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未來通信主導技術& N6 v6 B0 s9 c. m4 H( T1 A! Q
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: ' c0 @# z5 Q& I, j2 J
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。
( R$ t/ u# y% L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。
- C) _5 m: N* o# j" g& T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。# `) w3 \% ?0 a+ W: Y
無線區域網路與無縫隙通信(Wi-Fi/MiMax/LTE)。
. z1 ]4 L6 |6 ^* u8 J% V19th Century0 k: f0 E/ {9 x, F$ x
1846- earliest talk on EM wave, “Thoughts on ray vibrations,” Michael Faraday (1791-1867)
, K. R: X( i6 |+ m1 L1864 - “ Maxwell’s equations,” James Clark Maxwell (1831-1879)/ Z# W0 u2 g* Q9 l/ R
1887 - first microwave-like experiment, “electric spark at l~ 10 cm induces at a distance wire loop,” Heinrich Rudolf Hertz (1857-1894)7 ^ }- x+ h5 j
1895- wireless telegraphic communication# v+ |# t5 n$ D2 O4 p& i# Y
1900- trans-Atlantic Ocean telegraph, Guglielmo Marconi (1874-1937)/ E# K$ E5 L- Y7 I
20th Century
2 R# M% {4 t2 x0 N2 V$ r1921- magnetron, A.W.Hull
, G6 [* S% r; b1930- wave propagation in waveguide, George C. Southworth5 c, c5 d: N: Q. D# `7 |" `
1937- Klystron, Russell Varian, Siguard Varian and William Hansen8 A8 X' H( ~( H+ K, E& N8 E/ R
World War II – radar, MIT Radiation Laboratory
x4 @, M5 w, p& [! X2 Y* j9 t2 W) A~1950- coaxial cables for radio communication
4 o' ^6 k9 h* ] b ~" {~1960- satellite communication
) u7 X5 N1 S) F5 v |% s* d: W~1980- remote sensing satellite, DBS (direct broadcast satellite)
: ~, W# i0 ]# A- W% t) l~1990- PCN/PCS (personal communications network/person communication services), GPS (global positioning system), VSAT (very small aperture terminals)6 i2 h+ @7 K( f( G- H
~2000- Digital DBS, WLL (wireless local loop), GII (global information initiative) using mobile satellite network, fibers, cables and wireless.
6 [4 a7 E# y- z- R1 ?; f, t. P: ]+ P 21st Century – RF-SOC use standard mature Si-base technologies to design RFIC. |
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