C S SAP ) LOP con hOMU Ogc M
331 Type (3) BR /ASS (II)
3.3.5. Ca the 14p lich dich vy vi chat luvng dich vy (QoS)
Muc dich chinh cda viec lap lich (Bch vu nham cung cap mOt mire QoS hqp li cho lung lint luting nIumg van sir dung hieu qua tai nguyen.
Chuan IEEE 802.16 dinh nghia b6n lOrp dich vu:
UGS (Unsolicited Grant Service): Duqc thiet ke de h6" trq djch vu Constant Bit Rate (CBR) la loai djch vu duqc sit dung bOi cac kat n6i you eau bang thong c6 dinh vi kha dung lien tic trong than gian ket n6i. Djch vu CBR thuemg duqc dimg cho cac CEng dung thin gian thoc yeu cAu nghiem ng5t ve 40 trl va suy hao. Vi do cac ket n6i Tl/E1, CEng dung VoIP.
rtPS (Real-time Polling Service): Duqc thiet ke de 116 trq cac luting du lieu then
gian thin tren cac ket nun yeu cAu nghiem ngAt ye dO tie nhtmg lai khong yeu cau bang thong c6 dinh, kich thuerc goi bien d6i. Vi do: luting audio/video...
nrtPS (Non-Real-time Polling Service): Duqc thiet ke de ho trq cac luting de lieu khong del h6i thai gian thuc vi dO tre, yeti kich thuerc gel hien d6i va tot do de lieu
Chuang 3: Kan mac mgng troy cap WiMAX
t6i th'#u am tao. Vi dg: giao thtic truyen tai file FTP, cac dich vu ATM GFR (ATM Guaranted Frame Rate)...
BE (Best Effort): Dugc thiet ke de Jul trq cac luting du lieu thong thin:mg khong dbi hOi thin gian thgc cling nhtr dO tre.. Vi dg: dich vg duy'et Web.
MOi mot kett n6i tren kenh uplink dirge anh xa tharth mot luring dich vg ket hqp voi mot 16p dich vg cg the, dugc (filth danh ben gia tri SFID 32 bit (Service Flow Identifier).
M6i met dun vi lap lich dich vg la met top cac quy tic dugc tip dat tren b0 lop lich (scheduler) dm tram BS. MOi mot ket n6i luting fmg yeti mot dich vu du lieu rieng, di kern vOri cac tham s6 QoS tucmg img va dugc thtrcmg luting tgii thoi diem thiet lap ket n6i.
Khi cac packet da dugc phan loci tai 16p con hOi tp, mOi mot packet se dugc ket hqp veri met lop QoS thich hqp yeti you eau cita fmg dgng. Kien trite chuan IEEE 802.16 hO trq d6ng thin nhieu luring der wou veri cac mire QoS phan biet bao thoai, VoIP, video luring, TFTP, HTTP va email.
Chuang 3: Kiln trzic mang truy cap WiMAX