BodyQoS: Adaptive and Radio-Agnostic QoS for Body Sensor Networks

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BodyQoS Adaptive and Radio-Agnostic QoS for Body
Sensor Networks

• Gang Zhou
• College of William and Mary
• Jian Lu
• University of Virginia
• Chieh-Yih Wan, Mark D. Yarvis
• Intel Research
• John A. Stankovic
• University of Virginia

IEEE INFOCOM 2008
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Hurricane Katrina Relief
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911 Terrorist Attack
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Health Monitoring During Emergency

• Manual tracking of patient status, based on
  papers and phones, is the past
• Real-time continuous monitoring, through body
  sensor networks, is the future

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A Typical Body Sensor Network
Limb motion muscle activity
Heart rate blood oxygen saturation
Two-Lead EKG
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Quality of Service for Body Sensor Networks

• BodyQoS Goals
• Priority-based admission control
• Wireless resource scheduling
• Providing effective bandwidth

• Design Constraints
• Heterogeneous resources
• Heterogeneous radio platforms

Data
Control
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BodyQoS Contributios

• The first Running QoS System for Body Sensor
  Networks
• Asymmetric Architecture
• Most work for the aggregator
• Little work for sensor nodes
• Virtual MAC
• Separate QoS scheduling from underlying real MAC
• Easy to port to different radio platforms
• Effective BW Allocation
• Adaptive resource scheduling, so that
  statistically the delivered BW meets QoS
  requirements, even during interference

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Asymmetric Architecture

1. Asymmetric Architecture
2. Virtual MAC
3. Effective BW Allocation

BodyQoS



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Wireless Resource Abstraction

1. Asymmetric Architecture
2. Virtual MAC
3. Effective BW Allocation

Tinterval Npkt Spkt TPkt TmaxPkt TminSleep
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Wireless Resource Abstraction

1. Asymmetric Architecture
2. Virtual MAC
3. Effective BW Allocation

Npkt Spkt TPkt TmaxPkt TminSleep
The length of each interval The length of each interval The length of each interval The length of each interval The length of each interval The length of each interval
Tinterval
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Wireless Resource Abstraction

1. Asymmetric Architecture
2. Virtual MAC
3. Effective BW Allocation

Tinterval Npkt Spkt TPkt TmaxPkt TminSleep
The maximum number of packets QoS Scheduler can send/receive within each interval, if there is no interference The maximum number of packets QoS Scheduler can send/receive within each interval, if there is no interference The maximum number of packets QoS Scheduler can send/receive within each interval, if there is no interference The maximum number of packets QoS Scheduler can send/receive within each interval, if there is no interference The maximum number of packets QoS Scheduler can send/receive within each interval, if there is no interference The maximum number of packets QoS Scheduler can send/receive within each interval, if there is no interference
Npkt
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Wireless Resource Abstraction

1. Asymmetric Architecture
2. Virtual MAC
3. Effective BW Allocation

Tinterval Npkt Spkt TPkt TmaxPkt TminSleep
The effective data payload size in each packet that can carry application data The effective data payload size in each packet that can carry application data The effective data payload size in each packet that can carry application data The effective data payload size in each packet that can carry application data The effective data payload size in each packet that can carry application data The effective data payload size in each packet that can carry application data
Spkt
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Wireless Resource Abstraction

1. Asymmetric Architecture
2. Virtual MAC
3. Effective BW Allocation

Tinterval Npkt Spkt TPkt TmaxPkt TminSleep
The minimum time needed to send out a packet, if there is no interference The minimum time needed to send out a packet, if there is no interference The minimum time needed to send out a packet, if there is no interference The minimum time needed to send out a packet, if there is no interference The minimum time needed to send out a packet, if there is no interference The minimum time needed to send out a packet, if there is no interference
Tpkt
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Wireless Resource Abstraction

1. Asymmetric Architecture
2. Virtual MAC
3. Effective BW Allocation

Tinterval Npkt Spkt TPkt TmaxPkt TminSleep
The maximum time needed to send out a packet or finally report giving up, if it suffers maximum backoffs/retransmissions The maximum time needed to send out a packet or finally report giving up, if it suffers maximum backoffs/retransmissions The maximum time needed to send out a packet or finally report giving up, if it suffers maximum backoffs/retransmissions The maximum time needed to send out a packet or finally report giving up, if it suffers maximum backoffs/retransmissions The maximum time needed to send out a packet or finally report giving up, if it suffers maximum backoffs/retransmissions The maximum time needed to send out a packet or finally report giving up, if it suffers maximum backoffs/retransmissions
TmaxPkt
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Wireless Resource Abstraction

1. Asymmetric Architecture
2. Virtual MAC
3. Effective BW Allocation

Tinterval Npkt Spkt TPkt TmaxPkt TminSleep
The minimum time for putting radio to sleep, which includes the sleeping/activation switch time and also considers the energy cost The minimum time for putting radio to sleep, which includes the sleeping/activation switch time and also considers the energy cost The minimum time for putting radio to sleep, which includes the sleeping/activation switch time and also considers the energy cost The minimum time for putting radio to sleep, which includes the sleeping/activation switch time and also considers the energy cost The minimum time for putting radio to sleep, which includes the sleeping/activation switch time and also considers the energy cost The minimum time for putting radio to sleep, which includes the sleeping/activation switch time and also considers the energy cost
TminSleep
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Virtual MAC Operation

1. Asymmetric Architecture
2. Virtual MAC
3. Effective BW Allocation

BWeffective
Delivered Bytes / Actual Time
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Effective BW Allocation

1. Asymmetric Architecture
2. Virtual MAC
3. Effective BW Allocation

The ideal case no Interference
The general case when interference is present
If application requests BW bi, BodyQoS allocates
BW bi
That is, in each interval Tinterval, QoS
scheduler requests VMAC to send/receive Di
packets within time TiDiTpkt
Minimum per packet transmission time
Interval length
Packet size
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Effective BW Allocation

1. Asymmetric Architecture
2. Virtual MAC
3. Effective BW Allocation

The general case when interference is present
Max. MAC Retrans. Time
H
H
Interference
Interference
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Performance Evaluation Setup
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Performance

1. Adaptive QoS always delivers requested BW
2. Delivered BWs for RTP-Like QoS and best-effort
   reduce when interference increase
3. RTP-like QoS has better performance than
   best-effort

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Conclusions

• We designed, implemented, and evaluated the first
  Running QoS System for Body Sensor Networks
• Asymmetric Architecture
• Most work for the aggregator
• Little work for sensor nodes
• Virtual MAC
• Separate QoS scheduling from underlying real MAC
• Easy to port to different radio platforms
• Effective BW Allocation
• Adaptive resource scheduling, so that
  statistically the delivered BW meets QoS
  requirements, even during interference
• For more information, visit www.cs.wm.edu/gzhou

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The End
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Effective BW Allocation

1. Asymmetric Architecture
2. Virtual MAC
3. Effective BW Allocation

The general case when interference is present
Max. MAC Retrans. Time
H
H
Interference
Interference
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Implementation
Easy to Port to Different Radio Platforms
Only need to modify VMAC
VMAC lt100 lines of code
BodyQoS 3700 lines of code
Most Work Done at the Aggregator
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Evaluation -- Bandwidth Delivery Ratio

1. Adaptive QoS always delivers requested BW
2. Delivered BWs for RTP-Like QoS and best-effort
   reduce when interference increase
3. RTP-like QoS has better performance than
   best-effort

Aggregator Side
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Evaluation -- Data Buffer Fetching Speed

1. Adaptive QoS always maintains 4Kbps fetching
   speed
2. Fetching speeds of RTP-Like QoS and best-effort
   reduce when interference is present
3. Fetching speed of RTP-like QoS is higher than
   that of best-effort

Mote Side