hold for Wireless

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21 Νοε 2013 (πριν από 3 χρόνια και 6 μήνες)

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Loren Schwiebert

Wayne State University

Department of Computer Science


loren@wayne.edu

http://www.cs.wayne.edu/~loren

What does the Future
hold for Wireless

Sensor Networks?

What does the Future hold for Wireless Sensor Networks?

2

Why Wireless Sensors Now?


Moore’s Law is making
sufficient CPU performance

available with low power requirements in a small size.


Research in Materials Science has resulted in
novel
sensing materials

for many Chemical, Biological, and
Physical sensing tasks.


Transceivers for wireless devices

are becoming
smaller, less expensive, and less power hungry.


Power source improvements

in batteries, as well as
passive power sources such as solar or vibration
energy, are expanding application options.

Current State of the Art

in Wireless Sensors

What does the Future hold for Wireless Sensor Networks?

4

Typical Sensor Node Features


A sensor node has:


Sensing Material


Physical



Magnetic, Light, Sound


Chemical



CO, Chemical Weapons


Biological



Bacteria, Viruses, Proteins


Integrated Circuitry (VLSI)


A
-
to
-
D converter from sensor to circuitry


Packaging for environmental safety



Power Supply


Passive



Solar, Vibration


Active



Battery power, RF Inductance

What does the Future hold for Wireless Sensor Networks?

5

Advances in Wireless Sensor Nodes

Consider Multiple Generations of
Berkeley Motes

Model

Rene

Mica

Mica
-
2

Mica
-
Z

Date

1999

2002

2003

2004

CPU

4 MHz

4 MHz

4 MHz

4 MHz

Flash
Memory

8 KB

128 KB

128 KB

128 KB

RAM

512 B

4 KB

4 KB

4 KB

Radio

10 Kbps

40 Kbps

76 Kbps

250 Kbps

What does the Future hold for Wireless Sensor Networks?

6

Historical Comparison

Consider a
40 Year Old

Computer

Model

Honeywell H
-
300

Mica 2

Date

6/1964

7/2003

CPU

2 MHz

4 MHz

Flash

Memory

None

128 KB

RAM

32 KB

4 KB

What does the Future hold for Wireless Sensor Networks?

7

A Rosy Future for Wireless Sensors?


Is the effort on
wireless sensor protocols

a waste of time??


Can we just
wait 10
-
15 years

until we
have sensors that are very powerful??


NO!!

Will still face:


Very limited
storage


Modest
power

supplies

Proposed Applications of
Wireless Sensors

What does the Future hold for Wireless Sensor Networks?

9

Smart Home / Smart Office


Sensors controlling
appliances and
electrical devices in
the house.


Better lighting and
heating in office
buildings.


The Pentagon
building has used
sensors extensively.

What does the Future hold for Wireless Sensor Networks?

10

Biomedical / Medical


Health Monitors


Glucose


Heart rate


Cancer detection


Chronic Diseases


Artificial retina


Cochlear implants


Hospital Sensors


Monitor vital signs


Record anomalies

What does the Future hold for Wireless Sensor Networks?

11

Military

Remote deployment of
sensors for
tactical monitoring

of enemy troop movements.

What does the Future hold for Wireless Sensor Networks?

12

Industrial & Commercial


Numerous industrial and commercial
applications:


Agricultural Crop Conditions


Inventory Tracking


In
-
Process Parts Tracking


Automated Problem Reporting


RFID


Theft Deterrent and Customer
Tracing


Plant Equipment Maintenance Monitoring

What does the Future hold for Wireless Sensor Networks?

13

Traffic Management & Monitoring


Future cars could use
wireless sensors to:


Handle Accidents


Handle Thefts


Sensors embedded
in the roads to:


Monitor traffic flows


Provide real
-
time
route updates

Driving Forces for Adopting

New Technology

What does the Future hold for Wireless Sensor Networks?

15

Economic Factors


New technologies
replace existing
technologies

or
fill new niches

when
there are economic advantages.


Wireless sensors will
replace wired
sensors


No wiring


lower costs


More flexible deployments


Wireless sensors will
provide new services


Provide cost advantages or lower overhead


Improve product quality or product features

What does the Future hold for Wireless Sensor Networks?

16

Novelty

Some early adopters use new technology
simply for novelty or
the fun of it
.
Examples include:




Java rings

and internet watches.


Maybe wireless sensors for
dating

or
meeting new people?


Personal wireless sensors for
fun



a
temperature monitor you carry around?

What does the Future hold for Wireless Sensor Networks?

17

Legal / Liability


New technologies are adopted
because of
government mandates
:


Air bags in automobiles


Child safety seats


Companies employ new
technologies to
avoid being sued
!!


Temperature sensors to detect coffee
that is too hot??

What does the Future hold for Wireless Sensor Networks?

18


Entertainment


New technology is adopted for
entertainment
.


Playing
games

is major use of home PCs.


So is
Internet browsing
.


Games on cellular phones.


3D visualization for … games.


Games of
tag

using wireless sensors?


Interactive
role
-
playing games

with
sensors?

What does the Future hold for Wireless Sensor Networks?

19

Not

Technical Superiority


Useful technologies
may not dominate

the marketplace for several reasons.


Delay

in getting to market.


Lack of
standardization
.


Limited
applications
.


Consumer

preference


VHS vs. Betamax.


Weaker
marketing or capitalization
.


Unusual that there are
no alternative
technologies

that can be used.

Uses of New Technology

What does the Future hold for Wireless Sensor Networks?

21

Unexpected Killer Applications


Useful applications often
follow

available technology. For example,


PCs were available and people
looked for a killer app


Visicalc
.


The Internet was
not

created with
these current applications in mind:


World Wide Web


E
-
Commerce


Peer
-
to
-
Peer Digital Music Sharing

What does the Future hold for Wireless Sensor Networks?

22

Unanticipated Uses Arise


Once technology is available,
creativity

leads to new applications:


Sims Internet world


E
-
Bay auctions


Mirror for the Palm Pilot


Digital cameras with PC interface


What
surprising applications

for wireless
sensor networks?


Depends

on sensor technology/form factor

Some Technical Challenges

What does the Future hold for Wireless Sensor Networks?

24

Noisy Sensors

Sensor readings can be
inaccurate
.
Protocols need to recognize this.

GPS Sensor



Accurate within

2.8 meters

Relative Humidity Sensor


Accuracy of
±
5%

±
8% at 90% Relative Humidity

±
2% with calibration

What does the Future hold for Wireless Sensor Networks?

25

Wireless Channel Conditions


Limitations of wireless channels


Noisy


Interference


Link Contention


Unidirectional Links





But inherently a
broadcast

medium

What does the Future hold for Wireless Sensor Networks?

26

Environmental Factors


Wireless sensors need to operate in
conditions that are not encountered by
typical computing devices:


Rain, sleet, snow, hail, etc.


Wide temperature variations


May require separating sensor from electronics


High humidity


Saline or other corrosive substances


High wind speeds

What will Wireless Sensor
Networks Look Like in the
Near Future?

What does the Future hold for Wireless Sensor Networks?

28

Large
-
Scale Deployments


Sensor networks
will
grow in size

because of:


Lower cost


Better protocols


Advantages of
dense networks

Sensing Zone with sensor-coordinator,
sensing-collaborators, and backbone nodes
Level-0 to Level-1 backbone
Level-1 to Level-2 backbone
Sensor Coordinator
Sensing nodes
Level-1 Backbone node
Level-2 Backbone node
Sensing Zone Membership
What does the Future hold for Wireless Sensor Networks?

29

Heterogeneous Sensors


Homogeneous network of sensors has
been the typical assumption, but
not

the future!!


Combining sensors with
different functions


Hierarchy of sensors


a few expensive

powerful sensors

with more cheap sensors


Useful for special
communication

nodes


A few sensor nodes with
expensive
sensors
, such as GPS
-
equipped sensors

What does the Future hold for Wireless Sensor Networks?

30

Mobile Sensors

Sensors with
Micromachines

Low
-
Power Motors that Support Mobility

What does the Future hold for Wireless Sensor Networks?

31

General Purpose Sensors


Single
-
purpose

network is the typical
assumption, but
not

the future!!


Sensors for
evolving applications


Sensors that can
adapt

to changing
objectives


More memory and CPU

will allow more
complex applications


Flexibility increases
marketability

What does the Future hold for Wireless Sensor Networks?

32

Overlapping Coverage Areas


Sensors will be deployed for
specific
applications
, but


These deployments will
overlap

physically


Sensors will have
different
properties


Users will want to
combine these
different sensors

for new applications:


Temperature sensors for HVAC control


Location tracking of employees


Combine these for fire rescue operations

What does the Future hold for Wireless Sensor Networks?

33

Mixture of Wired and Wireless


Wireless sensors will become a
seamless

part

of larger networks!


Combining
wired sensors

with wireless
sensors


Wired sensors can have more power


Wired sensors can run TCP/IP


Accessing wireless sensors through the
Internet


Need a
gateway

to translate requests


Uploading/downloading information remotely


Modifying wireless sensor tasks remotely


Increased direct user interaction

Some Impediments to

Creating Future
Applications

What does the Future hold for Wireless Sensor Networks?

35

Need a Standardized Interface


Automated interaction between
sensors implies some
standard
mechanism

for communication!


Requires compatible wireless technology


Standardization a common theme


TCP/IP

for the Internet


Java

for Internet programming


Jini, SLP
, etc. for 802.11 wireless devices


Need a
service discovery protocol


Enables
standard interface

among
sensors above the physical layer

What does the Future hold for Wireless Sensor Networks?

36

Service Discovery Protocol

Anyone need


a printer?

What does the Future hold for Wireless Sensor Networks?

37

Service Discovery Protocol (cont.)


For a wireless sensor network, service
discovery
provides
:


Automated
calibration

of new devices


Highly
dynamic system configurations


Cooperation

among resource poor devices


Resource sharing

device solutions


Storage and long
-
range networking services
can be obtained from a nearby server


Less duplication

of functionality


Supports
novel

interactions in the future

What does the Future hold for Wireless Sensor Networks?

38

Security Issues


Concerns about
misuse and privacy


Privacy issues may
slow consumer
adoption

of technology


User tracking


RFID concerns


Has not proved true on the Internet!


Authentication and privacy are
not always
complementary

objectives


Do not want your
medical

sensor hacked!!


Data tampering
and

computer viruses

could be a nightmare!

What does the Future hold for Wireless Sensor Networks?

39

Liability and Safety Concerns


Companies may adopt wireless sensors
to reduce liability, but wireless sensors
could also
increase liability
:


Use in
critical applications

could be limited


Imagine a medical sensor fails!!


Or an automotive theft deterrent system failure


Companies will be
slow to adopt

technology that increases their legal
exposure


May delay adoption

What does the Future hold for Wireless Sensor Networks?

40

Software Engineering


Imagine a heterogeneous wireless
sensor network with
complex tasks
and

high levels of interaction



End
-
user level products


easy to use


Software design??


Debugging??


Remote software updates??


Example
: Send a request over the
Internet to turn on lights when your car
reaches home. The request
fails
.

What does the Future hold for Wireless Sensor Networks?

41

Summary and Conclusions


Wireless sensor networks have a

bright future


Many applications have been
proposed


Potential to
revolutionize

human
-
computer
interactions


Availability of sensors will lead to
new
and

exciting

applications


A lot of
research remains

to be done


Wireless sensors will
not

evolve into traditional
computers


Many
obstacles

to overcome


Allow
realism

to guide research efforts

What does the Future hold for Wireless Sensor Networks?

42

Acknowledgments

THANK YOU

Research collaborators (and for slides):


Professor Gregory Auner


Professor Sandeep K. S. Gupta


Professor Golden G. Richard III


Manish Kochhal

Technical Assistance: Joel Schwiebert