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Fourth Generation (4G) Wireless Systems

Jeremy Mayeres. Fourth Generation (4G) Wireless Systems. Topics. Cellphones 1G 2G 3G 4G/IMT-Advanced LTE WiMAX 4G Today Future of 4G Social/Ethical considerations. Cellphones. Radio telephony existed long before cell phones became popular

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Fourth Generation (4G) Wireless Systems

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  1. Jeremy Mayeres Fourth Generation (4G)Wireless Systems

  2. Topics • Cellphones • 1G • 2G • 3G • 4G/IMT-Advanced • LTE • WiMAX • 4G Today • Future of 4G • Social/Ethical considerations

  3. Cellphones • Radio telephony existed long before cell phones became popular • 1947 – Ring and Young working at Bell Labs develop idea of using “hexagonal cells” • 1973 – First cell phone call – Martin Cooper of Motorola

  4. 1G • Analog system • Advanced Mobile Phone System (AMPS) in the US • Frequency Division Multiple Access (FDMA) – Different frequency for each conversation • Issues • Listen in with a scanner • Spoofing

  5. 2G • Digital • Time Division Multiple Access (TDMA) • GSM (Global System for Mobile Communications) • D-AMPS (Digital AMPS, superseded by GSM) • iDEN (Integrated Digital Enchanced Network) • Code Division Multiple Access (CDMA) • IS-95/cdmaOne

  6. 2.5G and 2.75G • 2G with always-on data • General Packet Radio Service (GPRS) • 2.5G for GSM • Maxed at about 115 Kbps • 1xRTT • 2.5G for CDMA • Maxed at about 153 Kbps • Enhanced Data rates for GSM Evolution (EDGE) • 2.75G • Speeds up to 1 Mbps

  7. 3G • International Telecommunications Union (ITU) International Mobile Telecommunications-2000 (IMT-2000) • Requires minimum speed of 200 Kbps • 3rd Generation Partnership Project (3GPP) – 3G Upgrade for GSM • 3GPP2 – 3G Upgrade for CDMA

  8. 3G - UMTS • Universal Mobile Telecommunications System (UMTS) by 3GPP • Uses W-CDMA (Wideband CDMA) • Handles voice and data • Data speeds about 384 Kbps (R99) to 2 Mbps • More on this later…

  9. 3G – CDMA2000 • 3GPP2 Group • Backwards compatible with cdmaOne • 1xEV-DO (or just EV-DO) Evolution-Data Optimized • Rev. 0: Max speed of about 2.4 Mbps download, 153 Kbps upload • Rev. A: Max speed of about 3.1 Mbps download, 1.8 Mbps upload

  10. 4G • IMT-Advanced by ITU • Global use • High-quality services • User-friendly • High speeds: 1 Gbps stationary, 100 Mbps mobile • Spectrum efficiency • IP packet-switched network • LTE (Long Term Evolution) • IEEE 802.16 “WiMAX” (Worldwide Interoperability for Microwave Access)

  11. OFDMA • Orthogonal Frequency-Division Multiple Access • Split channel into sub-carriers • User is assigned multiple sub-carriers: • Closer to base gets more sub-carriers (more bandwidth) • Further away, get less sub-carriers, but use more power • OFDM also used in 802.11a/g/n

  12. MIMO • Multiple In – Multiple Out • Diversity • Avoid fading due to multipath interference, shadows • Spatial Multiplexing • Use multiple channels to get higher data rates

  13. LTE • 3GPP • Verizon, MetroPCS, AT&T, and Sprint • Upgrades UMTS • Uses MIMO, OFDMA • IP-based • 700 MHz Band • Speed: 100 Mbps download, 50 Mbps upload

  14. WiMAX • IEEE 802.16e-2005 • Scalable OFDMA (SOFDMA) – Scales the Fast Fourier Transform (FFT) size for different bandwidths • Primarily uses 2.5 GHz band in the US (Clear/Sprint) • Use as backhaul • Closer to WiFi • Speeds up to 40 Mbps

  15. Not technically 4G • WiMAX and LTE in today’s networks do not meet the IMT-Advanced criteria • Every major wireless 4G network fails to meet IMT-Advanced criteria • ITU accepts WiMAX and LTE as “Pre-4G” • Can also be called 3.9G • Networks still calling it 4G

  16. HSDPA, HSUPA, HSPA+ • “High Speed Packet Access,” part of 3GPP • D – Downlink, U – Uplink • HSDPA – 7.2 Mbps, HSUPA – 1.9 Mbps • HSPA+ (Evolved HSPA) • 84 Mbps download, 22 Mbps upload • MIMO • All-IP Option • Still part of 3G, UMTS • T-Mobile/AT&T calling it 4G

  17. So what satisfies IMT-Advanced? • LTE-Advanced (3GPP) and WirelessMAN-Advanced (IEEE 802.16m) • Not yet available • Will satisfy the 1 Gbps download speed requirement • What will this be called?

  18. Social/Ethical considerations • Is 4G just a marketing term? • Bringing broadband to everyone • Wireless capacity and Net Neutrality

  19. Sources • IMT-Advanced - Objective and Challenges by K. Jay Miyahara • An Overview of Next-Generation Mobile WiMAXTechnology by SassanAhmadi • On the Way towards Fourth-Generation Mobile: 3GPP LTE and LTE-Advanced by David Martin-Sacristian, et al. • History of Mobile Telephones (Wikipedia and related articles)

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