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EEE 264-1:Evolution of Modern Communications Systems
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Growth of cellular telephone subscribers throughout the world
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Second generation (2G) cellular methods 400 300 200 100 0 1st Generation Analog Subscribers Using Technology (millions) GSMIS-136 & PDC IS-95 CDMA
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Second generation (2G) systems Many of today’s cellular systems still use second generation (2G) technologies While first generation systems relied on FDMA/FDD and only FM, second generation standards use digital modulation and TDMA/FDD or CDMA/FDD
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Most popular 2G systems GSM (Global System Mobile) IS-136 (NADC) (North American Digital Cellular) PDC (Pacific Digital Cellular) IS-95 CDMA
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Key Specifications of leading 2G technologies-Frequency bands cdmaOne, IS-95, ANSI J-STD-008 GSM, DCS-1900, ANSI J-STD-007 NADC, IS-54/IS- 136, ANSI J-STD- 011, PDC Uplink Frequencies 824-849 MHz (US Cellular) 1850-1910 MHz (US PCS) 890-915 MHz (Europe) 1850-1910 MHz (US PCS) 800 MHz, 1500 MHz (Japan) 1850-1910 MHz (US PCS) Downlink Frequencies 869-894 MHz (US Cellular) 1930-1990 MHz (US PCS) 935-960 MHz (Europe) 1930-1990 MHz (US PCS) 869-894 MHz, (US Cellular) 1930-1990 MHz (US PCS) 800 MHz, 1500 MHz (Japan)
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Key specifications of leading 2G technologies-Modulation cdmaOne, IS-95, ANSI J-STD-008 GSM, DCS-1900, ANSI J-STD-007 NADC, IS-54/IS- 136, ANSI J-STD- 011, PDC DuplexingFDDFDDFDD Multiple Access Technology CDMATDMATDMA Modulation BPSK with Quadrature Spreading GMSK with BT = 0.3 /4 DQPSK Carrier Separation 1.25 MHz 200 kHz 30 kHz (IS-136) (25 kHz for PDC)
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Key specifications of leading 2G technologies-Data rate cdmaOne, IS-95, ANSI J-STD-008 GSM, DCS-1900, ANSI J-STD-007 NADC, IS-54/IS- 136, ANSI J-STD- 011, PDC Channel Data Rate 1.2288 Mchips/see 270.833 kbps 48.6 kbps (IS- 136) (42kbps for PDC) Voice Channels per Carrier 6488 Speech coding Code Excited Linear Prediction (CELP) @ 13kbps, Enhanced Variable Rate Codec (EVRC) @ 8 kbps Residual Pulse Excited Long Tern Prediction (RPE-LTP) @ 13 kbps Vector Sun Excited Linear Predictive Coder (VSELP) @ 7.95 kbps
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Evolution of 2.5G Mobile radio networks Evolution from 2G 2.5G required to support increased data rates for modern Internet applications. 2.5G are new data-centric standard that can be overlaid on existing 2G technologies 2.5G supports new web browsing format language called WAP (Wireless applications Protocol)
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WAP enables standard web pages to be viewed in a compressed format suitable for small portable hand-held wireless devices. First developed in Japan by NTT-DoCoMo I-mode for PDC network - supports games, color graphics and interactive web pages using 9.6 kbps 25 million Japanese subscribers in 2001 2.5G Mobile radio networks
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2.5G TDMA standards HSCSD (High Speed Circuit Switched Data) for 2.5G GSM o Allows a single mobile user to use more than one specific time slot as in GSM TDMA o Increases application rate from 9,600 bps (2G GSM) to 14,400 bps (2.5G GSM) o Ideal for streaming internet access or real-time interactive web sessions. o Can be implemented by a software change at existing GSM base stations.
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2.5G TDMA standards GPRS (General Packet Radio Service) 2.5G TDMA standards GPRS (General Packet Radio Service) GPRS for 2.5G GSM and IS-136 o Packet based data network suited for non-real time internet usage o E-mail retrieving, faxes and where download upload o GPRS can support more users that HSCSD, but in a bursty manner
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2.5G TDMA standards EDGE (Enhanced Data GSM Environment) More advanced upgrade to GSM standard Regains additional hardware/software at existing base stations New digital modulation format (8- PSK/octal PSK) Raw data rate of 547.2 kbps possible with 8 GSM slots of a GSM channel are allowed for each user
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2.5G CDMA standards IS-95B for 2.5G CDMA Medium data rate (MDR) service with throughput of 115.2 kbps per user (8 x 14.4 kbps) Advanced handoff procedures allows mobiles to search different radio channels independently
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Third generation (3G) wireless goals Unparalleled wireless access Multi Mbps Internet access using VoIP (Voice Over Internet Protocol), voice activated calls Ability to receive live music, interactive web sessions, voice and data access with multiple features at the same time, at all times
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ITU (International Telecommunications Union) proposed A global frequency band in 2000 MHz range Single wireless communications standard for all countries in the world IMT-2000. Single wireless communications standard for all countries in the world IMT-2000. World community remains split between GSM/IS-136/PDC and CDMA World community remains split between GSM/IS-136/PDC and CDMA Third generation (3G) wireless methods
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2G - 3G evolution IS-95 GSM IS-136 & PDC IS-95B HSCSD GPRS HSCSD cdma2000-1xRTT Cdma2000-1xEV, DV, DO cdma2000-3xRTT W-CDMA EDGE TD-SCDMA 3GPP2 3GPP
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3G CDMA standard-W-CDMA 3G W-CDMA (UMTS - Universal Mobile Telecommunications System) Packet based wireless service which enables computers, entertainment devices, telephones to connect to internet anytime, anywhere Packet data rates up to 2.048 Mbps per stationary user Broadcasting, VHE (Virtual Home Entertainment) m- commerce (mobile commerce), games, interactive video, virtual private technology - all possible from small portable wireless device
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3G CDMA standards-cdma2000 3G cdma2000 or cmda2000 IX New high data rate internet access with backward compatibility to IS-95 and IS-95B systems - 1.25 MHz bandwidth Instantaneous data rate of 307 kbps in packet mode Both FDD (mobile radio) and TDD (in-building cordless) applications
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3G TDMA standards 3G TD-SCDMA (Time Division Synchronous Code Division Multiple Access) Developed by CATT (Chinese Academy of Telecommunications Technology) and Siemens. Adopted by ITU as one of 3G options in 1999 Existing GSM - 3G evolution through additions of high data rate equipment in each GSM station - 1.6 MHz bandwidth Utilizes smart antennas, spatial filtering and joint detection technologies
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Broadband wireless services Wireless Local Loop (WLL) Demand for broadband internet and computer access from businesses and homes Fixed wireless equipment have advantages such as fixed path between T-R Microwave or millimeter radio frequencies used >28GHz - wave length is very small - small high gain antennas. Especially useful in developing nations with less telecommunications setup
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Emerging applications and markets for broadband services Wireless Mid-market business outside the urban core Wireless Copper/xDSL Small business Copper/xDSL Central Office Fiber Large business in high-density urban areas CableResidencesCableResidences Backbone Network Central Office DAX ISP OC-3
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Broadband wireless spectrum world- wide
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Broadband wireless services Wireless Local Area Networks (WLANS) UNII (Unlicensed National Information Infrastructure) hand allocated by FCC for low power spread spectrum 5.150 - 5.35 GHz, 5.725 - 5.825 GHz (1997),902- 928 MHz, 2400-2483.5MHz, 5.725-5.825 MHz (1980s end) IEEE 802.11 (1997) standard and IEEE 802.11b approved to provide guidelines for WLAN manufacturers
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IEEE 802.11 Wireless LAN 1 Mbps DBPSK 2 Mbps DQPSK 2 Mbps 4GFSK 1 Mbps 2GFSK DSSSDSSS FHSSFHSS Diffuse IR 850 TO 950 NM 2.4 GHZ IEEE 802.11b Extension 11 Mbps DQPSK--CCK BPSK--PBCC 5.5 Mbps DQPSK--CCK BPSK--PBCC IEEE 802.11
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High Performance Radio Local Area Network (HIPERLAN) Europe standard to provide similar capability to IEEE 802.11 5.2 GHz and 17.1Ghz frequency lands Up to 20 Mbps data rate at 50m range and vehicle speeds of 35km/hr Advanced standards include Europe’s ETSI- BRAN (Broadband Radio Access Network) and HIPERLAN/2.
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Personal Area Networks (PANs) Ability to replace cables between devices with wireless short range connection Bluetooth operates in 2.4GHz ISM band (2900- 2483.5MHz) with 1 MHz channel bandwidth Uses FH-SS TDD scheme with 1600 hps 1Mbps symbol rate using GFSK modulation IEEE 802.15 standards committee is our international forum for developing Bluetooth and other PANS
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PAN Bluetooth standard PAN Bluetooth standard
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Fourth Generation (4G) Systems
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Principle of high speed OFDM Principle of high speed OFDM Higher data rate implies narrower data pulse width: For example 200 Mbps => 5 ns pulse Narrow pulses are subject to instability and interference Solution is to replace single channel carrier with several subcarriers Subcarriers have lower date rate with more stable pulse widths
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Fifth generation (5G) systems Fifth generation (5G) systems
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