Past, Present, and Future of Mobile Computing

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Past, Present, and Future of Mobile Computing

• Yu CaiDepartment of Computer ScienceUniversity
  of Colorado at Colorado Springs

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Presentation outline

• Introduction on mobile computing
• Past of mobile computing
• Present of mobile computing
• Wireless LAN GSM/GPRS/CDMA
  Bluetooth
• Mobile IP Mobile Ad Hoc
  Network (MANET)
• PDA/SmartPhone/Laptop Sensor/Zigbee Mesh
  RFID
• Security
• Future of mobile computing

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What is mobile computing?

• Mobile computing is to describe technologies that
  
• enable people to access network services
  anyplace, anytime, and anywhere,
• with portable and wireless computing and
  communication devices. --- (where is this
  referenced? Provide citation!)
• Aspects of mobility
• User mobility
• Between different geographical locations
• Between different networks
• Between different communication devices
• Between different applications
• Device portability
• Between different geographical locations
• Between different networks

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Mobile Computing vs. Ubiquitous
Computing/Pervasive Computing

• Mobile Computing is a generic term describing the
  application of small, portable, and wireless
  computing and communication devices. This
  includes devices like laptops with wireless LAN
  technology, mobile phones, wearable computers and
  Personal Digital Assistants (PDAs) with Bluetooth
  or IRDA interfaces, and USB flash drives.
• Ubiquitous computing (ubicomp, or sometimes
  ubiqcomp) integrates computation into the
  environment, rather than having computers which
  are distinct objects. Another term for ubiquitous
  computing is pervasive computing. Promoters of
  this idea hope that embedding computation into
  the environment would enable people to move
  around and interact with computers more naturally
  than they currently do. -- http//en.wikipedia.or
  g/wiki/

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Applications of mobile computing

• Vehicles
• transmission of news, road condition, weather,
  music via DAB
• personal communication using GSM
• position via GPS
• local ad-hoc network with vehicles close-by to
  prevent accidents, guidance system, redundancy
• vehicle data (e.g., from busses, high-speed
  trains) can be transmitted in advance for
  maintenance
• Medical
• Nurses/Doctors in Medical offices are now using
  Wireless Tablet PCs/WLAN to collect and share
  patient information.
• Sales
• Sales representatives are using Tablet PCs with
  Smart phones for presentation, transmitting/access
  information among office, hotel, and customer
  location.
• Emergencies
• Early transmission of patient data to the
  hospital, current status, first diagnosis
• Provide mobile infrastructure in dealing with
  Natural Disaster (earthquake, hurricane, fire),
  terrorist attacks, war, ...

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Natural evolution of computing
More Flexible Resource Usage
Mobile Computing
LANs WorkStations
Networking
Timesharing
Batch
Single User OS
Freedom from Collocation
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Challenges in mobile computing

• Mobility means changes
• Hardware
• Lighter, smaller, energy management, user
  interface
• Low bandwidth, high bandwidth variability
• Kbit/s to Mbit/s, bandwidth fluctuation
• Security risk
• Devices more vulnerable, endpoint authentication
  harder
• Heterogeneous network
• Different devices, interfaces and protocols
• Location awareness
• Locality adaptation
• Higher loss-rates, higher delays, more jitter
• Connection setup time, hand-off
• Restrictive regulations of frequencies
• Frequencies have to be coordinated

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History of wireless communication

• 1896 Guglielmo Marconi,
• First demonstration of wireless telegraphy
• Based on long wave, requiring very large
  transmitters
• 1907 Commercial Trans-Atlantic Wireless Service
• Huge ground stations 30 x 100m antenna masts
• 1920 Discovery of short waves by Marconi
• Cheaper, smaller, better quality transmitters by
  vacuum tube
• 1982 Start of GSM in Europe (1G analog)
• 1983 Start of AMPS in America (1G analog)
• 1992 Start of GSM (2G digital)
• 1997 Wireless LAN - IEEE802.11
• 1998 Iridium satellite system
• 66 satellites

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History of wireless communication

• 1999 Standardization of additional wireless LANs
• IEEE standard 802.11b
• Bluetooth
• WAP (Wireless Application Protocol) access to
  many services via the mobile phone
• 2000 GSM with higher data rates (2.5G digital)
• HSCSD offers up to 57,6kbit/s
• First GPRS trials with up to 50 kbit/s
• 2001 Start of 3G systems
• IMT - 2000, several members of a family,
  CDMA2000 in Korea, UMTS tests in Europe

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Overview of mobile devices

• Smart phone
• voice, data
• simple graphical displays

• Pager
• receive only
• tiny displays
• simple text messages

• Laptop
• fully functional
• standard applications

Sensors, embedded controllers

• PDA
• graphical displays
• character recognition

• Wearable device
• human wearable
• non standard I/O

performance
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Overview of development
wireless LAN
cordlessphones
cellular phones
satellites
1980CT0
1981 NMT 450
1982 Inmarsat-A
199x proprietary
1983 AMPS
1984CT1
1G
1986 NMT 900
1997 IEEE 802.11
1987CT1
1988 Inmarsat-C
1989 CT 2
1999 802.11b, Bluetooth
1992 Inmarsat-B Inmarsat-M
1991 D-AMPS
1991 CDMA
1992 GSM
2G
1991 DECT
1993 PDC
2000 IEEE 802.11a
1994DCS 1800
1998 Iridium
2003 IEEE 802.11g
2.5G
2000GPRS
2007? IEEE 802.11N
2001 IMT-2000
3G
20?? Fourth Generation?
analogue
4G?
digital
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Overview of wireless services
Data Rates
Wireless LAN
10 Mbps
IR
1 Mbps
Cellular GSM, GPRS, CDMA,
50 Kbps
Satellite
10 Kbps
Wide
Local
Coverage Area
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Wireless LAN

• IEEE 802.11 standard a family of specifications
  for wireless LAN technology. The IEEE accepted
  the specification in 1997.
• 802.11 specifies an over-the-air interface
  between a wireless client and a base station or
  between two wireless clients.
• 802.11 up to 2 Mbps in the 2.4 GHz band.
• 802.11b up to 11 Mbps in the 2.4 GHz band.
• 802.11a/g up to 54 Mbps in the 5/2.4 GHz band.
• 802.11n up to 220 Mbps in the 2.4/5 GHz band
  (two proposals not approved yet). Vendors already
  selling 802.11pre-n devices.
• 802.11 promises true vendor interoperability.
  Every vendor must have a viable 802.11 product
  strategy.

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Wireless LAN Security

• WEP Wired Equivalent Privacy.
• A basic wireless LAN security mechanism.
• Easy to set up, commonly used.
• Dont rely on WEP for wireless security. There
  are a number of flaws in the WEP.
• Many wireless home networks dont even use WEP,
  which makes bad situation worse.
• MAC address based access control mechanism
  doesnt work.
• Use other security mechanisms such as VPN, PEAP
  and TTLS.
• Research project on PEAP / TTLS in our research
  group in University of Colorado.

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Wireless Ad Hoc Network

• Wireless Ad Hoc Network (peer to peer)
• A collection of autonomous nodes that communicate
  with each other by forming a multi-hop radio
  network in a decentralized manner.
• No infrastructure, no default router available
• every node needs to be a router
• Mobile Ad Hoc Networks (MANET)
• Host movement frequent
• Topology change frequent
• Wireless Ad Hoc Sensor Networks
• A number of sensors spread across a geographical
  area.
• Limited resources on sensors  

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Mobile IP

• Mobile IP is designed to allow mobile device
  users to move from one network to another while
  maintaining their permanent IP address.
• Motivation
• Changing the IP address is not desired when host
  moves.
• However, traditional scheme requires to change IP
  address when host moves between networks.
• Mobile IP provides an efficient, scalable
  mechanism for node mobility within the Internet.
  Mobile IP allows moving devices to maintain
  transport and higher-layer connections while
  moving.
• Applications
• Mobile IP is most often found in wireless WAN
  environments where users need to carry their
  mobile devices across multiple LANs with
  different IP addresses.

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Mobile IP Basic Idea
Mobile Node (MN)
Home Agent (HA)
2
Internet
home network
receiver
3
foreign network
COA ?
Foreign Agent (FA)
1. Sender sends to the IP address of MN, HA
intercepts packet (proxy ARP) 2. HA tunnels
packet to COA, here FA, by encapsulation 3.
FA forwards the packet to the MN
1
sender
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Mobile IP Basic Idea
HA
1
MN
Internet
home network
sender
FA
foreignnetwork
1. Sender sends to the IP address of the
receiver as usual, FA works as default router
CN
receiver
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Bluetooth

• Bluetooth is used to connect and exchange
  information between devices like PDAs, mobile
  phones, laptops, PCs, printers and digital
  cameras wirelessly.
• Named after a Denmark king Harold Bluetooth, who
  is known for his unification of previously
  warring tribes.
• Low-cost, short range (up to 10m), low power
  consumption, license-free 2.45 GHz band.
• Using the same frequency range, Bluetooth differs
  from Wi-Fi in that
• Different multiplexing schemes.
• Wi-Fi with higher throughput, greater distances,
  more expensive hardware, and higher power
  consumption.
• Applications
• Wireless mouse, wireless headset

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RFID Radio Frequency Identification

• RFID is a method of remotely storing and
  retrieving data using devices called RFID tags.
• An RFID tag is a small object, such as an
  adhesive sticker, that can be attached to or
  incorporated into a product.
• RFID tags contain antennas to enable them to
  receive and respond to radio-frequency queries
  from an RFID transceiver.
• No line-of sight required (compared to laser
  scanners)
• Withstand difficult environmental conditions
  (cold, frost etc.)
• Categories
• Active RFID battery powered, distances up to 100
  m
• Passive RFID operating power comes from the
  reader over the air, distances up to 6 m
• Applications
• Automated toll collection RFIDs mounted in
  windshields allow commuters to drive through toll
  plazas without stopping

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GSM

• One of the most popular standards for mobile
  phones in the world.
• Formerly Groupe Spéciale Mobile (founded 1982)
• Now Global System for Mobile Communication
• European standard, moving to North America
• More than one billion people use GSM phones as of
  2005, making GSM the dominant mobile phone system
  worldwide with about 70 of the world's market.
• GSM is a cellular network, which means that
  mobile phones connect to it by searching for
  cells in the immediate vicinity.
• One of the key features of GSM is the Subscriber
  Identity Module (SIM), commonly known as a SIM
  card. The SIM is a detachable smartcard
  containing the user's subscription information
  and phonebook.

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GSM Overview
HLR
OMC, EIR, AUC
fixed network
GMSC
NSS with OSS
VLR
MSC
MSC
VLR
BSC
BSC
RSS (Radio Subsystem) NSS (Network and switching
subsystem) OSS (Operation Subsystem) MS (Mobile
Station) BTS (Base Transceiver Station) BSC (Base
Station Controller) MSC (Mobile Services
Switching Center) GMSC (Gateway MSC) HLR (Home
Location Register) VLR (Visitor Location
Register) EIR (Equipment Identity Register) AUC
(Authentication Center ) OMC (Operation and
Maintenance Center )
RSS
MS
MS
BTS
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GPRS

• GPRS General Packet Radio Service
• It is a mobile data service available to users of
  GSM mobile phones. It is often described as
  "2.5G.
• GPRS is packet-switched which means that multiple
  users share the same transmission channel, only
  transmitting when they have data to send.
• GPRS provides moderate speed data transfer, by
  allocating unused cell bandwidth to transmit
  data.
• Poor bit rate in busy cells
• Usually, GPRS data is billed per kilobytes of
  information transceived
• In 3G mobile systems like UMTS (Universal Mobile
  Telecommunication System), voice and data
  services will be mixed in a normal communication.

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PDA

• Personal digital assistants (PDAs or palmtops)
• handheld devices that were originally designed as
  personal organizers, but became much more
  versatile over the years.
• A basic PDA usually includes a clock, date book,
  address book, task list, memo pad and a simple
  calculator.
• One major advantage of using PDAs is their
  ability to synchronize data with desktop,
  notebook and desknote computers.
• The currently major PDA operating systems are
• Palm OS by PalmSource, Inc
• Windows Mobile (Windows CE) by Microsoft
• BlackBerry by Research In Motion
• Symbian by a group of companies
• According to a Gartner market study, the overall
  market for PDAs shrunk by 5 in the first quarter
  (Q1) of 2004, compared to Q1 2003.

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Satellite Systems

• Like cellular systems, except that the base
  stations (i.e., satellites) move as will as
  mobile devices
• Satellite coverage attractive for areas of world
  not well served by existing terrestrial
  infrastructure ocean areas, developing countries
• IRIDIUM
• Motorola
• Voice, Data (2.4 kbps), Fax, Location Services
• 66 satellites in 6 polar orbits (780 km)
• Failed project

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Future mobile and wireless networks

• Shift industrial paradigm from piecewise
  solutions to end-to-end information systems
• Improved radio technology and antennas
• smart antennas, beam forming, multiple-input
  multiple-output (MIMO) 802.11N
• dynamic spectrum allocation
• Core network convergence
• IP-based, quality of service, mobile IP
• Ad-hoc technologies
• spontaneous communication, power saving,
  redundancy
• Simple and open service platform
• intelligence at the edge, not in the network (as
  with IN)
• more service providers, not network operators only

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Integrated mobile computing
Integration of heterogeneous fixed andmobile
networks with varyingtransmission characteristics
regional
vertical handover
metropolitan area
horizontal handover
campus-based
in-car, in-house, personal area
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IP-based next generation network ?
SS7 signalling
PSTN, CS core
server farm, gateways, proxies
broadcast
gateways
IP-based core
MSC
firewall, GGSN, gateway
SGSN
BSC
router
Internet
GSM
access points
private WLAN
private WPAN
RNC
UMTS
public WLAN
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Literature

• Jochen Schiller Mobile Communications
• Ivan Stojmeniovic Handbook of Wireless Networks
  and Mobile Computing
• Andrew Tanenbaum Computer Networks
• James D. Solomon Mobile IP, the Internet
  unplugged
• Charles E. Perkins Ad-hoc networking
• Papers, papers, papers,
• Mobile Computing Courses
• MIT http//nms.lcs.mit.edu/6.829-f01/
• Stanford http//www.stanford.edu/class/cs444n/
• UC Berkley http//www.cs.berkeley.edu/adj/cs294-
  1.f00/
• UT Austin http//www.cs.utexas.edu/users/ygz/395T
  /
• http//kunz-pc.sce.carleton.ca/sce536/
• http//www.cs.unc.edu/dewan/290/s02/lectures/lect
  ures.htm
• http//www.cs.arizona.edu/classes/cs630/fall01/630
  -1/contents.htm
• http//www.cs.ucsb.edu/cs290i_mc/index.html

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Thank you!