mobiluri telekomunikaciis miwispira da Tanamgzavruli sistemebi
mobiluri telekomunikaciis miwispira da Tanamgzavruli sistemebi
mobiluri telekomunikaciis miwispira da Tanamgzavruli sistemebi
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xolo amplitudebi mudmivi rCeba) ewodeba binaluri<br />
fazamanipulirebuli signali (bfms).<br />
Tu bfms-is elementarul impulsebs warmoadgenen<br />
xangrZlivobis sworkuTxovani Cipebi, maSin impulsis<br />
kompleqsuri amplitu<strong>da</strong> tolia:<br />
a= A exp γ <br />
j ,<br />
i<br />
sa<strong>da</strong>c A = const _ impulsis mudmivmoqmedi amplitu<strong>da</strong>a,<br />
0, π<br />
γi misi sawyisi fazaa. aseTi impulsis kompleqsuri<br />
momvlebi:<br />
S0 t <br />
1,<br />
{ 0,<br />
t [0, Δ]<br />
t ] ,0[<br />
; t <br />
] Δ , [<br />
diskretul formaSi sasargeblo informaciis<br />
signals aqvs Semdegi saxe:<br />
D=1*exp ( jd<br />
r ) , d r (0, π ).<br />
amitom kodiT mani pulirebuli ga<strong>da</strong>mtani six-<br />
Siris sainformacio signali iqneba:<br />
N1<br />
Dr i 0<br />
0<br />
r<br />
i0<br />
S(t)=Re{[ a S t i rNΔ<br />
exp j2π f t<br />
<br />
N1<br />
=Re{[A} . exp jdr<br />
exp<br />
jyi<br />
S0 t i<br />
rNΔ<br />
]exp j2πf<br />
0t<br />
<br />
r<br />
<br />
i0<br />
signalis miReba xorcieldeba optimaluri mim-<br />
Rebis meSveobiT, romelic iTvlis korelaciur integrals<br />
signalisaTvis:<br />
T<br />
,<br />
Z= x tS 0n<br />
tdt 0<br />
sa<strong>da</strong>c x(t) Semavali signalia, romelic Sedgeba<br />
sasargeblo signalisa <strong>da</strong> xmauris narevisagan; S(t)samisamarTo<br />
mimdevrobis sayrdeni aslia; T-kodis<br />
periodi. koreliatori axorcielebs Semavali far-<br />
30<br />
}<br />
Tozolovani signalis speqtris SekumSvas sixSiruli<br />
speqtris Semdgomi filtraciiT.<br />
rTuli signalebis korelaciuri <strong>da</strong>muSaveba iZle-<br />
va energetikuli mogebis saSualebas miRebis dros.<br />
b) koduri Tanmimdevrobebis kriteriumebis<br />
amorCeva<br />
koduri Tanmimdevrobebis arCeva CDMA sistemisaTvis<br />
<strong>da</strong>mokidebulia arxis ti pze: pir<strong>da</strong>piri an<br />
uku.<br />
kavSiris pir<strong>da</strong>pir arxSi upiratesoba eniWeba muSa<br />
arxebis taqtur <strong>da</strong> kadrul sinqronizacias. <strong>mobiluri</strong><br />
sadguris mimRebis Sesasvlelze narCundeba<br />
muSa arxebis samisamarTo mimdevrobebis taqturi<br />
<strong>da</strong> kadruli sinqronizaciis reJimi. arxebsSorisi<br />
xmauris minimizaciisaTvis kavSiris pir<strong>da</strong>pir arx-<br />
Si gamoiyeneba orTogonaluri signalebis ansambli.<br />
am dros mimRebis korelatori reagirebs mxolod<br />
am samisamarTo mimdevrobebze. mezobeli arxebis<br />
signalebze korelatoris gamoZaxili un<strong>da</strong> iyos<br />
nulis toli.<br />
uku arxSi situacia sxvagvaria. aq saWiroa signalebis<br />
ansambli kargi korelaciuri TvisebebiT.<br />
M abonentian sistemaSi iyeneben N sigrZis samisa-<br />
marTo mimdevrobebs. SemoviRoT aRniSvnebi: a k<br />
i<br />
31<br />
_ k-<br />
uri mimdevrobis i-uri simboloa, i=0,1,…,N-1;<br />
k=1,2,…M. maSin k <strong>da</strong> l mimdevrobebis urTierTkorelaciuri<br />
funqcia:<br />
N 1 1 k l<br />
R kl(m)<br />
a i a i ,<br />
N<br />
<br />
k l ,<br />
i0
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