Attila Trk, Lrnt Vajda, Pter Laborczi,

1
Building Scatternets in High Rate Multi-hop
Dynamic Personal Area Networks

• Attila Török, Lóránt Vajda, Péter Laborczi,
• Zoltán Fülöp, Balázs Barcsik
• Bay Zoltán Foundation for Applied Research
• Ambient Intelligence Group
• Budapest University of Technology and Economics
  
• Dept. of Telecommunications and Media Informatics
  

2
Outline

• Architectural aspects of a WPAN
• The need for topology extension (scatternet
  formation)
• The Normal and Hierarchical Superframes
• Simulation analysis
• Scatternet formation analysis
• Conclusions and future work

3
Architectural aspects

• WPANs (802.15.1/15.3/15.4) will be used in AmI
  systems. They have
• modes for power-saving, hibernating, etc.
• special roles are assigned for network members
  (master-slave relationships)
• a special infrastructure built from nw. elements
  for topology extension (scatternet)

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802.15.3 networks
B
B
Tr
Tr

• 802.15.3 employs a master (PNC) slave
  architecture
• MAC layer time-slotted superframe (SF) structure
• Superframes are constituted from Beacon, CAP,
  CFP
• Beacon broadcasted by PNC, carries control
  information
• PNC allocates the time-slots in CFP Guaranteed
  Time Slots (GTS) or Management Time Slots (MTS)
• The Hierarchical Superframe concept
• minibeacon, mini superframe

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802.15.3 networks

• Communication in Normal Superframe structure
• Communication in Hierarchical Superframe
  structure

B
B
B
B
rt-VBR
rt-VBR
rt-VBR
t
0
t(sched)
t(sched)
B
B
m b
m b
m b
m b
B
rt-VBR
rt-VBR
rt-VBR
t
0
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Piconet and Scatternet

• Piconet Master (Piconet Coordinator PNC) /
  Slave
• Scaternet Interconnection of several piconets
• All nodes in the scatternet can reach each other
• 802.15.3 Parent piconet Child piconet

PICONET
PARENT PICONET
SUPERFRAME
B
PARENT SUPERFRAME
CHILDSUPERFRAME
B
CHILD PICONET
SUPERFRAME
B
PARENT SUPERFRAME
CHILDSUPERFRAME
B
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The use of Hierarchical Superframes in Scatternets

• Communication in Normal Superframe structure
• Communication in Hierarchical Superframe
  structure

8
Scatternet performance analysis

• Simulation tool ns2 with 802.15.3 adhoc
  extension, java tool, CPLEX
• Ideal channel
• Multimedia traffic
• Performance measurement
• Analysis on Hierarchical Superframe Formation
• Analysis on Large Scatternet Formation
• Performance metrics
• JFR (Job Failure Ratio)
• RT (Response Time)
• of generated piconets

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Analysis on Hierarchical Superframe Formation
JFR
RT
The Superframe Size influence on performance
SFSize 6ms CSFSize 1.7ms
JFR
RT
SFSize 6ms CSFSize 2.5ms
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Analysis on Large Scatternet Formation
(Methodology)

• Two level analysis environment
• Analytical approach
• formal description of the optimal scatternet
  formation Integer Linear Programming (ILP)
• two heuristical scatternet formation methods
  (limited and random)
• Practical approach
• a realistic simulation analysis in ns2

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Results

• Heuristical algorithms
• Random
• Limited Node (4-10)
• Max Node
• Analytical
• ILP optimized

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Conclusions

• The use of Hierarchical Superframes in
  scatternets is highly recommended
• Need for large scatternet formation algorithms
• The random algorithm is a good approximation of
  the optimal algorithm
• Future work
• Scatternet formation based on traffic pattern
  (heuristic and analytic approach)

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Thank You!