قسمتی از اسلایدها History of wireless communication n1897: Marconi demonstrated transmission of radio waves to a ship at sea 29 km away n1915: Wireless telephony established– Virginia and Paris n1920’s: Radio broadcasting became popular n1930’s: TV broadcasting began n1946: First public mobile telephone service in US n1960’s: Bell Labs developed cellular concept– brought mobile telephony to masses n1960’s: Communications satellites launched nLate 1970’s: IC technology advances enable affordable cellular telephony– ushers in modern cellular era Modern cellular standards n1979: NTT (Japan), FDMA, FM, 25 kHz channels, 870-940 MHz n1983: AMPS (US), FDMA, FM, 30 kHz channels, 824-894 MHz n1985: TACS (Europe), FDMA, FM, 25 kHz channels, 900 MHz n1990: GSM (EuropeTDMA, GMSK, 200 kHz channels, 890-960 MHz n1991: USDC/IS-54 (), US), TDMA, p/4 DQPSK, 30 kHz channels, 824-894 MHz n1993: IS-95 (US), CDMA, BPSK/QPSK, 1.2 …
