Capture Sensing Simultaneous Access Exploiting the Capture Effect for Greater Spatial Reuse and Higher Bandwidth

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Capture Sensing Simultaneous AccessExploiting
the Capture Effect for Greater Spatial Reuse and
Higher Bandwidth
Xiaofan Jiang
EECS DepartmentUniversity of California, Berkeley
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Capture Effect
CSMA

• What happens when 2 packets collide?
• What information can we collect during a
  collision?
• How good (bad) is CSMA?

At R1
Nothing!
At R2
A
R1
T1
R1
T2
C
R2
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Capture Sensing Simultaneous Access

• According to my table
• T2 lt T1 -gt OK to send
• T3 gt T1 -gt NOT OK to send

• Build a table of stronger-weaker neighbors
• Propagate tables?
• Packet format
• Eliminating hidden-terminal

R1
T1
T2
T3
R2
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Status and Plan

• Future Plans (winter break and spring semester)
• Choose best one
• Implementation
• Deployment
• Assessment
• Dissemination

• Design space in spatial reuse (spectrum)
• CSMA vs CSSA vs No Carrier Sensing at all
• Protocol design
• Apriori vs adaptive
• 2nd tier tables
• TTS (CSMA-EX)
• RTS/CTS
• Bandwidth gain / (loss) under
• Point-point
• Broadcast
• Low-power listening
• Network layer choice
• Simulation (matlab)

Questions or suggestions?