Loren Schwiebert Wayne State University Department of Computer Science [email protected] loren What...
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Transcript of Loren Schwiebert Wayne State University Department of Computer Science [email protected] loren What...
Loren SchwiebertWayne State University
Department of Computer Science
[email protected]://www.cs.wayne.edu/~loren
What does the Future What does the Future hold for Wireless hold for Wireless Sensor Networks?Sensor Networks?
What does the Future hold for Wireless Sensor Networks? 2
Why Wireless Sensors Now?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.
What does the Future hold for Wireless Sensor Networks? 4
Typical Sensor Node FeaturesTypical 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 NodesAdvances 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 ComparisonHistorical Comparison
Consider a 40 Year Old Computer
Model Honeywell H-300 Mica 2
Date 6/1964 7/2003
CPU 2 MHz 4 MHz
Flash
MemoryNone 128 KB
RAM 32 KB 4 KB
What does the Future hold for Wireless Sensor Networks? 7
A Rosy Future for Wireless Sensors?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
What does the Future hold for Wireless Sensor Networks? 9
Smart Home / Smart OfficeSmart 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 / MedicalBiomedical / 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
MilitaryMilitary
Remote deployment of sensors for tactical monitoring of enemy troop movements.
What does the Future hold for Wireless Sensor Networks? 12
Industrial & CommercialIndustrial & 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 & MonitoringTraffic 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
What does the Future hold for Wireless Sensor Networks? 15
Economic FactorsEconomic 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
NoveltyNovelty
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 / LiabilityLegal / 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
EntertainmentEntertainment
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
NotNot Technical Superiority 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.
What does the Future hold for Wireless Sensor Networks? 21
Unexpected Killer ApplicationsUnexpected 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 AriseUnanticipated 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
What does the Future hold for Wireless Sensor Networks? 24
Noisy SensorsNoisy Sensors
Sensor readings can be inaccurate. Protocols need to recognize this.
GPS Sensor Accurate within
2.8 metersRelative 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 ConditionsWireless 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 FactorsEnvironmental 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 What will Wireless Sensor Networks Look Like in the Networks Look Like in the
Near Future?Near Future?
What does the Future hold for Wireless Sensor Networks? 28
Large-Scale DeploymentsLarge-Scale Deployments
Sensor networks will grow in size because of:– Lower cost
– Better protocols
– Advantages of dense networks
What does the Future hold for Wireless Sensor Networks? 29
Heterogeneous SensorsHeterogeneous 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 SensorsMobile Sensors
Sensors with Micromachines
Low-Power Motors that Support Mobility
What does the Future hold for Wireless Sensor Networks? 31
General Purpose SensorsGeneral 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 AreasOverlapping 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 WirelessMixture of Wired and WirelessWireless 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
What does the Future hold for Wireless Sensor Networks? 35
Need a Standardized InterfaceNeed 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 ProtocolService Discovery Protocol
Anyone need a printer?
What does the Future hold for Wireless Sensor Networks? 37
Service Discovery Protocol (cont.)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 functionalitySupports novel interactions in the future
What does the Future hold for Wireless Sensor Networks? 38
Security IssuesSecurity 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 ConcernsLiability 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 EngineeringSoftware 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 ConclusionsSummary 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