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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
- [7 o5 h0 f8 s) f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:
" x ~9 k" f$ k: t6 }' V& u. B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。 & a Y% s) d' Z& K
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。
/ B8 I2 a! e, e/ @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。/ t4 O( K) `8 m8 }: `" @2 v
無線區域網路與無縫隙通信(Wi-Fi/MiMax/LTE)。
m- @$ G* Y. z. b: p. x# K19th Century' p& x- h& n7 I& M9 H$ k% m0 `
1846- earliest talk on EM wave, “Thoughts on ray vibrations,” Michael Faraday (1791-1867)$ V- a2 Q/ X% A/ g3 H
1864 - “ Maxwell’s equations,” James Clark Maxwell (1831-1879)
# E3 L, i5 ]: z' F8 s5 W% q3 D' i1887 - first microwave-like experiment, “electric spark at l~ 10 cm induces at a distance wire loop,” Heinrich Rudolf Hertz (1857-1894)
9 G0 F8 H) C2 Y* H0 l3 [8 v1895- wireless telegraphic communication: ~1 m' }& O* e" S4 G. N* Z
1900- trans-Atlantic Ocean telegraph, Guglielmo Marconi (1874-1937)
& ]! g4 S, S& n$ I/ V0 b20th Century" H4 e3 Q& L' d1 N
1921- magnetron, A.W.Hull
0 c5 }, E& r' x/ F1930- wave propagation in waveguide, George C. Southworth
2 c) m r' G; V/ a0 T m1937- Klystron, Russell Varian, Siguard Varian and William Hansen
/ ?7 ~( M C' f& RWorld War II – radar, MIT Radiation Laboratory' D0 @3 b5 O4 u: p: f: R
~1950- coaxial cables for radio communication; p% |0 S6 `( x* g% b7 ?
~1960- satellite communication+ e( e5 D4 x, Y6 S3 U8 {
~1980- remote sensing satellite, DBS (direct broadcast satellite)5 `" F. {, s0 _
~1990- PCN/PCS (personal communications network/person communication services), GPS (global positioning system), VSAT (very small aperture terminals)
. ]6 e9 N+ K" L. }* A2 r# Z; W~2000- Digital DBS, WLL (wireless local loop), GII (global information initiative) using mobile satellite network, fibers, cables and wireless.
: O9 C* g$ v2 x! p2 _* ?" q 21st Century – RF-SOC use standard mature Si-base technologies to design RFIC. |
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