CSE 535 Mobile Computing Lecture 2: An Overview of Mobile Computing: Part I Motivation and Challenge

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CSE 535 Mobile ComputingLecture 2 An
Overview of Mobile Computing Part I Motivation
and Challenges

• Sandeep K. S. Gupta
• School of Computing and Informatics
• Arizona State University

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Agenda

• Introduction to Mobile Computing
• Introduction to Wireless Sensor Networking and
  Applications

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Mobile Computing

• The need for "information anywhere anytime" has
  been a driving force for the increasing growth in
  Web and Internet technology, wireless
  communication, and portable computing devices.
• The field of mobile computing is the merger of
  these advances in computing and communication
  with the aim of providing seamless and ubiquitous
  computing environment for mobile users.  
• Mobile computing techniques are essential for
  enabling distributed and net-centric applications
  which require remote and ubiquitous information
  access.

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Mobile Computing Challenges

• Mobile computing environments are characterized
  by severe resource constraints and frequent
  changes in operating conditions.
• This has led to many new and challenging problems
  which span several areas of computer science such
  as incorporation of support for mobility in
  network protocols, development of efficient and
  adaptive resource management techniques for
  wireless bandwidth and battery power, predicting
  mobility patterns, performance modeling and
  simulation of mobile applications, and supporting
  mobile real-time multimedia applications.

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MC - Fundamentals

• Mobile Computing gt Adaptive Computing and
  Communication
• Cross-Layer approach is need for
• Adaptation
• Conserving resources such as energy
• Mobile computing is distinct from distributed
  computing
• Mobile computing is an essential component of
  Ubiquitous computing.

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Mobility and Adaptability
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Example Adaptive Approaches

• Approach 1 Combine solutions with different
  optimality ranges/performance characteristics.
• Approach 2 Treat change in system state as a
  transient fault and use the techniques of
  designing fault-tolerant protocols
• Approach 3 Dynamically monitor the system state
  and use the solution which is suitable for the
  current system state.
• Many others - .

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Promises of Mobile Computing

• Global information services at any time from any
  location
• Mobile users as integrated consumers and
  producers of data and information
• Ubiquitous computing where mobile computers
  become an integral part of daily activities

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Mobile Applications

• Expected to create an entire new class of
  Applications
• new massive markets in conjunction with the Web
• Mobile Information Appliances - combining
  personal computing and consumer electronics
• Applications
• Vertical vehicle dispatching, tracking, point of
  sale, information service (yellow pages), Law
  enforcement
• Horizontal mail enabled applications, filtered
  information provision, collaborative computing

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Vertical Applications

• l Serve a narrow, niche application domain
• Services dispatch (taxi, fire, police,
  trucking)
• Sales tracking (point of sale, market trends)
• Mail and package tracking (courier, postal)
• Relatively easy to implement due to
• restrictions and assumptions
• homogeneous MUs
• limited numbers of users

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Horizontal Applications

• Broad, domain-independent applications serving a
  mass-market
• Electronic Mail and News
• Yellow Pages Directory Services
• Multimedia Merchant Catalogs
• Digital Libraries
• Location-based Information Filtering
• Driving force of mobile computing research

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Medical Example

• 911 Call
• Ambulance arrives/departs
• Closest hospital
• Access patient records
• Send vital signs
• Update patient records
• Page hospital personnel
• Order medical supplies

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Party on Friday

• Update Smart Phones calendar with guests names.
• Make a note to order food from Dinner-on-Wheels.
• Update shopping list based on the guests drinking
  preferences.
• Dont forget to swipe that last can of beers UPS
  label.
• The shopping list is always up-to-date.

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Party on Friday

• AutoPC detects a near Supermarket that advertises
  sales.
• It accesses the shopping list and your calendar
  on the Smart Phone.
• It informs you the soda and beer are on sale, and
  reminds you.
• that your next appointment is in 1 hour.
• There is enough time based on the latest traffic
  report.

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Party on Friday

• TGIF
• Smart Phone reminds you that you need to order
  food by noon.
• It downloads the Dinner-on-Wheels menu from the
  Web on your PC with the guests preferences
  marked.
• It sends the shopping list to your
• CO-OPs PC.
• Everything will be delivered by the time
• you get home in the evening.

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Wireless Networks
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Wireless Networks

• Cellular - GSM (Europe), TDMA CDMA (US)
• FM 1.2-9.6 Kbps Digital 9.6-14.4 Kbps
  (ISDN-like services)
• Cellular Subscribers in the United States
• 90,000 in 1984 4.4 million in 199013 million
  in 1994 120 million in 2000 187.6 million by
  2004 (Cahner In-State Group Report).
• Handheld computer market will grow to 1.77
  billion by 2002
• Public Packet Radio - Proprietary
• 19.2 Kbps (raw), 9.6 Kbps (effective)
• Private and Share Mobile Radio
• Paging Networks typically one-way communication
• low receiving power consumption
• Satellites wide-area coverage (GEOS, MEOS,
  LEOS)
• LEOS 2.4 Kbps (uplink), 4.8Kbps (downlink)

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Wireless Networks (Cont.)

• Wireless Local Area Networks
• IEEE 802.11 Wireless LAN Standard based systems,
  e.g., Lucent WaveLan.
• Radio or Infrared frequencies 1.2 Kbps-15 Mbps
• Packet Data Networks
• ARDIS
• RAM
• Cellular Digital Packet Data (CDPD)
• Private Networks
• Public safety, UPS.

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Wireless Local Area Network

• Data services IP packets
• Coverage Area Offices, buildings, campuses
• Roaming Within deployed systems
• Internet access via LAN.
• Type of services Data at near LAN speed.

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Wireless Characteristics

• Variant Connectivity
• Low bandwidth and reliability
• Frequent disconnections
• predictable or sudden
• Asymmetric Communication
• Broadcast medium
• Monetarily expensive
• Charges per connection or per message/packet
• Connectivity may be weak, intermittent and
  expensive

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Portable Information Devices

• PDAs, Personal Communicators
• Light, small and durable to be easily carried
  around
• dumb terminals InfoPad, ParcTab projects,
• palmtops, wristwatch PC/Phone, walkstations
• run on AA /Ni-Cd/Li-Ion batteries
• may be diskless
• I/O devices Mouse is out, Pen is in
• wireless connection to information networks
• either infrared or cellular phone
• specialized HW (for compression/encryption)

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Portability Characteristics

• Battery power restrictions
• transmit/receive, disk spinning, display, CPUs,
  memory consume power
• Battery lifetime will see very small increase
• need energy efficient hardware (CPUs, memory) and
  system software
• planned disconnections - doze mode
• Power consumption vs. resource utilization

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Portability Characteristics

• Resource constraints
• Mobile computers are resource poor
• Reduce program size interpret script languages
  (Mobile Java?)
• Computation and communication load cannot be
  distributed equally
• Small screen sizes
• Asymmetry between static and mobile computers

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Mobility Characteristics

• Location changes
• location management - cost to locate is added to
  communication
• Heterogeneity in services
• bandwidth restrictions and variability
• Dynamic replication of data
• data and services follow users
• Querying data - location-based responses
• Security and authentication
• System configuration is no longer static

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What Needs to be Reexamined?

• Operating systems
• File systems
• Database systems
• Programming Languages
• Communication architecture and protocols
• Hardware and architecture
• Real-Time, multimedia, QoS
• Security
• Application requirements and design
• 
  

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Wireless Sensor Networking Applications and
Challenges

• Sandeep Gupta
• Arizona State University
• Based on Slides by Prof. Loren Schwiebert, CS,
  Wayne State University

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What is a Wireless Sensor Network?

• Wireless Sensor Node Sensor Actuator ADC
  Microprocessor Powering Unit Communication
  Unit (RF Transceiver)
• An ad hoc network of self-powered and
  self-configuring sensor nodes for collectively
  sensing environmental data and performing data
  aggregation and actuation functions reliably,
  efficiently, and accurately.

GPS Sensor Node
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Limitations of Wireless Sensors

• Wireless sensor nodes have many limitations
• Modest processing power 8 MHz
• Very little storage a few hundred kilobits
• Short communication range consumes a lot of
  power
• Small form factor several mm3
• Minimal energy constrains protocols
• Batteries have a finite lifetime
• Passive devices provide little energy

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Some Sample Applications

• Industrial and Commercial Uses
• Inventory Tracking RFID
• Automated Machinery Monitoring
• Smart Home or Smart Office
• Energy Conservation
• Automated Lighting
• Military Surveillance and Troop Support
• Chemical or Biological Weapons Detection
• Enemy Troop Tracking
• Traffic Management and Monitoring

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Sensor-Based Visual Prostheses
Retinal Implant
Cortical Implant
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Organization into Ad Hoc Networks

• Individual sensors are quite limited.
• Full potential is realized only by using a large
  number of sensors.
• Sensors are then organized into an ad hoc
  network.
• Need efficient protocols to route and manage data
  in this network.

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Why Wireless Sensors Now?

• Moores 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.

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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

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Wireless Sensor Nodes Examples

• Consider Multiple Generations of Berkeley Motes

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Historical Comparison
Consider a 40 Year Old Computer
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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

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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

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Conclusions

• Fundamental to Mobile computing is various
  techniques in hardware/software to adapt to
  variation in resource availability taking into
  account contextual information including user
  preferences.
• Wireless sensor networking is enabling technology
  for pervasive/ubiquitous computing
• Next Class - Continue discussion on Adaptation
  techniques
• Read Chapter 1