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發表於 2008-11-18 01:21:37
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未來通信主導技術
% i5 d( J6 C% m- @, G; H6 M/ I個人通信服務環境中,除了全球性個人通信(UPT)為智慧型網路技術外,其餘皆是無線技術。無線技術可分三類:
, J( ~) W% |+ X高密度、低功率無線系統:在此所謂低功率是指六百毫瓦或更低,而細胞是指劃分成許多相互銜接之小服務區。一般而言,細胞半徑的大小是依通信量的多寡而定,大細胞涵蓋範圍約二至二十公里,小細胞在一公里以內,而微細胞則在一百公尺左右。 ]8 l1 i! Q. L( T1 b: j
高速度、廣涵蓋區域之細胞式行動電話系統:即為AMPSGSM和3G系統。
5 B' \* _1 G- Q7 j高密度、廣涵蓋區域之微細胞式系統:是採用如CT2、DECT、PHS或WACS等技術,從現有之固定電話用戶側著手。
: h4 J1 X2 W4 [$ f. Z# J, y無線區域網路與無縫隙通信(Wi-Fi/MiMax/LTE)。* M+ v" h! W- o6 L0 c. M, i
19th Century
" ]2 q2 U# |7 P; M1846- earliest talk on EM wave, “Thoughts on ray vibrations,” Michael Faraday (1791-1867). s- i! ?/ u% o' ~5 Q
1864 - “ Maxwell’s equations,” James Clark Maxwell (1831-1879)/ g% N/ `, A* h- ~+ F' X& a& b9 k
1887 - first microwave-like experiment, “electric spark at l~ 10 cm induces at a distance wire loop,” Heinrich Rudolf Hertz (1857-1894)
6 V% s; j. |$ |6 M% c1895- wireless telegraphic communication9 |2 n5 r) I) A: ?- ~
1900- trans-Atlantic Ocean telegraph, Guglielmo Marconi (1874-1937)5 q) B9 z2 n! t) @: V
20th Century
; z' s! f6 k/ c3 L& z( C1921- magnetron, A.W.Hull
: v( H' G8 n3 `) n9 {1930- wave propagation in waveguide, George C. Southworth
) Z; l# E3 }3 _2 g/ t7 h1937- Klystron, Russell Varian, Siguard Varian and William Hansen
% N) Q V9 g) {. y: nWorld War II – radar, MIT Radiation Laboratory
. D+ l& h- `8 x" D5 {3 {6 c/ l~1950- coaxial cables for radio communication
, @# ]; D- e8 p% u5 o~1960- satellite communication
1 r6 L0 l9 T; R0 i$ R~1980- remote sensing satellite, DBS (direct broadcast satellite)/ f4 H1 H- K) V9 L9 ~8 d
~1990- PCN/PCS (personal communications network/person communication services), GPS (global positioning system), VSAT (very small aperture terminals) c) q" M, d" X+ ]3 V
~2000- Digital DBS, WLL (wireless local loop), GII (global information initiative) using mobile satellite network, fibers, cables and wireless.$ e& \, Z& q, c3 b
21st Century – RF-SOC use standard mature Si-base technologies to design RFIC. |
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