Frequency Spectrum of Pulse f t Spectrum of
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Frequency Spectrum of Pulse f (t) Spectrum of Pulse with time adulation τ is ¥ F (w ) = ò f(t) e - jw t time 時間 dt - ¥ t / 2 ò = - jw t A e -t 2 dt -t / 2 = A é êe - jw ë - j w t 2 - e j w t 2 0 t 2 パルス信号の波形 Pulse waveform ù ú A t û æ wt ö = (At ) = (A t ) ÷ s in ç è 2 ø æ w t ö ç ÷ è 2 ø s in (p f t ) - Frequencies which give zero spectrum are p f t - = ± np f = ± n t 3 t - 2 t 1 3 1 t t t 0 Frequency 周波数 2 t （n: Integer） パルス信号のスペクトル Frequency spectrum of Pulse Communications Research Laboratory
Where do mobile communications go? ーBroadband, Different Systems and Internetー n Towards Broadband communications – – n Integrated Systems – n High data rate>>>Wide frequency band>>>MMwave Personal>>>Compact size terminals>>>small devices Mobile, Wireless LAN, Wireless Access, Home link Connection to Broadband Backbone Networks – Access to the broadband Internet Communications Research Laboratory
Trends of Wireless Access Systems in the World n 5 GHz-band（5. 15 - 5. 25 GHz ： 100 MHz) – – – n Millimeter-wave（40／ 60 GHz bands） – – – n USA (IEEE 802. 11)： 20 Mbps, OFDM Europe (HIPERLAN-2, ETSI BRAN)： 20 Mbps, ATM Japan (MPT) ： 20 Mbps, 20 MHz/ch, OFDM SAMBA：For vehicular in 40 GHz band MEDIAN ：High speed wireless LAN in 60 GHz band MMAC : High speed wireless LAN in 60 GHz band Satellite system（Ka-band、Millimeter-wave） – – Teledesic：Inter-satellite communication in MM-wave M-Star: 52 Mbps in 50/40 GHz Communications Research Laboratory
Multimedia Mobile Access Communication Systems (MMAC) n 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. f=5 GHz or 60 GHz n High speed Wireless Access Data=100 Mbps – – – n Frequency: 5/25/40/60 GHz Data rate（Quasi-fixed） f=60 GHz » 2000 : 25 Mbps Data=156 Mbps » 2010 : 156 Mbps Ultra high speed LAN – – Frequency : 60 GHz Data rate » 2000 : 156 Mbps » 2010 : 622 Mbps f=5 GHz Data=25 Mbps f=25 GHz Data=25 Mbps printed from MMAC Communications Research Laboratory
Millimeter-Wave Video Home Link Systems Communications Research Laboratory
Millimeter-Wave Video Home Link Systems 6 -Demonstration experiments inside a real house- Transmitter Received TV program of BS satellite. Transmitter is fixed on a top of a wall. Received TV program through a wall. (Transmitter is located in a next room. ) Communications Research Laboratory
7 Intelligent Transport Systems ITS NW Frequency integrating Converter IMT-2000 BS NW 1. 5 GHz PDC NW BS 12 GHz Satellite TV Receiving Station BS RF/Opt. Conv. YRP Bldg. Optical Cable Radio on Fiber Central Control Station 1. 9 GHz PHS NW RF/Opt. Conv. Antenna 36~37 GHz Road-to-Vehicle 60 GHz Experimental Course at YRP Intervehicle Communications Research Laboratory