self question
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sesefesTRANSCRIPT
Phn tp l g?, v d:Phn tn l g?, v d:M phng khc m t im g?:
La chn khong bo v da trn c s no?:Unswer1. Phn tp:Phn tp mt vn l s x l khng ging nhau i vi cc thnh phn ca vn .
Phn tp tn s: l cc thnh phn tn s khc nhau c x l c lpV d: FDMA
Phn tp thi gian: l cc thi im khc nhau c x l c lp vi nhauV d: TDMA
Phn tp khng gian: l cc vng khng gian khc nhau c x l c lp vi nhau
V d: SDMA
2. Phn tn
Phn tn l s dn tri cc thnh phn ca cng mt s vt trong mt phm vi no .Phn tn tn s: Tn hiu n tn s khi truyn qua knh n my thu gm cc thnh phn tn s khc nhau.
Nguyn nhn: Dch Doppler
Phn tn thi gian: Tn hiu pht qua knh v tuyn s n my thu ti nhng thi im khc nhau
Nguyn nhn: Truyn lan a ng
Phn tn khng gian: Tn hiu pht qua knh v tuyn s n my thu vi nhng gc ti (DOA) khc nhau
Nguyn nhn: Tn hiu b phn x qua cc chng ngi vt3. M phng v m t
M phng: l phng php nhm xy dng nn mt vn cn nghin cu no
M t: l phng php th hin mt vn bit no
V d:
Th hin ng cong BER thng qua cng thc s dng hm Q chnh l m t BER
Xy dng ng cong BER thng qua vic pht, thu tn hiu qua knh v tuyn v tnh BER cho mi ln pht c gi l m phng BER
4. C s la chn khong bo v TGKhong bo v ngoi mc ch tng chiu di k hiu OFDM ( gim tc k hiu pht) cn gip OFDM system chng li tri tr a ng ca knh.Chiu di khong bo v c la chn trn c s tri tr cc i ca knh, TG > Max (tri tr ca knh)