Topology Control and MAC Operation in PicoNOde

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Topology Control and MAC Operation in PicoNOde
BWRC Winter Retreat 2002

• Chunlong Guo
• Berkeley Wireless Research Center
• EECS, University of California at Berkeley

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12 Months Ago

• Node-based Channel Assignment

Wake-up Radio Low Power Synch
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During the Past 12 Months
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Topology in Ad Hoc Networks Basic Problem
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Node-Degree Based Algorithm

• Define D(w) as the degree of node w the number
  of neighbors w has.
• Pro Simple
• Con Convergence, and degraded global connectivity

• Solution Let node have some sense of global
  connectivity

HOW ?
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Design Goals

• Decision based on local information achieve best
  possible global connectivity
• Maintain a topology with small and close to
  uniform node degree
• Simple and efficient
• Minimum assumptions about radio propagation
  model, or hardware availability

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Cone Based Topology Control

• Define Cone Angle
• ? for each neighbor

• Algorithm Goal
• Find the minimum transmission power such that
  the union of the cone zones of neighbors covers
  360o

• Claim
• for ?lt2?/3, algorithm achieves optimal global
  connectivity
• R. Wattenhofer, L. Li, P. Bahl, Y. Wang, 2001

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PicoNode Phase 1 Neighborhood Discovery

• Define eight ?/2 zones

• Algorithm Goal Find minimum Tr power such that
  in any one of these zones, there is at least 1
  neighbor.

• Claim optimal global connectivity, with easy
  implementation and much less computation

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Phase 2 Node Degree Control Pruning
x

• Define
• power cost function p(n1,n2)

• Pruning Rule
• for u,v ? N(w)
• if p(w,u) p(u,v) gt ??p(u,v)
• remove v from N(w)
• here ? ? 1

• Claim
• for ? ? 2, we achieve strictly bounded node
  degree D(w) ? 6

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Phase 3 Interference Reduction Link Coloring

• Nodes use different channels to send packets to
  different neighbors with different transmission
  power
• For any u,v ? N(w), c(w,v) ?c(w,u)
• c(w,v) ? P(w,v), c(w,v) ? P(w,v)

• Number of channels needed
• m maxD(n) 1

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System Simulation Model

• Number of Nodes 100
• Coverage Area 100X100 M2
• Antenna Gains (Gt, Gr) 0dBi
• Threshold path loss 82dBW
• SIR Threshold r0 10dB
• Traffic Application Scenario
• all nodes periodically send UDP traffic to the
  monitor node at the boundary of the network (to
  compare to previous results)

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Phase 1 Topology Performance
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Phase 2 Topology Performance
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Network Life Time Performance
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MAC signaling and Energy Profile
ACK
CTS
Node B
WUP
DATA
Node A
Useful data
Power Profile
Tr
Th
Tw

• E(useful data traffic) E(overhead traffic)
  E(idle)

EPB
L(useful data traffic) 1-p(collision)
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Radio Parameters

• Simplistic Wakeup Channel Interference Model
• Radio Transmission 1mW
• Radio Reception 1.5mW
• Traditional Radio Monitering 1mW
• Wakeup Radio 5uW
• Packet Header/Tailor 7Bytes
• Wakeup Radio Signal Rate 10Kbps
• Equivalent Wakeup Packet Length 8bits
• Wakeup Response Time 1ms
• Traffic Scenario Poisson arrival of packets of
  length 50 Bytes, uniformly to every neighbor.

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Protocol Energy Performance
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Future Research

• Mobility Efficiency
• Improve Channel Model
• Feed Information from Network Layer into MAC
• Protocol Signaling Fine Tuning

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Conclusion

• Link-Zone-Based Transmission Power Control
• Link Coloring for Data Transmission
• Node Coloring for Local Address
• Wake-up Radio Signaling
• Power Reduced

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QA