Mohammad Ariful Huq

1
Minimizing Channel Access Delay for Emergency
Traffic in IEEE 802.15.6?Wireless Body Area
Network (WBAN)

• Mohammad Ariful Huq
• Supervisor Eryk Dutkiewicz

2
Outlines

• Introduction
• Necessity of MAC Protocol for WBAN
• IEEE 802.15.4, IEEE 802.15.6 , MEB MAC
• Channel Access Delay Minimization for Emergency
  Traffic
• Simulation Results

3
Outlines

• Introduction
• Necessity of MAC Protocol for WBAN
• IEEE 802.15.4, IEEE 802.15.6 , MEB MAC.
• Channel Access Delay Minimization for Emergency
  Traffic
• Simulation Results

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Wireless Network
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Introduction

• WBAN is RF based wireless networking technology
  that interconnects tiny nodes with sensors in,
  on, or around a human body.
• A typical WBAN consists of a
• number of inexpensive, lightweight,
• miniature sensor platforms, each
• featuring one or more
• physiological sensors like
• Motion Sensors
• ECG (Electrocardiograms)
• Sp02
• Breathing Sensors
• Blood pressure
• EMG (Electromyograms)
• EEG(Electro-encephalograms)
• Blood Glucose Sensors

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Introduction

• Network size of WBAN
• Application dependent
• ( up to 256 devices)
• WBAN Sensors could be located on
• The body as intelligent patches
• Integrated into clothing
• Implanted below the skin
• Embedded deeply in tissues

Figure Positioning of a Wireless Body Area
Network in the realm of wireless networks.
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SENSING ACTIVITIES IN MEDICAL BANS
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WBAN Traffic Classification

• Normal traffic Based on normal operation
  between device and coordinator.
• On-demand traffic Initiated by Coordinator to
  know certain information.
• Emergency traffic In case of critical
  condition.

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WBAN Architecture

• Level 1 contains in-body and on-body BAN Nodes
  (BNs)
• Level 2 contains a BAN Network Coordinator (BNC)
  that gathers patients vital information from the
  BNs and communicates with the base-station.
• Level 3 contains a number of remote base-stations
  that keep patients medical/non-medical records
  and provides relevant (diagnostic)
  recommendations.

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WBAN Applications
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CodeBlue
CodeBlue is the project of Harvard University
trying to develop novel applications of wireless
sensor network technology to medical
applications. Many products of the project have
great potential to apply to practice.
Figure 6Intel SHIMMER motes
Stroke patient rehabilitation monitoring system
CodeBlue.
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Mercury A Wearable Sensor Network Platform for
High-Fidelity Motion Analysis
SHIMMER sensors being worn on a patient's arm.
The Intel SHIMMER mote, including a triaxial
accelerometer
The SHIMMER mote connected to its programming
board.
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VitalDust Wireless vital sign monitoring

• Mica2-based pulse oximeter
• Measures heart rate, blood oxygen
  saturation
• Telos-based two-lead Electrocardiogram
• PDA- and PC-based applications for multi-patient
  triage

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Outlines

• Introduction
• Necessity of MAC Protocol for WBAN
• IEEE 802.15.4, IEEE 802.15.6 , MEB MAC.
• Channel Access Delay Minimization for Emergency
  Traffic
• Simulation Results

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Major Sources of Energy Waste in Sensor Network

• Collision Two nodes emit at the same time
• 2. Idle Listening Node listens to an idle
  channel
• 3. Overhearing Node listens for a message sent
  to another node

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Energy in WBAN

• Battery lifetime is very important
• Required Lifetime
• Swallowable Camera Pills 12 hours
• Cardiac Defibrillators and pacemakers 5 years
• Reducing the waste of energy can maximize
  battery lifetime
• How to improve energy efficiency
• Routing
• Mobile Base Station
• Energy efficient MAC protocol

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Major MAC Protocol Approaches

• Contention Based (CSMA/CA)
• Nodes need to perform CCA before transmission of
  data
• If the channel is busy, the node defers its
  transmission till it becomes idle.
• Its infrastructure-free
• Ad hoc feature
• Good adaptability to traffic fluctuation
• Schedule Based(TDMA)
• Channels are divided into fixed/variable time
  slots which are assigned to nodes that transmit
  during its slot period
• Free of idle listening, overhearing and packet
  collisions because of the lack of medium
  competition,
• But require tight time synchronization.

18
Outlines

• Introduction
• Necessity of MAC Protocol for WBAN
• IEEE 802.15.4, IEEE 802.15.6 , MEB MAC.
• Channel Access Delay Minimization for Emergency
  Traffic
• Simulation Results

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802.15.4 Superframe Format
Inactive period
Active period
CAP
CFP
Contention Free Period
beacon
beacon
Contention Access Period
Transmitted by network coordinator. Contains
network information, frame structure and
notification of pending node messages.
Network beacon
Contention period
Access by any node using CSMA-CA
Guaranteed Time Slot
Reserved for nodes requiring guaranteed bandwidth
Sleep period
Inactive Period
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802.15.6 Superframe Format
The EAP is Emergency Access Period. -gt In this
period only devices with emergency traffic can
contend. The RAP(Random Access Period) can be
used by any device both emergency and
non-emergency. -gt The data that are accumulated
in the device buffers have a priority assigned to
them. Each of the devices have to contend with
backoff windows according to their priority.
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Outlines

• Introduction
• Necessity of MAC Protocol for WBAN
• IEEE 802.15.4, IEEE 802.15.6 , MEB MAC.
• Channel Access Delay Minimization for Emergency
  Traffic
• Simulation Results

22
Channel Access Delay

• Channel Access Delay is the duration from the
  time when a packet arrives at the queue until the
  designated packet gains access to the channel.

23
MEB-MAC Superframe Format

• Listening Window is placed periodically in
  Scheduled Access Phase to reduce the access delay
  of Emergency Data.
• A Listening Window is dedicated to emergency
  alarms to provide high reliability with low
  delay.

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Algorithm for Inserting Listening Window
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Average Channel Access Delay
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Outlines

• Introduction
• MAC Protocol for WBAN
• IEEE 802.15.4, IEEE 802.15.6 , MEB MAC.
• Channel Access Delay Minimization for Emergency
  Traffic
• Simulation Results

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Simulation Result Channel Access Delay
Comparison
Congested Scenarios
Non Congested Scenarios
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Thank You

• ?