munini uruta ubwinshi bwikimenyetso cyatanzwe.
Muri ubu bwoko bwo kuzimya ibice byose bya frequence yibimenyetso byakiriwe bihindagurika muburyo bumwe icyarimwe.Birazwi kandi nko kudahitamo gushira.
• Ikimenyetso cya BW << Umuyoboro BW
• Ikimenyetso cyigihe >> Gutinda gukwirakwira
Ingaruka zo kuzimangana bigaragara nkigabanuka muri SNR.Iyi miyoboro igabanuka izwi nka amplitude itandukanye cyangwa imiyoboro migari.
2.b) Guhitamo inshuro
Ihindura ibice bitandukanye byerekana ibimenyetso bya radio hamwe na amplitude atandukanye.Kubwibyo izina guhitamo kugabanuka.
• Ikimenyetso cya BW> Umuyoboro BW
• Igihe cyikimenyetso <Gutinda gukwirakwira
Bishingiyedoppler ikwirakwirahari ubwoko bubiri bwo gushira viz.gushira vuba no kugenda buhoro.Doppler ikwirakwiza ubwoko bugenda bugabanuka biterwa numuvuduko wa mobile ni ukuvuga umuvuduko wakira kubijyanye na transmitter.
2.c) Kugabanuka vuba
Ikintu cyo kuzimangana byihuse kigaragazwa nihindagurika ryihuta ryibimenyetso ahantu hato (ni ukuvuga umurongo mugari).Iyo ibimenyetso bigeze mubyerekezo byose byindege, kuzimangana byihuse bizerekanwa mubyerekezo byose.
Kugabanuka byihuse bibaho mugihe umuyoboro utera igisubizo uhinduka byihuse mugihe cyigihe.
• Gukwirakwiza doppler ndende
• Igihe cyikimenyetso> Igihe cyo guhuza
• Guhindura Ibimenyetso <Guhindura Umuyoboro
Ibipimo bivamo gukwirakwiza inshuro cyangwa guhitamo guhitamo bitewe na doppler ikwirakwira.Kwangirika byihuse nigisubizo cyo kwerekana ibintu byaho no kugenda kwibintu ugereranije nibyo bintu.
Mugihe cyihuta, kwakira ibimenyetso ni igiteranyo cyibimenyetso byinshi bigaragarira mubice bitandukanye.Iki kimenyetso ni igiteranyo cyangwa itandukaniro ryibimenyetso byinshi bishobora kubaka cyangwa gusenya bishingiye ku cyiciro cyo guhinduranya hagati yabo.Icyiciro cyimibanire giterwa numuvuduko wikigenda, inshuro zoherejwe hamwe nuburebure bwinzira.
Kwangirika vuba bigoreka imiterere ya baseband pulse.Uku kugoreka ni umurongo kandi kuremaISI(Interineti Ikimenyetso).Kuringaniza imihindagurikire y'ikirere bigabanya ISI mu gukuraho kugoreka umurongo guterwa n'umuyoboro.
2.d) Buhoro buhoro
Buhoro buhoro kugabanuka nigicucu cyinyubako, imisozi, imisozi nibindi bintu hejuru yinzira.
• Gukwirakwiza Doppler Ntoya
Ikiringo c'ikimenyetso <
• Guhindura Ibimenyetso >> Guhindura Umuyoboro
Ishyirwa mu bikorwa rya moderi zishira cyangwa kugabanuka kugabanuka
Gushyira mubikorwa moderi zigenda zishira cyangwa kugabanuka kugabanuka harimo Rayleigh gushira, Rician fading, Nakagami fading na Weibull fading.Ikwirakwizwa ryumuyoboro cyangwa moderi byashizweho kugirango bishire kugabanuka mubimenyetso bya baseband nkuko bisanzwe bigenda bisabwa.
Rayleigh irashira
• Muri moderi ya Rayleigh, gusa Non Line of Sight (NLOS) ibice byagereranijwe hagati ya transmitter niyakira.Bifatwa ko nta nzira LOS ibaho hagati ya transmitter niyakira.
• MATLAB itanga "rayleighchan" imikorere yo kwigana imiyoboro ya rayleigh.
• Imbaraga zitangwa ku buryo bugaragara.
• Icyiciro gikwirakwizwa kimwe kandi cyigenga kuri amplitude.Nubwoko bukoreshwa cyane bwa Fading mu itumanaho ridafite umugozi.
Rician
• Muburyo bwa rician, ibice byombi byumurongo (LOS) nibitari umurongo wa Sight (NLOS) bigereranwa hagati ya transmitter niyakira.
• MATLAB itanga "ricianchan" imikorere yo kwigana imiyoboro ya rician.
Nakagami gushira
Umuyoboro wa Nakagami ni moderi y'ibarurishamibare ikoreshwa mu gusobanura imiyoboro y'itumanaho ridafite aho sgnal yakiriwe ihura na Multath fading.Irerekana ibidukikije hamwe no kugabanuka gukabije nko mumijyi cyangwa mumujyi.Ikigereranyo gikurikira kirashobora gukoreshwa mukwigana umuyoboro wa Nakagami ugabanuka.
• Muri uru rubanza twerekana h = r * ejΦInguni Φ isaranganywa kimwe kuri [-π, π]
• Impinduka r na Φ zifatwa ko zigenga.
• Nakagami pdf igaragazwa nkuko byavuzwe haruguru.
• Muri pdf ya Nakagami, 2σ2= E {r2}, Γ (.) Nigikorwa cya Gamma na k> = (1/2) nigishushanyo kigenda kigabanuka (impamyabumenyi yubwisanzure ijyanye numubare wongeyeho Gaussion random variable).
• Byabanje gukorwa muburyo bushingiye kubipimo.
• Akanya yakira imbaraga ni Gamma yatanzwe.• Hamwe na k = 1 Rayleigh = Nakagami
Weibull irashira
Uyu muyoboro nubundi buryo bwibarurishamibare bukoreshwa mugusobanura umuyoboro wogutumanaho.Umuyoboro wa Weibull usanzwe ukoreshwa muguhagararira ibidukikije hamwe nubwoko butandukanye bwibihe bigenda bishira harimo intege nke kandi zishira.
Aho,
2σ2= E {r2}
Isaranganya rya Weibull ryerekana ubundi buryo bwo gukwirakwiza Rayleigh.
• Iyo X na Y ari iid zeru bisobanura impinduka za gaussiya, ibahasha ya R = (X.2+ Y.2)1/2ni Rayleigh yatanzwe.• Icyakora ibahasha isobanurwa R = (X.2+ Y.2)1/2, hamwe na pdf ihuye (umwirondoro wo gukwirakwiza imbaraga) ni Weibull yatanzwe.
• Ikigereranyo gikurikira kirashobora gukoreshwa mukwigana moderi ya Weibull igenda.
Muriyi page twanyuze mu ngingo zinyuranye zigenda zishira nkibigenda bishira umuyoboro, ubwoko bwacyo, moderi igenda ishira, ibyifuzo byabo, imikorere nibindi.Umuntu arashobora gukoresha amakuru yatanzwe kururu rupapuro kugirango agereranye kandi akure itandukaniro riri hagati yikigero gito cyo kugabanuka no kugabanuka kwinshi, itandukaniro riri hagati yo kugabanuka kwinshi no guhitamo guhitamo kugabanuka, itandukaniro riri hagati yo kuzimangana no kugabanuka gahoro, itandukaniro riri hagati ya rayleigh fading na rician fading na n'ibindi.
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Igihe cyo kohereza: Kanama-14-2023
