Algorithms for Universal Spectrum Sharing

1
Algorithms for Universal Spectrum Sharing

• How dynamic is the channel in a mobile
  environment and how will it effect algorithm
  choice?
• Considered correlation encoding for OFDM?
  Trellis coded OFDM?
• SVD The presence of multiple reflectors can
  reduce the SNR at the receivers. How is the SNR
  going to be improved?
• How do you plan to couple with the implementation
  (ie circuits) people?
• In beam forming, the assumption is made that all
  receive channels are identical. In practice, this
  is not true. Is anything being done regarding
  channel equalization? What about error analysis
  of scheme? Antenna pattern mismatch? Etc.

2
Baseband Analog Radio Frequency Circuits

• What about uplink? Is mobile Tx difficult in low
  power? Mixers - what do you lose with squarewave
  mixer and do people try for more linear methods?
• Considered subharmonic sampling in Matlab
  Simulink or receiver architecture? Does Simulink
  model of flicker noise have correct statistics?
  What is the front end dynamic range? What is
  ACIR? Any channel switching time requirements
  placed on synthesizer?
• High dynamic circuit compatibility or feasibility
  with low voltage supply -
• How does one verify a mixed-signal IC?
• Is there any real motivation to make a
  single-chip radio? (i.e. mixed signal)
• How realistic is a an automated analog design
  flow?

3
PicoRadios

• How does the PicoRadio group plan to cultivate
  analog IP/talent in order to meet its broad
  system goals?
• Multiple access scheme? Say, I want to deploy
  more pico nodes on a different network?
• Do you envision pico-radios evolving into
  massively-parallel, scaleable multiprocessor
  systems? (meaning, is that a possible app?)
• In some places you reference Power proportional
  to distance 4 and some Power proportional to
  distance 2. The savings in power assumes
  distance 4 which is it? Would avoiding
  unreachable places work?

4
PicoRadios

• If you have mobile pico radios inside an area
  covered by Fixed piconodes, will the system
• Support such an application?
• Can the system support a query of a specific
  mobile pico radio?
• From a gateway into the fixed piconode network?
• What is the planned frequency band for the pico
  radio? Full duplex? Half duplex?
• How well does VCC estimate the performance of
  dedicated logic?
• Is simulation an essential part of protocol
  design?

5
Protocols and Two Chip Intercom

• Is simulation an essential part of protocol
  design?

6
Design Flows for Radios SOC

• Is the design flow advancing the state of the
  art? Are there commercial tools that solve the
  problem?
• That state flow translator is amazing. You should
  give that guy a degree or a bonus or something.
• 1 - Interconnection delay management between
  modules for 0.15 to 0.1um. 2 - Placement of
  modules to achieve desired time delays. 3 - How
  are the timing constraints of the architecture
  level mapped to the physical blocks? 4 - Routing
  to achieve timing goals is a challenge. How will
  the proposed design flow achieve timing goals?

7
Ultra Wide Band

• Doesnt UWB hit the region of diminishing returns
  in the Shannon SNR vs. bps/Hz curve?
• How do you cope with mobility - changes in
  multipath and synchronization?