70 likes | 152 Views
(. ). f. t. ¥. ò. -. w. j. t. w. =. (. ). (. ). F. f. t. e. d. t. -. ¥. t. -. t. t. 2. /. 2. 2. ò. -. w. j. t. =. A. e. d. t. -. t. /. 2. é. ù. w. w. t. t. A. -. j. j. t. -. 2. 2. =. e. e. ê. ú. A. w. ë. û. -. j. w. t. æ. ö.
E N D
( ) f t ¥ ò - w j t w = ( ) ( ) F f t e d t - ¥ t - t t 2 / 2 2 ò - w j t = A e d t - t / 2 é ù w w t t A - j j t - 2 2 = e e ê ú A w ë û - j w t æ ö ç ÷ s i n è ø 2 ( ) = t A æ w t ö ç ÷ è ø 2 ( ) p t s i n f ( ) t = A ( ) p t f 1 3 1 - t t t 2 3 2 - - t = ± p p f n t t t n \ = ± f t Frequency Spectrum of Pulse Spectrum of Pulsewith time adulation τis time 時間 0 Pulse waveform パルス信号の波形 Frequency 周波数 Frequencies which give zero spectrum are 0 (n: Integer) Frequency spectrum of Pulse パルス信号のスペクトル
Where do mobile communications go?ーBroadband, Different Systems and Internetー • Towards Broadband communications • High data rate>>>Wide frequency band>>>MM-wave • Personal>>>Compact size terminals>>>small devices • Integrated Systems • Mobile, Wireless LAN, Wireless Access, Home link • Connection to Broadband Backbone Networks • Access to the broadband Internet
Trends of Wireless Access Systems in the World • 5 GHz-band(5.15- 5.25 GHz :100 MHz) • USA (IEEE 802.11):20 Mbps, OFDM • Europe (HIPERLAN-2, ETSI BRAN):20 Mbps, ATM • Japan (MPT) :20 Mbps, 20 MHz/ch, OFDM • Millimeter-wave(40/60 GHz bands) • SAMBA:For vehicular in 40GHz band • MEDIAN :High speed wireless LAN in 60GHz band • MMAC : High speed wireless LAN in 60GHz band • Satellite system(Ka-band、Millimeter-wave) • Teledesic:Inter-satellite communication in MM-wave • M-Star: 52Mbps in 50/40 GHz
f=5 GHz or 60 GHz Data=100 Mbps f=60 GHz Data=156 Mbps f=5 GHz Data=25 Mbps f=25GHz Data=25 Mbps Multimedia Mobile Access Communication Systems (MMAC) • Main mission • MMAC are Mobile Communication Systems which can transmit ultra high speed, high quality Multimedia Information "anytime and anywhere" with seamless connections to optical fiber networks. • High speed Wireless Access • Frequency: 5/25/40/60 GHz • Data rate(Quasi-fixed) • 2000 : 25Mbps • 2010 : 156Mbps • Ultra high speed LAN • Frequency : 60 GHz • Data rate • 2000 : 156Mbps • 2010 : 622Mbps printed from MMAC
Millimeter-Wave Video Home Link Systems -Demonstration experiments inside a real house- Transmitter Receiver Received TV program through a wall. (Transmitter is located in a next room.) Received TV program of BS satellite. Transmitter is fixed on a top of a wall.
Intelligent Transport Systems ITS NW Central Control Station Frequency integrating Converter 12GHz Satellite TV IMT-2000 NW Receiving Station BS 1.5GHz PDC NW 1.9GHz PHS NW BS BS RF/Opt. Conv. YRP Bldg. RF/Opt. Conv. Antenna Optical Cable Radio on Fiber 36~37GHz Road-to-Vehicle 60GHz Intervehicle Experimental Course at YRP