Adaptive and robust QoS in wirelessenabled sensing devices for Assisted Living

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Adaptive and robust QoS in wireless-enabled
sensing devices for Assisted Living

• Bach Bui, Marco Caccamo, Jennifer C. Hou, Lui Sha
• Department of Computer Science
• University of Illinois at Urbana Champaign

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Why real-time QoS is important for Assisted
Living?

• Real-time wireless-enabled vital sign meters for
  transporting measurements on a continuous basis.
• Real-time wireless channels for notifying on-site
  caregivers and/or designated relatives in the
  case of emergency situations.

Home Environment
IEEE 802.15, 802.11 WLAN
Monitoring
Internet
A
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L
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Device
Service
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Proposed Research by the UIUC Team

• Software safety, robustness and availability
• Management and control of dependency relations
  between software components
• Evolvability and interoperability
• Interface engineering
• Security and privacy
• Security for information storage and wireless
  communication facilities
• Role-based trust management who can gain access
  to what information
• QoS provisioning
• Both system-wide QoS and wireless QoS for a wide
  variety of reminder, monitoring, localization,
  and time-critical emergency services

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Proposed Research by the UIUC Team

• QoS provisioning
• Both system-wide QoS and wireless QoS for a wide
  variety of reminder, monitoring, localization,
  and time-critical emergency services

Poor/no QoS!
Guaranteed QoS!
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Example of an emergency situation

• Mary goes to her bedroom to take a nap. The floor
  is slippery because it was just washed. Nobody
  else is at home and she falls down injuring
  herself.
• A wearable sensing device equipped with
  microphone, sounder and accelerometer can
  autonomously detect this emergency and issue a
  real-time emergency message to on-site caregivers
  and designated relatives

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Example of an emergency situation

• A wearable sensing device equipped with
  microphone, sounder and accelerometer can
  autonomously detect this emergency and issue a
  real-time emergency message to on-site caregivers
  and designated relatives
• The sensing device is totally independent and
  does not need any activation,
• The sensing device can provide remote real-time
  monitoring of vital signs (e.g. heart rate)
• An audio channel can be established to
  immediately check the conditions of the patient
  or detect if he/she is unconscious.
• Robustness is achieved by deploying a small
  wireless sensor network in the house/yard to
  ensure redundant monitoring, robust message
  delivery/routing
• The sensor network would allow basic monitoring
  even in the case the elderly person forgot to
  carry the wearable sensor or the device failed.

Light sensor, temperature sensor, sounder,
microphone, 2-Axis accelerometer Network
802.15.4 ZigBee Compliant
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Networked Software Architecture
TV
Monitoring Center
Peripheral Bluetooth Network
Fixed Butler PC
earplug
Internet
A.L. Device
WLAN(e.g. IEEE 802.11, 802.15)
It is possible to deploy a small sensor
network with cheap sensors to monitor (acoustic
sensors) a house and its yard
Proxy PDA
Bluetooth Medical Meters
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ZigBee IEEE 802.15.4
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ZigBee IEEE 802.15.4
We want to provide real-time QoS for peer to
peer multi-hop communication
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IEEE 802.15.4 and QoS

• For low latency applications or applications
  requiring specific data bandwidth, the PAN
  coordinator may dedicate portions of the active
  superframe to that application. These portions
  are called guaranteed time slots (GTSs).
• It needs a network coordinator
• Synchronization is achieved by means of a beacon
  packet
• It works well for clustered star networks, but it
  does not scale well for multi-hop real-time
  packet delivery.

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Multi-hop QoS extension for IEEE 802.15.4

• For multi-hop real-time delivery, we are
  investigating how to offer a distributed access
  scheme that does not require clock
  synchronization and provides bounded delay
  (statistical or deterministic guarantee)

8 fixed priorities (real-time traffic)
MAC layer
Fixed Butler PC
CSMA-CA (background traffic)
Help!
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QoS extension for IEEE 802.15.4
Throughput comparison between 802.15.4 MAC and
prioritized access
Data rate
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QoS extension for IEEE 802.15.4

• Summary of properties required by a QoS extension
  for wireless-enabled sensing devices in Assisted
  Living
• Robustness
• a single device failure should not affect the
  entire system
• reliable respect to human errors (the elderly
  might forget to wear the device, he/she will not
  reboot the system if it fails!)
• Multi-hop (each room of the house has a
  stationary sensor)
• Bounded message delivery (for remote real-time
  and interactive monitoring)
• Low power consumption (minimum mantainance,
  battery should last for months)
• Secure channel