صفحه محصول - پاورپوینت بررسی شبکه های سلولی موبایل

پاورپوینت بررسی شبکه های سلولی موبایل (pptx) 51 اسلاید

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تعداد اسلاید: 51 اسلاید

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به نام خدا بررسی شبکه های سلولی موبایل History of wireless communication 1897: Marconi demonstrated transmission of radio waves to a ship at sea 29 km away 1915: Wireless telephony established-- Virginia and Paris 1920's: Radio broadcasting became popular 1930's: TV broadcasting began 1946: First public mobile telephone service in US 1960's: Bell Labs developed cellular concept-- brought mobile telephony to masses 1960’s: Communications satellites launched Late 1970's: IC technology advances enable affordable cellular telephony-- ushers in modern cellular era Modern cellular standards 1979: NTT (Japan), FDMA, FM, 25 kHz channels, 870-940 MHz 1983: AMPS (US), FDMA, FM, 30 kHz channels, 824-894 MHz 1985: TACS (Europe), FDMA, FM, 25 kHz channels, 900 MHz 1990: GSM (EuropeTDMA, GMSK, 200 kHz channels, 890-960 MHz 1991: USDC/IS-54 (), US), TDMA, p/4 DQPSK, 30 kHz channels, 824-894 MHz 1993: IS-95 (US), CDMA, BPSK/QPSK, 1.25 MHz channels, 824-894 MHz and 1.8-2.0 GHz 1993: CDPD (US), ) Cellular Digital Packet Data(: FHSS, GMSK, 30 kHz channels, 824-894 Mhz 2001: UMTS/IMT-2000 (3rd generation European cellular standard), supports data and voice (up to 2 Mbps), 1885-2025 MHz and 2110-2200 Mhz Wireless data standards IEEE 802.11: wireless LAN/ad-hoc networking, 1, 2 or 11 Mbps, DSSS or FHSS with CSMA/CA RTS-CTS-ACK, 2.4 - 2.4835 GHz Bluetooth: replacement for cables, short range (10 or 100 m), low power (1 or 100 mW), low cost, 1 Mbps max data rate, local piconets with master-slave operation HomeRF: wireless home networking, 150 feet range, up to 10 devices, SWAP protocol IEEE 802.15: wireless PAN, modes for low (< 10 kbps), medium (up to 200 kbps), and high (> 20 Mbps) data rates Facts about wireless communication Over 50% of US households have a cellular phone by 2003 Over 170M wireless data users(2003); projected to reach 1.3 billion by 2004 Over 200M mobile phone subscribers in Western Europe Global revenue from wireless portals predicted to grow from $700M to $42 billion by 2005 Worldwide wireless subscribers to reach 1 billion by Q3 2002 WLAN revenues predicted at $785M by 2004 Forecasting a 59 percent growth rate for wireless usage in rural areas between 2000 and 2003 Underlying concepts Electromagnetics Antennas, wave propagation, channel modeling Signals and systems Filtering, Fourier transforms, block-diagram design Digital signal processing Equalization, spread-spectrum, source coding Communications Modulation, noise analysis, channel capacity, channel coding Enabling technologies Digital integrated circuits RF generation devices (efficient power amps, sleep modes, improved oscillators, smart antennas) Source coding (data compression) Modulation (improved efficiency) Multiple-access techniques (increase number of users) Channel coding/forward error correction (improve probability of successful reception) Software programmable radios سلولهاي راديويي منفرد پليس آتش نشاني تاكسي راديو و تلويزيون اورژانس