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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
8 k( N. h) f5 o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: % U3 ~8 E$ \" S
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。
5 }8 c. D1 y5 R+ W" |; }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 L4 x3 ?+ k/ U* D8 q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。% U0 T- C- _6 F: c. T3 {1 L
無線區域網路與無縫隙通信(Wi-Fi/MiMax/LTE)。
2 G, l8 E' S$ k, J/ K. m1 U4 M" W19th Century
5 y' ]5 M$ f8 E; V. N/ Y; Z d9 f3 E1846- earliest talk on EM wave, “Thoughts on ray vibrations,” Michael Faraday (1791-1867)2 C& x1 e, _2 S# s u
1864 - “ Maxwell’s equations,” James Clark Maxwell (1831-1879)
0 O1 j$ `9 z1 u" h& W* d9 V1887 - first microwave-like experiment, “electric spark at l~ 10 cm induces at a distance wire loop,” Heinrich Rudolf Hertz (1857-1894)
$ a4 U( I4 x$ e5 |6 O% P2 T1895- wireless telegraphic communication
* z2 M; d v7 y9 I8 u1900- trans-Atlantic Ocean telegraph, Guglielmo Marconi (1874-1937); o; T8 f$ u" k: X @6 T+ u1 N; _
20th Century, h" P4 U8 D' d$ o5 C
1921- magnetron, A.W.Hull
) V1 h, j3 P' g; Y+ g1930- wave propagation in waveguide, George C. Southworth
% R7 S+ }- S% w( A5 h; B1937- Klystron, Russell Varian, Siguard Varian and William Hansen
1 {' N" ~; w" l% x2 WWorld War II – radar, MIT Radiation Laboratory
% h1 _( L" t3 s4 A* H5 P* v, K' o& l~1950- coaxial cables for radio communication: t% }4 I/ M4 s" i
~1960- satellite communication
2 \$ m: y4 K# A8 [1 b8 T~1980- remote sensing satellite, DBS (direct broadcast satellite)
$ e! k: j! c& q* f E$ E~1990- PCN/PCS (personal communications network/person communication services), GPS (global positioning system), VSAT (very small aperture terminals)6 ~9 y+ o' f/ ?; O9 H* a
~2000- Digital DBS, WLL (wireless local loop), GII (global information initiative) using mobile satellite network, fibers, cables and wireless./ [- A2 W1 C# m6 l& |
21st Century – RF-SOC use standard mature Si-base technologies to design RFIC. |
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