EMERGING TECHNOLOGIES IN WIRELESS

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EMERGING TECHNOLOGIES IN WIRELESS

• Jack H. Winters

Chief Scientist, Motia jwinters_at_motia.com
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Outline

• Technologies
• Service Limitations
• Multiplatform Systems
• Conclusions

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SUMMARY

• New wireless technologies
• Physical Layer
• WiFi (IEEE802.11a/b/g, n)
• WiMax
• UWB
• Bluetooth
• EvDO
• RFID
• Zigbee
• Applications VoIP
• Interconnection Mesh networks, WLAN-WWAN
  convergence

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Wireless System Enhancements
Peak Data Rate
High performance/price
100 Mbps
WiMAX
10 Mbps
Enhanced
1 Mbps
BlueTooth 2.4GHz
100 kbps
High ubiquity and mobility
Range
10 feet
100 feet
1 mile
10 miles
60 mph
2 mph
10 mph
30 mph
Mobile Speed
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Service Limitations of Wireless

• Quality of service for each user is not
  consistent
• Too far away from the access point/base
  station/etc.
• Behind a wall
• In a dead spot
• Working off a battery, as with a laptop
• Suffering from low bandwidth due to
  range/interference
• VoIP applications cannot tolerate fading or brief
  outages

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Solutions

• Change among platforms to maximize performance
• Further enhance performance of each system
  through
• Smart Antennas
• Being implemented today (e.g., MIMO)
• Ad Hoc Networks
• Interconnections of multiple clients
• Combination of Smart Antennas with Ad Hoc
  Networks (can give greater gains than the sum of
  the two)

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Multiplatform Devices

• Multimode devices adapt to maximize performance,
  minimize cost and/or power
• Laptops with WiFi, WiMax, and Cellular (GSM,
  EDGE, WCDMA, EvDO)
• Handsets with WiFi and Cellular
• VoIP
• Single spatial stream 802.11n under discussion

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Smart Antennas

• A smart antenna is a multi-element antenna where
  the signals received at each antenna element are
  intelligently combined to improve the performance
  of the wireless system. The reverse is performed
  on transmit.
• Smart antennas can
• Increase signal range
• Suppress interfering signals
• Combat signal fading
• Increase the capacity of wireless systems

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Smart Antennas

• Antenna gain of M
• Suppression of M-1 interferers
• M-fold multipath diversity gain (with multipath)
• With M Tx antennas (MIMO), M-fold data rate
  increase in same channel with same total
  transmit power (with multipath)

• Simple beam tracking
• limited interference suppression
• limited diversity gain

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Multiple-Input Multiple-Output (MIMO) Radio

• With M transmit and M receive antennas, can
  provide M independent channels, to increase data
  rate M-fold with no increase in total transmit
  power (with sufficient multipath) only an
  increase in DSP
• Indoors up to 150-fold increase in theory
• Outdoors 8-12-fold increase typical
• Measurements (e.g., ATT) show 4x data rate
  capacity increase in all mobile indoor/outdoor
  environments (4 TX and 4 RX antennas)
• 216 Mbps 802.11a (4X 54 Mbps)
• 1.5 Mbps EDGE
• 19 Mbps WCDMA

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Gains for with Smart Antennas

• WiFi/WiMax (4 antennas)
• 13 dB (one side), 18 dB (both sides) gt 2-4
  times range, throughput
• Cellular (4 antennas)
• gt6 dB gain on receive 2X range, throughput

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Multiplatform Smart Antenna Systems

• WiFi, WiMax, Cellular
• Use one array (4 antennas) for all platforms
• Digital interface from array (RFIC) to BB/MACs
• Cable from laptop display back or handset case
• Standard in development
• JC-61 (initially for 802.11n) single merged
  proposal at next meeting in July

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JEDEC Standard JC-61 Block Diagram
Baseband I/Q
RX_CLK
802.11n, WiMax, Cellular RFIC
802.11n , WiMax, Cellular Baseband/MAC Processor
Host Interface
RX_DATA
JESD96 Interface A/D, D/A, Control Logic
TX_DATA
TX_CLK
Control Signals
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Mobile Ad Hoc/Mesh Networks

• Network of wireless hosts which may be mobile
• No pre-existing infrastructure
• Multiple hops for routing
• Neighbors and routing changes with time
  (mobility, environment)

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Impact of Smart Antennas in Ad Hoc Networks

• Since smart antennas are a physical layer
  technique, existing approaches for MAC/routing in
  ad hoc networks will work with smart antennas,
  but these MAC/routing techniques need to be
  modified to achieve the full benefit
• Need to use hooks
• Hooks for frequency assignment techniques to
  include reusing a frequency (up to M-1 times).
• Hooks for the inclusion of multiple radio
  capability to include multiple radios in the same
  channel.
• This can be done in such a way to actually reduce
  the complexity of the MAC/routing algorithms.

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Conclusions

• Wide variety of wireless technologies, each with
  different capabilities
• Multiplatform devices will allow for adaptation
  among platforms to maximize performance
• Smart antennas and ad hoc network techniques with
  these various platforms will further enhance and
  overcome most of current wireless limitations
• Adaptation of platforms, signal processing, and
  interconnection techniques may look confusing,
  but if done correctly will lead to high
  performance, ubiquitous wireless systems, without
  requiring user sophistication