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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/ b! q) M/ U* |# V3 y8 {
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: ' h7 W) z) v- C5 _3 x# \! U
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 R8 ~2 Z' U/ z1 s( H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 T7 [. v2 x/ d4 |1 d; T# Q+ O# i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。
! J1 Q+ n, y- [: ]無線區域網路與無縫隙通信(Wi-Fi/MiMax/LTE)。* w: x" o) ^* [
19th Century$ _* C# O6 ~1 f2 S! H1 h! C
1846- earliest talk on EM wave, “Thoughts on ray vibrations,” Michael Faraday (1791-1867)
, r; V6 @8 h) U1864 - “ Maxwell’s equations,” James Clark Maxwell (1831-1879): Z7 c1 f, L' m: Y. J
1887 - first microwave-like experiment, “electric spark at l~ 10 cm induces at a distance wire loop,” Heinrich Rudolf Hertz (1857-1894)3 s2 l3 h: q- n% V! Z
1895- wireless telegraphic communication' _/ Q9 `+ w: j: Y
1900- trans-Atlantic Ocean telegraph, Guglielmo Marconi (1874-1937)
3 k; k7 d' n" i9 g8 H+ e* ]20th Century
$ c0 s% q0 i2 L. ^# y1921- magnetron, A.W.Hull7 T: x" L5 a% l$ @9 A7 ~
1930- wave propagation in waveguide, George C. Southworth( \/ x; I" w# O6 S( D' \
1937- Klystron, Russell Varian, Siguard Varian and William Hansen
+ h# x- z7 X7 J& P7 FWorld War II – radar, MIT Radiation Laboratory
! e7 B. l6 v5 {' l! Q! c. Q~1950- coaxial cables for radio communication _( O) U a t
~1960- satellite communication/ d4 h8 D; S9 \& q# s3 T3 S6 _5 `1 j5 R
~1980- remote sensing satellite, DBS (direct broadcast satellite)
8 C7 i) ` k) b% L~1990- PCN/PCS (personal communications network/person communication services), GPS (global positioning system), VSAT (very small aperture terminals)
8 V5 I% e" l; o, B! G~2000- Digital DBS, WLL (wireless local loop), GII (global information initiative) using mobile satellite network, fibers, cables and wireless.; }: h0 b" x) V! }; R! z+ y
21st Century – RF-SOC use standard mature Si-base technologies to design RFIC. |
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