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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
/ A2 L' R* [) N+ i. u/ L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: 4 E& b4 Z$ N3 ^/ X( {5 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。 7 q$ j' d7 P2 D( ^1 ]
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。
9 ?) X" U0 l+ G1 X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。
3 {* z3 B0 n# l4 E無線區域網路與無縫隙通信(Wi-Fi/MiMax/LTE)。
1 k7 M3 e/ q! c19th Century
9 w' r p7 C6 U; X9 w+ Z! x1846- earliest talk on EM wave, “Thoughts on ray vibrations,” Michael Faraday (1791-1867), E, J0 K4 G: s( d! t: f3 L1 z$ q& P
1864 - “ Maxwell’s equations,” James Clark Maxwell (1831-1879)
* [' M( e) @* f, U k1887 - first microwave-like experiment, “electric spark at l~ 10 cm induces at a distance wire loop,” Heinrich Rudolf Hertz (1857-1894)
0 @% ?" X' h$ X9 U. f" X1895- wireless telegraphic communication
& K9 o) `/ m! R& k1900- trans-Atlantic Ocean telegraph, Guglielmo Marconi (1874-1937)
; Q0 j. Q' M) F8 a20th Century
. C+ `5 X w; C* `% K" H; R1921- magnetron, A.W.Hull( k1 \ m4 {! T# V
1930- wave propagation in waveguide, George C. Southworth
, D% }7 ^8 W1 a1937- Klystron, Russell Varian, Siguard Varian and William Hansen: p1 q1 [0 M' W- ]2 S
World War II – radar, MIT Radiation Laboratory, A; C* a: U6 @ }+ n
~1950- coaxial cables for radio communication; k+ u& A5 ?0 d- a
~1960- satellite communication9 j$ h4 ~4 S1 C1 Y, z
~1980- remote sensing satellite, DBS (direct broadcast satellite)& q0 J! R$ ]2 V7 G3 o) m
~1990- PCN/PCS (personal communications network/person communication services), GPS (global positioning system), VSAT (very small aperture terminals): s! ]/ F# G. m9 ~; p
~2000- Digital DBS, WLL (wireless local loop), GII (global information initiative) using mobile satellite network, fibers, cables and wireless.
+ n4 m& z8 e- R$ S 21st Century – RF-SOC use standard mature Si-base technologies to design RFIC. |
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