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Department of Information EngineeringUniversity
of Padova, ITALY
A Soft-QoS Scheduling Algorithm for Bluetooth
Piconets
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Department of Information EngineeringUniversity
of Padova, ITALY
Special Interest Group on NEtworking
Telecommunications
A Soft-QoS Scheduling Algorithm for Bluetooth
Piconets
Andrea Zanella, Daniele Miorandi, Silvano
Pupolin, Andreola Cristian
andrea.zanella, daniele.miorandi,
silvano.pupolin, freccia_at_dei.unipd.it
WPMC 2003, 21-22 October 2003
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Outline of the contents

• Motivations Purposes
• Bluetooth Basic
• Soft-QoS for Bluetooth SFPQ
• Simulations Result
• Concluding Remarks

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What and Why

• Motivations Purposes

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Motivations

• Demand for QoS support over portable electronic
  devices is increasing
• audio/video streaming
• interactive games
• multimedia

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Hard Soft QoS
Hard-QoS
Soft-QoS

• Widely used in wired networks
• Integrated Services flow based (RSVP)?
• Differentiated Services class based

• Suitable for wireless networks
• Applications may work even if, for short periods
  of time, QoS requirements are not satisfied
• Deals with limited bandwidth and radio channel

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Soft-QoS parameters

• QoS parameters required per link
• Minimum peak band Br
• End-to-End Delay Dr
• Soft QoS parameter Target Satisfaction index
• ?r percentage of pcks expected to satisfy QoS
  constrains
• ?r 1 ? hard QoS (or wealthy clients)?
• ?r 0 ? pure best-effort (or poor clients)?

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Aim of the study

• Adding Soft-QoS support to BT piconets
• Design of Soft-QoS scheduling algorithm
• Analysis of the proposed algorithm

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What the standard says

• Bluetooth basic

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Introduction to QoS issues

• QoS in Bluetooth networks

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Hard QoS the FPQ scheme

• QoS parameters required per link
• Expected Data Rate
• Maximum acceptable Delay

• Slave Analyzer determines
• Probability of queued packets (Pdata)?
• Time interval since last POLL/NULL

• Selection Algorithm
• Determine priority for each link
• Select the link with highest priority

• Limits
• Inefficient short-period
• service differentiation

Lapeyrie, Turletti, Fair and efficient Polling
algorithm with QoS support,INFOCOM03
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Soft QoS support

• Soft-FPQ algorithm for Bluetooth piconets

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Soft-QoS the SFPQ scheme

• Strategy
• Dynamic estimation of the satisfaction level
  of each link
• Adjust priorities according to
• Traffic characteristics
• Classic QoS parameters (max delay, min data
  rate)?
• Estimated Satisfaction Margins

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Example of dynamic estimation
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Priority Evaluation

• Traffic Demand
• QoS Request

Fairness
Normalized Satisfaction Index
Constants
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NS2 Simulation

• Simulation of QoS Bluetooth Piconet

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Simulation Scenario

• Piconet with 7 slaves
• Only upstream traffic
• One application per slave
• One application ?1 (Hard QoS)?
• One application ?0.9
• One streaming video application ?0.9
• 4 Best Effort applications ?0.2
• Simulation dynamic
• Slaves with high ? are active for all the
  simulation time
• Best Effort transmissions start sequentially
  seconds apart
• When all the applications are active the system
  gets close to saturation

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Satisfaction perceived (2/3)?
Target Satisfaction ?0.9
Heavy Load
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Delay Distribution

• Video Streaming Delay Distribution
• Low traffic

• Video Streaming Delay Distribution
• High traffic

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Conclusions Future work

• In summary, we have
• introduced the Satisfaction Index parameter
• proposed a method to dynamically estimate the
  perceived satisfaction
• modified the priorities computation to take into
  account satisfaction margins
• In other words, we have provided Soft QoS in
  Bluetooth
• Better service differentiation
• Efficient resource distribution
• Next steps
• Dynamic parameters tuning
• Extension of the algorithm to Scatternet
  structures

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Department of Information EngineeringUniversity
of Padova, ITALY
A Soft-QoS scheduling algorithm for Bluetooth
piconets
Questions?
Andrea Zanella, Daniele Miorandi, Silvano
Pupolin, Andreola Cristian