Transcript Survey on body area network - SJTU Wireless and Sensor

Survey on body area network
姜升
Structure
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BAN
Sensor devices
Communication technology
PHY
Network and MAC
Energy
Application
BAN
• A body area network (BAN)
is a wireless network of
wearable computing
devices. The network
consists of several
miniaturized body sensor
units together with a single
body central unit.
BAN
• Deployment
• Data rate
• Mobility
BAN
WSN
Deployment
BAN does not employ
redundant nodes, and only
added when they are
needed.
WSN is often deployed in places that may
not be easily accessible by operators which
require more nodes to be placed to
compensate for node failures.
Data rate
BAN may occur in a more
periodic manner and stable
data rate.
Most WSNs are employed for event-based
monitoring where events can happen at
irregular intervals.
Mobility
BAN users may move around, WSN nodes are usually considered
so that the nodes share the
stationary.
same mobility pattern.
Sensor devices
• Inertial motion unit (Accelerometer and
Gyroscope)
• Blood glucose
• Blood pressure
• CO2 gas sensor
• Electrocardiogram (ECG)
• Electroencephalogram (EEG)
• Blood oxygen
• Electromyography (EMG)
• Humidity and temperature sensors
Communication technology
• UWB (Ultra wideband)
• Zigbee
• Bluetooth
Technology
Frequency
band
Data rate (b/s)
Coverage
distance
Network
topology
UWB
3.1~10.6GHz
480M
<10
star
Zigbee
2.4GHz
250K
30~100
Star/mesh
Bluetooth
2.4GHz
1M
10
star
PHY
Studies focus on characteristics of the signal
propagation: around the body
(LOS/NLOS)/inside the body
• Factors affecting the signal propagation
– Location of the BAN user
– Location of the sensor node
– Current activity of the human body
PHY
• Measurement
– Radio signals are generated in the network
analyzer, input in the body through the TX,
received in the RX and evaluated in the network
analyzer.
PHY
Characteristics of signal propagation
• LOS
– It is found that the increase of distance between TX and RX
causes an increase of the path loss
– The dominant propagation path is the direct wave
– In classroom, the power of reflected waves exceeded that
of the direct wave for the lower body
• NLOS
– The propagation wave is more likely to diffract around the
human body rather than to pass through it
– The dominant path is reflected wave in classroom is
reflected wave.
PHY
– The difference between body shapes (i.e. male, female
and child) are at least as large as the impact of a patient's
arm movements.
• In the body
– Signals propagating in the body are attenuated mainly due
to absorption of power in the tissue. The path loss is much
higher than the free space propagation.
– the frequency bands between 200MHz to 600MHz are
suitable in the range from 0 to 3GHz.
– In frequency range of 3-11 GHz, The signal attenuation in
the body increases when the frequency increases. Human
body has a good response to signal transportation in the
bands between 3-5 GHz.
Network and MAC
• Network
– DTN routing/probabilistic routing
Network and MAC
• MAC
– Scheduling based
– Contention based
Scheduling based MAC
Contention basted MAC
Power consumption
Low
high
Bandwidth utilization
Maximum
low
Transmission efficiency
High
low
Network and MAC
• MAC
– Most current MAC protocols specifically
developed for BAN are based on IEEE 802.15.4, as
most of the radios used in WBANs are based on
IEEE 802.15.4 compliant chip set.
Energy
• Energy consumption
– Sensing
– Communication
– Data processing
• Approach
– Turn on/off the radio periodically
– Reducing idle listening/contention/overhearing
Energy
Network
topology
MAC
Approach
The coordinator utilizing the priority
of the nodes to make adjustment
BSNMAC
TDMA/CS
MA mixed
Star
topology
H-MAC
TDMA
based
Star
topology
CICADA
TDMA
based
Tree
topology
Exploiting
heartbeat
rhythm
information
to
perform
time
synchronization
Setting up a network tree for data
gathering and communication using
distributed slot assignment
Star
topology
Using master-slave approach and
assigning an extra slot to the node for
direct communication at alarming time
Omeni
TDMA
based
Energy
Protocol
Network topology
Approach
Anybody
Mesh
Using clustering to reduce
the number of direct
transmissions to the
remote base station
Application
Application
• Training
• Health monitoring
• Positioning
– Particle filtering/Kalman filtering/range
free/ML/LS/DV-hop
Application Scenario
Feedback
Training
Dance/golf/swimming/football/p
hysical rehabilitation
Guidance
Health
monitoring
Remote health monitoring/falling
detection
Physical information and
alarming
Positioning
Location
Thanks!