I Prees ►i s FCS 4 04 Yeats j COL Munn *0 E la ann e n
32 kenh con MA h6a, dieu the vi bien dO dupe thiet lap rieng cho m& kenh con de t6i uu Ma vies soh ding tai nguyen ming.
uu Ma vies soh ding tai nguyen ming.
Qua trinh kenh con Ma dem lai cho he thong khit Wing mem deo tong quoin 19
Wing th8ng va Ong suet phit, din den std ding tai nguyen hieu qua han. Hien ling
kenh con h6a dirge trinh bay ten hinh 3.8 va 3.9
OFDM 111111 111111 OFOM canter r 11111)1 OF DMA Gaol) GfOUP 2 111-11111-111 I 11-11111111 NI COMM •••■■ Subchonnel 1 OFD
SuOCIIIMOI 2 IAA carries
■■11. POof
Subchannel 3
Hinh 3.8 OFDM vit OFDMA
OFDM ban =dog Nitta tic, =di kb. Iidv tbj do aen 45 4 PT POI CFDA Mho a.dy *CPG, tft ci tic thy smog etc troyda adds d adc pad I/4
edi elm Sc .1 *drat 'Ids& tale It
''''''IIIfuld ' ''
Mid MU W QE cld sod=a Masao sag shuns d met phd Saw va taw gic, do of y AA pbdcd clod at clomp WI dug lag ling IM
Hinh 3.9 Hieu ring kenh con hod (sub channelization) b. Cdc 6k tinh lay PHY cao can frond Mobile WIMAX
Wimax di ding der dua ra cac ky thuat: diet' cite thich nghi va mA hoi AMC (Adaptive modulation and coding), yeu ciu lap hti ttr ding ideu ket hqp HARQ (Hybrid Automatic Repeat Request) vi phin hoi kenh nhanh CQICH (Fast Channel Feedback) de nAng cao kith Wing phtl song, dung luqng cho Wimax tong cic (mg dvng di dung.
> Dieu chi Hutch nghi vd ma boa AMC
Trong bat ley mpg da to bao-cellular nio, thus bao di dung se tit* nghiem qua cac dieu kien cna dubng truyen phit thay poi theo th&i gian Ara cic vj tri Luang (mg. V6i cong nghe OFDMA, bieu d6 mA hod vi dieu the nhAt djnh c6 the ditch Cmg ten moi thus bao thy theo coic dieu kien alit dubng din de t6i da hoi thong luqng kenh
Fftgialty(:111fIen)
T6c dO ma h6a
1/2, 2/3, 3/4, 5/6 1/2, 2/3, 5/6 (thy chip) 1/2, 2/3, 3/4, 5/6 1/2, 2/3, 5/6 (thy chon)
CC
GIAI PHAP CONG NGH>~ WiMAX
truyen, trong khi duy tri chit luqng dubng truyen ten m8i thug bao. Wri he th6ng OFDMA, cic sting mang con dugc dieu chi ved QPSK hoitc dieu chi QAM hieu qui hon vit thfr to cao han voi bieu d6 dieu chi tinh vi ham, dat dirge thong luqng cao horn nhung cling a bj tic dOng ctia nhieu vi cic tap Am han. Biing phuang phip dieu chi thich irng va bieu do ma hoa 18i, viec dip ang ti le nay dam bao s6 bit ctia m6i sting mang con dirge tai uu tucmg duang vol CINR can thiet de dim bito kit n6i vo tuyen On
djnh. Cac He thong OFDMA cling c6 the lam tang thong luqng toi tic thug bao ci
nhan bang cach lam tang s6 luong kenh con dit cap tai bit ;Et thbi diem Mo.
Minh 3.10 Dieu chi thick nghi va ma Ma dim tren khocing each win BS
Trong WiMAX di dung 6 duerng xu6ng, bit buOc phiti co cac h8 trq dieu chi QPSK, 16QAM va 64QAM. Con 6 duang len, 64QAM la tut chon. Ca ma hoa xoin vi ma hoa Turbo yang voi toe dO ma thay deri va ma 1#p cling dugc h8 trq. Ngoiti ra, ma kh6i Turbo vi ma kiem tra chin le mat thip LDPC (Low Density Party Check Code) cling dugc h6 trq nhu la mot tinh Sing tut chop. Cac phuang duly dieu chi va ma Ma dirge h8 trq trong 802.16e dugc liet ke trong bang 3.4:
Bang 3.4 Cdc phuang that dieu chi va Ma Ma clurrc hot try trong 802.16e
Su kit hop cac kq thu(it dieu chi va ttic dO ma h6a dil cung cap sir phan giai hqp
ly cho tot dO dr lieu nhu minh hot,* cho bang 3.5 bieu di& tot dO cid lieu cho 2 kenh 5 va 10 MHz veri cac kenh con PUSC. DO dai khung la 5ms, m6i khung o5 48 Id hieu OFDM, v6i 44 Id hieu OFDM la httu dung cho viec truyen di? lieu. Cac gii trj dugc dinh diu am chi ra tot dO bit caa Icy thulit 64QAM tut chon cho duOng UL. Bang 3.5 the hien tot dO dtt lieu 16p PHY trong Mobile WiMAX.
Phan Tien Tang
GIAI PHAP CONG NGHe WiMAX
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