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

2 Wireless Subscriber Growth Subscribers in Millions Internet Source ITU, Merrill Lynch

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

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

5 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 Broadband Vision

6 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 Broadband Wireless - Metrics

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

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

9 Channel Impairments C I FadingCo-Channel Intf.

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

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

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

13 What is MIMO Wireless ? TxTx RxRx Diversity: Increased Diversity Spatial Multiplexing: Increased rate TxTx RxRx

14 SISO Tx Rx MIMO Tx R Rx MIMO Leverage in Diversity Reduces Fading Dramatically

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

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

17 Spatial Multiplexing Increases Speed SINR BPS/Hz 10 dB20 dB x4 1x1

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

19 MIMO Advantage Coverage Capacity Number of Antennas N Coverage Capacity 2345 High Power Networks Low Power Networks

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

21 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 Airburst TM - The MIMO Pioneer

22 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 Summary