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Southern Methodist University EETS 8315 / TC752-N Advanced Topics in Wireless Communications Spring2005 http://engr.smu.

Southern Methodist University EETS 8315 / TC752-N Advanced Topics in Wireless Communications Spring2005 http://engr.smu.edu/eets/8315 Lecture 11: WIMAX Instructor: Dr. Hossam H’mimy, Ericsson Inc. hossam.hmimy@engr.smu.edu (972) 583-0155. Announcement. WiMAX forum.

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Southern Methodist University EETS 8315 / TC752-N Advanced Topics in Wireless Communications Spring2005 http://engr.smu.

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  1. Southern Methodist University EETS 8315 / TC752-N Advanced Topics in Wireless Communications Spring2005 http://engr.smu.edu/eets/8315 Lecture 11: WIMAX Instructor: Dr. Hossam H’mimy, Ericsson Inc. hossam.hmimy@engr.smu.edu (972) 583-0155

  2. Announcement

  3. WiMAX forum • The WiMAX mission is to make the 802.16 interoperable. Just like WiFi did for 802.11. • No WiMAX compliant products today, foreseen during 2005. The first WiMAX products will be based on 802.16d. • Intel is the most powerful player in WiMAX forum • Architecture specification work initiated in a new sub-group

  4. WiMAX forum .. • FDD as well as TDD • Licensed as well as unlicensed spectrum • Licensed needed to guarantee wide area service • No single global spectrum assigned, possibilites: • 5.8 GHz • 3.5 GHz • 2.5 GHz, (IMT-2000 more likely in this band) • 2.3 GHz

  5. 50% Interest in Portable Broadband Services (n = 3,370 U.S. Broadband Households) 40% 37% 30% 20% 20% 13% 9% 8% 10% 7% 5% 0% Definitely 2 3 Neutral 5 6 Definitely would would not Source: Unlicensed Broadband Wireless: Solutions and Applications © 2004 Parks Associates 38% of US households are interested in a Portable Broadband Service... 38%

  6. Broadband Technologies DSL/Fiber 802.16 3G Evolved • Fixed • Triple Play (Video) • IP Telephony • Internet • Fixed • Nomadic • IP Telephony • Internet • Full mobility • Full roaming • All over the world • POMS • IP Telephony • Internet

  7. Similar to .16a Errata Jul 2004 802.16d WiMAX Standards Roadmap WiMAX = interoperable subset of this (< 6 GHz) Some Mobility 2005 ? 802.16e 2 – 11 GHz NLOS Jan 2003 802.16a 802.16 10 – 66 GHz LOS Sep 2000 NOTE: IEEE 802.16 specifies only layer 1 & 2

  8. 802.16 for Broadband Wireless Access • DSL complement • DSL is not available, e.g. poor copper infrastructure • DSL OPEX too high, e.g. low population density • Central Office is too far away for DSL • CLEC bypassing incumbent • DSL competition • If DSL is available, hard to beat 802.16

  9. WiMAX segments, High level pros and cons • Backhaul, Fixed, point to point – LOS • High Bitrate • Low Interference • Clear Signal – No multipath fading • Relatively Low Cost • DSL, Fixed up to portable, Point to point, point to multipoint – NLOS • Relative high bitrate, but lower • One cell • Still relative cheap • Low to moderate interference-> Static radio environment • WAN and Mobile environment • Significantly lower bitrate • High interference. More multipath fading and dopplershift effects

  10. IEEE 802.16 Standard WiMAX

  11. Feature Benefit 256 point FFT OFDM waveform Built in support for addressing multipath in outdoor LOS and NLOS environments Adaptive Modulation and variable error correction encoding per RF burst Ensures a robust RF link while maximizing the number of bits/second for each subscriber unit TDD and FDD duplexing support Address varying worldwide regulations where one or both may be allowed Flexible Channel sizes (such as 3.5 MHz, 5 MHz, 10 MHz, and so on) Provides the flexibility necessary to operate in many different frequency bands with varying channel requirements around the world Designed to support smart antenna systems Smart antennas are fast becoming more affordable, and as these costs come down their ability to suppress interference and increase system gain will become important to BWA deployments WIMAX Features

  12. WiMAX Modulation and Coding The further the subscriber is from the base station, the greater the likelihood of a lower form of modulation and a higher amount of coding and thus a lower bit-rate

  13. Fit with Other Technologies • Whether 802.16a will complement or clash with certain other technologies remains to be seen. For a while, at least, it will certainly be complementary to 802.11a, enabling Wi-Fi users to dramatically extend their distance from wired networks.

  14. Modulation / Code rate QPSK 1/2 QPSK 3/4 16 QAM 1/2 16 QAM 3/4 64 QAM 2/3 64 QAM 3/4 1,75 MHz 1.45 2.18 4.36 5.82 6.55 2.91 3,5 MHz 5.82 8.73 13.09 4.36 11.64 2.91 7,0MHz 5.82 11.64 17.45 23.27 26.18 8.73 14,0 MHz 11.64 17.45 23.27 34.91 46.55 52.36 20,0 MHz 24.40 32.53 48.79 65.05 73.19 16.26 Theoretical WiMAX Raw Bandwidth (Mbit/s)* *OFDM 256 FFT. Includes MAC and preamble overhead

  15. Theoretical Coverage (Km)* Type of Area Rooftop Antenna Window/Fixed Antenna Indoor/Portable Antenna <20 Km using NLOS** Rural <8 Km <4 Km Suburban <4 Km <2 Km N/A Urban N/A <2 Km <1 Km *Approximate distances only, depends heavily on geographical area **<50 Km is the theoretical maximum for LOS. Assumption is a NLOS base station and a rooftop antenna for better reception and maximum uplink power

  16. Portability (Mobility) in 802.16e • New network reference model • New BS-BS interface (IB) and BS-server interface (A) defined • Authentication and service authorization (ASA) servers provide authorization, authentication, billing, management, provisioning and other services. EAP is defined for SIM cards, and other means of Authentication.

  17. Enhancements for mobility in 802.16e – Layer 2 • Handover (HO) process defined in MAC including • cell reselection • target BS scanning • network re-entry • HO decision and initiation and HO cancellation. • MAC messages for each of the handover functions defined. • Broadcast paging message defined. • Neighbor topology advertisement messages defined. • Option of using mobile IP provided. To be defined in May-05. WG active. • Full QoS supported. All four GSM/WCDMA classes.

  18. Enhancements for mobility in 802.16e – Layer 1 • Sleep mode, paging enabled. • Fast time alignment (ranging) mechanism • Flexible FFT sizes depending on channel bandwidth to ensure OFDM symbol duration is compatible with mobility requirements • Soft handover, i.e., transmit/receive from multiple BS • Fast channel feedback • Fast BSS handover involving maintenance of sync to multiple BS’ while transmitting/receiving from anchor BS • New MIMO, STC modes • MIMO soft-handoff based macro-diversity transmission • Space-time codes for 3 antenna configurations. Fixed version has 2 and 4 antenna modes.

  19. some differences • MAC • 802.11: Contention-based MAC (CSMA/CA), basically wireless Ethernet. • 802.16: Dynamic TDMA-based MAC with on-demand bandwidth allocation. • OFDM • 802.11a: 64 FTTs • 802.16d: 256 FFTs • Spectrum • 802.11: limited channels in Un-license spectrum • 802.16: multiple channels in licensed & Un-license spectrum

  20. Comparison 802.11 and 802.16 Technology Range Coverage Data rate Scalability QOS 802.11 < 300 feet Optimized for indoor short range 2.7 bps/Hz peak. <= 54Mbps in 20MHz 1-10 CPE CSMA/CA No QOS 802.16 < 30 Mile ( typical 3~4) Outdoor LOS & NLOS 5bps/Hz peak, <100Mbps in 20 MHz 1- hundreds CPE TDMA On demand BW  voice Video, data

  21. Broadband Wireless systems WiMAX • Wireless Broadband • Laptop centric • Fixed  Portability • Line-of-Sight & Non Line-of-Sight • IEEE Layer 1 & 2 standard • Data optimized • Optimized for Fixed High data rate • Evolution towards mobility Drivers: • Data optimized network (simple) • DSL complement 3G Evolved • Mobile Broadband • Phone & laptop • Full mobility • Non line-of-sight • 3GPP and 3GPP2 standard • Voice/data optimized • Optimized for Mobility • Evolution towards Higher Data Drivers: • Mobile Broadband for incremental investment • National & global roaming networks

  22. Peak Bit Rates Comparison Channel Bandwidth FDD/TDD Peak bit-rate DL Peak Bit-rate UL Standards compliant GSM/GPRS 3GPP FDD 160 kbps 160 kbps 200KHz EDGE FDD 480 kbps 480 kbps 3GPP WCDMA FDD/TDD 2 Mbps 2 Mbps 3GPP 5Mhz HSDPA FDD 14.4 Mbps 7.68 Mbps 3GPP CDMA2000 1x FDD 640 kbps 450 kbps 3GPP2 1xEV-DO 1.25 MHz FDD 3.1 Mbps 1.8 Mbps 3GPP2 1xEV-DV FDD 3.1 Mbps 1.8 Mbps 3GPP2 IEEE 802.16d -20 MHz FDD/TDD - 75 Mbps - 75 Mbps IEEE _ Flarion FDD 1.25 MHz 3.2 Mbps 900 kbps

  23. Propagation difference between 1900MHz and other frequencies ( H-O Model) • 2100MHz ( Delta = 1.1dB) • 2400MHz ( Delta = 2.6dB) • 3500MHz ( Delta = 7dB) • 850 MHz ( Delta = -12 dB)

  24. WiMax IEEE802.16a, e • Understanding WiMax • http://www.intel.com/netcomms/technologies/downloads/305150.pdf • http://www.intel.com/netcomms/technologies/wimax/304471.pdf • http://www.wimaxforum.org/certification/White_Papers/ • OFDM • http://www.intel.com/netcomms/technologies/wimax/303787.pdf • Adaptive modulation • http://www.intel.com/netcomms/technologies/wimax/303788.pdf

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