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4g – evolution and

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  • 1. Presented by : SAYAN DASETC 3rd year BESU

2. NetworkName Access SpeedGeneratio technology(max in n kbps) 1G AMPS/TACSTDMA5.6 2GGSMFDMA 9.6+TDMA2.5G GPRS FDMA 170(theo)+TDMA115(prac)2.75GEDGE FDMA473(theo)+TDMA384.6(prac) 3GUMTS WCDMA 2000 4G HSPAOFDMA1Gbps, LTE-A 3. Steady growth of technology 4. Complicated circuitry in mobiles(WCDMA+FDMA+TDMA) Less coverage area (1km off-peak hrs, 500 m-peak hrs) .... Worse than 2G Separate 3G base stations are requaired 2.5Ghz Band spectrum is very costly 5. OFDMA = Orthogonal Frequency DivisionMultiplexing Access Technology UWB=Ultra Wide Band [500MHz 3GHz] Smart Antenna using MIMO technology Supports IPv6 SDR= Software Radio System 6. OFDMA = OFDM (d/l) + SCFDM(u/l) large number of closely spaced orthogonal sub-carrier signals are used to carry data onseveral parallel data streams or channels Since 2G or 3G spectrum can be utilised , there isno immediate need of buying separate 4Gspectrum Uses IFFT during transmission and FFTduring receiving Cyclic prefixes removes interchannel and co-channel interference 7. BLOCK DIAGRAM OF OFDMA 8. OFDM can combat multipath interference with morerobustness and less complexity. OFDMA can achieve a higher MIMO spectral efficiency dueto providing flatter frequency channels than a CDMA rakereceiver can. No cell size breathing as more users connect. Allows simultaneous low-data-rate transmission fromseveral users. Pulsed carrier can be avoided. Lower maximum transmission power for low data rateusers. Shorter delay, and constant delay. Contention-based multiple access (collision avoidance) issimplified. Further improves OFDM robustness to fading andinterference. 9. Fading problemsReflectedsignalsarrive spreadoutover 5 to 20Delay microsecondSpread Path Loss path loss up to ~ 150 dB (that is a 1 followedRayleigh by 15 zeroes) Fadingrapid fading of 20 to 30 dB(power varies by 100 to 1000 timesin level at rates of about 100 times per second) 10. Paths Base Station Subscriber 11. Dynamic Packet Assignment ~ 50 % improvement in performance 2. Mobile sends measurements of path losses for nearby bases to serving base 4. Bases assign channels to all packets/mobiles 5. Bases forward channel assignment 1. Mobile locks toinfo to nearby bases the STRONGEST base 3. Serving base forwardsmeasurementsto nearby bases 12. IPv4 IPv6 Address32 bit number128bit numberSize AddressDotted Decimal Hexadecimal Notation FormatNotation3FFE:F200:0234:AB00: of 2^32 2^128AddressesRemarks AddressLarger address space, Multicasting, Better ExhaustionMobility 13. IF band pass filtering equivalent, demodulation,amplification, detectors, noise reduction, noiseblanking, etc. are all done in software The phone would be automatically switch fromoperating on a CDMA frequency to a TDMAfrequency whenever it is requaired through theuse of soft ware. Hence hardware complications , use of complexcircuitry is removed..