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Title: Mobile%20Computing%20and%20its%20Research%20Challenges


1
Mobile Computing and its Research Challenges
  • Gihwan Cho
  • ghcho_at_cs.chonbuk.ac.kr

2
Outline
  • Lecture overview
  • What is mobile computing
  • System model
  • Wireless networking
  • Mobile IP overview
  • Inherent characteristics
  • Application perspective
  • Case studies
  • Research thrusts

3
Lecture Overview
  • Lecture (about 8 weeks)
  • mobile computing and its research thrusts
  • Internet protocol, next generation Internet
  • cellular networks
  • Mobile IP, its related topics
  • routing optimization
  • fast handoff
  • security issues
  • http//cs.chonbuk.ac.kr/ghcho/courses/mobcomputin
    g.html
  • Then, in depth seminar
  • 2examination, 1 report

4
What is Mobile Computing
  • A computing paradigm that supports mobile hosts,
    in which users are capable of accessing
    information anywhere, anytime
  • wireless networks portable computers
  • traditional networks mobile users ( location
    sensors)
  • Seamless connectivity
  • cf. ubiquitous computing
  • cf. nomadic computing
  • cf. wearable computing
  • cf. virtual reality

5
Background
80s
90s
70s
00s
Personal Computing
Downsizing
Shared gt Dedicated
Distributed Computing
Networking
Centralized gt Distributed
Mobile Computing
More Downsizing and Wireless Networking
Static gt Mobile
  • Information superhighway
  • - timely news, and way too much of it
  • - information where people want to be

6
Evolution of Computing Paradigm
  • Over time, the evolution of computing has
    decreased the tight coupling between the user and
    his or her computing resource and environment (R.
    H. Katz, Adaptation and Mobility in Wireless
    Information Systems, IEEE Personal Communications
    Magazine, 1994)

More flexible resource usage
Mobile Computing
LANs WSs (Distributed Computing)
Networking
Timesharing
Batch
Single User, OS
Freedom from collocation
7
Nomadic Computing University of Helsinki
  • Provide a rich set of computing and communication
    capabilities and services to nomads as they move
    in a transparent, integrated and convenient form
  • enables access to the fixed network services from
    virtually anywhere and anytime
  • Nomadicity independence of (or free from )
  • location
  • motion
  • computing platform
  • communication device
  • communication bandwidth

8
Wearable Computing (I) CMU( Intimate
Computing)
  • Well-designed mobile and wearable devices can
    offer more portable and effective ways for people
    to relate to the information
  • use of human body as a support environment for
    the devices
  • human body is active, its form is diverse and
    changing
  • the physical shape of wearable and their active
    relationship with the human form
  • Ergonomics design issue
  • comfort for a wide range of body sizes
  • ruggedness
  • user safety
  • hygiene/cleanliness

9
Wearable Computing (II) MIT
  • A real person's computer should be worn, much as
    eyeglasses or clothing are worn, and interact
    with the user based on the context of the
    situation
  • on the waist, wrist, pocket, underwear
  • unobtrusive input devices
  • heads-mounted displays

10
Ubiquitous Computing (I) Xerox Palo Alto
  • Methods of enhancing computer use by making many
    computers available throughout physical world,
    environment, but making them effectively
    invisible to the user (Weisers position)

11
Ubiquitous Computing (II) Georgia tech FCE(
Everyday Computing)
  • Intelligent and interactive human-centric systems
    that support and augment our daily lives
  • the attempt to break away from the traditional
    desktop interaction paradigm and move
    computational power into the environment that
    surrounds the user
  • Three themes
  • natural interface
  • context-aware application
  • automated capture and access
  • Aware computing
  • identify the users, locate them, determine their
    focus of attention, and attempt to ascertain
    their intentions, i.e., be aware

12
Pervasive Computing IBM
  • Make easy life with smart devices
  • enable people to accomplish an increasing number
    of personal and professional transactions using a
    new class of intelligent and portable devices
  • simplifies life by combining open standards-based
    applications with everyday activities
  • Objects
  • gives us tools to manage information easily
  • can help us manage information quickly,
    efficiently, and effortlessly

13
Virtual Reality vs. Embodied Virtuality
Virtual Reality
Embodied Virtuality
(Mobile Computing)
ref Zerox Palo Alto
14
System Model
  • An augmented form from distributed computing
    environment, with using wireless networks and
    mobile hosts
  • Different networks
  • fixed network and wireless network
  • Mobile Host (MH)
  • online mobility or offline mobility
  • occasionally disconnection
  • Mobile Agent (MA)
  • beaconing / solicitation
  • hand-off procedure

15
Basic System Model
Fixed Network
  • Mobile
  • Agent 10

Mobile Agent 20
Fixed Server
Fixed Host
MH 21
MH 12
Host Moving
MH 11
Wireless Network 2
Disconnected MH
Wireless Network 1
16
Mobile Computers
17
Post PC ?
  • John Hennessys position computer, Aug. 1999
  • The new applications come from the new era we
    are moving into
  • Post PC is named by David Patterson at UC
    Berkeley
  • information appliances are absolutely a big part
    in the future
  • (these devices offer limited functionality, so
    they are cheap and easy to use, and they come in
    an explosive variety)
  • we are moving into a world where there are many
    more than just one or two computers per person
  • in such a world your network connection becomes
    more important than any one computing devices

18
Wireless Access Network
  • Future mobile information systems will be built
    upon heterogeneous wireless overlay networks

19
Wireless Access Technologies
Mbps
Wired
100
Mobile Broadband Systems
Wireless Local Area Networks
10
1
FPLMTS/UMTS/IMT-2000
PCS
0.1
Cordless
Cellular
0.01
Office or Room
Building
Stationary
Walking
Vehicle
Indoors
Outdoors
UCB, Katz
20
Wireless Networking
  • Wireless overlay

ref UCBs BARWAN
21
Wireless Networking Bluetooth (I)
  • Overview
  • small size (0.5 inch2)
  • cheap price (below 5 per chip)
  • low power consumption (100mW)
  • small scale radio propagation range (10-100m)
  • wireless link connection (IR or 2.4GHs ISM RF
    band)

22
Wireless Networking Bluetooth (II)
  • Usages
  • the three-in-one phone
  • cordless telephone(in home), cellular phone(in
    public area), walkie-talkie(between Bluetooth
    phones)
  • Internet bridge

23
Wireless Networking Bluetooth (III)
  • Usages (cont)
  • the interactive conference
  • data exchanging for conferences
  • exchanging business card automatically
  • ultimate head set
  • forwarding voice to head set from cellular or
    telephone

24
Wireless Networking WLAN (I)
  • Overview
  • IEEE 802.11 wireless LAN standard
  • operating in the 2.4GHz (ISM area)
  • modulation and signaling characteristics
  • FHSS(Frequency-Hopping Spread Spectrum)
  • DSSS(Direct-Sequence Spread Spectrum)
  • IR(Infrared Rays)
  • bandwidth support
  • IEEE 802.11 max 2Mbps
  • IEEE 802.11b a dual 5.5Mbps and 11Mbps
  • radio range
  • max 3Km with external antenna

25
Wireless Networking WLAN (II)
  • Merits of W-LAN
  • installation speed, simplicity, and flexibility
  • mobility
  • reduced cost of ownership
  • scalability

26
Location Sensor Technology
  • Active badges a means of locating individuals
    within a building by determining the location
  • sends out an IR burst coded with its 48bits long
    identifier every 10 sec., and it is picked up by
    sensors in line-of-sight within 30m
  • over 1500 badges and 2000 sensors are deployed
    throughout a number of European universities, and
    some places elsewhere
  • information about the location of individuals is
    made available through the WWW active badge
    service

ref Olivetti
27
Wireless Internet IMT-2000 (I)
  • Overview
  • worldwide roaming capability
  • concurrent support of voice and packet data
  • capability for multimedia applications, and a
    wide range of services and terminals

28
Wireless Internet IMT-2000 (II)
  • Incorporated IP

ref LG presentation Current
Status,Developments Standardization of IMT-2000
29
Wireless Internet IMT-2000 (III)
  • Separated IP network

ref LG presentation Current
Status,Developments Standardization of IMT-2000
30
Infrastructure in Practical
  • Internet Wireless networking

31
Why Mobile IP ? (I)
  • Background
  • Internet explosion
  • increasing the mobile workforce, and mobile users
  • increased reliance on networked computing
  • prevailing the portable devices, technologies
  • IPv4 routing considerations
  • two level hierarchical address structure (network
    id, host id)
  • longest prefix (network id) matching based static
    routing
  • host id based routing may produce the scalability
    problem
  • if a host moves around, the network id should be
    changed!
  • then, the routing scheme to the MH may not
    applied!!
  • clearly, a corresponding host does not know (need
    not by network layering concept) the moving
    hosts current network id

32
Why Mobile IP ? (II)
  • So, which layer should take charge of host
    mobility?
  • applications, transport? IP? NI?
  • sure, IP could give to higher level protocols the
    abstraction that the network address remains
    unchanged, therefore Mobile IP
  • Mobile IP allows users of portable computers to
    move form one place to another and yet maintain
    transparent network access through the wireless
    link
  • Initially, it does not assumed in design phase,
    for the host mobility nature, so much
    appropriated to macro mobility
  • however, in the practical point of view, most
    moving entities have some degree of moving
    pattern, that is micro mobility family

33
Mobile IP Overview (I)
  • Three steps with the protocol
  • agent discovery MAs may advertise their
    availability for they provide service, or a newly
    arrived MH may send a solicitation to learn if
    any prospective agents are present
  • ICMP router discovery
  • registration when an MH is away from home, it
    registers its care-of address with its HA
  • UDP control messages
  • tunneling datagrams sent to an MH is away from
    home must be tunneled to hide its home address
    from intervening routers
  • encapsulation protocol

34
Mobile IP Overview (II)
Correspondent Node
HA (HA)
FA (FA)
Mobile Node
Agent Solicitation
agent discovery
Agent Advertisement
Registration Request
Registration Request
Registration Reply
registration
Registration Reply
Data sent
Data received
tunneling
35
Mobile IP Overview (III)
agent discovery
36
Triangle Routing
  • Triangle routing is undesirable
  • Increased network utilization (sensitivity to
    network partition)
  • Irregularity of performance variance

Internet Host
Home-based Location
Reply Path
Tunneling
Home Agent
MH k
Host Moving
37
Related Issues
  • Triangle routing
  • routing optimization
  • Registration overhead (delay)
  • fast handoff
  • Security
  • reverse tunneling, AAA
  • When mobile node moves around
  • Ad hoc routing

38
Inherent Characteristics
  • Location
  • sender does not (need not) know that its
    destination is moving
  • but, the destination could be currently anywhere
  • Wireless medium
  • limited bandwidth and higher error rates
  • broadcasting-based and less symmetrical
    transmission
  • Disconnection
  • voluntary (sometimes spurious) nature
  • limited battery life
  • Logical structure
  • an underlying logical structure is modified as
    hosts move

39
Inherent Constraints
  • Mobile hosts are resource poor
  • weight, power, size
  • Mobility leads to communication uncertainty
  • bandwidth, latency, error, intermittent, cost
  • Power management is a great concern
  • deferred action, less communication
  • Mobility hurts security and robustness
  • theft, destruction, privacy

40
Distributed Computing (DC) vs. Mobile Computing
(MC) (I)
  • Distributed system a collection of computers
    connected by a communications subnet and
    logically integrated in varying degrees on
    purpose to resolve a task co-operatively
  • MC is a next logical step of DC
  • Centralized or Distributed
  • Fixed or Mobile
  • resource CPU, memory gt network
  • paradigm client-server gt peer-to-peer

41
Distributed Computing (DC) vs. Mobile Computing
(MC) (II)
  • Many problems of MC are subsumed by DC, but the
    solutions are quite different due to the
    different system model
  • Location transparency is a goal in DC,
    additionally location awareness is a requirement
    in MC
  • In addition, MC must
  • deal with wide variations in resources
  • adapt to changes in the environment
  • handle network partitions and partial failures
  • accommodate multiple administrative domains
  • take scalability seriously

42
A Paradox
  • The integration of wired- and wireless- network
    is a natural, logical extension of the two
    networks
  • But, it is a horrible conflict of opposing
    technical, operational and social dynamics
  • Mobile computing impacts as
  • good performance
  • high speed illusion
  • dynamic transmission
  • huge storage and processor

high speed flexible transmission huge resource
low speed broadcast and symmetrical limited
resource
43
Application Perspectives
  • When mobile computer will be the norm in real
    life?
  • What applications put pressure the trend?
  • vertically integrated services
  • electric mail, news, bulletin boards
  • horizontally integrated services
  • wwww(wireless www), mobile multimedia access
  • location dependent information services
  • movies currently playing at local theaters?
  • navigation system
  • CSCW (Computer Supported Collaborative Works)
  • emergency, military, sales, education, game

44
Some Implications to Mobile Application
  • Productivity as someone being able to do
    something more in equal amount of time or less
  • Time value of information
  • example) vending machine operator
  • Requirements to assist field engineers
  • support for geographical information
  • support for collaboration
  • support for voice communications
  • operation in a heterogeneous processing
    environment
  • operation in a heterogeneous networking
    environment

45
Mobile Application Technology
  • Horizontal technologies
  • wireless file access
  • mobile multimedia data service
  • wireless web browser
  • Vertical technologies
  • mobile end systems
  • wireless local- and wide-area networks
  • sensor technology for location tracking

46
Mobile Application Systems
  • Wearable computing
  • Tour guide
  • Mobile house information system
  • Maintenance assistance in the field
  • Classless education
  • Mobile medical information system
  • Personal area network
  • Moving detection on the floor
  • Mobile office

47
Wearable Computing (I) MIT, IBM, gatech
  • A real person's computer should be worn, much as
    eyeglasses or clothing are worn, and interact
    with the user based on the context of the
    situation

48
Wearable computer system (II) CMU
  • The speech translator smart module
  • Language Translator (LT), Speech Recognizer (SR)

49
Bill Gates House washington post
  • Guests will receive electronic badges that will
    relay information about their preference. When
    they move, lights will brighten or dim, the
    temperature will be adjusted, the pictures
    displayed on the video screens will change,
    favorite music will play on the stereo

50
HyperAudio ecate.itc.it
  • A system able to organize exhibition contents
    taking into account the visitor's needs and the
    layout of the exhibit

51
Maintenance Area CMU
  • Maintenance records, manuals, parts inventories
  • vehicle or aircraft repair, transportation
    control
  • construction or mining

52
Classless Education CMU
  • Takes part in a class anywhere, with benefit
    wireless medium and hand-hold mobile terminals

53
Easy Living MS
  • Detect and/or analyze users behavior (intension)
    intelligently, and then provide the most
    effective information to the users current
    situation

Applications/UIs
Geometric Model
Queries
Measurements
Commands
Sensors
Actuators
Physical World
54
CLiF A Mobile Medical Information System
www.egd.igd.fhg.de
  • Record data of the analysis of functional
    disorders of the masticatory system during
    examination
  • Provide a simpler and cost effective means for
    recording, a faster data availability and a
    better data quality

55
PAN (Personal Area Network) MIT
  • Permit to send data through the body, such as a
    handshake could exchange business cards, a hand
    on a doorknob could unlock it, or fingers
    touching a keyboard could transmit a
    cryptographic key

56
Smart Floor gatech
  • Gravity! it keeps our feet on the ground
  • Smart Floor is a system that identifies and
    tracks people based on their footfalls
  • Application area includes home activities, art
    and dance performance, and entertainment

57
Mobile Office ex) an automobile insurance
adjuster
58
Application Area Presumed (I)
  • Customer service
  • providing e-services and solutions anytime,
    anywhere
  • a variety of useful objects can sense your
    presence and seamlessly cooperate to give you
    enhanced customer service
  • Business
  • capturing information from a beacon on your
    mobile device is like bookmarking the physical
    world
  • an executive can enter a conference room, beam
    her electronic business card to everyone in the
    room, and send her presentation to the connected
    projector - no laptop, no wires

59
Application Area Presumed (II)
  • Education
  • becomes an educational lab that can be accessed
    instantly via open, web-based tools and software
  • appliances like watches provide both a link to an
    individual's identity and to the e-services
    network
  • Personalization
  • technology saves lives by providing a vital link
    to emergency medical services
  • accessed immediately by service providers who
    need to know the status of your physical condition

60
Application Area Presumed (III)
  • Safety
  • all vehicles can be mobile appliances, with their
    own presence on the web
  • provides a physical location, and a corresponding
    mobile web presence for the vehicle and
    driving-related services
  • Responsiveness
  • emergency services are made more effective
    through the use of smart, connected appliances
  • the fireman's visor is actually a context-aware
    appliance with the ability to display real-time
    building and victim information

61
Summary multiple disciplines for mobile
applications
  • Mobile application system design is an exciting
    new opportunity in the vertical and horizontal
    domains

Wireless WWW
Mobile Multimedia Data Service
Mobile File Service
Mobile End System
Wireless Networking
Location Tracking
62
Research Thrust 1 Infrastructure
  • Issue locating a mobile host, and delivering
  • datagrams to its current location
  • Mobility support protocols
  • mobile IP, CDPD, IMT2000
  • Location optimization
  • Transport adaptation
  • Security and privacy
  • Location overhead vs. routing optimization
  • Columbia univ., Rutgers Univ., UCB, Univ.
    Kentucky,
  • Univ. Trier, Sony, IBM,

63
Thrust 2 Power Consumption
  • Issue extending the limited battery life to
    save
  • host mobility duration
  • Adjusting CPU clock rate
  • C2 power saving with C speed reduction
  • Operating system
  • Programming language
  • Database query processing
  • Energy saving vs. service delay
  • Intel, Micro Soft, UCB, Xerox PARC,
    Apple

64
Thrust 3 Mobile Terminals
  • Issue ergonomic designing the mobile terminals
    to move without any disturbance
  • Ergonomic design
  • packaging (wearable)
  • input (pen, speech, gesture, intention)
  • High degree processing (ASICs, CMOS, MMIS)
  • digital signal processing, error correction
  • Display technology (LCD, data spectacles)
  • power consumption, hand-free
  • Standford, Xerox PARC, Apple

65
Thrust 4 Distributed Algorithm
  • Issue supporting intermittently moving
  • and/or disconnected clients
  • Mobile mutual exclusion
  • Mobile multicast
  • Indexed broadcasting
  • Weekly consistency
  • Semantic based transaction processing
  • Application transparent vs. aware
  • Rutgers Univ., Purdue Univ., CMU, Stanford
    Univ.,
  • Michigan Univ., Southern Methodist Univ.,
    Pittsburgh Univ.

66
Thrust 5 Mobile Multimedia
  • Issue providing video service through low
  • bandwidth and heterogeneous
  • QoS filtering
  • Content-based meta (generative) video
  • Different video quality
  • Variable compression rate
  • Video resolution vs. transmission delay
  • Cambridge Univ., Lancaster Univ.,CMU,
  • Univ. Pennsylvania, EXODUS Project, UCB

67
Thrust 6 Location Dependent
Applications
  • Issue giving users or applications control
  • over their whereabouts
  • Message delivery and display based on
  • location of recipient
  • identity of sender
  • contents of message
  • nearby display terminals
  • others in the vicinity
  • User control vs. application control
  • Rutgers Univ., Monash Univ., Univ.
    Washington,
  • Univ. Trier, Univ. Waterloo

68
Thrust 7 Wireless WWW
  • Issue browsing the most useful information
  • in a given place with simple I/O device
  • Caching and prefetching
  • Dynamic URL
  • Active document
  • Document filtering
  • WAP (Wireless Application
  • Protocol) Forum WML
  • Univ. Washington, MIT, Univ. Helsinki,
    IBM, GIT

69
Research Thrust Summary
Needs
Solutions
Systems
Location dependent Multimedia Energy efficient
Mobile terminal Networking infrastructure System
software
Components
Mobility support protocols Low power
design Signal processing
Technologies
70
Academic bodies doing research on Mobile
Computing
purdue,1997
71
Industrial bodies doing research on Mobile
Computing
purdue,1997
72
Publications Categorized by Area of Computing
Science
purdue,1997
73
Related Information
  • Conferences and Publications
  • USENIXs Mobile and Location Independent
    Computing Symposium
  • IEEE Workshop on Mobile Computing Systems and
    Applications
  • IEEE symposium on Wearable Computers
  • ACM/IEEE Conference on Mobile Computing and
    Networking (MobiCom)
  • ACM/IEEE symposium on Ubiquitous Computing
  • ACM and BSPs Wireless Networks Journal (WINET)
  • Mobile Networks and Nomadic Application
    Journal (NOMAD)
  • Mobile Networking and Applications
    (MONET)
  • Mobile Computing and Communications Review
    (MC2R)
  • IETF mobile-ip working group
  • http//www.ietf.org/mobileip
  • http//www.ietf.org/seamoby
  • http//www.ietf.org/aaa
  • http//www.ietf.org/manet
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