past, present, and future of mobile computing

6/2/2005 Yu Cai/MTU Talk 1

Past, Present, and

Future of Mobile Computing

Yu CaiDepartment of Computer Science

University of Colorado at Colorado Springs

Yu Cai/MTU Talk 26/2/2005

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


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


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.org/wiki/


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, ...


Natural evolution of computing

Freedom from Collocation

MoreFlexible

ResourceUsage

Single UserOS

Batch

Timesharing

Networking

LANs + WorkStations

Mobile Computing


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


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


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


Overview of mobile devices

performanceperformance

Pager• receive only• tiny displays• simple text messages

Smart phone• voice, data• simple graphical displays

PDA• graphical displays• character recognition

Wearable device• human wearable• non standard I/O

Sensors,embeddedcontrollers

Laptop• fully functional• standard applications


Overview of developmentcellular phones satellites

wireless LAN

cordlessphones

1992:GSM

1994:DCS 1800

2001:IMT-2000

1987:CT1+

1982:Inmarsat-A

1992:Inmarsat-BInmarsat-M

1998:Iridium

1989:CT 2

1991:DECT

199x:proprietary

1997:IEEE 802.11

1999:802.11b, Bluetooth

1988:Inmarsat-C

analogue

digital

1991:D-AMPS

1991:CDMA

1981:NMT 450

1986:NMT 900

1980:CT0

1984:CT1

1983:AMPS

1993:PDC

2000:GPRS

2000:IEEE 802.11a

20??Fourth Generation?

1G

2G

2.5G

3G

4G?

2003:IEEE 802.11g

2007?:IEEE 802.11N


Overview of wireless servicesData Rates

Coverage AreaLocal Wide

10 Mbps

1 Mbps

10 Kbps

50 Kbps

WirelessLAN

IR

Cellular: GSM, GPRS, CDMA,

Satellite


APAP

AP

Wired Network

AP: Access Point

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.

Wireless LAN


Wireless LAN Security

WEP: Wired Equivalent Privacy. A basic wireless LAN security mechanism. Easy to set up, commonly used. Don’t rely on WEP for wireless security. There are a number of

flaws in the WEP. Many wireless home networks don’t even use WEP,

which makes bad situation worse. MAC address based access control mechanism doesn’t

work. Use other security mechanisms such as VPN, PEAP and

TTLS. Research project on PEAP / TTLS in our research group in

University of Colorado.


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


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.


Mobile IP: Basic Idea

Internet

sender

Foreign Agent (FA)

Home Agent (HA)Mobile Node (MN)

home network

foreignnetwork

receiver

1

2

3

1. Sender sends to the IP address of MN, HA intercepts packet (proxy ARP)2. HA tunnels packet to COA, here FA, by encapsulation3. FA forwards the packet to the MN

COA: ?


Mobile IP: Basic Idea

Internet

receiver

FA

HA

MN

home network

foreignnetwork

sender

1

1. Sender sends to the IP address of the receiver as usual, FA works as default router

CN


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


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


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.


GSM Overview

fixed network

BSC

BSC

MSC MSC

GMSCOMC, EIR,

AUC

VLR

HLR

NSSwith OSS

RSS

VLR

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 )

MS

BTS

MS


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.


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.


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


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


Integrated mobile computing

regional

metropolitan area

campus-based

in-car,in-house,

personal area

verticalhandover

horizontalhandover

Integration of heterogeneous fixed andmobile networks with varyingtransmission characteristics


IP-based next generation network ?

IP-basedcore

SS7 signalling

InternetGSM

UMTS

publicWLAN

RNC

BSC

firewall, GGSN,gateway

gateways

server farm,gateways, proxiesPSTN, CS

core

MSC

SGSNrouter

broadcast

accesspoints private

WLANprivateWPAN


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/lectures.htm http://www.cs.arizona.edu/classes/cs630/fall01/630-1/contents.htm http://www.cs.ucsb.edu/~cs290i_mc/index.html


Thank you!

past, present, and future of mobile computing

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