Transcript Transport Protocols for Wireless Multimedia Sensor Network

Trends in
Wireless [Multimedia] Sensor
Networks
Mr.M.Balasubramani
Asst. Professor
CSE Department
PSNA CET
Faculty seminar
14.02.2015
1
Agenda
•
•
•
•
•
•
•
•
•
•
•
Intro..
Features
Applications-WSN:WMSN
Goals/characteristics of WMSN
Architecture
Challenges/Issues
Components & characteristics of wireless video
systems
Factors influencing the design
Application domains
Proposals…
Interesting applications…
2
Introduction
Sensor networks VS ad hoc networks:
• The number of nodes in a sensor network > the nodes in
an ad hoc network.
• Sensor nodes are densely deployed.
• Sensor nodes are limited in power, computational
capacities and memory.
• The topology of a sensor network changes frequently.
• Sensor nodes mainly use broadcast, most ad hoc
networks are based on p2p.
• Sensor nodes may not have global ID.
3
Wireless Sensor Networks (WSNs)
Wireless Sensor Networks
features
• Homogeneous devices
• Stationary nodes
• Dispersed network
• Large network size
• Self-organized
• All nodes acts as routers
• No wired infrastructure
• Potential multihop routes
4
Applications of
Sensor networks
6
Applications of sensor networks
Military applications
• Monitoring friendly forces, equipment and
ammunition
• Investigation/survey of opposing forces and
terrain
• Battlefield surveillance(observation)
• Battle damage assessment
• Nuclear, biological and chemical attack
detection
7
Applications of sensor networks
Environmental applications
• Forest fire detection
• Biocomplexity mapping of the environment
• Flood detection
• Precision agriculture
8
Applications of sensor networks
Health applications
• Tele-monitoring of human physiological data
• Tracking and monitoring patients and doctors
inside a hospital
• Drug administration in hospitals
9
Applications of sensor networks
Home and other commercial applications
•
•
•
•
•
Home automation and Smart environment
Interactive museums
Managing inventory control
Vehicle tracking and detection
Detecting and monitoring car thefts
10
WSNs - Applications
• Applications
• Habitat monitoring
• Disaster relief
• Target tracking
• Agriculture
11
What’s so special about WMSNs ?
• computation-communication paradigm of
traditional WSNs
• focused only on reducing energy consumption
• WMSNs applications have a second goal, as
important as the energy consumption
• delivery of application-level quality of service (QoS)
• mapping of this requirement to network layer metrics,
like latency
• This goal has (almost) been ignored in
mainstream research efforts on traditional WSNs
13
What’s so special about WMSNs ?
• Resource constraints
• sensor nodes are battery-, memory- and processingstarving devices
• Variable channel capacity
• multi-hop nature of WMSNs implies that wireless link
capacity depends on the interference level among
nodes
• Multimedia in-network processing
• sensor nodes store rich media (image, video), and
must retrieve such media from remote sensor nodes
with short latency
14
Wireless Multimedia Architecture
Wireless Multimedia
Challenges
•
•
Adaptive Decoding - Optimizing rich digital media
for mobile information devices with limited
processing power, limited battery life and varying
display sizes
Error Resilience - Delivering rich digital media over
wireless networks that have high error rates and low
and varying transmission speeds
Network Access - Delivering rich digital media
without adversely affecting the delivery of voice and
data services
•
•
Negotiable QoS for IP multimedia sessions as well
as for individual media components
Components of a
Wireless Video System
Input
Video
Transport + Network Layer
Video
Packetizer
Encoder
Channel
Modulator
Encoder
Wireless
Channel
Output
Video
Video
Decoder
Depacketizer
Channel
Decoder
Tradeoff: Throughput,
Reliability, Delay
Demodulator
Characteristics of
a Wireless Video System
• The capacity of wireless channel is limited by
the available bandwidth of the radio spectrum
and various types of noise and interference
• The wireless channel is the weakest link of
multimedia networks – mobility causes fading
and error bursts
• Resulting transmission errors require error
control techniques (such as FEC - forward
error control and ARQ – automatic repeat
request)
The Case for
Scalable Video Coding
• In emerging wireless applications, multimedia
data will be streamed:
• over various access networks (GPRS, UMTS,
WLANs, etc.)
• to a variety of devices (PCs, TVs, PDAs, cellular
phones, etc.)
• The transmission of multimedia data need to
cope with unpredictable bandwidth variations:
• due to heterogeneous access technologies of
receivers (3G, 802.11a, etc.) or
• due to dynamic changes of network conditions
(interference, etc.)
Factors Influencing
Sensor Network Design
20
Factors influencing sensor network
design
21
Factors influencing sensor network
design
•
•
•
•
•
•
•
Fault Tolerance
Scalability
Hardware Constrains
Sensor Network Topology
Environment
Transmission Media
Power Consumption
22
Factors influencing sensor network
design
Fault tolerance
•
Fault tolerance is the ability to sustain
sensor network functionalities without any
interruption due to sensor node failures.
•
The fault tolerance level depends on the
application of the sensor networks.
23
Factors influencing sensor network
design
Scalability
• Scalability measures the density of the
sensor nodes.
• Density = (R) =(N R2)/A


R – Radio Transmission Range
24
Factors influencing sensor network
design
Production costs
• The cost of a single node is very important
to justify the overall cost of the networks.
• The cost of a sensor node is a very
challenging issue given the amount of
functionalities with a price of much less
than a dollar.
25
Factors influencing sensor network
design
Hardware constraints
26
Factors influencing sensor network
design
Sensor network topology
• Pre-deployment and deployment phase
• Post-deployment phase
• Re-deployment of additional nodes phase
27
Factors influencing sensor network
design
Environment
• Busy intersections
• Interior of a large machinery
• Bottom of an ocean
• Surface of an ocean during a tornado
• Biologically or chemically contaminated field
• Battlefield beyond the enemy lines
• Home or a large building
• Large warehouse
• Animals
• Fast moving vehicles
• Drain or river moving with current.
28
Factors influencing sensor network
design
Transmission media
In a multihop sensor network,
communicating nodes are linked by a
wireless medium. To enable global
operation, the chosen transmission
medium must be available worldwide.
• Radio
• infrared
• optical media
29
Factors influencing sensor network
design
Power Consumption
• Sensing
• Communication
• Data processing
30
proposals …
• Cooperative Caching:
• multiple sensor nodes share and coordinate cache data
to cut communication cost and exploit the aggregate
cache space of cooperating sensors
• Each sensor node has a
moderate local storage
capacity associated with it,
i.e., a flash memory
31
Proposals…
• Organize nodes into groups based on their data request pattern
and their mobility pattern
• Zone Co-operative, Cluster Cooperative: form clusters of
nodes based either in geographical proximity or utilizing widely
known node clustering
32
Proposals…
• CacheData: intermediate nodes cache the data
to serve future requests instead of fetching data
from their source
• CachePath: mobile nodes cache the data path
and use it to redirect future requests to the
nearby node which has the data instead of the
faraway origin node
• the placement of caches
33
The cache discovery protocol (1/2)
A sensor node issues a request for a multimedia
item
• Searches its local cache and if it is found (local
cache hit) then the K most recent access
timestamps are updated
• Otherwise (local cache miss), the request is
broadcasted and received by the mediators
• These check the 2-hop neighbors of the requesting
node whether they cache the datum (proximity
hit)
• If none of them responds (proximity cache miss),
then the request is directed to the Data Center
34
The cache discovery protocol (2/2)
When a mediator receives a request, searches its
cache
• If it deduces that the request can be satisfied by a
neighboring node (remote cache hit), forwards the
request to the neighboring node with the largest
residual energy
• If the request can not be satisfied by this mediator
node, then it does not forward it recursively to its own
mediators, since this will be done by the routing
protocol, e.g., AODV
• If none of the nodes can help, then requested datum is
served by the Data Center (global hit )
35
Application Domains
• Home networking: Smart appliances, home security,
smart floors, smart buildings
• Automotive: Diagnostics, occupant safety, collision
avoidance
• Industrial automation: Factory automation, hazardous
material control
• Traffic management: Flow monitoring, collision
avoidance
• Security: Building/office security, equipment tagging,
homeland security
• Environmental monitoring: Habitat monitoring, seismic
36
Some Interesting Applications
The ring sensor
Monitors the physiological status of the
wearer and transmits the information to
the medical professional over the Internet
Nose-on-a-chip
It is a MEMS-based sensor
It can detect 400 species of gases and
transmit a signal indicating the level to a
central control station

37
iButton
• A 16mm computer chip armored in a
stainless steel
• Can Up-to-date information
• can travel with a person or object
38
iButton Applications
• Caregivers Assistance
• Do not need to keep a bunch of keys. Only one
iButton will do the work
• Elder Assistance
• They do not need to enter all their personal
information again and again. Only one touch
of iButton is sufficient
• They can enter their ATM card information
and PIN with iButton
• Vending Machine Operation Assistance
39
iBadge - UCLA
• Investigate behavior of children/patient
• Features:
•
•
•
•
Speech recording / replaying
Position detection
Direction detection / estimation(compass)
Weather data: Temperature, Humidity, Pressure, Light
40
iBadge - UCLA
41
Thank you
for your attention!
Any questions?
42