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Broadband Wireless The MIMO Advantage

Broadband Wireless The MIMO Advantage. A. Paulraj Stanford University & Iospan Wireless. Wireless Internet and Mobile Computing SNRC/Accel Symposium Stanford University May 16, 2001. Subscriber Growth. 2000. Wireless. Subscribers in Millions. 1000. Internet. 0. 1985. 2010. 2005.

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Broadband Wireless The MIMO Advantage

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  1. Broadband Wireless The MIMO Advantage A. Paulraj Stanford University & Iospan Wireless Wireless Internet and Mobile Computing SNRC/Accel Symposium Stanford University May 16, 2001

  2. Subscriber Growth 2000 Wireless Subscribers in Millions 1000 Internet 0 1985 2010 2005 1995 Source ITU, Merrill Lynch

  3. Price / Performance Growth Price / Performance in 5 Years P/P Growth in 5 years Moore’s Law 2

  4. Limits to Growth ? Fundamental / Device / Material Limits Today Radio 1 ~ 3 Ghz Source IEEE Proc.

  5. Broadband Vision • Anytime and anywhere connectivity to high quality and high speed multimedia services to support operations at office and home, and to access entertainment, learning, health care, financial, .. services • Single device, uniform, personalized, secure, seamless and portable service

  6. Broadband Wireless - Metrics Traffic: Asynchronous/ Isochronous, average loading (6-10%), low or no error tolerance • User Metric: Time (delay) to down load large files, probability of delay exceeding x2 target • Carrier metrics • Capacity: Number of users per cell (with target download rates) for x MHz spectrum allocation or (BPS* / Hz )/ Cell • Coverage Metric: (BPS* /Hz) x Cell Area

  7. Principal Challenges in Wireless High Quality Seamless High Speed Low Power

  8. Impairments / Constraints Application Constraints TCP Behavior Mixed QoS Variable channel Bursty Traffic Path Loss Fading Co-channel Intf

  9. Channel Impairments 10 5 0 -5 -10 -15 Fading Co-Channel Intf. C I

  10. Challenge of Speed • Deploy more bandwidth, but • Increases spectrum $ • Reduces cell size, increases infrastructure $ • Forces cell splitting, increases infrastructure $ $ ~ Speed 1.5 Speed

  11. Challenge of Quality • Add margin for signal fading ( into noise and co-channel interference) • Reduces cell size, increases infrastructure $ • Reduces reuse (= cell capacity), increases infrastructure $ $ ~ Quality 2 Link Quality (1 - Outage)

  12. Infrastructure Cost Technology ? $ Speed and Quality increases $$ Load /Square Mile

  13. Rx Tx What is MIMO Wireless ? Diversity: Increased Diversity Rx Tx Spatial Multiplexing: Increased rate

  14. Tx Tx R Rx MIMO Leverage in Diversity SISO 1 SISO 1 1 1 MIMO 2 MIMO 2 2 2 5 5 5 5 Rx Reduces Fading Dramatically

  15. Diversity Enables Better Coverage SISO Signal/Noise MIMO Noise Floor Range

  16. Signal / Intf. Ratio Diversity Enables Better Reuse SISO MIMO Interference Aggressive Weak Reuse

  17. Spatial Multiplexing Increases Speed 30 BPS/Hz 4x4 1x1 0 10 dB 20 dB SINR

  18. Past and Present Supernovae ? SNR Set Point 8 dB 4x4 *Over TDMA inMul Access Networks

  19. MIMO Advantage High Power Networks Capacity Coverage Capacity Coverage Low Power Networks 2 3 4 5 Number of Antennas N

  20. Broadband Access Standards 4 Macro Airburst (MIMO OFDM) 802.16 4G ? Micro WCDMA Cell Size (MIMO OFDM) MIMO Hyperlan MIMO Hyperaccess Loc 802.11a 0.2 2 20 200 Data Rate MBPS

  21. Airburst TM - The MIMO Pioneer • Developed by Iospan Wireless for fixed, large cell, broadband access • PHY based on MIMO-OFDM • MAC with packet reservation and advanced scheduling • Very high coverage and spectrum efficiency • IPR Licensed from Stanford University

  22. Summary • High speed and high quality broadband wireless is an emerging opportunity • MIMO technology now widely recognized as a fundamental leverage for improving price/performance • Iospan Wireless has developed core air interface technology for large cell fixed access applications

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