Selected Emerging Topics

1
Selected Emerging Topics

• Smart Antennas
• Software Radios
• The Ideal Wireless Future?

2
Power Asymmetry

• Macrocell base stations have higher downlink
  power than mobile devices have uplink power
• Why?
• Is this true for microcell approaches?

3
Smart Antennas

• Smart antennas are really antenna systems
• Arrays of multiple antennas
• Digital signal processors
• Sophisticated algorithms
• Benefits
• Enhanced range
• More capacity (space-division multiplexing)
• Better multipath performance
• Reduced cost (with lower power needed, etc.)

4
Antennas from dumb to smart

• Omnidirectional
• Directional and/or sectorized
• Diversity (switched or combining)
• Switched beam (finite of fixed patterns)
• Adaptive array (infinite of patterns)
• Spatial division multiple access (SDMA)
  (real-time tracking of individual users)

5
Software Radios

• Changing the mix of hardware (less) and software
  (more) to provide multi-mode, multi-band,
  multi-functional, dynamically configurable radios

Graph from Deborah Shapley, The Universal Cell
Phone, Technology Review, April 2001, pp. 58-62.
6
Benefits

• Fewer, standardized architectures
• Better interoperability, roaming, etc.
• Lower cost products services
• Over-the-air upgradeability
• Advanced networking (meshing, etc.)

7
Tiers

• Tier 0 Hardware Radio (turn the knobs . . .)
• Tier 1 Software Controlled Radio (a typical
  modern radio, to some extent)
• Tier 2 Software Defined Radio (software-configura
  ble modulation, security, etc.)
• Tier 3 Ideal Software Radio (everything
  programmable right up to the antenna)
• Tier 4 Ultimate Software Radio (for comparison .
  . . Includes GPS, smartcards, other functions)

8
Your Ideal Wireless Future?